23rd YEAR 1917 Krd EDITION STANDARD WIRING FOR ELECTRIC LIGHT AND POWER AS ADOPTED BY THE FIRE UNDERWRITERS OF THE UNITED STATES IX ACCORDANCE 'WITH THE NATIONAL ELECTRICAL CODE, WITH EXPLANATIONS, ILLUSTRATIONS AND TABLES NECESSARY FOR OUTSIDE AND INSIDE WIRING AND CON- STRUCTION FOR ALL SYSTEMS, TOGETHER WITH A SECTION ON HOUSE WIRING. . o. PUSHING, JR. Fellow Am, Inst. Elecl. Engrs. WITH THE CO-OPERATION OF THE WIRING COMMITTEE OF THE COMMERCIAL SECTION OF THE NATIONAL ELECTRIC LIGHT ASSOCIATION AND THE SOCIETY FOR ELECTRICAL DEVELOPMENT INDEX TO PUBLISHED BY H. C. GUSHING, JR., PULITZER BLDG., NEW YORK U. S. A. PREFACE THE Author, with the collaboration of Mr. F. E. Cabot, Chairman of the Electrical Com- mittee of the National Fire Protection Association, and with the Co-operation of the Wiring Commit- tee of the Commercial Section of the National Elec- tric Light Association, and the Society for Electrical Development, has made it his aim in compiling the following pages to set forth, as clearly as possible, the essential rules and requirements for safe and efficient exterior and interior wiring and construc- tion for electric light, heat and power. The object of this book is to standardize, as much as possible, all work of this nature and to respectfully suggest to the Electrical Engineer, Architect, House-owner, Contractor and Wireman just what is required by Fire Underwriters' Inspectors throughout the United States. Copyright, 1917, A. B. Cashing. f t THE GENERATOR All generators, whether 'for central station or iso- lated lighting or power work, should be located in a dry place so situated that the surrounding atmo- sphere is cool. If the surrounding air is warm it reduces the safe carrying capacity of the machine, and is likely to allow such temperatures to rise in Proper installation of dynamo or motor on filled wooden base frame. the machine itself as to burn out either armature or field, or both. A generator should not be installed in any place where any hazardous process is car- ried on, nor in place where it would be exposed to inflammable gases or flying combustible materials, as the liability of occasional sparks- from the com- imitator or brushes might cause more or less serious explosions. Foundations. Wherever it is possible, generat- ors should be raised or insulated above the sur- rounding floor on wooden base frames, which should be kept filled to prevent the absorption of moisture, and also kept clean and dry. When it is impracticable to insulate a generator on account af its great weight or any other reason, the Inspection Department of the Board of Fire Underwriters having jurisdiction may, in writing, permit the omission of the wooden base frame, in which case the frame should be permanently and effectively grounded. Generators operating at a potential of over 550 volts should always have their base frames permanently grounded. When a frame is grounded the insulation of the entire system depends upon the insulation of the generator conductors from the frame, and if this breaks down the system is grounded and should be put in proper condition at once. Grounding Generator Frames can be effectually done by firmly attaching a wire to the frame and to any main water pipe inside the building, on the street side of the meter, if there is one. The wire should be securely fastened to the pipe by screwing a brass plug into the pipe and soldering the wire to this plug or by approved ground clamps. When the generator is direct driven an excellent ground is attained through the engine coupling and piping. Wherever high voltage machines have their frames grounded a small board walk should be built around them and raised above the floor on porcelain or glass insulators, in order that the at- tendant may be protected from shock when adjust- ing brushes or working about the machine. Accessibility, Sufficient space should be left on all sides of the generator, or motor, and especially at the commutator end, so that there may be ample room for removing 1 armatures, commutators, or other parts at any time. Circuit Breakers and Fuses. Every constant potential generator should be protected from ex- cessive current by a fuse, or equivalent device of approved design, such as a circuit breaker. Such devices should be placed on or as near the dynamo as possible. For two-wire, direct-current generators, single pole protection will be considered as satisfying the above rule, provided the safety device is located and connected that the means for opening same is actuated by the entire generator current thus com- pletely opening the generator circuit. When two-wire, direct-current generators are used in conjunction with balancer sets to obtain a neutral for three-wire systems, a protective device should be installed which will operate and discon- nect the three-wire system should an excessive un- balancing of voltage occur. If a generator, not electrically driven, in a two-wire system has one terminal grounded, the circuit breaker above men- tioned should be placed in the grounded lead. For three-wire direct-current generators, either compound or shunt wound, a safety device should be placed in each armature lead of sufficient capacity and so arranged as to take care of the entire current from the armature. 5 The safety devices for this service should be a double-pole, double-coil overload circuit-breaker, or a four-pole circuit-breaker connected in the main and equalizer leads and tripped by means of two overload devices, one in each armature lead. The safety devices thus required should be so inter- locked that no one pole can be opened without si- multaneously disconnecting both sides of the arma- ture from the system. Fuses should never be used for this class of protection. In general, generators should preferably have no exposed live parts and the leads should be well in- sulated and thoroughly protected against mechanical injury. This protection of the bare live parts against accidental contact would apply also to all exposed, uninsulated conductors outside of the generator and not on the switchboard. Waterproof Covers, though not required, should be provided for every generator and motor and placed over each machine as soon as it is shut down. Negligence in this matter has caused many an arm- ature or field coil to burn out, as only a few drops of water are necessary to cause a short circuit, when the machine is started up again, that might do many dollars' worth of damage, to say nothing of the in- convenience of having to shut off light or power when it is most needed, and for an indefinite length of time. Name Plates. Every generator and motor should be provided with a name plate, giving the maker's name, the capacity in volts and amperes and normal speed in revolutions per minute. This will show e exactly what the machine is designed for, and how it should be run. Terminal blocks when used on generators should be made of approved non-combustible non-absorp- tive, insulating material, such as slate, marble or porcelain. Wiring from Generators to switchboards and thence to outside lines should be in plain sight or readily accessible, and should be supported entirely throughout upon non-combustible insulators (such as glass or porcelain) and in no case should any wire come in contact with anything except these in- sulators, and the terminals upon the generators and switchboard. When it becomes necessary to run these wires through a wall or floor, the holes should be protected by some approved non-combustible insulating tube, such as glass or porcelain, and in every case the tube should be so fastened that it shall not slip or pull out. Sections of any conduit, whether armored or otherwise, that are chopped off for this purpose, should not be used. All wires for generator and switchboard work should be kept so far apart that there is no liability of their coming in contact with one another, nor of short circuit from metallic tools used about them. All wire used in this class of work should be the best quality of "rubber covered" (see page 76). Bus-bars on switchboards, may be made of bare metal so that additional circuits may be readily attached. They should have ample carrying capacity, so as not to heat with the maximum current likely to flow through them under natural conditions. (See "Capa- city of Wire Table," page 91.) So much trouble in T past years has arisen from faulty construction of switchboards, and the apparatus placed upon them, that strict requirements have been necessarily adopted by engineers as well as insurance inspectors, and the following suggestions are recommended by the latter; although it is advisable, when possible, that all wires from generators to switchboards be in plain sight and readily accessible, wires from generator to switchboard may, however, be placed in a conduit in the brick or cement pier on which the generator stands, provided that proper precau- tions are taken to protect them against moisture and to thoroughly insulate them from the pier or foun- dation. If lead-covered cable is used, no further protection will be required. If liable to moisture, however, cable with grounded lead sheath or grounded conduit should be used. A smooth runway is desired. If iron conduit is provided, double braided rubber-covered wire will be satisfactory. In wiring switchboards with regard to their ground de- tectors, voltmeters, pilot lights, potential transform- ers or other indicating instruments. Nothing smaller than No. 14 B. & S. gage "rubber covered" wire should be used, and no such circuit should carry over 660 watts. Such circuits should be protected by approved enclosed fuses. (See pp. 110-113.) The Switchboard should be so placed as to re- duce to a minimum the danger of communicating fire to adjacent combustible material, and, like the generator, should be erected in a dry place and kept free from moisture. It is necessary that it should be accessible from all sides when the wiring is done on the back of the board, but may be placed against B a brick, stone or cement wall when all wiring is on the face of the switchboard. The board should be constructed wholly of non- combustible material and never built up to the ceil- ing; a space of three feet, at least, should separate the top of the board from the ceiling and at least eighteen inches should separate the wall from the instruments or connections, when the wiring is done on the back of the board. Wires with inflammable outer braiding, when brought close together, as fre- quently happens on switchboards, should each be surrounded with a tight, non-combustible covering. Flame proofing should be stripped back on all cables a sufficient amount to give the necessary in- sulation distances for the voltage of the circuit on which the cable is used. Every instrument, switch or apparatus of any kind placed upon the switch- board should have its own non-combustible insula- ting base. This is required of every piece of appa- ratus connected in any way with any circuit. If it is found impossible to place the resistance box, rheo- stat, or regulator, which should, in every case, be made entirely of non-combustible material upon the switchboard, it should be placed at least one foot from combustible material or separated there- from by a non-inflammable, non-absorptive insulat- ing material. This will require the use of a slab or panel of non-combustible, non-absorptive insulating material such as slate, soapstone or marble, some- what larger than the rheostat, which should be secured in position independently of the rheostat supports. Bolts for supporting the rheostat should be countersunk at least ^ inch below the surface at the back of the slab and the holes over the heady of the bolts filled with insulating material. For proper mechanical strength, the slab should be of a thickness consistent with the size and weight of the rheostat, and in no case to be less than -j inch. If resistance devices are installed in rooms where dust or combustible flyings would be liable to accu- mulate on them, they should be equipped with dust- proof face plates. Where protective resistances are necessary in connection with automatic rheostats, incandescent lamps may be used, provided that they do not carry or control the main current nor con- stitute the regulating resistance of the device. When so used, lamps should be mounted in por- celain receptacles upon non-combustible supports, and should be so arranged that they cannot have impressed upon them a voltage greater than that for which they are rated. They should in all cases be provided with a name-plate, which should be per- manently attached beside the porcelain receptacle or receptacles and stamped with the candle-power and voltage of the lamp or lamps to be used in each receptacle. Wherever insulated wire is used for connection between resistances and the contact device of a rheostat, the insulation should be "slow burning." (See page 77.) For large rheostats and similar resistances, where the contact devices are not mounted upon them, the connecting wires may be run together in groups so arranged that the maxi- mum difference of potential between any two wires in any group shall not exceed 75 volts. Each group of wires should either be mounted on non-combust- 10 ible, non-absorptive insulators giving at least ^ inch separation from surface wired over, or, where it is necessary to protect the wires from mechanical injury. Each group may be encased in approved flexible tubing and placed in approved conduit, the flexible tubing to extend at least i inch beyond the ends of the conduit. Special attention is again called to the fact that switchboards should not be built down to the floor, nor up to the ceiling, but a space of at least ten or twelve inches should be left between the floor and the board, and thirty-six inches between the ceiling and the board, when pos- sible, in order to prevent possible fire from commu- nicating from the switchboard to the ceiling, and also to prevent the forming of a partially concealed space very liable to be used for storage of rubbish and oily waste. Where floor is of brick, stone or concrete, the switchboard may go to the floor, but for cleanliness and safety space should always be provided when possible. Lightning Arresters should be attached to each wire of every overhead circuit connected with the station. It is recommended to all electric light and power companies that arresters be connected at intervals over systems in such numbers and so located as to prevent ordinary discharges entering (over the wires) buildings connected to the lines (see p. 59.) Arresters for Stations and Sub-stations should be located in readily accessible places away from combustible materials, and as near as practicable to the point where the wires enter the building. Station arresters are often placed in plain sight on the switchboard. The switchboard, however, 11 does not necessarily afford the only location meet- ing these requirements. In fact, if the arresters can be located in a safe and accessible place away from the board, this should be done, for, in case the arrester should fail or be seriously damaged there would then, be no chance of starting arcs on the board. In all cases, kinks, coils and sharp bends in the wires between the arresters and the outdoor lines should be avoided as far as possible. They should be connected with a thoroughly good and permanent ground connection by metallic strips or wires having a conductivity not less than that of a No. 6 B. & S. copper wire, and these should be run as nearly in a straight line as possible from the arresters to the earth connection. Ground wires from lightning arresters should not be attached to gas-pipes within the buildings. It is often desirable to introduce a choke coil in circuit between the arresters and the dynamo. In no case should the ground wire from a lightning arrester be put into iron pipes, as these would tend to impede the discharge. Unless a good damp ground is used in connection with all lightning arresters, they are little better than useless. Ground connections should be of the most approved construction, and should be made where permanently damp earth can be conveniently reached. For a bank of arresters such as is com- monly found in a power house, the following in- structions will be found valuable : First, dig a hole six feet square directly under the arresters until permanently damp earth has been reached; second, 12 cover the bottom of this hole with two feet of crushed coke or charcoal (about pea-size) ; third, over this lay 25 square feet of No. 16 copper plate ; fourth, solder at least two ground wires, which should not be smaller than No. 4, securely across the entire surface of the ground plate; fifth, now cover the ground plate with two feet of crushed coke or charcoal; sixth, fill in the hole with earth, using running water to settle. A practical and effective method of installing an outside line arrester is shown on page 59. All lightning arresters should be mounted on non- combustible insulating bases, and be so constructed as not to maintain an arc after a discharge. Testing of Insulation Resistance. All circuits except such as are permanently grounded, as de- scribed on pages 56 and 57, should be provided with reliable ground detectors. Detectors which indicate continuously and give an instant and permanent in- dication of a ground are preferable. Ground wires from detectors should not be attached to gas pipes within the building. Where continuously indicating detectors are not used, the circuits should be tested at least once per day (see page 75), and preferably oftener. Data obtained from all tests should be recorded and preserved for examination. Fire Extinguishers. At least one, or more if the size of the installation demands it, good ap- proved extinguisher should be in plain sight and readily accessible, one which is capable of extin- guishing electrical fires or arcs without danger of transmitting a shock to the operator (see page 258.) is Storage or Secondary Batteries should be in- stalled with as much care as generators, and in wir- ing to and from them the same precautions and rules should be adopted for safety and the prevention of leaks. The room in which they are placed should not only be kept dry, but exceptionally well venti- lated, to carry off all fumes which are bound to arise. The insulators for the support of the second- ary batteries should be glass or porcelain, as filled wood alone would not be approved. The use of any metal liable to corrosion should be avoided in cell connections of secondary batteries of the lead and sulphuric acid type. Oily Waste should be kept in approved metal cans (made entirely of metal, with legs raising them at least three inches above the floor, and with self- closing covers) and removed daily. Attendance. A competent man should always be kept on duty where generators are operating. MOTORS. The Installation of Motors. All motor's when operating at a potential in excess of 550 volts should have no exposed live metal parts, and have their base frames permanently and effectively grounded. When operating at a potential of 550 volts or less, their base frame should be permanently and effect- ively grounded wherever feasible. Where ground- ing of the frame is impracticable, special permission for its omission may be obtained, in writing, by the local insurance or city inspection department, in which case the frame should be permanently and ef- fectively insulated. Wooden base frames used for 14 this purpose and wooden floors which are depended upon for insulation where for any reason it is necessary to omit the base frames should be kept filled to prevent absorption of moisture and be kept clean and dry. Motors operating at a potential of 550 volts or less should be wired with the same precautions as required by rules for inside wiring (see pages 89 to 96) for wires carrying a current of the same volume. Motors operating at a potential between 550 and 3,500 volts should, except in central or sub-stations, be wired with approved multiple conductor, metal sheathed cable in approved metal conduit. All ap- paratus and wiring connected to the high tension circuit should be completely enclosed in substantial grounded metal shields or casings and the conduit should enter and be properly secured to such casings or to suitable terminal boxes screwed or bolted to the casings. The insulation of the several conductors for high potential motors, where leaving the metal sheath of cables, should be thoroughly protected from mois- ture and mechanical injury. This may be accom- lished by means of a pot head, see illustration on page 52, or some equivalent method. The conduit should be substantially bonded to the metal casings of all fittings and apparatus connected to the inside high tension circuit. Where outside conductors directly enter the motor room special permission in writing should be ob- tained to install the wires for high potential motors 15 according to the general rules for high potential systems. (See pages 159 to 160.) Conductors carrying the current of only one motor should be designed to carry a current at least 25 per cent, greater than that for which the motor is rated. Where the conductors under this rule would be overfused in order to provide for the start- ing current, as in the case of many of the alternat- ing current motors, the conductors should be of such size as to be properly protected by these larger fuses. The current used in determining the size of the conductor carrying the current of only one varying (or variable) speed motor should be the percentage of the 3O-minute current rating of the motor as given for the several classifications of service in the following table : Percentage of current rating Classification of Service of motor Operating valves, raising or lower- ing rolls 200 Rolling tables 180 Hoists, rolls, ore and coal handling machines 150 Freight and passenger elevators, shop cranes, tool heads, pumps, etc 120 Varying speed motors are motors in which the speed varies automatically with the load, decreasing when the load increases, and vice versa. It does not mean motors in which the speed is varied by the use of different windings or grouping of windings, or motors in which the speed is varied by external M means, and in which, after adjusting to a certain speed, the speed remains practically constant. Each motor with its starting device should be pro- tected by a cut-out and controlled by a switch (see page 43), said switch plainly indicating whether "on" or "off." Small motors may be grouped under the protection of a single set of fuses, provided the rated capacity of the fuses does not exceed 10 amperes and the total wattage of the circuit does not exceed 660. With motors of one- fourth horse power or less, on circuits where the voltage does not exceed 300, single pole switches may be used. Such switches, however, should never be used as service switches or circuits located in damp places, nor placed in the neutral wire of a three-wire sys- tem, except in the two-wire branch circuit supplying not more than 660 watts. The switch and rheostat should always be located within sight of the motor. Where the circuit-breaking device on the motor- starting device disconnects all wires of the circuit, the switch may be omitted. Overload-release devices on motor-starting de- vices will not be considered to take the place of the cut-out required for this class of work. An automatic circuit-breaker disconnecting all wires of the circuit may serve as both switch and cut-out. (See page 44.) Where a rubber-covered conductor, see page 76, carries the current of only one A. C. motor of a type requiring large starting current it may be pro- tected by a fuse or an automatic circuit breaker without time limit device. The rated continuous current capacity of a time limit circuit breaker pro- 17 tecting a motor of the above type need not be greater than 125% of the motor current rating, providing the time limit device is capable of preventing the breaker opening during the starting period. In most cases where A. C. motors of the above type are started by means of autostarters the cur- rent-carrying capacity of wires meeting the rule will not exceed the following percentages of the full load currents of the motors. Rated full load current Percentage o- 30 amperes 250 31-100 " 200 Above 100 " 150 Rheostats should be so installed as to comply with all the suggestions on this subject given on pages 9 to II. Auto starters, unless equipped with tight casings . enclosing all current-carrying parts, in all wet, dusty or linty places, should be enclosed in approved cut- out boxes or cabinets. Where there is any liability of short circuits across their exposed live parts be- ing caused by accidental contacts, a railing should also be erected around them. Motors should not be run in series-multiple or multiple-series, except on constant-potential systems. When deemed necessary, motors should be en- closed in an approved case. Such enclosures should be readily accessible, dust proof and sufficiently ventilated to prevent an exces- sive rise of temperature. Where practicable the sides should be made largely of glass, so that the motor may be always plainly visible. The use of an enclosed type motor is recom- 18 mended in dusty places, being preferable to wooden boxing. All motors permanently located on wooden floors should be provided with suitable drip pans. When motors are combined with ceiling fans, they should be hung from insulated hooks, or else there should be an insulator interposed between the motor and its support. Every motor should be provided with a name- plate, giving the maker's name, the capacity in volts and amperes, and the normal speed in revolutions per minute. All varying (or variable) speed motors should be marked with the maximum current which they can safely carry for 30 minutes, starting cold. Motor terminal blocks should be made of ap- proved non-combustible, non-absorptive, insulating material such as slate, marble or porcelain. Adjustable speed motors, if controlled by means of field regulation, should be so' arranged and con- nected that they cannot be started under weakened field. The use of soft rubber bushings to protect the lead wires coming through the frames of motors is peimitted, except when installed where oils, grease, oily vapors or other substances known to have rapid deleterious effect on rubber are present in such quan- tities and in such proximity to motors as may cause such bushings to be liable to rapid destruction. In such cases hardwood properly filled, or preferably porcelain or micanite bushings should be used. Starting and Stopping Motors (Direct Current) One rule at all times to be remembered in starting 19 and stopping motors is, switch first, rheostat last, which means, in starting, close the switch first, and then gradually cut out all resistance as the motor speeds up. To stop the motor open the switch first and then cut in all the resistance of the rheostat Motor Starting Rheostat or "Resistance Box" with No-Voltage Release. Slate front carries lever, contacts and release spool, mounted on a ventilated box of pressed steel which serves as a container for the resistance. which is in series with the motor armature. When starting any new motor for the first time, see that the belt is removed from the pulley and the motor started with no load. Never keep the rheostat handle on any of its coils longer than a moment, as they are not designed to regulate the speed of the motor, but to prevent too large a flow of current into the armature before the latter has attained its full speed. The illustration above shows a rheostat which is designed to automatically protect the armature of a motor. The contact "arm is fitted with a spring which constantly tends to throw the arm on the "off-point" and open the circuit, but is prevented from so doing, while the motor is in operation, by o the small electro-magnet, shown on the face of the rheostat, which consists of low resistance coil con- nected in series with the field winding of the motor. This magnet holds the contact arm of the rheostat in the position, allowing the maximum working cur- rent to flow through the armature while it is in operation. If, for some reason or other, the current sup- plied to the motor be momentarily cut off, the speed of the armature generates a counter current which also tends to hold the arm in position as long as there is any motion to the motor armature, but as soon as the armature ceases to revolve all current ceases to flow through the electromagnet, thereby releasing the rheostat handle, which flies back to the "off" point, as shown in the illustration, and the motor armature is out of danger. Such a device is of great value where inexperienced men have to handle motors, and are unaware that the first thing to be done when a motor stops for any reason what- ever is to open the circuit, and then cut in all the resistance in the rheostat to prevent too large an tn-rush of current when the motor is started up again. The Circuit Breaker for under and over loads is also a most valuable protection in such cases. Motor Wiring Formulae (Direct Current). To find the proper size of wire for direct-current motors proceed as follows: e = voltage of motor. d = single distance from generator to motor in feet. v = volts loss in lines. k = efficiency of motor. (See table below.) 10.8 Resistance in ohms of a wire I ft long and .001 inch diameter. Then in size or wire circular mils (cm) horsepower X 746 X 2d X 10.8 c.m. = e X v X k horsepower X d X 16113.6 or simplified cm = e X v X k Compare the size of wire thus found with that al- lowed by the underwriters for full load current of motor, -|- 25%. If it be smaller it must be increased to at least that figure to be approved and the re- sulting lower line loss accepted. (See table, p. 91.) THE AVERAGE MOTOR EFFICIENCY (K). I h.p. and under 75 per cent. 3 h.p. to 5 h.p 80 per cent. 5 h.p. to 10 h.p 85 to 90 per cent. Over 10 h.p 90 per cent. The tables and examples worked out on pages 79 to 82 will give the desired results, in many cases of smaller installations without having to use the above direct current formulae. CURRENT REQUIRED BY MOTOR (Direct Current.) To find current required by a motor when the horse-power, efficiency and voltage are known, use the following formula: Let C = current to be found. H. P horse-power of motor. E = voltage of motor circuit. K = efficiency of motor in per cent. H. P. X 746 X ioo E X K The table of "amperes per motor" given on the following page, will, in many cases, prevent the necessity of working out the above formula. By adding the volts indicated in the (page 25) table to the voltage of the lamp or motor, the re- sult shows the voltage at the dynamo for losses in- dicated. Thus, 10 per cent, on no volt system is: 12.22 volts added to no equal 122.22, showing that the dynamo must generate 122.22 volts to take care of a 10 per cent, loss in the line (for A. C., see pp. 83-89). SIZES OF FUSES, IN AMPERES, FOR MOTORS EQUIPPED WITH OVERLOAD STARTING RHEOSTATS. Horsepower. 115 Volts. 230 Volts. 500 Volts. 0.5 8 4 2 1 15 8 4 2 30 15 7 3 40 20 10 4 50 25 12 6 60 30 16 7.5 90 45 20 10 115 60 25 15 175 90 40 20 225 115 60 25 300 150 60 80 350 175 76 85 400 200 90 40 460 826 100 50 600 800 186 23 iC^H 00 OS O* <-< c4 CO Tji U5 Q [^ DIRECT CURRENT GENERATORS AND MOTORS General Information Output The output of a generator in watts may be obtained by multiplying the current in amperes by the e.m.f. in volts. To obtain the horse power, the product obtained in the first operation is divided by 746. Volts x Amperes Horsepower - 746 See equivalent values, page 200. Windings Depending upon the character of field winding employed, direct-current generators and motors are classified under one of the following three general groups. I Shunt wound 2 Series wound 3 Compound wound See diagrams pages 43-47. Shunt- Wound Generator The field winding of a shunt-wound generator is composed of a large number of turns of wire or strap of comparatively high resistance, which is connected directly to the armature terminals, forming, in parallel with the main circuit, a shunt circuit through which only a small percentage of the total current flows. The regulation characteristic of a shunt- wound machine is such that the voltage is a maximum at no load, and drops as the load increases unless regu- lated by the manipulation of a rheostat in the field circuit. 26 Series- Wound Generator The field winding of a series-wound generator is composed of a heavy wire or strap connected in series with the armature and external circuit. With this type of machine the total current delivered flows through the field winding and the voltage varies directly with the load. The greater the load the higher the voltage. Generally, a slight load is required to make these machines pick up voltage. Compound- Wound Generator A compound- wound machine has both shunt and series winding. It may be generally assumed that the shunt field is so designed that on open circuit, the series field be- ing idle, the machine will generate the desired line voltage. The result of applying load would, as noted under "Shunt Generator," tend to lower the terminal voltage ; but it is here that the utility of the compound winding becomes apparent. The series coils reinforce the shunt field in direct proportion to the increase of load and thus hold the terminal voltage constant, balancing the drop due to in- creased copper loss and armature reaction at the heavier loads. It is a difficult matter to design a machine for exact voltage under all conditions and for this rea- son additional hand regulation is provided in the form of a rheostat in the shunt-field circuit. It is easily possible and quite generally desirable to have a compound-wound generator over-com- pounded, i. e., provided with a series field of suffi- cient strength to not only hold the voltage constant but increase it with increase of load. The over- compounding is customarily given as the percentage 27 of the no-load terminal voltage which the increase in voltage from no load to full load represents. Thus a 9 per cent, over-compounded 23<>volt generator will have a full-load voltage of approximately 250. Shunt Motors This is by far the most common type of winding, and is generally applied to motors designed for operating at constant speed under con- stant or varying loads. Nearly all commercial ap- plications, particularly those of large capacity, re- quire this type of motor. When necessary, consid- erable speed variation can usually be secured by means of a rheostat in the field circuit, increased re- sistance resulting in an increased speed. Series Motors Series motors are variable speed machines particularly adapted to a few special uses, such as railway and crane service, but are not extensively employed in the field of work to which this book is devoted. The characteristic features of a series motor are its great torque at starting and low running speeds. Compound-Wound Motors For some special classes of service, in which it is necessary to start under heavy load and later operate at approximate- ly constant speed, a series winding is added to assist the shunt field at the low speed points. As in the case of the compound generator, a com- pound motor combines the characteristics of both shunt and series motors. In most cases, however, the series winding has comparatively little effect ex- cept during the starting period. Connections for Parallel Operation Parallel operation of direct-current generators is effected in a comparatively easy manner if machines are of the 28 same make and voltage or are designed with similar electrical characteristics. If they are shunt-wound machines, no connections other than main leads are required as the inherent regulation characteristics are such as to insure proper division of the load. If they are compound-wound machines, the addition of equalizer connections between the machine is re- quired. See diagram page 46. If the generators have different compounding ratios, it will be neces- sary to change adjustments so that all machines have the same inherent regulation ; i. e., with shunt field adjusted by rheostat for same voltage at no load, the compounding is such as to produce the same voltage on all at full load. The way to determine if all machines have the same regulation is to test them individually. Equalizer An equalizer, or equalizer connec- tion, connects two or more generators operating in parallel at a point where the armature and series field leads join, thus placing the armatures in multi- ple and the series in multiple, in order that the load may be divided between the generators in proportion to their capacities. The object of the equalizer, as the name implies, is to divide the total load between the machines ac- cording to their capacity. Consider, for example, two compound-wound machines operating in parallel without an equalizer. If, for some reason, there is a slight increase in speed of one machine, it would take more than its share of load ; and the increased current flowing through the series field would strengthen the magnetism, raise the voltage, and cause the machine to take a still greater amount un- 29 til it carried the entire load. When equalizers are used, the current flowing through each series coil is proportional to the resistance and is independent of the load on any machine ; consequently an in- crease of voltage on one machine builds up the volt- age of the other at the same time, so that the first machine cannot take all the load, but will continue to share it in proper proportion with the other generators. OPERATION General Rules Leave all switches open when machine is not running. (See page 43.) At all times keep the generator or motor clean and free from oil and dust, especially from copper or carbon dust. With high-voltage machines a small accumulation of dust on the windings may be the cause of serious burn-out. Keep small pieces of iron and bolts and tools away from the frame. Any such fragment attracted to the pole of a field magnet may jam between the armature and pole and cause serious damage. Occasionally give the machine a thorough in- spection. The higher the voltage of the generator or motor, the oftener this should be done. Starting Generators See that the bearings are well supplied with oil and that the oil rings are free to turn. Inspect all connections for loose screws or wires. Start slowly. See that the oil rings are revolving properly. Turn in all resistance in the field rheostat, then bring the machine up to speed. 30 Adjust the rheostat for the normal voltage of the generator. Throw on the load. Causes of Insufficient Voltage The following causes may prevent generators from developing their normal e. m. f. (electro motive force). The speed of the generator may be below normal. The switchboard instruments may be incorrect and the voltage may be higher than that indicated, or the current may be greater than is shown by the readings. The series field may be reversed, or part of the shunt field reversed or short-circuited. The brushes may be incorrectly set. A part of the field rheostat or other unnecessary resistance may be in the field circuit. Reversing Polarity To change the polarity, if a generator keeps the same rotation, it is necessary to reverse the magnetism in the field circuit which is done by exciting the shunt field in the opposite direction. Reversing Rotation To change the rotation but not the polarity, it is necessary to reverse either the magnetism or the armature leads. The simplest method, and the one recommended, is to reverse the leads to the armature and the leads to the commu- tating-pole winding. In all commutating-pole machines, it must be borne in mind that the direction of current in the armature and commutating-pole windings always bear the same relation to each other, and, if the armature current is reversed for any reason, the commutating-pole coils must be re- versed. 31 To Parallel To throw a machine on the line ir "parallel" with machines already operating. Bring the machine up to normal speed. With a voltmeter connected to its terminals, gradually bring up the voltage by cutting out resist- ance in the rheostat until approximately the voltage of the other machines is reached. Throw in equal- izer switch. Adjust voltage, if necessary. Throw in main switches. Adjust rheostat till generator takes its proportion of the load. The proper volt- age to obtain before throwing a generator in parallel with others can be found by trial. It may vary slightly from line voltage depending on local condi- tions, regulation, etc. Excitation of D. C. Generators When start- ing up, a generator may fail to excite itself. This may occur even when the generator operated per- fectly during the preceding run. It will generally be found that this trouble is caused by a loose con- nection or break in the field circuit, by poor contact at the brushes due to a dirty commutator or per- haps to a fault in the rheostat, or incorrect position of brushes. Examine all connections; try a tem- porarily increased pressure on the brushes ; look for a broken or burnt out resistance coil in the rheostat. An open circuit in the field winding may sometimes be traced with the aid of a magneto bell ; but this is not an infallible test as some magnetos will not ring through a circuit of such high resistance as some field windings have even though it be intact. If no open circuit is found in the rheostat or in the field winding, the trouble is probably in the armature. But if it be found that nothing is wrong with the 32 connections or the winding it may be necessary to excite the field from another generator or some other outside source. A very simple means for getting a compound- wound machine to pick up is to short-circuit it through a fuse having approximately the current capacity of the generator. If sufficient current to melt this fuse is not generated, it is evident that there is something wrong with the armature, either a short-circuit or an open circuit. If, however, the fuse has blown, make one more attempt to get the machine to excite itself. If it does not pick up, it is evident that something is wrong with the shunt vvinding or connections. If a new machine refuses to excite and the con- nections seem to be alright, reverse the connections ; i. e. connect the wire which leads from the positive brush to the negative brush and the wire which leads from the negative brush to the positive brush. If this change of connections does no good, change back and locate the fault. To Shut Down Generator Reduce the load as much as possible by throwing in resistance with the field rheostat. Throw off the load by opening the circuit-breaker, if one is used, otherwise open the feeder switches and finally the main generator switches. Shut down the driving machine. Wipe off all oil and dirt, clean the machine and put it in good order for the next run. Starting Constant-Speed Motors, Shunt or Compound See that bearings are well supplied with a good lubricating oil and that oil rings are free 38 to turn. Inspect all connections for loose screws or wires. Make sure that the lever arm of the starting box or controller is in the "off" position. (See p. 20.) Close the main switch. Close the field switch. Move lever arm of starting box or controller to the running position, pausing long enough on each notch to allow the motor to come up to the speed of that notch. If using a controller, throw the short-circuiting switch and move controller handle back to the start- ing position. If using a starting box, the lever arm should remain in the running position. To Shut Down Constant-Speed Motors Open the main switch or circuit-breaker. (See pp. 43-44.) After the motor has come to rest, see that the lever arm of the starting box has returned to its original position. Open the field switches. Clean the machine thoroughly and put in order for next run. Starting Adjustable-Speed Motors Examine shunt-field rheostat and see that all resistance is cut out. Follow all directions given under "Constant Speed Motors." After motor is running on full-line voltage, gradu- ally cut in resistance in the shunt-field rheostat until the motor is up to the desired speed. To Shut Down Adjustable-Speed Motors Gradually cut out the resistance in the shunt-field rheostat until the machine is running on a full field. 34 Follow directions given under "To Shut Down Constant Speed Motors." Starting Series Motors Follow same instruc- tions as those given for "Starting Constant Speed Motors," except there is no field switch to close. To Shut Down Series Motors Open main switch. Examine machine carefully; wipe off all dirt or oil, and put in good shape for next run. Opening of Feeder Circuits If a line fuse blows or a circuit-breaker opens, first open the switch corresponding to that line, and then replace the fuse and close the breaker. The switch may now be closed again. If the circuit opens the sec- ond time, there is something wrong on the line probably a short-circuit and this should be cor- rected at once. If for any reason, such as a short-circuit or a heavy overload on the line, the circuit-breakers or switches hold an arc when opened, such an arc should be extinguished if possible by using dry sand, a supply of which should always be kept convenient- ly at hand. In case the arc cannot be extinguished in this manner, as a last resort, open the field cir- cuit of the machine or shut the generator down en- tirely. When the arc forms on the machine or on the generator side of the breakers, a shut-down is generally imperative., but should not be made if it can possibly be avoided. (See "Pyrene," p. 258.) Brushes The ends of all brushes should be fitted to the commutator so that they make good contact over their entire bearing face. This can be most easily accomplished after the brushholders have 35 been adjusted and the brushes inserted. Lift a set of brushes sufficiently to permit a sheet of sand- paper to be inserted. Draw the sandpaper in the direction of rotation under the brushes releasing the pressure as the paper is drawn back being care- ful to keep the ends of the paper as close to the commutator surface as- possible and thus avoid rounding the edges of the brushes. It will be found by this means a satisfactory contact is quickly se- cured, each set of brushes being similarly treated in turn. If the brushes are copper plated, their edges should be slightly beveled, so that the copper does not come in contact with the commutator. Commutator surface speeds of direct-current turbo-generators are somewhat higher than for standard machines of other types owing to their larger diameter. For this reason it is usually neces- sary to use a self-lubricating brush. Brushes in the market that have this characteristic are ordinarily of graphite nature and are weaker mechanically and hence more easily broken than the carbon brushes for lower-speed machines. They are also softer and reasonable care should be exercised in handling them when the machine is taken apart or assembled. Rough handling or carelessness will probably cause breakage. With graphite brushes of good quality, no oil should be necessary for lubricating the commutator ; and as a rule, oil will have a tendency to "gum" the surfaces of the brushes, unless used very sparingly. Besides maintaining the brushes in the proper position, the following points should be observed : Make frequent inspection to see that Brushes are not sticking in holders. Pig tail shunts are properly attached to brushes and holders. Tension is changed as brush wears. Copper plating is cut back so it does not make contact with the commutator. Worn-out brushes are replaced before they reach their limit of travel and break contact with the com- mutator. Remove any free copper picked up by the face of the brush. Commutator The commutator is perhaps the most important feature of the whole machine in that it is most sensitive to abuse. Under normal conditions, it should require little attention beyond frequent inspection. The surface should always be kept smooth, and if, through extreme carelessness, neglect, or accident, it becomes badly roughened, the armature should be removed and the commuta- tor turned down in an engine lathe. Sometimes with large machine it is more convenient to rig up a temporary trueing device, leaving the armature in its own bearings and running it slowly either as a shunt motor or from a separate belted motor. Ordinarily, unless in very bad condition, it may be dressed down with a piece of sandstone conveniently mounted in a device especially designed for this purpose. Sometimes a little sandpapering is all that is neces- sary. Emery cloth or paper should never be used for this purpose on account of the continued abrasive action of the emery which becomes em- bedded in the copper bars and brushes. Even when 37 sandpaper is used the brushes should be raised and the commutator wiped clean with a piece of canvas lubricated with a very small quantity of vaseline or oil. Cotton waste should never be used and an excess of lubricant must be avoided. Under normal conditions the commutator should become dark and highly polished after a few weeks' operation, and so remain unchanged for years. Trouble is sometimes experienced from the burn- ing out of mica insulation between segments. This is most commonly caused by allowing the mica to become oil soaked or by the bars loosening and thus allowing foreign conducting material to work its way in between them. It is rarely, if ever, defi- nitely traced to excessive voltage between bars. When this burning does occur it may be effectively stopped by scraping out the burned mica and filling the space with a solution of sodium silicate (water glass), or other suitable insulating cement. Even with the most careful workmanship, high mica will sometimes develop and start sparking, which burns away the copper and aggravates the difficulty. By prompt action, serious damage can be prevented by cutting away the mica to a depth of one-thirty-second to one-sixteenth of an inch be- low the adjacent copper. A hack-saw blade held be- tween suitable guides will serve the purpose of a cutter. Bearings Most machines have self-oiling bear- ings. The well should be filled to such a height that the rings will carry sufficient oil upon the shaft. If the bearings are too full oil will be thrown out along the shaft. The oil should be renewed about 38 once in six months, or oftener if it becomes dirty and causes the bearings to heat. Bearing housings are usually supplied with outlet holes for overflow of the oil. The oil should be kept slightly below the level of the holes. The bearings must be kept clean and free from grit. They should be frequently examined to see that the oil supply is properly maintained and that the oil rings do not stick. Use only the best quality of oil. New oil should be run through a strainer if it appears to contain any foreign substance. If the oil is used a second time, it should first be filtered and, if warm, allowed to cool. Hot Box or warm bearing is probably due to one of the following causes: Excessive belt tension. Failure of the oil rings to revolve with the shaft. Rough bearing surface. Improper fitting of the journal boxes. Bent shaft. Use of poor grade of dirty oil. Bolts in the bearing cap may be too tight. End thrust, due to improper leveling. A bearing may become warm because of excessive pressure exerted by the shoulder of the shaft against the side of the bearing. End thrust, due to the magnetic pull, rotating part being "sucked" into the field because it extends beyond the field poles further at one end than at the other. Excessive side pull, because the rotating part is out of center. If a bearing becomes hot, first feed heavy lubri- 39 cant copiously, loosening the nuts on the bearing cap ; and then, if the machine is belt-connected, slacken the belt. If relief is not afforded, shut down, keeping the machine running slowly until the shaft is cool, in order that the bearing may not "freeze." Renew the oil supply before starting again. A new machine should always be run at a slow speed for an hour or so in order to see that it operates properly. The bearings should be care- fully watched to see that the oil rings are revolving and carry a plentiful supply of oil to the shaft. Belts The belt on a belt-connected machine should be tight enough to run slowly without slip- ping, but the tension should not be too great or the bearings will heat. Belts should run with the inside lapping, not against it, and the joints should be dressed smooth so that there will be no jarring as it passes over the pulley. The crowns of driving and driven pulleys should be alike as "wobbling" of belts is sometimes caused by pulleys having unlike crowns. If this is caused by bad joints, they should be broken and cemented over again. A wave mo- tion or flapping is usually caused by slippage ber tween the belt and pulley, resulting from grease spots, etc. It may, however, be a warning of an ex- cessive overload. This fault may sometimes be corrected by increasing the tension, but a better remedy is to clean the belt. A back and forth move- ment on the pulley is caused by unequal stretching of the edges of the belt. If this does not cure itself shortly examine the joints. If they are evenly made and remain so, the belt is bad and should be discarded. See formula for belting, page 252. 40 Sparking at the brushes may be due to any one of the following causes : The machine may be overloaded. The brushes may not be set exactly at the point of commutation. A position can always be found where there is no perceptible sparking, and at this point the brushes should be set and secured. The brushes may be wedged in the holders or have reached the end of their travel. The brushes may not be fitted to the circumfer- ence of the commutator. The brushes may not bear on the commutator with sufficient pressure. The brushes may be -burnt on the ends. The commutator may be rough, if so, it should be smoothed off with sandpaper, not emery cloth. A commutator bar may be loose or may project above the others. The commutator may be dirty, oily or worn out. The carbon brushes may be of an unsuitable grade. The brushes may not be equally spaced around the periphery of the commutator. Some brushes may have extra pressure and may be taking more than their share of the current. High mica. Vibration of the brushes. These are the more common causes, but sparking may be due to an open circuit or loose connection in the armature, This trouble is indicated by a bright spark which appears to pass completely around the commutator, and may be recognized by the scarring of the commutator at the point of opfl 41 circuit. If a lead from the armature winding to the commutator becomes loose or broken it will draw a bright spark as the break passes the brush posi- tion. This trouble can be readily located, as the insulation on each side of the disconnected bar will be more or less pitted. The commutator should run smoothly and true, with a dark, glossy surface. Heating of Field Coils Heating of field coils may develop from any of the following causes : Too low speed. Too high voltage. Too great forward or backward lead of brushes. Partial short-circuit of one coil. Overload. Heating of Armature Heating of the arma- ture may develop from any of the following causes : Too great a load. Short circuit in coils. Grounds on armature or commutator. 42 An approved installation in every detail, and wiring connections foi shunt-wound, four-pole motor, using two enclosed fuses instead of circuit breaker. a An approved installation in every detail, and wiring connections, for shunt-wound bipolar motor, using circuit breaker instead of double-pole fuse cut-out. 44 CONNECTIONS FOR DIRECT CURRENT MOTORS D. P. inclosed Fuse SERIES MOTOR 4-POLE SHUNT MOTOR 4-POLE CONNECTIONS FOR DIRECT CURRENT DYNAMOS. Rheostat , Rheostat THREE WIRE DISTRIBUTION Rheostat MULTIPLE DISTRIBUTION-TWO WIRE CONNECTIONS FOR DIRECT CURRENT MOTORS & DYNAMOS COMPOUND MOTOR 2-POLE COMPOUND DYNAMO COMPOUND MOTOR 4-POLE COMPOUND DYNAMO 47 OUTSIDE WIRING AND CONSTRUCTION Service Wires (those leading from the outside support on the building, through the wall and to the main cut-out and switch) should be "Rubber Covered," as described on page 76, under that head- ing. Line Wires, other than service wires, may have an approved "weatherproof" covering. (See page 78,) if kept free from awnings, signs and shutters. Bare Wires may be used through uninhabited and isolated territories free from all other wires, as in such places wire covering would be of little use, as it is not relied on for pole insulation. For Insulated Wires. For Bare Wire or Cable. Clark Insulator Clamps. Tie Wires should have an insulation equal to that of the conductors they confine, within city limits, or some permanent insulated clamp that will not injure the insulation of the wires. Space between Wires for outside work, whether for high or low tension, should be at least one foot, and care should be exercised to prevent any possi- bility of a cross connection by water. Wires should O O o' o' rH CO rH W itt t> if) OO O rH OJ 10 o* * oooo inrH d d o I-H co t-' o 10 o J OO-*rHCOrHOCOinmCOt-OOOO5 V U S oo oo os o rH -* 05 m CM t- ^ eo I-H o o ,S **H" O oooooooooo woo-* y . jg coooeotooJoc*ooco-*i^rHoo rw +* l~ CO^COCOCMrH JT." moooooooco ^OieoocoinmoirH O5COOO-*rHOJt-ir3'*CO(NrH" 0000000000 -*0000 CO COW S rH rH SOinooooooommmo ot^-in inooioinininc^cso TucNJocommcoi^tv-i-jioo-^ino T< co co e* 1-1 I-H rH oooooooooocoooo* 00-*O500COOOOincOWrH 1>CO t* CO CO (M r-l rH rH "Jff ooinoooooooosmmoo ~ v n O5 m 01 CO rH O5 -H m O5 O O5 CO l> t_ 3'S W oOOOOOOo QOOO C vjoia5rHTt o o o o o o o o o o o o o _<* . .5 >OOOOOOOOOCNOO^ *i >> )OOcO^^OOiOOCO-^l^rHoO *4-i_ri *^ co Tti oo oo I-H *# m 05 o co ^0*^ l- 1 CO i^l rH ** C3 co -5i co 05 05 ?- co ex oo co eo 05 oo co 4)03 ooinooooooommmo rt i- ^ "-5 J>CoScOt^t-rHCOCOOO5Wl>SS rtSi S ^S' ft rH Oil>;O '^' COCI ''~ lr ~' "^ ^ c S^ *-?ja * 5 I-H CM CO * 10 CO 00 OJ inmomodoomominoin ^ r ^ r HrHS* QOt "' r5Ule<5(NC> " H 81 this number we travel up the vertical column and we find a loss of about 6 actual volts, or at a 5 per cent, loss, which would greatly reduce the candle-power or brilliancy of the lamps. A larger wire should, therefore, be used. A convenient type of pocket wire gauge, one- half actual size, for measuring wire from No. 18 to No. ooo B. & S. gauge. On the front is given the safe carrying capacity of copper wires in am- peres, and on the reverse side the approximate decimal equivalent of the various sizes of wires. 82 Wiring Calculations for Alternating Current. When figuring wire sizes for Alternating Current, except in cases of long distances, the following methods of calculating should be used. ' As compared with the circular mileage of each conductor of a two wire system, that of each con- ductor of other systems, transmitting same power with the same distance, volts lost, and lamp voltage is, for: 3 wire, single phase 25.0% 4 wire, single phase 11.1% 4 wire, two phase S-% 3 wire, two phase 50.0% with middle wire 75 % 4 wire, three phase, with neutral. . 16.6% 3 wire, three phase 50.0% All wires of each system ; except 3 wire two phase ; considered of same size. We will now take an example in each system and show how to calculate the wire size. Three Phase, Three Wire. What size wire should we use to run 1-220 volt, 30 horsepower in- duction motor; and light 102-220 volt, 60 watt mazda lamps; a distance of 400 feet to the center of distribution with the loss of 7 volts? Let us refer to the table on page 84. Here we see that the amperes per phase (same as amperes per terminal) of a 3 phase, 220 volt, 30 H.P. motor is 81. We must calculate the amperes per phase for the lamps by using this formula: total watts of lamps Amperes = 1.73 X volts 83 c * . 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'. '. '. 1030 800 000 840 550 .0125 2474 ~o ... 1092 900 000 920 600 .0111 2795 "Is 1152 1 000 000 1000 650 .0100 3106 c S 1209 1 100 000 1080 690 .0091 3416 *H W 1263 1 200 000 1150 730 .0083 3727 O fcjj 1314 1 300 000 1220 770 .0076 4038 03 g, *' 1364 1 400 000 1290 810 .0071 4348 *? (U *' ... 1413 1 500 000 1360 850 .0066 4658 .- w 1459 1 600 000 1430 890 .0062 4968 * " 1504 1 700 000 1490 930 .0058 5278 o " 1548 1 800 000 1550 970 .0055 5588 " ... 1572 1 900 000 1610 1010 .0052 5898 " ... 1630 2 000 000 1670 1050 .0050 6208 The lower current carrying limit (fifth column) is specified for rubber-covered wires to prevent gradual deterioration of the high insulations by the heat, of the wires, but not from fear of igniting the insulation. The carrying capacity of Nos. 18 and 16 B. & S. gauge wire is given, but no smaller than No. 14 should be used for general wiring purposes. Insulated aluminum wire 84% of the carrying capacity of the above figures. 91 TENSILE STRENGTH OF COPPER WIRE. Breaking: weight. Breaking weight. Pounds. Pounds. Numbers, Numbers, B. & S. G. B. & S. G. Hard- An- Hard- An- drawn. nealed. drawn . nealed 0000 8310 5650 9 616 349 000 6580 4480 10 489 277 00 5226 3553 11 388 219 4558 2818 12 307 174 1 3746 2234 13 244 138 2 3127 1772 14 193 109 3 2480 1405 15 153 87 4 1967 1114 16 133 69 5 1559 883 17 97 55 6 1237 700 18 77 43 7 980 555 19 61 34 8 778 440 20 48 27 The strength of soft copper wire varies from 32,000 to 36,000 pounds per square inch, and of hard copper wire from 45,000 to 68,000 pounds per square inch, according to the degree of hardness. EQUIVALENT CROSS SECTIONS OF WIRES. BROWN & SHARP GAUGE. 0000 000 00 1 2 3 4 2- 2 1 2- 2 2 3 2- 4 2 5 2- 6 2 7 4-3 4 4 4 5 4 6 4 7 4- 8 4 - 9 4-10 8 6 8 7 8 8 8 9 810 811 812 8 H 16 9 1610 1611 1612 16-13 1614 1615 1616 3212 3213 3214 32-15 3216 3217 32-18 6415 6416 6417 04-18 5 2- 8 411 8-14 1617 6 2 9 412 8-15 16-18 7 210 4-13 8-16 3 211 4-14 817 9 212 415 818 10 2-13 416 11 2-14 417 12 215 4-18 1J 2-16 14 2-17 15 218 128-18 l' and's 2 All wiring should be protected on side walls from mechanical injury. This may be done by putting a substantial boxing about the wires, allowing an air space of one inch around the conductors and closed at the top (the wire passing through bushed holes) and the boxing extending about five feet above the floor. Sections of metal conduit may be used (the wire being protected by approved flexible tubing), and in most cases this practice is preferable. All bushings should be made of non-combustible, non- absorptive insulating material such as glass or por- celain and should be used wherever wires go through walls, floors, timbers or partitions. They should be long enough to bush the entire length of the hole in one continuous piece, or else the hole must first be bushed by a continuous waterproof tube. This tube may be a conductor, such as iron pipe, but in that case the wire should be protected by a continuous length of approved flexible tubing extending one inch from each end of the pipe or conduit or far enough to keep the wire absolutely out of contact with the pipe. If iron pipes, conduits, or metal mouldings are used with alternating currents, the two or more wires of the circuit should always be placed in the same conduit. When crossing floor timbers in cellars or in rooms where they might be exposed to injury, wires should be attached, by their insulating supports, to the un- der side of wooden strips not less than one-half inch in thickness and not less than three inches wide. When wires are run immediately under roofs, or in proximity to water tanks or pipes they will be con- sidered as exposed to moisture and care should be taken as described on pages 99 and 152. The installation of electrical conductors in mould- ing, or on insulators, in elevator shafts will not be approved, but conductors may be installed in such shafts if encased in approved metal conduits, see page 138, or armored cables. See page 135. In three wire (not three-phase) systems, the neu- tral should be of sufficient capacity to carry the maximum current to which it may be subjected. Porcelain Insulating Tube for partition and walls. Underground Conductors. All underground con- ductors should be protected against moisture and mechanical injury where brought into a building, and all combustible material should be kept from the immediate vicinity. They should not be so arranged as to shunt the current through a building around any catch-box. Where underground service enters building 94 through tubes, the tubes should be tightly closed at outlets with asphaltum or other non-conductor, to prevent gases from entering the building through such channels. No underground service from a subway to a building, and no service from a private generating plant should supply more than one building, except by special permission, unless the conductors are pro- perly protected by fuses and are carried outside all the buildings but the one served. Conductors in con- duit or duct under two inches of concrete under a building, or buried back of two inches of concrete or brick within a wall are considered as lying outside of the building. These suggestions do not apply to factory yards and factory buidings under single oc- cupancy or management. * Switches, Cut-outs and Circuit -Breakers On constant potential circuits, all service switches and all switches controlling circuits supplying cur- rent to motors or heating devices, and all fuses should be so arranged "that the fuses will protect and the opening of the switch will disconnect all of the wires ; that is, in the two-wire system the two wires, and the three-wire system the three wires, should be protected by the fuses and disconnected by the operation of the switch. When installed without other automatic overload protective devices automatic overload circuit break- ers should have the poles and trip coils so arranged as to afford complete protection against overloads and short circuits. In two or three-phase three-wire circuits and two-phase four-wire circuits there 95 should be a trip-coil in each of two phases, and in four-wire three-phase circuits there should be a trip- coil in each phase. If a circuit breaker is also used in place of the switch it should be so arranged that no one pole can be opened manually without discon- necting all the wires. This, of course, does not apply to the grounded circuit of street railway systems. They should not be placed where exposed to me- chanical injury nor in the immediate vicinity of easily ignitible stuff or where exposed to inflammable gases or dust or to flyings of combustible material. Where the occupancy of a building is such that switches, cut-outs, etc., cannot be located so as not to be exposed as above, they should be enclosed in approved dust-proof cabinets with self-closing doors, except oil switches and circuit breakers which have dust-tight casings. Cabinets and cut-out boxes should be of metal when used with metal conduit, armored cable or metal moulding systems. (See page 126.) They should also, when exposed to dampness, be enclosed in a moisture-proof box. The cover of the box should be so made that no moisture which may collect on the top or sides of the box can enter xt. Time switches, sign flashers and similar appli- ances should be of approved design and enclosed in approved cabinets. See page 122. Series Arc Lamp Wiring. All wiring in build- ings for constant current series arc lighting should be with approved rubber covered wire and the cir- cuit arranged to enter and leave the building through 96 an approved double contact service switch, which means a switch, mounted on a non-combustible, non- absorptive insulating base, capable of closing the main circuit and disconnecting the branch wires when turned "off"; this switch should be so con- structed that it will be automatic in action, not stop- ping between points when started, and must prevent an arc between points under all circumstances, and should indicate, upon inspection, whether the current be "on" or "off." Such a switch is necessary to cut the high voltage current completely out of the build- ing by firemen in case of fire or when it becomes necessary to make any changes in the lamps or wir- ing. It should be in a non-combustible case. This class of wiring should never be concealed or encased except when required by the Electrical In- spector, and should always be rigidly supported on porcelain or glass insulators which will separate the wiring at least one inch from the surface wired over, and should be kept at least eight inches from each other. Except within the structure of lamps, or hanger-boards or in cut-out boxes or such fixtures when a less distance is necessary. This class of wir- ing should, on side walls, be protected from me- chanical injury by a substantial boxing, retaining an air space of at least one inch around the conductors, closed at the top (the wires passing through bushed holes), and extending not less than seven feet from the floor. When crossing floor timbers in cellars, or in rooms where they might be exposed to injury, wires should be attached by their insulating supports to the under side of a wooden strip not less than one-half an inch in thickness. Instead of the run.- 97 ning-boards, guard strips on each side of and close to the wires will be sufficient. These strips to be not less than seven-eighths of an inch in thickness and at least as high as the insulators. Except on joisted ceiling, a strip one-half of an inch thick is not considered sufficiently stiff and strong. For spans of say eight or ten feet, where there is but little vibration, one-inch stock is gen- erally sufficiently stiff ; but where the span is longer than this or there is considerable vibration, still heavier stock should be used. Series arc lamps, now rapidly going out of use, being replaced by gas filled high efficiency mazda or tungsten lamps, should be isolated from inflammable material, and should be provided at all times with a glass globe surrounding the arc, and securely fas- tened upon a closed base. Broken or cracked globes should not be used. They should be provided with a wire netting (having a mesh not exceeding one and one-fourth inches) around the globe, and an approved spark arrester when readily inflammable material is in the vicinity of the lamps, to prevent escape of sparks of carbon or melted copper. It is recommended that plain carbons, not copper-plated, be used for lamps in such places. Outside arc lamps should be suspended at least eight feet above sidewalks. Inside arc lamps should be placed out of reach or suitably protected. Arc lamps, when used in places where they are exposed to flyings or easily inflammable material, should have the carbons enclosed completely in a tight globe in such manner as to avoid the necessity for spark arresters. "Enclosed arc" lamps, having tight inner globes, may be used in such places. Series Incandescent Lamp Wiring The same suggestions given for the wiring for series arc lamps should apply to this class of work as well. Each series incandescent lamp should be provided with its own automatic cut-out. Each lamp should be suspended from a hanger-board by a rigid tube. In no way should they come in contact with, or be connected to, gas fixtures. No electro-magnetic device for switches and no multiple-series or series- multiple systems of lighting should be used. Special Wiring for damp places such as brew- eries, packing houses, stables, dye houses, paper or pulp mills, or buildings specially liable to moisture or acid or other fumes liable to injure the wires or their insulation, except where used for pendants should always be done with approved rubber cov- ered or weather-proof wire, and rigidly supported on porcelain or glass insulators which separate the wires at least one inch from the surface wired over and must be kept apart at least two and one-half inches for voltages up to 300 and four inches apart for higher voltages. The wire in such damp places should contain no splices as it is almost impossible to tape a splice that will prevent acid fumes from getting at the copper surface. Automatic Cut- Outs Fuses and Circuit Breakers On constant potential systems the general rules, for all voltages, require that a circuit-breaker or fuse 99 be placed on all service wires, either overhead or underground, in the nearest accessible place to the point where they enter the building and inside the walls, and arranged to cut off the entire current from the building. Departure from this rule may be authorized only under special permission in writing. Where the switch required on all service wires is inside the building, the cut-out (circuit-breaker or fuse) should be placed so as to protect it, unless the switch is of the knife-blade type and is enclosed in an approved box or cabinet, under which condition the switch may be placed between the source of the sup- ply and the cut-out. It is always safer, however, to place the cut-out between the source of supply and the service switch. Cut-outs should never be placed in any permanent- ly grounded service wire. In risks having private plants, the yard wires run- ning from building to building are not considered as service wires, so that cut-outs would not be required where the wires enter buildings, provided that the next fuse back is small enough to properly protect the wires inside the building in question. Cut-outs should be placed at every point where a change is made in the size of wire [unless the cut- out in the larger wire will protect the smaller (see current carrying capacity of wires page 91)]. Cut-outs should not be placed in any permanent- ly grounded wire. They should be in plain sight, or enclosed in an approved cabinet, and readily accessi- ble. They should not be placed in the canopies or shells of fixtures. Link fuses (see pages 105-107) may be used 100 only when mounted on apprcvsa, b^ses which, except on switchboards should be .mounted in approved cut- out boxes, or cabinets/ 'A space 'of 'at least 'two inches should be provided between the open-link fuses and metal, or metal lined walls or metal, metal lined or glass paneled doors of cabinet or cut-out boxes. Cut-outs should be so placed that no set of small motors, small heating devices or incandescent lamps, whether grouped on one fixture or on several fixtures or pendants (nor more than 16 medium size or 25 candelabra size sockets or lamp receptacles) requir- ing more than 660 watts, will be dependent upon one cut-out. By special permission, in cases where wiring equal in size and insulation to No. 14 B. & S. gage approved rubber-covered wire is carried direct into keyless sockets or receptables, and where the loca- tion of socets and receptacles is such as to render unlikely the attachment of flexible cords thereto, the circuits may be so arranged that not more than 1,320 watts (or thirty-two sockets or receptacles) will be dependent upon the final cut-out. Except for signs and outline lights sockets and lamp receptacles will be considered as requiring not less than 40 watts each, if of the medium size, or 25 watts each if of candelabra size. Receptacles (see page 150) for attachment plugs (see page 114) rated at not over 660 watts each may be connected to ordinary branch circuits, and when so installed will be considered as requiring not less than 40 watts. Heating and other appliances rated not over 660 watts each may be connected to such 101 receptacles only when the normal load in use on the circuit* at any time, wfll not exceed 660 watts. A cut- out should be provided for each receptacle rated above 660 watts. All branches or taps from any three-wire system which are directly connected to lamp sockets or other translating devices, should be run as two-wire circuits if the fuses are omitted in the neutral or if the difference of potential between the two outside wires is over 250 volts, and both wires of such branch or tap circuits should be protected by proper fuses. (See page no.) The above should also apply to motors, except that small motors may be grouped under the protection of a single set of fuses, provided the rated capacity of the fuses does not exceed 10 amperes. When 1,320 watts are dependent upon one fusible cut-out, as is allowed in outline lighting, signs and large chandeliers, the fuses may be in accordance with the following table : 125 volts or less 20 amperes 126 to 250 volts 10 amperes Fused rosettes (see page 153) may be used only for open work in large mills. Approved link fused rosettes may be used at a voltage of not over 125 and approved enclosed fused rosettes at a voltage of not over 250, the fuse in the rosette not to exceed 3 am- peres, and a fuse of over 25 amperes should not be used in the branch circuit. The rated capacity of fuses (see pp. 112 and 113). should not exceed the allowable carrying capacity of the wire as given in the table on page 91. Circuit breakers should not be set more than 30 per cent. 102 above allowable carrying capacity of the wire, unless a fusible cut-out is also installed on the circuit. Where a rubber-covered conductor carries the cur- rent of only one A. C. motor of a type requiring large starting current, it may be protected by a fuse or an automatic circuit breaker. The rated continu- ous current capacity of a time limit circuit breaker protecting a motor of the above type need not be greater than 125 per cent, of the motor current rat- ing, provided the time limit device is capable of pre- venting the breaker opening during the starting per- iod. In the great majority of cases where A. C. motors of the above type are started by means of autostart- ers the current-carrying capacity of wires meeting the rule will not exceed the following percentages oi the full load currents of the motors, Rated full load current Percentage o- 30 amperes 250 31-100 " 200 Above loo " 150 For the protection of wires having safe carrying capacities exceeding the rated capacity of the largest approved enclosed type fuses, approved enclosed fuses, see pages 108-113), arranged in multiple, may be used, provided as few fuses as possible are used and the fuses are of equal capacity, and provided the cut-out terminals are mounted on a single continuous pair of substantial bus bars. The total capacity of the fuses should not exceed the safe carrying capa- city of the wires. This does not apply to motor cir- cuits. Fixture wire or flexible cord, see page 149, of No. 103 i8 B. & S. gage will be considered as properly pro- tected by 10 ampere fuses. Each conductor of motor circuits, except on main switchboard or when otherwise subject to competent supervision, should be protected by an approved fuse, whether automatic overload circuit breakers are installed or not (see page 45.) Single phase motors may have one side protected by an approved automatic overload circuit breaker only, if the other side is protected by an approved fuse. Circuit breakers will be approved for circuits hav- ing a maximum capacity greater than that for which approved enclosed fuses are rated. (See page 44.) Circuit Breakers. All circuit breakers, for volt- ages of 550 or less, should be mounted on non-com- bustible, non-absorptive, insulating bases, such as slate or marble. Bases with an area of over twenty- five square inches should have at least four support- ing screws. Holes for the supporting screws should be so- located or countersunk that there will be at least one-half, of an inch space measured over the surface between the head of the screw or washer and the nearest live metal part, and in all cases when be- tween parts of opposite polarity should be counter- sunk. They should be plainly marked with the name of the maker and the current and voltage for which they are designed. Cut-Outs. All small safety devices which, under this heading, mean fuses of the open link or enclosed or cartridge type, should be supported on bass of non-combustible, non-absorptive, insulating material. Cut-outs should be of the enclosed type, when not 104 arranged in approved cabinets, so as to obviate any danger of the melted fuse metal coming in contact with any substance which might be ignited thereby. Cut-outs should operate successfully on short-cir- cuits, under the most severe conditions with which they are liable to meet in practice, at 25 per cent, above their rated voltage, and for link fuse cut-outs with fuses rated at 50 per cent, above the current for which the cut-out is designed, and for enclosed fuse cut-outs with the largest fuses for which the cut-out is designed. With link fuse cut-outs there is always the possi- bility of a larger fuse being put into the cut-out than it was designed for, which is not true of approved enclosed fuse cut-outs. Again the voltage in most plants can, under some conditions, rise considerably above the normal. The need of some margin, as a factor of safety to prevent the cut-outs from being ruined in ordinary service, is therefore evident. The most severe service which can be required of a cut-out in practice is to open a "dead short-circuit,'' with only one fuse blowing. Every enclosed fuse should be marked where it will be plainly visible when installed with the name of the maker, and current and voltage for which it is designed. Link Fuse Cut-Outs.- The following suggestions are intended to cover open link fuses mounted on slate or marble bases, including switchboards, tablet- boards and single fuse-blocks. They do not apply to the ordinary porcelain cut-out blocks, enclosed fuses, or any special or covered type of fuse. When tablet-boards or single fuse-blocks with such open 105 link fuses on them are used in general wiring, they should be enclosed in cabinet boxes made to meet the requirements. This is necessary, because a severe flash may occur when such fuses melt, so that they would be dangerous if exposed in the neighborhood of any combustible material. Such cut-outs should be mounted on bases made of strong non-combustible, non-absorptive, insulating material. The design of the base should be such that considering the material used, the base will with- stand the most severe conditions liable to be met in practice. Bases with an area of over twenty-five square inches should have at least four supporting screws. Holes for supporting screws should be kept outside of the area included by the outside edges of the fuse terminals, and should be so located or coun- tersunk that there will be at least one-half of an inch space, measured over the surface, between the head of the screw or washer and the nearest live metal part. The following spacings should be attended to for this class of fuses : Minimum Separation of Minimum Nearest Metal Parts of Break- Opposite Polarity. Distance. Not over 125 Volts: 10 amperes or less. . . 24 i ncn Z A mcn 1 1- 100 amperes. i 24 101-300 " i I 301-1,000 " i >4 " IJ4 " 106 Not over 250 Volts: 10 amperes or less. . . ii-ioo amperes 101-300 " 301-1,000" iV 2 inch I Clinch 'T/I t( i!j4l " 2 The link fuses used in this class of cut-out, should all have contact surfaces or tips of copper, or other hard metal, and securely soldered to the fuse wire. Switches. All service wires, either overhead or underground, should be controlled by a service switch in the nearest readily accessible place to the An Approved Double Pole Knife Switch, Showing Terminals for Approved Enclosed Fuses. Always install so that the handle will be up when circuit is closed. point where the wires enter the building, and ar- ranged to cut off the entire current. Service cut-out and switch should be arranged to cut off current from all devices including meters. 107 Service switches should indicate plainly whether they are open or closed. In risks having private plants the yard wires run- ning from building to building are not considered as service wires, so that switches would not be required in each building if there are other switches conveni- ently located on the mains or if the generators are near at hand. All switches should be placed in dry, accessible places, and be grouped as far as possible. All knife switches should be so placed that gravity will not tend to close them. (See cut p. 107.) Double-throw knife switches should be mounted so that the throw will be horizontal, but if the throw be vertical a lock- ing device should be provided so constructed as to insure the blades remaining in the open position when so set. Enclosed-Fuse Cut-Outs Plug and Cartridge Type. The bases of all enclosed fuse cut-outs should be made of non-combustible, non-absorptive, insulating material. Blocks with an area of over twenty-five square inches must have at least four supporting screws. Holes for supporting screws should be so located or countersunk that there will be at least one-half of an inch space, measured over the surface, between the screw-head or washer and the nearest live metal part, and in all cases where between parts of opposite polarity should be coun- tersunk. Except for scalable service and meter cut-outs, terminals should be either the Edison plug, spring clip or knife blade type, to take the corresponding standard enclosed fuses. 108 All enclosed fuse cut-outs should be classified as regards both current and voltage as given in the fol- lowing table, and should be so designed that the bases of one class cannot be used with fuses of an- other class rated for a higher current or voltage. STANDARD PLUG OR CARTRIDGE CUT- OUTS Nat over 250 Volts: Not over 600 Volts: 0-30 amperes. 0-30 amperes. 31-60 31-60 61-100 " 61-100 " IOI-2OO " IOI-2OO " 201-400 201-400 " 401-600 " Sealable Service and Meter Cut-Outs. Not over 250 Volts: Not over 600 Volts: 0-30 amperes. 0-30 amperes. 31-60 31-60 " 61-100 " 61-100 101-200 " 101-200 " Enclosed Fuses Plug and Cartridge Type Plugs, commonly known as Edison Fuse Plugs, should not be used to protect circuits of over 30 am- peres at 125 volts. This, of course, includes any cir- cuit of a three- wire 125-250 volt system with grounded neutral. The large size Edison Plug is designed for circuits between 31 and 60 amperes at 250 volts. Enclosed Fuses (Cartridge Type) Should be so constructed that with the surround- ing atmosphere at a temperature of 75 degrees Fah- 109 renheit they will carry indefinitely a current 10 per cent, greater than that at which they are rated, and and at a current 25 per cent greater than the rating, they will open the circuit without reaching a tem- perature which will injure the fuse tube or termin- als of the fuse block. With a current. 50 per cent, greater than the rating and at room temperature of 75 degrees Fahrenheit the fuses starting cold, should blow with the time specified below : 0-30 amperes I minute 31-60 " 2 minutes 61-100 " 4 " 101-200 " 6 " 201-400 " 12 401-600 " 15 They should be marked where it will be plainly visible, with the name, trade-mark of the maker, the voltage and current for which the fuse is de- signed, and the words "National Electrical Code Standard." Each fuse has a label, the color of which is green for 25O-volt fuses and red for 600- volt fuses. No enclosed fuses should ever be refilled by the user but should be returned to their makers, who will refill them at a nominal cost, and in strict ac- cordance with their ratings. There are no "Renewable" or "Refillable" en- closed or cartridge fuses, so-called, approved by the National Board of Fire Underwriters, or appear in the list of Electrical Fittings published by the Na- tional Board of Fire Underwriters. Following is a list of makers of approved en- 110 closed or cartridge fuses: Bryant Electric Co.. "Bryant"; Chicago Fuse Mfg. Co., "Union"; De- troit Fuse & Mfg. Co., "Arkless" ; D. & W. Fuse Co., "D. & W."; General Electric Co., "G. E."; Johns-Pratt Co., "Noark" (H, W. Johns-Manville Co., sole agents) ; Westinghouse Elec. & Mfg. Co., "Westinghouse." Cartridge Fuses Ferrule and Knife Blade Contacts. For dimensions of National Electrical Code Standard fuses see two following pages. All switches should be so wired that blades will be "dead" when switch is open. Up to 250 volts and thirty amperes, approved indi- cating snap switches are suggested in preference to knife switches on lighting circuits. Single pole switches should never be used as ser- vice switches nor for the control of outdoor signs or circuits located in damp places, nor placed in the neutral wire of a three- wire system, except in the two- wire branch, or tap circuit supplying not more than 660 watts. Three-way switches are considered as single pole switches. 111 Table of Dimensions of the Standard Cartridge i 1 > > , -C.H 1 ftjj , /| J : , -^J- //\\ 1 ! 0- 6O A roi* cAtvrr MPCRC* tmcic r U "M 1 Form 1. CARTRIDGE FUSE Ferrule Contact. Voltage. 0-250 Rated Capacity. Amperes. A B C Length over Terminals. Inches. Distance between Contact Clips. Inches. Width of Contact Clips. Inches 0-30 31-60 1 3 i if ! 61-100 101-200 201-400 401-600 ~ 5 | E 4 5 6 if 251-600 0-30 31-60 I r* 4 4 1 61-100 101-200 201-400 7* 9i S. n| 6 8 7 i 112 National Electrical Code Enclosed Fuse. Q1-60O A.MPCRE.S J [ Form 2. CARTRIDGE FUSE-Knife Blade Contact. D E F G Dia. of Ferrules or Thickness Min. Length of Ferrules or of Dia. of Width of Terminal Rated Capacity. of Terminal Terminal Blades Tube. Blades. Blades. Outside of Tube. Amperes Inches. Inches. Inches. Inches. , j i cs 0-30 if i f i 31-60 i i i f 61-100 if ii ii E 101-200 i 2 if o 201-400 i 2* H 2 40i-6oo' B ~7T j ^ B 0-30 'A 1 i 1 31-60 i I xi 4 ** 61-100 If if ii S 101-200 i If 2i if* 201-400 113 Where flush switches or receptacles are used, whether with conduit systems or not, they should be enclosed in an approved box constructed of iron or steel, in addition to the porcelain enclosure of the switch or receptacle. At floor outlets, attachment plugs and receptacles should be enclosed in approved floor outlet boxes especially designed for this purpose. Where possible, at all switch outlets, unless out- let boxes which will give proper support for switches are used, a seven-eighths inch block should be fas- tened between studs or floor timbers flush with back of lathing to hold tubing and to support switches. When this cannot be done, wooden base blocks, not less than three-fourths inch in thickness, securely screwed to lathing, or approved fittings designed for the service, should be provided for switches. Sub-bases of non-combustible, non-absorptive, insulating material, which will separate the wires at least ene-half inch from the surface wired over, should be installed under all snap switches used in exposed knob and cleat work . Sub-bases should also be used in moulding work, but they may be made of hardwood or they may be omitted if the switch is especially designed and approved for mounting directly on the moulding. Knife Switches should be mounted on non-com- bustible, non-absorptive, insulating bases such as slate, marble or porcelain. Hinges of knife switches should not be used to carry current unless they are equipped with spring washers, held by lock-nuts or pins, or their equiva- lent, so arranged that a firm and secure connection 114 will be maintained at all positions of the switch blades. Spring washers should be of sufficient strength to take up any wear in the hinge and maintain a good contact at all times. All switches should have ample metal for stiffness and to prevent rise in temperature of any part of over 50 degrees Fahrenheit at full load, the contacts being arranged so that a thoroughly good bearing at every point is obtained with contact surfaces advised for pure copper blades of about one square inch for every seventy-five amperes. They should be plainly marked where it can be read, when the switch is installed, with the name of the maker and the current and the voltage for which the switch is designed. Switches designed for 25o-volt D. C. or 5oo-volt A. C. circuits, without fuses on the switch base, should be marked 250 V., D. C., 500 V., A. C. When 25o-volt fuse terminals are mounted on the switch base the marking of the switch should be 250 V., D. C. and A. C. When 6oo-volt fuse terminals are mounted on the switch base the terminals should be spaced for 6oo-volt fuses and the switches marked 500 volts A. C. Triple pole switches designed with I25~volt spac- ings between adjacent blades should be marked 125 volts and may be used on three-wire D. C. or single phase systems having not more than 125 volts be- tween adjacent wires and not more than 250 volts between the two outside wires. When designed with 25O-volt spacings between 115 adjacent blades triple pole switches must be marked 250 volts and may be used on three-wire D. C. or single phase systems having not more than 250 volts between adjacent wires and not more than 500 volts between the two outside wires. It is* not necessary to give all the dimensions and spacings required on knife switches. All the wire- man wants to know is that it is of approved make with the maker's name and the current and voltage plainly marked on the switch. Electric Heaters. Each heater of more than six (6) amperes or 660 watts capacity should be pro- tected by a cut-out, and controlled by a switch or plug connector plainly indicating whether "on" or "off" and located within sight of the heater. Heaters of six (6) amperes or 660 watts capacity or less, may be grouped under the protection of a single set of fuses, provided, the rated capacity of the fuses does not exceed ten (10) amperes, or may be con- nected individually to lighting circuits when the nor- mal load in use on the circuit at any time will not ex- ceed 660 watts. Flexible conductors for smoothing irons and sad irons, and for all devices requiring over 250 watts, must have an approved insulation at least one-sixty- fourth inch thick, a braided covering of asbestos one-thirty-second inch thick and of special quality, and outer braid one-sixty-fourth inch thick enclos- ing either all the conductors as a whole or each con- ductor separately. With portable heating devices, approved plug connectors should be used, so arranged that the plug 116 may be pulled out to open the circuit without leaving any live parts so exposed as to render likely acci- dental contact therewith. The connector may be located at either end of the flexible conductor or in- serted in the conductor itself. Smoothing irons, sad irons and other heating de- vices that are intended to be applied to combustible articles, should be provided with approved stands. Stationary heaters, such as radiators, ranges, plate warmers, etc., should be so located as to fur- nish ample protection between the device and sur- rounding combustible material. Every heater should be provided with a name- plate, giving the maker's name and the normal capa- city in volts and amperes, or in volts and watts. LOW-POTENTIAL SYSTEMS Any circuit attached to any transforming device, machine, or combination of machines, which de- velops a difference of potential between any two wires or between any wire and the ground of not over 550 volts, is considered as a low-potential cir- cuit. The primary circuit should not exceed a poten- tial of 3,500 volts, unless the primary wires are in- stalled in accordance with the suggestions given on pages 63-67 for lines of over 5,000 volts, or are underground. For 550 volt motor equipments a margin of ten per cent, above the 550 volt limit will be allowed at the generator or transformer. All wires, on low-potential systems, should, when entering cabinets, cut-out boxes or junction boxes, except where they are in conduit, armored cable or metal molding, be protected by non-combustible, 117 non-absorptive, insulating bushings, which fit tightly the holes in the box or cabinet and are well secured in place. The wires should completely fill the holes in the bushings, so as to keep out dust, tape being used to build up the wires if necessary. For con- cealed knob and tube work, or for open work in dry places, approved flexible tubing, see page 134, will be accepted in lieu of bushings, providing it extends from the last porcelain support into a wooden cabi- net, or is secured to a metal cabinet, cut-out box, junction or switchbox by an approved fitting. No wiring should be laid in plaster, cement or similar finish, and should never be fastened with staples nor should it be fished for any great distance, and only in places where the inspector can satisfy himself that the rules have been complied with. Twin wires should never be used, except in con- duits, or where flexible conductors are necessary. All wires, where exposed to mechanical injury, be suitably protected. When crossing floor timbers in cellars, or in rooms where they might be exposed to injury, wires must be installed in approved conduit, see page i38,or armored cable, see page 135, or be at- tached by their insulating supports to the under side of a wodden strip, not less than one-half inch in thickness and not less than three inches in width. Instead of the running boards, guard strips on each side and close to the wires will be accepted. These strips to be not less than seven-eighths of an inch in thickness and at least as high as the insulators. Protection on side walls should extend not less than seven feet from the floor and should consist of 118 substantial boxing, retaining an air space of at least one inch around the conductors, closed at the top (the wires passing through bushed holes) or ap- proved metal conduit or pipe of equivalent strength. When metal conduit or pipe is used, the insulation of each wire should be reinforced by approved flexi- ble tubing extending from the insulator next below the pipe to the one next above it, and the wire is ap- proved for conduit use, see page 129. The two or more wires of a circuit each with its flexible tubing (when required), if carrying alternating current must be placed within the same pipe, to avoid trouble from induction. In damp places the wooden boxing may be prefer- able because of the precautions which would be ne- cessary to secure proper insulation if the pipe were used. With this exception, however, iron piping is considered preferable to the wooden boxing, and its use is strongly urged. It is especially suitable for the protection of wires near belts, pulleys, etc. When wires are run in unfinished attics, or roof spaces they will be considered as concealed, and when run in close proximity to water tanks or pipes, will be considered as exposed to moisture. In unfinished attics, or roof spaces, wires are con- sidered as exposed to mechanical injury, and should not be run on knobs on upper edge of joists. For open work in dry places all wires should be rigidly supported on non-combustible, non-absorp- tive insulators, which will separate the wires from each other and from the surface wired over in ac- cordance with the following table : 119 Voltage Distance from Distance between Surface. Wires. o to 300 \% inch 2^ inch 301 to 550 I inch 4 inch Rigid supporting requires under ordinary condi- tions, where wiring along flat surfaces, supports at least every four and one-half feet. If the wires are liable to be disturbed, the distance between sup 1 - ports should be shortened. In buildings of mill con- struction, mains of not less than No. 8 B. & S. gage, where not liable to be disturbed, may be separated about six inches, and run from timber to timber, not breaking around, and may be supported at each tim- ber only. Such wiring should not be "dead-ended" at a rosette, socket or receptacle unless the last support is within twelve inches of the same. In damp places, or buildings specially subject to moisture or to acid or other fumes liable to injure the wires should have rubber insulation to protect them against water and protection against corrosive vapors, either weatherproof or rubber insulation should be used and they should be rigidly supported on non-combustible, non-absorptive insulators, which separate the wire at least one inch from the surface wired over, and must be kept apart at least two and one-half inches for voltages up to 300, and four inches for higher voltages. The same rigid supporting should be given such wiring as described on the preceding page. 120 Snap Switches All flush, push-button, door, fixture and other snap switches used on constant-potential systems should have their current-carrying parts mounted on non-combustible, non-absorptive, insulating bases, such as slate or porcelain, and the holes for supporting screws should be countersunk not less than one-eighth of an inch. There should in no case be less than three-sixty-fourths of an inch space between supporting screws and current-carry- ing parts. Sub-bases should be so designed as to separate the wires at least one-half inch from the surface wired over and be of a non-combustible, non-absorptive, insulating material, except for use with wooden moulding, where they may be of hard wood. All snap switches should have ample metal for stiffness and to prevent rise in temperature of any part of over 50 degrees Fahrenheit at full load. All such switches should "make" and "break" with a quick snap, and should not stop when motion has once been imparted by the button or handle. No exposed parts of any styles of snap switch should be in electrical connection with the circuit and every such switch should be plainly marked with the name or trade-mark of the maker and the current and voltage for which the switch is de- signed. On flush switches these markings are sometimes placed on the sub-plate. On surface switches with covers constructed of porcelain or other moulded in- sulating material the marking is frequently on the inside of the cover. On all other types they should 121 be placed on the front of the cap, cover or plate. Switches which indicate whether the current is "on" or "off" are recommended. Cabinets and Cut-Out Boxes. When cabinets intended for ^enclosing feeder and circuit branch panelboards and similar devices they may be de- signed for either surface or flush mounting and are usually provided with removable frames or matts, trims, etc., in which the swinging doors are hung; when for the enclosure of apparatus connected with- in the cabinet to the wires of more than four cir- cuits they should have a back wiring space or one or more side wiring spaces, side gutters or wiring compartments unless the wires leave the cabinet di- rectly opposite their terminal connections. When intended for installation out-of-doors they should be of the "weatherproof" pattern. Cut-out-boxes are intended for enclosing single devices or combinations of devices connected within the cut-out box to the wires of not more than four circuits and usually are designed for surface mount- ing having swinging doors or covers secured directly to the wall of the box. When intended for installa- tion out-of-doors they also should be of the "weatherproof" pattern. The construction of all cabinets and cut-out boxes should be such as to insure ample strength and rigidity. The spacing within cabinets and cut-out boxes should be sufficient to provide ample room for the distribution of wires and cables placed in them, and for a separation between metal parts of cabinets or cut-out boxes and current-carrying parts of de- 122 vices and apparatus mounted within them as fol- lows: Cabinets and cut-out boxes should be deep enough to allow the doors to be closed when 3O-ampere branch circuit panelboard switches having spool or composition handles or when switches of combina- tion cut-outs are in any position, and when other single throw switches are thrown open as far as their construction and installation will permit. Outlet, Junction and Flush Switch Boxes should be of pressed steel having wall thickness not less than .078 inch or of cast metal having wall thickness not less than one-eighth inch, and should be well galvanized, enameled or otherwise properly coated, inside and out, to prevent oxidation. All such boxes should be plainly marked, where it may readily be seen when installed, with the name or trade-mark of the manufacturer, and should be arranged to secure in position the conduit or flexi- ble tubing protecting the wire. Switch and outlet boxes should be so arranged that they can be securely fastened in place independ- ently of the support afforded by the conduit piping, except that when entirely exposed, approved boxes, which are threaded so as to be firmly supported by screwing on to the conduit, may be used. Switch and receptacle boxes should completely enclose the switch or receptacle on sides and back, and should provide a thoroughly substantial support for it. Boxes for floor outlets should be designed to completely enclose the receptacle and attachment plugs, if any, to protect them from mechanical in- jury and to exclude moisture. 123 Covers for outlet boxes if made of metal should be equal in thickness to that specified for the walls of the box. Covers may also be made of porcelain or other approved material, but should be of such form and thickness as to afford suitable protection and strength. Panel Boards. In the relative arrangement of fuses and switches, the fuses may be placed between the bus-bars and the switches, or between the switches and the circuits. When the branch switches are between the fuses and bus-bars, the connections should be so arranged that the blades will be dead when the switches are open. When there are exposed live metal parts on the back of board, a space of at least one-half inch should be provided between such live metal parts and the cabinet in which the board is mounted. All panelboards should be marked where the marking can be plainly seen when installed, with the name or trade-mark of the manufacturer and the maxi- mum capacity in amperes and the voltage for which the board is designed. For a really permanent and high class installation of a distributing centre, the following specifications are recommended: Panel boards should be made as per the Under- writers Laboratory Label Service Specifications for Panel Boards and have label attached. The panel boards should be natural black oiled finish slate % inch thick and equipped on face of panel, with such switches, fuse connections, bus bars and other apparatus as follows, all exposed metal parts should be copper, polished and wherever not 124 used for contact should be lacquered. All fuse con- nections for mains and sub-feeders should be for National Electrical Code Standard cartridge fuses, and all fuse connections for circuit branches should be for 30 amperes (N. C. cartridge fuses) (Edison plug fuses). Each panel board should be equipped with main switch and main fuse connection. Main fuse connection and main switch and bus bar should be of an ampere capacity equal to the number of circuit branches multiplied by 3 ampere for the 3- wire system, and by 6 ampere for the 2-wire system, plus the full ampere capacity of any sub- feeder con- nections. Each panel board should be equipepd with D. P. circuit branches for the number of circuits shown on wiring plans, and 2 branches in addition for extra circuits. Each circuit branch should be equipped with D. P. fuse connection (connected to bus bar) and a D. P. (30 amp. knife) (10 amp. snap) (10 amp. push button) switch. All switches, either knife, snap or push button, should be pro- tected by the fuses. Cabinets should be made as per the Underwriters' Laboratory Label Service Specification for Cabinets and have label attached. Boxes Cabinet boxes should be made of all steel, of the gutter type and arranged for mounting flush into walls or partitions. The boxes should be formed from one piece of sheet steel, having flanged corners securely fastened with not less than 2 rivets and with ^ mcn flange turned in at front edges, and when panel is, not over 24 inches wide should have gutters as follows : 125 For panels not over 30 inches high, not less than 3 inch gutter. For panels over 30 inches and not over 50 inches high, not less than 3^ inch gutter. For panels over 50 inches and not over 76 inches high, not less than 4 inch gutter. Barriers Cabinets are to be equipped with Cabinet and Panelboard Complete. For approved makes see page 269. gutter barriers made in 4 sections of Y> inch black oiled slate, of the proper width to allow necessary space between panel board and front. Fronts Fronts should be made from one piece of sheet steel and for cabinets with 3 inch gutters 126 should be not less than No. '12, and for all larger cabinets not less than No. 10. Moulding Work (Wooden and Metal). All wiring in moulding, either wooden or metal (see page 128) should be done with approved rubber covered wire and should be in continuous lengths from outlet to outlet, or from fitting to fit- ting, no joints or taps should be made in moulding. Where branch taps are necessary in moulding work approved fittings for this purpose should be used. No class of moulding work should ever be done in damp places or in concealed -locations or when the difference of potential between any two wires in the same system exceeds 300 volts. When electrical construction is being carried out in metal moulding these mouldings may extend through walls and par- titions if the moulding and capping are in continuous lengths where passing through the walls and parti- tions. Not more than four No. 14 B. & S. gage rub- ber covered wires, and no single circuit of more than 1,320 watts should ever be used in metal mould- ing. For alternating current systems if in metal mould- ing the two or more wires of a circuit should be in- stalled in the same moulding. In many cases this is being done for direct cur- rent systems also, so that they may be changed to alternating systems at any time, induction troubles preventing such a change if the wires are in separate metal mouldings. Wooden Mouldings. They should have, both outside and inside, at least two coats of waterproof 127 material, or be impregnated with a moisture repel- lent, should be made in two pieces, a backing, and a capping, and should afford suitable protection from abrasion. They should be so constructed as to thoroughly encase the wire, be provided with a ton- gue not less than one-half inch in thickness between the conductors, and have exterior walls which under grooves should not be less than three-eighths inch in thickness, and on the sides not less than one-fourth inch in thickness and made of hard wood. Metal Mouldings. Each length of metal mould- ing should have its maker's name or trade-mark stamped in the metal. (For Installation, see p. 146.) All metal moulding should be constructed of iron or steel with backing at least .050 inch in thickness, Samples of Approved Metal Moulding. For approved makes see page 268. and with capping not less than .040 inch in thickness, and so constructed that when in place the raceway will be entirely closed. It should be thoroughly gal- 128 vanizecl or coated with an approved rust preventive both inside and out to prevent oxidation. . Elbows, couplings and all other similar fittings should be constructed of at least the same thickness and quality, of metal as the moulding itself, and so designed that they will both electrically and mechanically secure the different sections together and maintain the continuity of the raceway. The interior surfaces should be free from burrs or sharp corners which might cause abrasion of the wire cov- erings, and at all outlets be so arranged that the conductors cannot come in contact with the edges of the metal, either of capping or backing. Metal mouldings should be used for exposed work only and should be so constructed as to form an open raceway to be closed by the capping or cover after the wires are laid in. Conduit Work. All wires for this class of work should have an approvel rubber insulating covering, and within the conduit tubing should be without splices or taps. Such wires should be double braided for twin, twisted pair or multiple conductor cables and for all single conductors of No. 6 B. & S. gage and larger. Slow burning insulation (see page 77) may, how- ever be used in permanently dry locations where ex- cessive temperatures are present. No wires should ever be drawn in conduits until all mechanical work on the building has been, as far as possible, com- pleted. Conductors in vertical conduit risers should be supported within the conduit system in accordance with the following table: 129 No. 14 to o inclusive every 100 feet. No. oo to oooo inclusive every 80 feet. Above oooo to 350,000 C. M. inclusive every 60 feet. Above 350,000 C. M. to 500,000 C. M. inclusive every 50 feet. About 500,000 C. M. to 750,000 C. M. inclusive every 40 feet. Above 750,000 C. M. every 35 feet. The following methods of supporting cables are recommended : Approved clamping devices constructed of or em- ploying insulating wedges inserted in the ends of conduits. Junction boxes (see page 123) may be inserted in the conduit system at the required intervals, in which insulating supports of approved type should be in- stalled and secured in a satisfactory manner so as to withstand the weight of the conductors attached thereto, the boxes to be provided with proper covers. Cables may be supported in approved junction boxes on two or more insulating supports so placed that the conductors will be deflected at an angle of not less than 90 degrees, and carried a distance of not less than twice the diameter of the cable from its verticle position. Cables so suspended may be ad- ditionally secured to these insulations by tie wires. For alternating systems the two or more wires of a circuit should be drawn in the same metal conduit. It is advisable, whenever possible, to do the same thing when wiring metal conduit for direct current, as suggested for metal moulding, so that at any time ISO a change might be made from direct to alternating current the necessity of rewiring the conduits would be avoided. A single conduit should not contain more than four two-wire, or three-wire circuits of the same system, and should never contain circuits of differ- ent systems. Concealed "Knob and Tube'* Work. All wiring of this class should be done with approved rubber covered wire and' should be rigidly supported on non- combustible, non-absorptive insulators which separ- ate the wire at least one inch from the surface wired over. When possible, this class of wiring should be run singly on separate timbers, or studding, and kept at least five inches apart. Such wiring should be separated from contact with the walls, floor timbers and partitions through which they may pass by non-combustible, non-ab- sorptive, insulating tubes, such as glass or porce- lain. (See page 94.) Wires passing through cross timbers in plastered partitions should be protected by an additional tube extending at least four inches above the timber. Rigid supporting requires, under ordinary condi- tions, where wiring along flat surfaces, supports at least every four and one-half feet. If the wires are liable to be disturbed the distance between supports should be shortened. At distributing centers, outlets or switches where space is limited, and the five-inch separation cannot be maintained, each wire should be separately en- cased in a continuous length of approved flexible tubing. (See page 134.) 131 When it is impracticable, in this class of work, to place the whole of a circuit on non-combustible supports of glass or porcelain, that portion of the circuit which cannot be so supported should be in- stalled with approved metal conduit, or approved armored cable (see p. 135) except that if the differ- ence of potential between the wires is not over 300 volts, and if the wires are not exposed to moisture, they may be fished if separately encased in approved flexible tubing, extending in continuous lengths from porcelain support to porcelain support, from porcelain support to outlet, or from outlet to outlet. When using either conduit or armored cable in mixed concealed knob and tube work, the sugges- tions for conduit work or armored cable work should be complied with as the case may be. All wires, in knob and tube work, at all outlets, except where conduit is used, should be protectel by approved flexible tubing, extending in continuous lengths from the last porcelain support to at least one inch beyond the outlet. In the case of combina- tion gas and electric outlets the tubes on the wires should extend at least flush with the outlet ends of gas caps, and if box or plate is used, gas pipes should be securely fastened into the outlet box of plate to secure good electrical connection. When the surfac at any outlet is broken, it should be repaired so as to leave no holes or open spaces at such outlet. In the best practice approved outlet boxes or plates are installed at all outlets, and the wires to be protected by approved flexible tubing, extending in 1S2 continuous lengths from the last porcelain support into the box. Porcelain knobs, tubes, . cleats and bushings should have the manufacturer's name, initials or trade-mark stamped in the porcelain. Tubes and Bushings should be straight and free from rough projections and with their ends and in- teriors smooth and rounded. Cleats should hold the wires firmly in place with- out injury to the covering. All cleats for voltages up to 300 should separate the wires one-half inch from the surface wired over and two and one-half inches from each other. Split knobs should be constructed in two parts, a base and a cap, arranged to hold the wire firmly in place without injury to its covering. Solid knobs should be constructed with smooth groove, to con- tain wire. Bearing points on the surface wired over should be made by a ring or by ridges on the outside edge of the base, to provide for stability. At least one- fourth inch surface separation should be maintained between the supporting screw or nail and the con- ductor, and the knob should be so constructed that the supporting screw or nail cannot come in contact with the conductor. For wires larger than No. 4 B. & S. gage, split knobs (or single wire cleats) should be so constructed as to require the use of two sup- porting screws. Knobs should separate the wire at least one inch from the surface wired over. Flexible Tubing. Should have a sufficiently smooth interior surface to allow the ready introduc- 133 tion of the wire and be constructed of or treated with materials which will serve as moisture repel- lents. The tube should be so designed that it will with- stand all the abrasion likely to be met with in prac- tice and the linings, if any, should not be removable in lengths of over three feet. The one-fourth inch tube should be so flexible that it will not crack or break when bent in a circle with six-inch radius at 50 degrees Fahrenheit, and Samples of Approved Flexible (Non-Metallic) Tubing. For Approved Makes see page 268. the covering should be thoroughly' saturated with a dense moisture-proof compound. Other sizes must be as well made and none should convey fire on the application of a flame to the exterior of the tube when held in a vertical position. All flexible tubing should be sufficiently tough and tenacious to withstand severe tension without in- jury. 184 It should have a distinctive marking the entire length of the tube, so that it may be readily iden- tified. Armored Cables, When wiring is done with armored cable, the cables should be continuous from outlet to outlet or to junction boxes or cabinets, and the armor of the cable should properly enter and be secured. In case of service connections and main runs, this involves running such armored cable continuously into a main cut-out cabinet or gutter surrounding the panelboard, as the case may be. Armored cables should be equipped at every outlet with an approved outlet box, as recommended in conduit work. For concealed work in walls and ceilings com- posed of plaster on wooden joist or stud construc- tion, outlet boxes and also cut-out cabinets should be so installed that the front edge will not be more than one- fourth inch back of the finished surface of the plaster, and if this surface is broken or incom- plete it should be repaired so that it will not show any gaps or open spaces around the edges of the outlet box or of the cut-out cabinet. On wooden walls or ceilings, outlet boxes and cut-out cabinets should be so installed that the front edge will either be flush with the finished surface or project there- from. This need not apply to concealed work in walls or ceilings composed of concrete, tile or other non-combustible material. In buildings already constructed where the condi- tions are such that outlet box can not be installed, 135 these appliances may be omitted provided the ar- mored cable is firmly and rigidly secured in place. The metal armor of cables should be permanently and effectually grounded to water piping, gas piping or other suitable grounds, provided that when con- nections are made to gas piping, they should be on the street side of the meter. If the armored cable system consists of several separate sections, the sec- tions should be bonded to each other, and the system grounded, or each section may be separately grounded. The armor of cables and gas pipes should be se- curely fastened in outlet boxes, junction boxes and cabinets, so as to secure good electrical connection. If armor of cables and metal of couplings, outlet boxes, junction boxes, cabinets or fittings having protective coating of non-conducting material, such as enamel, such coating should be thoroughly re- moved from the threads of both couplings and the armor of cables, and from surfaces of the boxes, cabinets and fittings where the armor of cables or ground clamp is secured in order to obtain the re- quisite good connection. Grounded pipes should be cleaned of rust, scale, etc., at place of attachment of ground clamp. Connections to grounded pipes and to armor of cables should be exposed to view or accessible and should be made by means of approved ground clamps. Ground wires should be of copper, at least No. 10 B. & S. gage (where largest wire contained in cable is not greater than No. o B. & S. gage), and need not be greater than No. 4 B. & S. gage (where 136 the largest wire contained in cable is greater than No. o B. & S. gage). When armored cables are installed in so-called fireproof buildings in course of construction or af- terwards if exposed to moisture, or where it is ex- posed to the weather, or in damp places, such as breweries, stables, etc., the cable should have a lead covering placed between the outer braid of the con- ductors and the steel armor. This lead covering is not necessary when the cable is run against brick walls or laid in ordinary plaster walls unless same are continuously damp. When entering junction boxes, and at all other outlets, etc., armored cable should be provided with approved terminal fittings which will protect the in- sulation of the conductors from abrasions, unless such junction or outlet boxes are specially designed and approved for use with the cable. Junction boxes should always be installed in such a manner as to be accessible. For alternating current systems armored cable should have the two or more conductors of the cir- cuit enclosed in one metal armor. All bends should be so made that the armor of the cable will not be injured. The radius of the curve of the inner edge of any bend should not be less than one and a half inches. The conductors in armored cable should be rub- ber covered. Interior Conduits. Conduit smaller than one- half inch electrical trade size should never be used. A conduit installation should be continuous from 137 outlet to outlet or to junction boxes or cabinets, and the conduit should properly enter, and be secured to all fittings and the entire system mechanically se- cured in position and free from burs. Samples of Rigid Interior Conduit with Coupling. For Approved Makes See Page 268. In case of service connections and main runs, this involves running each conduit continuously into a main cut-out cabinet or gutter surrounding the panel board, as the case may be. Every conduit installation should be completely finished before wires are drawn in. Conduit systems should be equipped at every out- let with an approved outlet box. At exposed ends of conduit (but not at fixture outlets) where wires pass from the conduit system without splice, joint or tap, an approved fitting having separately bushed holes for each conductor should be used, such as "Condulets." For concealed work in walls and ceilings com- posed of plaster on wooden joist or stud construc- tion, outlet boxes and also cut-out cabinets should be 118 so installed that the front edge will not be more than one-fourth inch back of the finished surface of the plaster, and if this surface is broken or incomplete it should be repaired so that it will not show any gaps or open spaces around the edges of the outlet box or the cut-out cabinet. On wooden walls or "Condulet" bodies for flush switches and receptacles. There are hundreds of styles of "Condulets" for various interior condulet outlets. See "Condulets" page 268. ceilings, outlet boxes or plates and cut-out cabinets should be so installed that the front edge will either be flush with the finished surface or project there- from. This is not necessary in concealed work in walls or ceilings composed of concrete, tile or other non-combustible material. In buildings already constructed where the condi- tions are such that an outlet box can not be installed, these appliances may be omitted, providing the con- duit ends are bushed and secured. 189 Metal conduits where they enter junction boxes, and at all other outlets, should be provided with ap- proved bushings or fastening plates fitted so as to protect wire from abrasion. In all conduit systems the metal of the conduit should be permanently and effectually grounded to water piping, gas piping or other suitable grounds, provided that when connections are made to gas pip- ing, they are on the street side of the meter. If the conduit system consists of several separate sections, the sections should be bonded to each other, and the system grounded, or each section may be separately grounded. Where short sections of conduit (or pipe of equivalent strength) are used for the protection of exposed wiring on side walls such conduit or pipe need not be grounded. Conduits and gas pipes should be securely fas- tened in outlet boxes, junction boxes and cabinets, so as to secure good electrical connections. If conduit, couplings, outlet boxes, junction boxes, cabinets or fittings, having protective coating of non-conducting material, such as enamel, such coat- ing must be thoroughly removed from threads of both couplings and conduit, and such surfaces of boxes, cabinets and fittings where the conduit of ground clamp is secured in order to obtain the re- quisite good connection. Grounded pipes should be cleaned of rust, scale, etc., at place of attachment of ground clamp. (See page 123.) Connections to grounded pipes and to conduit should be exposed to view or accessible, and be made by means of approved ground clamps. Ground wires must be of copper, at least No. 10 140 SIZE OF CONDUITS FOR THE INSTALLATION OF WIRES AND CABLES. NUMBER OF CONDUCTORS IN SYSTEM. One Two Three Four conductor conductors conductors conductors in a in a in a in a conduit. conduit. conduit. conduit, Size Size Size Size conduit, in. conduit, in. conduit, in. conduit, in. Electrical Electrical Electrical Electrical Size Trade Trade Trade Trade B & S. Size Size Size Size 14 J4 54 54 54 12 10 fl g I 8 54 1 1 1 6 54 1 154 154 5 y 4 154 154 154 4 54 1/4 154 154 3 2 % 154 1/2 1 % 154 2 2 00 1 154 2 2 00 1 2 2 254 000 1 2 2 *2 0000 154 2 254 CM 200000 154 2 854 254 250000 854 3 2 300000 1/4 254 3 400000 154 3 2 3 354 500000 154 3 3 354 600000 154 3 354 700000 2 3/4 354 800000 2 354 4 900000 2 354 4 1000000 2 4 4 1250000 254 454 454 1500000 254 454 5 1750000 3 5 5 2000000 3 5 6 TWIN CONDUCTOR. 14 54 54 1 1 12 54 1 1/4 10 54 l 154 154 141 3 CONDUCTOR CONVERTIBLE SYSTEM. Size of Conductors Size Conduit, in. 2-conductor Size B. & S. 1-conductor Size B. & S. Electrical Trade Size 14 12 10 10 8 6 1 8 6 5 4 2 1 1 4 8 2 1 00 000 0000 Ijl 00 000 0000 250000 350000 400000 550000 2 3 ^ 250000 300000 400000 500000 600000 800000 1000000 1250000 8 3 4 600000 700000 800000 1500000 1750000 2000000 4 SINGLE CONDUCTOR COMBINATION. NOTE Where special permission has been secured to use more than four two-wire, or three three-wire circuits in a single circuit, the following table to apply: No- of Size Conduit, in. Wires Electrical Trade Size 3 No. 14 R.C. solid # 5 No. 14 R.C. solid & 10 No. 14 R.C. solid 1 18 No. 14 R.C. solid 1^ 24 No. 14 R.C. solid 1^ 40 No. 14 R.C. solid 2 74 No. 14 R.C. solid 2*/ 2 90 No. 14 R.C. solid 8 B. & S. gage (where largest wire contained in con- duit is not greater than No. o B. & S. gage), and need not be greater than No. 4 B. & S. gage (where largest wire contained' in conduit is greater than No. o B. & S. gage). 142 Junction boxes must always be installed in such a manner as to be accessible. All elbows or bends in a conduit installation should be so made that the conduit will not be in- jured. The radius of the curve of the inner edge of any elbow should not be less than three and one- half inches and should have not more than the equi- valent of four quarter bends from outlet to outlet, the bends at the outlets not being counted. Metal Conduits. Each length of metal conduit should have the maker's name or initials stamped in the metal that inspectors can readily- see it. Rigid Metal Conduit. The tube used in the manufacture of the conduit should be of mild steel ; and should be of sufficiently true circular section to admit of cutting true, clean threads; it should be very closely the same in wall thickness at all points. All surfaces of the tube should be protected against corrosion by one of the following or some other approved methods. Enamel Conduit. The enamel coating on either the inside or the outside surface of the finished con- duit should not soften at ordinary temperatures; it should have an even and smooth appearance and should be of a uniform quality at all points of the length of the tube. Conduits With Metallic Coating. The metallic coating on either the inside or the outside surface of the finished conduit should not soften at ordinary temperatures, and should be of uniform quality at all points of the length of the tube. 148 If the interior surface is not given a metallic pro- tective coating it should be coated with an approved enamel. Elbows, bends and similar fittings must be made of full-weight material, such as is specified for the conduit proper, and must be treated, coated, threaded, etc., in every way corresponding to the conduit so far as they apply. Threads upon conduits, couplings, elbows and bends should be full and clean cut. Their pitch and form should conform to the Briggs' standard for pipe threads. If threads are cut after the protective coatings are applied they should be treated to prevent corrosion taking place before the conduit is actually installed. The number of threads of the threaded portion should be in accordance with the following table : Electrical Number of Trade threads size. per Inches. inch. Y* 18 ft 18 */2 14 H 14 8 8 8 144 Conduit Threads (Continued) Elec. Trade Size No. Threads inches. per inch. 4 8 4J4 8 5 >, 8 6 8 The finished conduit as shipped should be in ten- foot lengths, with each end reamed and threaded. For each length at least one coupling must be fur- nished. The finished conduit with coupling should not weigh less than is given in the following table: Electrical Trade size inches. J* H 13/4 3 3/2 4 Minimum weight of finished conduit ten, 10- foot lengths with couplings. Pounds. 38.5 51.5 79.0 105 153 201 249 334 527 690 831 982 1150 1344 1770 14ft Flexible Conduits should be so flexible that the conduit may be bent in a curve, the inner edge of which has a radius equal to that specified in the fol- lowing table, without opening up the tube at any point. Weight in Pounds ^ jg per 100 ft. oj, ai g|8 ll| l^-s Ht^ Single Strip Double Strip 111 5/16 1 1% 15! 2 "S 56 13/16 1 2 2 .025 .034 .040 .040 .055 .055 .060 .060 .060 29 54 68 108 132 171 224 277 20J4 62 2 78^ 129J^ 158 205 269 332 2J4 2/4 5 6 2 8 If of steel the metal should be thoroughly gal- vanized or coated with an approved rust preventive. Metal Mouldings. An installation of metal mouldings (see p. 128) should be continuous from outlet to outlet, to junction boxes, or approved fit- tings designed especially for use with metal mould- ings, and should at all outlets be provided with ap- proved terminal fittings which will protect the insu- lation of conductors from abrasion, unless such pro- tection is afforded by the construction of the boxes or fittings. Such mouldings where passing through a floor should be carried through an iron pipe extending from the ceiling below to a point five feet above the floor, which will serve as an additional mechanical 146 protection and exclude the presence of moisture often prevalent in such locations. Where the mechanical strength of the moulding itself is adequate, the protecting piping from the ceiling below need extend only to a point three inches above the flooring. Where such mouldings pass through a partition the iron pipe required for passing through floors may be omitted and the moulding passed directly through, providing the partition is dry and the moulding is in a continuous length with no joint or coupling within the partition. The backing of all metal moulding should be se- cured in position by screws or bolts, the heads of which should be flush with the metal. The metal of moulding should be permanently and effectually grounded to water piping, gas piping, or other suitable grounds, provided that when connec- tions are made to gas piping, as in the case of metal conduit, they should be on the street side of the meter. If the metal moulding system consists of several separate sections, the sections should be bonded to each other and the system grounded, or each section may be separately grounded. Metal mouldings and gas pipes should be securely fastened to outlet boxes, junction boxes and cabi- nets, so as to secure a good electrical connection. Moulding should be so installed that adjacent lengths of moulding will be mechanically and electrically se- cured at all points. If metal moulding, couplings, outlet boxes, junc- tion boxes, cabinets or fittings having protective coating of non-conducting material such as enamel, 147 such coating should be thoroughly removed from the couplings of the metal mouldings, and from the sur- faces of boxes, cabinets and fittings, where the metal moulding or ground clamp is secured in order to ob- tain the requisite good connection. Connection to grounded pipes and to metal mould- ings should be made by means of approved ground clamps, and the ground wires should be copper, at least No. 10 B. & S. gage. As the two or more wires of an alternating current circuit are required to be placed in a single iron con- duit, to prevent induction trouble, so must similar circuits be placed in single metal moulding. Fixtures. All electric light fixtures supported at outlets in metal conduit, armored cable, or metal moulding systems, or from gas piping or any grounded metal work, or when installed on metal walls or ceilings, or on plaster walls or ceilings con- taining metal lath, or on walls or ceilings in fireproof buildings, should be insulated from such supports by approved insulating joints (see page 151) placed as close as possible to the ceiling or walls. Gas pipes should be protected above the insulating joint by approved insulating tubing, and where out- let tubes are used they should be of sufficient length to extend below the insulating joint, and should be so secured that they will not be pushed back when the canopy is put in place. In connection with insulating joints fixture cano- pies of metal should be thoroughly and permanently insulated from metal walls or ceilings, or from plas- ter walls or ceilings on metal lathing, and from out- let boxes. 148 Canopy insulators (see page 151) should be se- curely fastened in place, so as to separate the canopies thoroughly and permanently from the sur- face and outlet boxes from which they are designed to be insulated. For fixtures which are not attached to gas pipes or conduit unless outlet boxes or other approved fittings which will give proper support for fixtures are used, a seven-eighths inch block should be fas- tened between studs or floor timbers flush with the back of lathing to hold tubing and to support fix- tures. When this cannot be done, wooden base blocks, not less than three-quarter inch in thickness, securely screwed to lathing, should be provided. Fixtures having so-called flat canopies, tops or backs, should not be used except where outlet boxes are installed, and for out-door use they should be of water-tight construction. Fixture wires (see p. 104), should be not smaller than No. 18 B. & S. gage, and should have an ap- proved rubber insulating covering. In wiring certain design of show-case fixtures, ceiling bulls-eyes and similar appliances in which the wiring is exposed to temperatures in excess of 1 20 degrees Fahrenheit from the heat of the lamps. approved slow-burning wire shoud be used. Supply conductors, and especially the splices to fixture wires, should be kept clear of the grounded part of gas pipes, and, where shells or outlet boxes are used, they should be made sufficiently large. When fixtures are wired on the outside the con- ductors should be so secured as not to be cut or 149 abraded by the pressure of the fastenings or motion of the fixtures. Fixtures thus wired should not be used in show windows or in the immediate vicinity of especially inflammable stuff. Chain fixtures should be wired with flexible con- ductors. Wires of different systems should never be con- tained in or attached to the same fixture, and under no circumstances should there be a difference of potential of more than 300 volts between wires con- tained in or attached to the same fixtures. Fixture Wires, which may be either solid or stranded conductor, should never be smaller than No. 1 8 B. & S. gage (no wire smaller than No. 14 B. & S. gage should be used in any work outside of fixtures) and should conform to the following table for the wiring of fixtures : B. & S. Ampere Capacity. Gage. Rubber Slow-burning Insulation. . Insulation. 18 3 5 16 6 10 14 15 20 12 20 25 Conductors used in wiring fixtures should be of approved fixture wire, approved flexible cord or approved rubber-covered wire, excepting that ap- proved slow-burning wire. All electrical fittings (including insulating joints, sockets, receptacles, switches, attachment plugs, etc.) should be of approved types. 160 Canopy Insulators should be of approved types. They should be securely fastened in place so as to separate the canopies thoroughly and permanently from the surfaces and outlet boxes from which they are designel to be insulated. Each fixture (after wiring and assembly) should be tested with a magneto which will ring through a resistance of at least 50,000 ohms and show no short circuits between conductors or contacts between con- ductors and metal parts of fixtures. Each fixture should be marked with the manufac- turer's name or trade-mark. Insulating Joints. All a wireman needs to know about an insulating joint is that it is officially ap- proved and bears the maker's name or trade-mark. The same is true of Canopy Insulators. A Macallen Insulating Joint. B Macallen Canopy and Insulating Joint in Position. C Macallen Canopy Insulator. Sockets. In rooms where inflammable gases may exist the incandescent lamp and socket should be enclosed in a vapor-tight globe, and supported on a pipe-hanger, wired with approved rubber-covered wire soldered directly to the circuit. 151 In damp or wet places, or where exposed to cor- rosive vapors, weatherproof sockets especially ap- proved for the location should be used. Unless made up on fixtures they should be hung by separate stranded rubber-covered wires not smaller than No. 14 B. & S. gage, which should preferably be twisted together when the pendant is over three feet long. These wires should be soldered direct to the cir- cuit wires but supported independently of them. Weatherproof Socket for damp places. Sockets and receptacles installed over specially inflammable stuff or where exposed to flyings of combustible material, should be of the keyless type, and unless individual switches are provided, should be installed at least seven and one-half feet above the floor, or should be so located or guarded that the lamps cannot be readily backed out by hand. When the socket is not attached to a fixture, the inlet if threaded should be not less than three- 152 Max. amp. at any Max. amp. at any voltage voltage Watts Volts. Watts. Volts. 75: 125 54 75 125 1 250 250 iy 2 600 250 6 660 250 6 660 660 1500 250 1500 600 eight inch pipe size, and should be provided with an approved insulating bushing. Sockets and Lamp Receptacles. Lamp holding devices are classified according to the diameters of the lamp bases. One-half inch are known as Can- delabra, one inch as Medium, and one and a half inch as Mogul Bases and are rated as in the fol- lowing table: Key. Keyless Nominal Diam. Candelabra J# in Medium 1 " (a) Mogul \y 2 in All sockets and receptacles should be marked with the name or trade-mark of the manufacturer and with the watts and volts which apply to the class. The rating marks may be abbreviated, as, for ex- ample, "250 W., 250 V." Double-ended Sockets. Each lamp holder should be rated as specified above, the device being marked with a single marking applying to each end. All sockets, not attached to fixtures, if with threaded inlet, should be provided with a strong in- sulating bushing. Rosettes for ceiling work, both fused and fuse- less, should have all their current-carrying parts 153 mounted on porcelain, be plainly marked where it may readily be seen after the rosette has been in- stalled, with the name or trade-mark of the manu- facturer, and the rating in amperes and volts. Fuse- less rosettes are rated 3 amperes, 250 volts; fused rosettes with link fuses, not over 2 amperes, 135 volts. Flexible Cord. Where the difference of potential between the two wires is over 300 volts, flexible cord should not be used, nor should flexible cord be used as a support for clusters. It should be used only for pendants, wiring of fixtures, portable lamps or motors, portable heating apparatus or other portable devices. For all portable work, including those pendants which are liable to be moved about sufficiently to come in contact with surrounding objects, flexible wires and cables especially designed to withstand this severe service should be used. When necessary to prevent portable lamps from coming in contact with inflammable materials, or to protect them from breakage, they should be sur- rounded with a substantial guard. Unless provided with approved metal armor, flexi- ble cord should not be used in show windows or in show cases. Flexible cord should be protected by insulating bushings where the cord enters a lamp socket. . It should be so connected to all fittings that strain is taken from the joints and binding screws. When passing through covers of outlet boxes it 154 should be protected by approved bushings especially designed for this purpose. Arc Lamps on Constant-Potential Circuits. Where arc lamps may be installed, although now rapidly being displaced by mazda or tungsten lamps, (see p. 166), a cut-out for each lamp or each series of lamps should be provided. The branch conductors should have a carrying capacity about fifty per cent, in excess of the normal current required by the lamp. They should be furnished with only such resist- ances or regulators as are enclosed in non-combus- tible material, such resistances being treated as sources of heat. Incandescent lamps, however, should not be used for this purpose. All such arc lamps should be supplied with globes and protected by spark arresters and wire netting around the globe. Outside arc lamps should be suspended at least eight feet above sidewalks. Inside arc lamps should be placed out of reach or suitably protected. Lamps when arranged to be raised or lowered, either for carboning or other purposes, should be connected up with stranded conductors from the last point of support to the lamp, when such con- ductor is larger than No. 14 B. & S. gage. Economy and compensator coils for arc lamps should be mounted on non-combustible, non-absorp- tive, insulating supports, such as glass or porcelain, allowing an air space of at least one inch between frame and support, and should in general be treated as sources of heat. 165 Vapor Lamps. Enclosed Mercury Vapor Lamps. Lamps of this kind (see page 167) should have cut-out for each lamp or series of lamps ex- cept when contained in single frame and lighted by a single operation, in which case not more than five lamps should be dependent upon single cut- out. They should only be furnished with such resist- ances as regulators as are enclosed in non-combust- ible cases, such resistances to be treated as sources of heat. In locations where these resistances or regu- lators are subject to flyings of lint or combustible material, all openings through cases must be pro- tected by fine wire gauze. Gas Filled Incandescent Lamps. Mazda or tungsten gas filled lamps (see p. 166) should be so grouped that not more than 660 watts (nor more than 1 6 sockets or 'receptacles) should be dependent on one cut-out except that in cases where wiring equal in size to No. 14 B. & S. gage is carried directly into keyless sockets or receptacles, the location of which is such as to render unlikely the attachment of flexible cords thereto, the circuits should be so arranged that not more than 1,320 watts (or 32 sockets or receptacles) will be dependent on the final cut-out. Where a single socket or receptacle is used on a circuit the limitation of watts on the final cut- out should be the maximum capacity for which such socket or receptacle is approved. Gas filled lamps should not be used in show win- dows or in other locations where inflammable mater- ial is liable to come in contact with lamp equipment 156 except where used in connection with fixtures where temperature of any exposed portion of same does not exceed 200 degrees Fahr. They should not he used in connection with me- dium-base sockets or receptacles if of above 200 watts nominal capacity nor with Mogul base sockets or receptacles if of above 1,500 watts capacity. If of about loo watts, they should not, if provided with a shade, reflector, fixture or other enclosure above the socket, be used in either medium or Mogul base type or sockets or receptacles having fibre or paper linings. Fixtures within buildings should be wired with conductors of slow-burning or asbestos covering where the temperature to which wire is subjected at any point exceeds 120 degrees Fahr. Where fix- tures are placed outside of buildings rubber insulated - wire should be used. Insulation Resistance of Wiring Installation. The complete installation in any building should have a resistance between conductors and between con- ductors and ground not less than that given in the following table : Up to 5 amperes 4,000,000 ohms " 10 " 2,000,000 " 25 " 800,000 " " 50 " 400,000' " 100 " 200,000 " 2OO " lOOjOOO " 400 " 50,000 " 800 " 25,000 " 1,000 " 12,500 157 The test should be made with all cut-outs and safety devices in place. If the lamp sockets, recep- tacles, electroliers, etc., are also connected, only one- circuit Breaker. The New I'-T-E Circuit Breaker with Time Limit Feature. For Approved Makes See page 268. half of the resistances specified in the table will be necessary. TRANSFORMERS Oil Transformers. No transformers of this class should be placed inside of any building except cen- tral stations and sub-stations. Air cooled transformers should not be placed in- side of any building excepting central stations or sub-stations, if the highest voltage of either primary or secondary exceeds 550 volts, and with the excep- 158 tion of bell ringing and other signalling transform- ers, be so mounted that the case will be at a distance of at least one foot from combustible material or separated therefrom by non-combustible, non-ab- sorptive, insulating material, such as slate, marble or soapstone. This will require the use of a slab or panel somewhat larger than the transformer. Decorative Lighting Systems. Decorative Lighting, by which is meant temporary work, should be done with an approved system, such as the Elblight system, and the potential between the wires of any circuit should not be over 150 volts and also provided that no group of lamps requiring more than 1,320 watts shall be dependent on one cut- out. HIGH POTENTIAL SYSTEMS 55 T0 3>5 VOLT s Any circuit attached to any machine or combina- tion of machines which develops a difference of potential between any two wires of over 550 volts and less than 3,500 volts, is considered as a high- potential circuit, and as coming under this class, un- less an approved transforming device is used, which cuts the difference of potential down to 550 volts or less. For 550 volt motor equipments a margin of ten per cent, above the 550 volt limit at the genera- tor or transformer is permissible without coming un- der high-potential systems. All wires for high-potential systems should have an approved rubber-insulating covering, and should be always in plain sight, and never encased. 159 Such wires should be rigidly supported on glass or porcelain insulators, which raise the wire at least one inch from the surface wired over, and should be kept at least eight inches apart. Rigid supporting requires under ordinary condi- tions, where wiring along flat surfaces, supports at least about every four and one-half feet. If the wires are liable to be disturbed the distance between supports should be shortened. In buildings of mill construction, mains of not less than No. 8 B. & S. gage, where not liable to be dis- turbed, may be separated about ten inches and run from timber to timber, not breaking around, and may be supported at each timber only. This class of wiring should be protected on side walls from mechanical injury by a substantial box- ing, retaining an air space of one inch around the conductors, closed at the top (the wires passing through bushed holes) and extending not less than seven feet from the floor. When crossing floor tim- bers, in cellars, or in rooms where they might be ex- posed to injury, wire should be attached by their in- sulating supports to the under side of a wooden strip not less than one-half an inch in thickness. EXTRA-HIGH POTENTIAL SYSTEMS OVER 3,500 VOLTS. Any circuit attached to any machine or combina- tion of machines which develops a difference of potential, between any two wires, of over 3,500 volts, is considered as an extra-high-potential circuit, and as coming under this class, unless an approved trans- 100 forming device is used, which cuts the difference of potential down to 3,500 volts or less. Primary wires carrying over 3,500 volts should No. Fred M. Locke. Suspension Insulators for Extra High Voltages. Insulators for other voltages see page 51. never be brought into or over buildings, except pow- er stations and sub-stations. The secondary wires should be installed under the suggestions given in the preceding section for high- potential system when their immediate primary wires lei carry a current at a potential of over 3,500 volts, un- less the primary wires are installed in accordance with the suggestions given for the construction of constant potential lines of over 5,000 volts as shown on page 63, or are entirely underground, within city, town and village limits. Approval of Apparatus and Supplies. Every ar- ticle or fitting intended for use in electrical wiring or construction or in connection therewith should, be- fore being manufactured or placed upon the market, be submitted to the Underwriters' Laboratories, 207 East Ohio street, Chicago, for examination and re- port. Branch offices are located in thirty-two other cities of the United States and Canada. The New York office, at 135 William street, is equipped for the conduct of examinations and tests of all electri- cal devices under the same conditions as those af- forded at the principal office and testing station in Chicago. The amounts of the fees are in proportion to the nature and extent of the work required in examina- tions and tests. When such article or device is ap- proved and found safe and suitable for the use in- tended, it is placed on the List of Electrical Fittings issued semi-annually by the Underwriters' Labora- tories, for use in accordance with the rules and re- quirements of the National Electrical Code as given in the foregoing pages of this book. When buying electrical supplies of any description make sure that they have been approved, or that their use will be permitted. If there is any ques- tion about it, make your supply dealer, or the manu- 16* .facturer give you a guarantee that they will be ap- proved by the Fire Underwriters' Inspector if in- stalled in accordance with the rules and requirements of the National Electrical Code. Electrical Inspection. The principal points re- garding the safe installation of dynamos, motors, heaters and outside and inside wiring, as required by the insurance underwriters, have been briefly set forth in this little book, which has been compiled simply for reference and not as a teacher : a book designed to settle most of the doubtful questions which might arise in the mind of the engineer or contractor as to just what will be considered safe by insurance inspectors. There will probably arise questions which cannot be settled by reference to the suggestions herein contained, and, therefore, a great deal has to be left to the judgment of the construct- ing engineer and inspector. In every such case the Inspection Department having jurisdiction should be consulted with perfect assurance that nothing un- reasonable will ever be demanded in the way of spe- cial construction. Every piece of wiring or electrical construction work, whether open or concealed, should be in- spected, and notictf, therefore, should always be sent by the contractor or engineer to the board having jurisdiction immediately upon completion of any work. Negligence in this matter has frequently caused floors to be torn up when doubtful work has been suspected, and at the cost to the contractor. 163 LIGHT AND ILLUMINATION Light and Illumination are two distinctly dif- ferent things. Light is the raw product with which we work. It is produced in many ways that differ greatly in quantity and quality. By the application of light itself, or combined with various reflecting, refracting, absorbing or diffusing equipment, illumi- nation is obtained as a result. The general principles of light should be clearly understood, that illumi- nation may be intelligently brought about. Light. Light is radiant energy. It varies in color, intensity and direction. Candle Power is the Unit of Intensity of Light and is measured by comparison with a definite specified standard. The ordinary method of rating an incandescent lamp is Mean Horizontal Candle Power. It is the average intensity of light given out by the lamp in a horizontal direction when the lamp is hanging vertical. This does not give a true value of the candle power of the lamp, as few incandescent lamps radiate the same amount of light in other di- rections than the horizontal. The Mean Spherical Candle Power of a lamp is the average intensity of light in all directions about the lamp. It is usually less than the Mean Horizontal Candle Power, de- pending upon the characteristics of the individual lamp. If the Mean Horizontal Candle Power is known, the Mean Spherical Candle Power can be ap- proximated by multiplying by what is called the Reduction Factor of the lamp; of the standard Mazda "B" lamp this Reduction Factor is about .78 ; with a gas-filled Mazda "C" lamp, the Reduction Factor is about .90. Both Candle Power terms refer 1*4 only to average intensity of light, but do not give the measurement of a total quantity of light from a lamp. The Unit of Quantity of light in one Lumen. The total quantity of light from a lamp is 12.57 times its Mean Spherical Candle Power. The effi- ciency of the lamp is expressed in terms of a quan- tity of light produced in lumens and the power in- put. This gives a rating according to Lumens per Watt. Method of Producing Light. The three most common methods of producing light commercially, are Arc Lamps, Vapor Lamps and Incandescent Lamps. The first two are widely used for certain classes of work and to cover special conditions. The Incandescent Lamp, however, is the most common and easiest used, on account of the great variety of sizes and forms available. Incandescent Lamps are produced in the fol- lowing classes: Carbon Filament, burning in vacuum. Metalized Filament, burning in vacuum. Tantalum Filament, burning in vacuum. Tungsten Filament, burning in vacuum. Tungsten Filament, burning in inert gas. The first three classes of lamps are rapidly being superseded by the last two classes. The Tantalum Lamp was a great step in advance over the Carbon Filament and Metalized Filament, but the Tung- sten Filament or Mazda Lamp followed so closely that little progress was made. It has practically been eliminated from the market. 105 Illumination is the result of application of light, with light itself, or with equipment to assist in the MAZDA B LAMPS (VACUUM) Volts Watts C. P. W. P.C. Amps. Hot Res. 110 10 7.7 1.30 0.0909 1210.0 " 15 13.0 1.15 0.1363 807.0 " 20 18.2 1.10 0.1818 605.0 " 25 23.8 1.05 0.227 484.0 " 40 38.8 1.03 0.364 302.5 " 60 60.0 1.00 0.546 201.7 " 100 105.0 .95 0.909 121.0 " 150 150.0 1.00 1.363 80.7 " 250 2G3.0 .95 2.272 48.4 Volts Watts C.P. W. P. C. Amps. Hot Res. 220 25 19.2 1.20 0.1130 1936.0 M 40 33.3 1.12 0.1818 1210.0 60 50.0 1.10 0.273 807.0 " 100 90.9 1.00 0.455 484.0 ' 150 143.0 1.00 0.682 322.6 " 250 250.0 .95 1.136 193.6 MAZDA C LAMPS (GAS FILLED) Watts per Total Spherical Volts Watts Lumens Candle Amps. Hot Res. 110 200 2795 .90 1.82 60.5 100 1257 1.00 0.909 121.0 300 4600 .82 2.73 40.3 400 6130 .82 3.64 30.3 500 8060 .78 4.55 24.2 M 750 12740 .74 6.82 16.1 " 1000 17960 .70 9.09 12.1 Total Watts per Volts Watts Lumens Sph. C. P. Amps. Hot Res. 220 200 2514 1.00 0.909 242.0 300 4100 .92 1.36 161.2 400 5590 .90 1.82 121.2 500 7395 .85 2.27 96.8 750 11500 .82 3.41 64.5 " 1000 16120 .78 4.55 48.4 For comparative sizes see page 169. distribution, direction and diffusion of light. The Unit of Intensity of Illumination is One Foot Can- 166 MAZDA' LAMP VARIATIONS 9 'o Change in Voltage % C. P. % Watts % C. P. % Watts Mazda B Mazda B Mazda C Mazda C (Vacuum) (Vacuum) (Gas Filled) (Gas Filled) 10 9 39.3 35.0 16.3 14.6 36.3 32.3 15.9 14.3 8 30.7 12.9 28.4 12.7 4) 7 11.8 24.6 V 11.2 03 Cfl 20.8 9.5 u 5 8 18.6 9 8.0 B 17.2 ft 7.9 C 4 o C 14.7 o C 6.4 o 18.6 s 6.2 3 CH 10.9 4.8 t i 10.1 t-i 4.7 2 7.2 3.2 6.6 3.1 1 3.6 1.6 3.3 1.6 Normal 1 3.5 1.6 3.3 1.6 2 6.9 3.1 6.4 8.0 3 10.2 n 4.7 9.5 4.6 55 4 18.4 9 6.2 u 12.5 6.0 nj 6 s 16.6 2 7.8 a 15.5 % 6.5 u 6 s 19.7 o 9.3 s 18.2 a 9.0 W 7 Q 22.7 Q 10.9 21.0 10.4 ^ 8 25.6 12.4 Q 23.8 V p 12.0 9 28.5 13.9 26.4 13.3 10 31.3 15.4 29.0 15.0 COOPER HEWITT LAMP UNITS DIRECT CURRENT Type Watts Length of Tubes, ins. Candle Power i Watts >er Candle H . 192 21" 300 64 Double H 385 2-21" ea 600 64 K 385 45" 700 55 P 385 50" 800 48 ALTERNATING CURRENT (60-cycle, 95-125 volts) 365 50" 800 .46 Power Factor COOPER HEWITT QUARTZ LAMP DIRECT CURRENT Y for 110 volts 418 Z for 220 volts 725 1000 2400 .40 die. This is the amount of light falling on a sur- face of one square foot area, every part of which is a distance of one foot from a source of light of one 167 candle power. The quantity of light falling upon this surface under these conditions is one Lumen, thus the application of one Lumen of light to an area of one square foot will produce a resulting il- lumination of one foot candle. An approximate idea of this intensity of illumination can be obtained by hanging a 25-W Mazda "B" Lamp in a vertical posi- tion, then the light falling upon the vertical surface, held about four feet ten and a half inches away from this lamp, will result in illumination intensity of one foot candle. The source of light is very seldom such that the light radiated will result in illumination where it is desired, or is it possible to place the source of light where good results would be obtained. It is there- fore necessary to use various types of equipment to re-direct the light where it is desired and in such a manner that it will be most useful. The equipment may reflect, refract or diffuse the light, or may com- bine these, but the result produced, namely the il- lumination, should be such that best results would be obtained for the conditions. In planning illumina- , tion the following general principles of good illumi- nation should be kept in mind. The amount of illu- mination should be sufficient for the requirements of the surface lighted. The intensity of illumination should be fairly uniform. The lamps should be so placed that they will give the above results and also so that they will not be in direct range of vision un- der normal conditions. The equipment used with the lamps should be such that the eye is protected from a direct view of the filament under all normal con- ditions. When practical, extreme contrast between 168 Comparative Sizes of Mazda 01 Tungsten Lamps. S-Vacuum Filled PS-Gas Filled MAZDA 1 B COIL 25 AND 40 WATTS 105-125 VOLTS PS-25 100 WATTS 105- 125 VOLTS S-21 60 WATTS 105-125 VOLTS 220-250 VOLTS S-17 10, 15 AND 20 tf lOS^sToLTS S-19 25 AND 40 WATTS 105-125 VOLTS PS-40 400 AND 500 WATK 105-125 VOLTS 750 AND 1000 WATTS 105-125 VOLTS 169 sources of light and immediate surroundings should be avoided. In order to obtain proper results as to distribution, outlets should not be placed further apart than twice the possible mounting height of lamps. This applies to all systems of interior light- ing and especially to direct lighting. Interior illumination can be divided into three classes according to the appliances used and the method of transmitting the light to the working plane. These are direct lighting, indirect lighting, and semi-indirect lighting. With Direct Illumination the source of light is comparatively small and of high candle power inten- sity. When proper equipment is used this form of illumination is most efficient. Excellent control and distribution of light can be had. The efficiency of direct illumination under normal conditions, will vary between 40 per cent, and 50 per cent, although in special cases, with the best Opaque Reflectors, as high as 65 per cent, of light generated by the lamp reaches the working plane. With direct lighting most of the illumination on the working plane is re- ceived directly from the source of light. A small percentage of this light may, however, be reflected from walls or ceilings. As a result, sharp shadows and reflections from shiny objects are liable to occur. There is liable to be a certain amount of glare. As a result eye efficiency is reduced. The efficiency of various systems of direct lighting are approximately as follows : One-piece Mirror Glass Reflector 65 per cent. Clear Prismatic Reflectors 55 Heavy Density Opal Reflectors 45 170 Aluminized Metal Reflectors 45 per cent. Medium Density Opal Reflectors 40 " Satin Finished Prismatic Reflectors. ... 40 " Porcelain Enameled Steel Reflectors .... 40 " Opal Enclosing Globes 35 " Bare Lamps 28 " These figures are for average conditions, with deep bowl type reflectors and medium colored floor, walls and ceiling. In very large areas with light walls, and ceiling these figures will be increased 5 per cent, to 10 per cent. Indirect Illumination. With indirect illumina- tion practically all of the useful light is received from the ceiling and a small amount from the walls. The primary source of light may be contained in bowl fixtures, cornices, floor pedestals or brackets. The secondary source of light is a large area of the ceiling, the foot candle intensity of which is low. As a result the light is very well diffused and uni- formly distributed, although the efficiency is less than the direct lighting. For successful results it is ab- solutely necessary that the most efficient reflectors be used to throw the light on the ceiling in ordr that the total efficiency may be the highest possible. One- piece mirrored glass reflectors are the standard equipment for such work, although enameled steel reflectors are also used. It is also necessary that the ceiling be of a very light color, either light ivory, light cream or white being preferable. The color of the side walls is not so important, although most sat- isfactory results are obtained with medium color on the side walls, especially up to eight or ten feet from 171 the floor. Under these conditions and with mirrored glass reflectors efficiency will vary between 28 and 39 per cent. Indirect Illumination is especially desirable where sharp shadows, .reflections from shiny objects or glaring light sources are found to be annoying. The actual eye efficiency is highest under this method of artificial illumination. There is less eye strain and eye fatigue than with direct lighting or semi-indirect lighting where the efficiency is high. In planning installations of indirect illumination, the manufacturer's data, which is easily available, should be followed closely. Semi-Indirect Lighting. Semi-indirect illumi- nation is generally considered as lighting by means of lamps placed in opalescent glass bowls. These vary greatly in density and amount of transmitted light through the bowl, so that many of them, especially those showing the highest efficiency, are quite the same as direct lighting with enclosing diffusion globes. General engineering practice has set a stand- ard that requires less than 50 per cent, of resulting illumination to be received direct from the bowl, or source of light, in order to be classed with semi-in- direct illumination. The efficiency of this method of lighting will vary between 30 and 40 per cent, de- pending upon the density and shape of the bowls and color of walls and ceiling. With this method of lighting the harsh effects of direct illumination are greatly reduced, the shadows are not so intense and because of the amount of light reflected from the ceiling, there is a better diffsion. There is slightly less eye strain and fatigue than with direct illumi- nation, but the advantage is not so great as with in- direct lighting. The efficiency figures given above refer to the amount of light received at the working plane, as compared with the amount of light generated with- in the lamps. The working plane is normally the average desk or counter height, thirty or thirty-six inches from the floor. Knowing the quantity of light or total lumens generated by the lamps, and the efficiency of the system of lighting, the average lumens received on the working plane can be esti- mated. One lumen per square foot results in illumi- nation of one foot candle. On the other hand, if the desired illumination on the working plane is known, and also the efficiency of the proposed system of lighting, the total lumens necessary at the lamps can be estimated and from this the number and size of lamps determined. The following table shows the required illumination for various classes of service. These are average figures and will vary according to individual requirements. Illumination Required for Various Classes of Service Service Foot Candles. Armory 2-3 Auditorium 1-3 Automobile, Garage 2-3 Automobile, Showroom 4-6 Ball Room 2-3 178 Required Illumination (Continued) Service. Foot Candles. Bank 3-4 Billboard 5-15 Billiard Room, General 1-2 Billiard Room, Table ... 5-8 Bowling Alley, Pins 4-0 Bowling Alley, Alley i-o Barber Shops* 3-5 Cafe 2-4 Cars, Street 2-3 Court, Tennis 5-8 Court, Handball 5-8 Church 1-3 Corridor -5-i-5 Court Room 2-4 Desk* 4-6 Draughting Room* 7-10 Gymnasium 1-3 Hospital, Operating Table 12-18 Hospital, Ward " 1-2 Hotel, Dining Room 1-4 Hotel, Guest Room 1.5-2 Hotel, Lobby 2-4 Hotel, Writing Room 2-4 Library, Reading Room* 3-4 Library, Stack Room 1.5-2 Lunch Room 2-4 Market 2-4 Moving Picture* O-S" 1 ^ Museum 2-4 Office* 4-5 Power House ...-..- 2-3 174 Required Illumination (Continued) Service. Foot Candles. Residence 1-2 Restaurant ' 2-5 School* 3-4 Show Window 10-40 Stock Room 0.5-2 Store, Clothing 4-7 Store, Drug 4-6 Store, Dry Goods 3-6 Store, Furniture 2-3 Store, Grocery 3-5 Store, Jewelry 4-7 Store, Shoe 3-5 Store, Tobacco 3-5 Theatre 1-3 Warehouse 0.5-2 Wharf -5-i-5 * Some form of Semi-indirect or Totally Indirect lighting par- ticularly desirable. Show Window Lighting. This special field of lighting requires attention especially fitting its con- ditions. The sources of light should always be hid- den from view. They should be located in the front of the window close to the glass and should be mounted either at the ceiling of the window or from the transom bar. Special reflectors are received giv- ing a distribution of light particularly adapted to flooding the window with strong illumination, but preventing light being wasted through the window on the sidewalk or on the top of the window. In- dividual reflectors are best equipment for this work, 176 the most efficient being one-piece mirrored glass re- flectors, followed closely by special prismatic glass reflectors. In general, lamps used for show window lighting should be either 60- Wor lOO-W Mazda "B" Lamps, or loo-W Mazda "C" Lamps. Most standard equipment is for use with these lamps. Under special conditions for very small windows or limited space, tubular lamps or special small lamps may be used. The number of lamps required for show window lighting can be estimated from usual practice, which varies between five and ten watts per square foot for floor area in the window. Win- dows with dark trimmings and dark goods on display require more light than those in which light colors predominate. The following formulae will be of assistance in calculating illumination : C.P. , Candle Power. M.H.C.P. = Mean Horizonal Candle Power. M.S. C.P. = Mean Spherical Candle Power. R.F. = Reduction Factor (Expressed as decimal). W. = Energy in Watts. L. = Total Lumens. L(e) c= Lumens effective at working plane. LperW = Lumens per Watt (Measure of Lamp Efficiency.) Wper CP c= Watts per Candle Power. Ft.Cd. = Illumination (lumens per square foot). W =CP. x (W per C.P.) 170 w W. per C.P. = - C.P. Candle Power of a W lamp (M.H.C.P.) = W. per C.P. M.S.C.P. != M.H.C.P. X R.F. Lumens of Lamp = W X (Lumens per W.) Lumens of Lamp = M.S.C.P. X I2 -57 M.H.C.P. X R.F. X 12.57- L Efficiency of Lamp =, Lumens per Watt == W Total Lumens available = L. per W. : X W X No. of Lamps. L(e) z= L X Efficiency of Lighting System. L(e) L X Eff. of System Ft. Cd. = - Sq. Ft. Sq. Ft. (Area to be lighted) L(e) = Ft. Cd. 'X Sq. Ft. Efficiency of Lighting System L(e) FtCd. X Sq.Ft. L Total lumens of lamps Ft. Cd. X Sq.Ft. M.S.C.P. X 12.57 X No. Lamps. 17T HOUSE WIRING. Special Suggestions and Recommendations to the House Owner, Architect, Contractor and Wiremaw, with the co-operation of the Wiring Committee of the Commercial Section of the National Electric \Light Association and the So- ciety for Electrical Development, in Accordance with the Rules and Requirements of the Na- tional Board of Fire Underwriters. Obtaining Service. In every case where the electric wires have not been introduced into a house, it is necessary to con- sult the central station as to the terms on which service can be obtained. When the wires are not even on the street it will always be necessary for the central station to make an extension, involving additional mains, as the electric wires in the street are called, and usually additional poles for overhead wires, or digging for conduits for underground wires. It may be noted here that the current for trolley service is not suitable for house lighting, nor is such service allowed by the insurance interests in any part of the country. No one but the central station representative can determine the cost of making an extension, and all that can be said in this general treatise is that some- times the central station will extend its wires with- out any guarantee, on the chance that the new busi- ness will be profitable. In other cases the prospec- tive customer is asked to guarantee a definite in- come for a term of years, or to make a deposit 178 towards the cost of the extension, to be returned out of the income ; or in extreme cases, even to paj the whole cost. Each case has to be considered separately; but in this country a somewhat general rule is to make extensions when the annual income, either estimated or guaranteed, is equal to about half the cost of the additional investment, or cost of the extension beyond the point to which the lines have been already built. In regard to whether the service is overhead or underground, this usually depends on the character of the neighborhood, dense city districts being sup- plied underground, and suburban or country dis- tricts overhead. If in a district where the wires are underground, the central station extends the mains along the street, and usually branches from the mains to the lot line without further charge for the branch. Sometimes the street construction is such that the house service comes from the wire directly oppo- site. In other cases there are manholes in the street at convenient intervals, and the wires run directly from such manhole to the house. Sometimes a charge is made by the central sta- tion for the whole of the branch to the house, but more usually there is no charge for the work in the public streets, and often the wire is carried free to the house wall, especially if the house is close to the street. If, however, there is a wide lawn a charge is often made, running from 75 cents to $1.50 per foot, according to circumstances. In the case of new houses it is often convenient to use the 179 same trench or conduits for the telephone wires also, and sometimes even for the water pipe. As the central station will always either do this underground work itself or furnish definite and complete specifications, no further reference need be made to it here. In the case of overhead wires questions about the extension of the central station wires in the street come up. The householder should appreciate that overhead wires are installed only in districts where the cost of underground is prohibitive, so that if the central station cannot obtain the right to set the necessary poles in such districts it may not be able to extend the wires at. all. When the necessary poles are near enough the central station will usually run the wires from the pole to the house without further charge. In other cases, as when the house sets far back, or when for some special reason the wires have to enter the house in the rear, it may be necessary to set poles on the private property, for which work the central station will frequently make a charge, which should run from say $10 to $50, about $25 for each pole together with the wire, cross arms, insulators, etc. Of course, when the customer is willing to pay for it, the central station will run its wires down the pole into the ground and supply the house by an underground service, even in overhead districts. The Code rules governing outside work for both overhead and underground are as follows:; a. Line wires must have an approved weather- proof or rubber insulating covering (see p. 78). 180 That portion of the service wires between the main cut-out and switch and the first support from the cut-out or switch on outside of the building must have an approved rubber insulating covering, but from the abov0-mentianed support to the line, ex- cept when run in conduit, may have an approved weatherproof insulating covering if kept free from awnings, swinging signs, shutters, etc. b. Line wires must be so placed that moisture cannot form a cross connection between them; must be not less than one foot apart except when in con- duit or in the form of multiple conductor cable; must not be in contact with any substance other than their insulating supports. Multiple conductor cables must be secured to strain insulators spaced not less than one foot from any adjacent woodwork and in turn secured to petticoat or strain insulators by strain wires. For conduit work, wires must be placed so as to conform to rules for unlined conduit except that conduit system must be waterproof, (see p. 129). c. Must be at least eight feet above the highest point of Hat roofs (see p. 53) and at least one foot above the ridge of pitched roofs over which they pass or to which they are attached and roof struc- tures must be substantially constructed. Wherever feasible, wires crossing buildings should be sup- ported on poles independent of the buildings. d. Must, where exposed to the weather, be pro- vided with petticoat insulators of glass or porce- lain (see pp. 51 and 161) ; porcelain knobs or cleats and rubber hooks will not be approved. Wires on the exterior walls of buildings must be supported 181 at least every fifteen feet, the distance between sup- ports to be shortened if wires are liable to be dis- turbed. Where not exposed to the weather, low poten- tial wires may be supported on glass or porcelain knobs which will separate the wires at least one inch from the surface wired over, supports to be placed at least every four and one-half feet. e. Must be so spliced or joined as to be both mechanically and electrically secure without sol- der (see p. 50). The joints must then be soldered, to insure preservation, and covered with an insula- tion equal to that on the conductors. All joints must be soldered, unless made ivith some form of approved splicing device (see p. 50). /. Must, where they enter buildings, have drip loops outside, and the holes through which the con- ductors pass must be bushed with non<- combustible, non-absorptive, insulating tubes slanting upward toward the inside. For low-potential systems the service wires may be brought into buildings through a single iron con- duit. The conduit to be equipped with an approved service-head (see pp. 52 and 54). The inner end must extend to the service cut-out, and if a cabinet is required by the Code must properly enter the cabinet. Metal conduits containing service wires must be insulated from the metal conduit, metal moulding, or armored cable system within the build- ing and all metal work on or in the building or they must have the metal of the conduit permanently and effectually grounded to ivater piping, gas piping or other suitable grounds, provided that when connec- 189 tions are made to gas piping, they must be on the street side of the meter. This ground connection to be independent of and in addition to any other ground wire on metal conduit, metal moulding or armored cable systems within the building. If conduit, couplings or fittings having protective coating of non-conducting material such as enamel are used, such coating must be thoroughly removed from threads of both couplings and conduit, and such surfaces of fittings where the conduit or ground clamp is secured in order to obtain the requisite good connection. Grounded pipes must be cleaned of rust, scale, etc., at place of attachment of ground clamp. Connections to grounded pipes and to conduit must be exposed to view or accessible, a/nd must be made by means of approved ground clamps. Ground wires must be of copper, at least No. 6 B. & S. gage (where largest ^vire contained in con- duit is not greater than No. o B. & S. gage), and need not be greater than No. 4 B. & S. gage (zvhere largest wire contained in conduit is greater than No. o B. & S. gage). They shall be protected from me- chanical mjury. g. Electric light and power wires must not be placed on the same cross-arm with telegraph, tele- phone or similar wires, and when placed on the same pole with such wires the distance between the two inside pins of each cross-arm must not be less than twenty-six inches. h. The metallic sheaths of cables must be per- manently and effectively connected to . Switch for lighting Fixture A volt receptacle in which case the appliance would probably be destroyed to say nothing of the fire hazard involved. Receptacles for lighting purposes are usually no volts. In addition to the lighting receptacles which are usually installed for reading lamps, piano lamps, sio etc., there should be one or two spare receptacles in each main room and hall. One of the receptacles in main living room or hall should be placed so as to be near a suitable location for a Christmas tree, so that this may be illuminated without unsightly wires showing in the room. A porcelain lamp receptacle, mounted in a con- dulet or outlet box, is often placed under the 1 1 1 1 TT 8$ X Bracket Outlet for 2 f^\ S, R Outlet for ' ' s - Tf Piano Player, J. Incandescent Lamps xU 50 Watt each equivalent Vacuum Cleaner Special Floor Outlet for Heating and Cooking (J? p-, Table Bell Push-to . 1 LlJ Kitchen Annunciator FJJ LIVING ROOM x > \ A S| ^ , . Outlet for Moving Picture ^ Ceiling Outlet for 4 ^ .a -m Lamp. Tea Table. Toaster, CO Incandescent Lamps ^^ Tea Pot, Coffee Percolator ^ 50 Watt each equiva- j| | V ^ , \ Outlet for Pan, Cigar \ /Lighter, Portable \ / Lamp, etc. I* J See B ^^--'S 3 r2l Q See B 1 ll S 3 ' 3-Way Switch for lighting ' .Fixture A from either Side of Entrance kitchen range-hood and the conduit run around under the hood to the side wall where the control- ling switch is located. Outdoor Decoration Receptacles. Art. I9b: A waterproof receptacle and plug should be located outside the main entrance, con- 911 trolled by a switch in hall for step and walk can- opy lighting. A similar receptacle and plug may be placed high up on pillar or wall of porch for electric decora- tions. These receptacles should be on a separate circuit from panel and controlled by a switch at porch door. To Pantry 3_\v a y Switch Outlet for lighting I ^.---'^ Fixture B in Pantry ""~^ ---^ ,1 SeeB 3 3- Way Switch Outlet Y-X R V for lighting Fixture A *-* \ Bracket Outlet for 2 \ Incandescent Lamps \ 50 Watt each equivalent \ Special Flooi Outlet \ /for Electric Cooking \ r Toaster, Egg Boiler, i; \ (S^\ Chafing Dish, Percolator Serving 1 ^t r^-. Table Bell Push to | A ' -" Kitchen Annunciator hn Outlet for Elec. "til Serjving Tray, Dr{nk Mixer v Ceiling Outlet for 4 Incandescent Lamps 50 Watt each equivalent Table { ' \ < DINING \ROOM \ Special Outlet for \ Heater, Fan, \ Vacuum Cleaner, SeeB \ etC ' / y-^( sX7XSee /X\^ >A< 3- Way Switch Outlet for S" ^*J. R ^> I -L . lic-htiiie- Fixture A J E -"- ' Push to Annunciator rvi in Kitchen " ' Porch Receptacles. Art. igc: The living porch should have one or more flush wall receptacles placed in the side wall twelve or fifteen inches above the floor (to prevent water splashing on them). These receptacles for use of reading lamp, chafing-dish, percolator, etc. 212 Bedroom porches may have a similar receptacle for reading light. Servants' or kitchen porches should have a re- ceptacle pilot light and switch (see Art. 18), so that ironing may be done on the porch in hot weather. Shettld-a receptacle should be on a separate circuit. Mantel Receptacles. Art. ipd : Receptacles for mantel candles may be placed in the wall just above the shelf, or, where the design will permit, in the shelf itself. These Ceiling Outlet for 2 ncandescent Lamp!, . 50 Watt each (2)B equivalent PANTRY Outletfor Water Sterilize Ceiling Outlet for 2 ^ Incandescent Lamps \ 50 Watt each equivalent -s 1 Special Heating Outlet for Hot Water Heater, / Bath Room Heater * Ls.p.switdNBATH ROOM \for lighting - Fixture A Bracket Outlet for 2 Incandescent Lamps valent Outlet for Vibrator, Hair Dryer, Shaving Mirror, Elec. Bath \2\ Cabinet receptacles should be controlled by a switch at con- venient location. Bed Receptacles. Art. 196 : Two receptacles, one for reading lamp and one for heating pad or similar sick room appli- ance, should be placed at the side of each bed and 213 connected to iio-volt lighting circuit. These may both be in the same outlet box and covered with one plate. Alongside of this equipment but not in con- tact with same, may be placed a bell receptacle with removable portable cord and hand "pear push" for bell call. This bell receptacle and plug must be of entirely different design from the two before men- tioned so that by no possibility may the bell plug be attached to either of the other receptacles. These tlet for Sewing Machine Motor Vacuum Cleaner Bracket Outlet for 2 Incandescent Lamps 50 Watt each equivalent SEWING ROOM Outlet for -J2J Fan, Iron O< Ceiling Outlet for 3 i,j_X Incandescent Lamps 50 Watt each equivalent Push to Kitchen p-i Annunciator i r bell portables are connected to the same bell wires as the wall push button at door, so that either point rings the same bell or drop on the annunciator. Floor Receptacles. Art. ipf : Where receptacle outlets come in the floor, they should be placed in specially designed floor boxes which have cone shaped tops projecting above the floor to prevent water entering the box and to protect the wires. When these portables are 214 not in use, the cone top can be removed and a flush top substituted. Stereopticon Receptacles. Art. 20: Stereopticon and moving picture ma- chines are now made for home use. The recep- tacles for some have a larger capacity than those for lighting and are usually placed at the end of the long living room or hall. They should be connected to no-volt power and by means of two No. 8 wires. Vacuum Cleaner Receptacles. Art. 21 : Flush receptacles for portable vacuum cleaners should be so located that the thirty to fifty feet (30 to 50') of cord that goes with the cleaner will enable the operator to reach all parts of the house. They should be so arranged that the plugs are not interchangeable, except for the very small type as explained in Art. ipa. The momentary rush of current with many of the larger portable vacuum cleaners would blow the fuses of small cir- cuits and it is advisable to put these receptacles on a separate No. 12 wire, and as but one point is used at a time, all the vacuum cleaner receptacles in the residence may be placed on the same circuit. Dining Room Special Front Outlet. Art. 22: There should be a receptacle and cuitlet box placed in the floor under the dining-room table, a little off the center, so as to clear the center leg of table. This should be fitted with a removable plug connected to permanent table wiring (which is car- ried up the center leg of the table along the under framework and out on the crossbars, where the wir- ing should terminate in three no-volt fused power 215 receptacles. One of these may be used for electric chafing-dish or egg boiler, one for electric toaster and one for electric coffee percolator. This enables the housewife to use the above appliances and dis- connect and remove them as desired, without reach- ing to the floor and with practically no exposed connections, except the short ones over the edge of the table. The three receptacles under the edge of the table may, if desired, be mounted in a neat box to match the woodwork. (See Dining Room, p. 212.) Other Power Receptacles. Art. 23 : Flush receptacles for power and heating appliances are of sizes depending on capacity, but for most residence work, the standard 660 watt receptacle and plug manufactured by many com- panies, is satisfactory in the great majority of cases. For different classes of apparatus and voltage, these receptacles should not be interchangeable (see Art. ipa). For use with heating or similar appliances, they should be in connection with pilot lights and switches, as explained in Art. 18. This type of combined switch and receptacle should be used for laundry and pressing irons (and provision should be made at ironing table to hold up the cord con- necting the iron). A laundry iron receptacle should always be placed to the right of the laundress. Cellar Lighting. Art. 24: Usually 10 or 15 watt lamps are suf- ficient for cellar lighting except in case of work bench or lathe, which should be brightly lighted by 25 watts or 40 watt lamps. (See pp. to .) . Outlets should be so located as to illuminate 216 sinks, furnaces and any pumps or apparatus that need attention. Store rooms and vegetable rooms should be well lighted from ceiling with controlling switch at door. The wine room switch should pref- erably be placed outside the door, so that the room may be inspected through glass or grating of door without unlocking. There should be at least one outlet in cellar con- trolled, by pilot switch at the head of the stairs (see Art. I5e), and where there are few lights in the cellar it is sometimes advisable to put all on such a switch. (See Cellar, p. 208.) Porch Lighting. Art. 25 : Porches are usually lighted from ceil- ing outlets controlled by a switch at porch door with receptacles for reading lamps, etc. (See Art. ipc. (See Porch, p. 209.) Room Lighting. Art. 26: In addition to mantel lights (see Art. igd), side or ceiling lighting should be so designed as to properly illuminate all portions of a room (see pages 164-177), in such a manner as to allow the shifting of furniture from time to time without destroying the harmony of the interior. For this reason residence outlets should not be limited to the fewest possible permissible with the original furniture layout, but should be planned with a view of any re-arrangement of furnishings. Outlets not needed with first scheme may be capped until re- quired. For economy as well as for convenience, room lighting should be controlled by switches (see Art. I5a). Most rooms require one or more recep- tacles for portable lights (Art. 19). 217 A cigar lighter may be placed on the lighting cir- cuit of den or living room. It uses very little cur- rent and does away with burnt matches. It needs no switch beyond the self-contained one. WIRING DIAGRAMS FOR FLUSH SWITCHES POINT 3 POINT! 3 POINT* 4 POINT CONNECTIONS: t. 2. 3. OFF ! SPEED FAN MOTO Dining room the table should be well lighted by ceiling domes or showers. For bedrooms, in addition to the above room lighting, there should be a receptacle for desk lamp and there should also be a reading lamp at bed. (See Art. 196.) Hall Lighing. Art. 27 : Halls require a soft general illumina- tion and the addition of portable table and vase 218 lights is often advantageous. In addition to the wall switches for the regular lights, there should be up and down control between floors as mentioned in Art. i5b. (See Hall, p. 205.) Pantry Lighting. Art. 28: The pantry should be well lighted from a high center outlet so that contents of dress- ers and cupboards may easily be seen and this out- let should be controlled by a switch. (See Pantry, P- 213.) WIRING DIAGRAMS FOR SURFACE SWITCHES CONNECTIONS. i O , 3 CIRCUIT ELECTROLIER CONNECTIONS 1, 1*2. 142*3, OFF. ELECTROLIER* 3 SPEED FAN MOTOR. CONNECTIONS 1. 2. 3. OFF. Kitchen Lighting. Art. 29: Kitchens are generally lighted from ceiling outlet controlled by switch at door. When, however, there are appliances around side wall at 219 which the cook works, there would be a shadow if only the center fixtures were used, and side out- lets should be added at such points and at the sink. The range-hood should have a light under same, as detailed in Art. ipa. (See Kitchen, p. 209.) Laundry Lighting. Art. 30: Laundries are usually finished in light color and need comparatively little general illumina- tion from ceiling fixture controlled by a switch at door. A drop light should be provided at ironing table and a side light at laundry machine. (^See Laundry, p. 209.) Bath Room Lighting. Art. 31 : Most bath rooms may be well lighted by means of a 2-light ceiling fixture or side outlets placed over the mirror, the fixtures projecting 8 to 15 inches from wall and with two inverted lights in such position as to light top of head and each side of face, controlled by a switch at door. Bath room lights should never be so placed as to throw the shadow of anyone in the room on the window shade. (See Bath Room, p. 213.) Sewing Room Lighting. Art. 32 : The general illumination of the sewing room may be from the ceiling with switch control. Side lights should be installed to brightly illuminate the sewing machine and cutting table and also the chair used for hand sewing. An outlet for electric pressing iron (see Art. 32), should be installed and when the room is used in hot weather an electric fan adds to comfort. An 8-inch fan takes very lit- tle current 20 to 40 watts, and can be used on lamp socket. (See Sewing Room, p. 214.) 220 Closet Lighting. Art. 33 : Closet lights are desirable unless room fixtures are so placed as to illuminate them. Es- pecially is this true of storage and servants' closets as it insures cleanliness. Closet lights should be controlled by wall or door switches. (See Art. I5d.) (See Closet, p. 206.) Play Room Lighting. Art. 34 : The play room should be brightly lighted from the ceiling and controlled by a switch at door. This will prevent accidents to or from low side fix- tures. The play room should also be wired for use as a bedroom with side lights and receptacles with outlets capped up for future use. If receptacles for play toys are installed they should be of such a character as not to permit the toys being connected to other outlets. Servant Room Lighting. Art. 35: It pays to light servants' room from high ceiling lights designed for wide distribution of lighting and install switch at door for control of same. The lights will be thus used more econom- ically and the fixtures cannot be carelessly mis- handled. Workshop Lathe. Art. 36 : Many owners like to provide a small workshop for their own use. A small wood turn- ing lathe can be operated by a motor consuming about 200 watts. This lathe may be controlled by either a motor starter and switch, or by means of a switch only, as detailed in An. 16. (See Cellar.) 221 House Pump. Art. 37 : Where city water supply is not available and a well is used, a tank located on roof or attic can STANDARD PANEL Two wire mains, and not more than 16 lights to be con- trolled. 3 POINT SWITCH Method of wiring for burglar lighting 2 wire. be filled by electric pump. The well pipe may be from i^-inch diameter up, depending on the quan- tity of water needed. The motor may be controlled by hand or it may be automatic in action, as noted in Art. 17. (See Cellar, p. 208.) If wiring is installed a double throw switch is 222 usually placed in the basement or at the pump to permit hand operation so that tests may be made from time to time to see that everything is working satisfactorily. Water cocks may be placed around the lawn and water pumped through them directly STANDARD PANEL Three wire mains, and not more than 16 lights to be con' trolled. Method of wiring for burglar lighting 3 wire. for watering lawn, or for fire purposes without us- ing up the water in the tank. Refrigeration. Art. 38: Where ice is expensive or difficult to 288 obtain, an ice box refrigerator electrically operated can be installed. These outfits require little atten- tion and in addition to keeping the box cool, can be used to make a small amount of ice for table and sick room use. Stereopticon. Art. 39: Stereopticon and moving picture ma- chines are now made for residence use and are fast becoming an important part of the equipment of every home, especially where there are young peo- ple. Special receptacle should be provided as de- tailed in Art. 20. Vacuum Cleaner. Art. 40: Portable vacuum cleaners are well known and much used. They should not be con- nected to the branch circuits feeding lights and small appliances (see Art. 9), but should be pro- vided with a special circuit and their own outlets (See Art. 21.) Sometimes a permanent machine is installed in the basement with pipes carried con- cealed in the walls and with convenient outlets on each floor to which hose may be attached. In such a case it is advisable to place near the motor an au- tomatic distant control switch and carry one No. 14 wire branch circuit to flush receptacles placed close to each hose outlet. The plug is attached to the end of the hose with a small chain. The connections are such that when the hose is in use and the plug inserted into the receptacle, the cleaner will start up and when the hose is removed thus pulling out the receptacle plug the motor stops, preventing waste of current. The receptacles that are used for 224 connection to portable machines and their circuit are not used in this case. Plate Warmer. Art. 41 : Plate warmers are very convenient and add much to the ease of service and success of din- ners. They may be placed under dressers or pantry table and should be fitted with 2 or 3 heat switch and pilot light. When the first set of cold plates is placed in warmer, the switch is turned to high heat and left on for fifteen (15) minutes, when the lower heat is turned on and keeps the contents hot. Dish Washer. Art. 42: Electric dish washers are of many makes occupy small space do their work quickly and well and need little attention. They may be fitted with a switch on machine or at wall. (See Art. 16.) Metal Polisher. Art. 43: An electric silver and metal polisher consists of a J4 h.p. or 34 h.p. or larger. The ends of the motor shaft are arranged to receive various brushes, buffers, felt wheels and other fittings, all of which can be obtained with the outfit. By using such a machine the knives, forks, spoons and silver- ware may be kept in the best condition with a small expenditure of time and energy. Should have switch and receptacle on wall, omitting pilot light. (See Art. 18.) Ice Cream Freezer. Art. 44: An electric ice cream freezer insures the best and purest home product with but little 225 trouble. The electric current expense is negligible. Should have switch on machine with receptacle on wall or combined switch and receptacle on wall, omitting pilot light. (See Art. 18.) Electric Cooking Range Art. 45 : Cooking by electricity is fast coming into more general use. The freedom from odors and escaping gas, the cleanliness and the application of heat only where needed, appeals strongly to the housekeeper and in many parts of our country, such cooking may now be done as cheaply as with gas. (See Art. 5.) An electric range for a family of six would oc- cupy a floor space of about 22 inches by 28 inches. It is generally fitted with a number of separate switches for the various parts and utensils and should be on a separate 3-wire feeder with 3-pole main switch and pilot light. (See Kitchen, p. 209.) Ironing Table. Art. 46: Laundry ironing tables may be .pur- chased complete with swinging arms to take care of the cords and with two (2) irons for different classes of work and so arranged with automatic stands that the iron when not in actual use takes only enough current to keep it hot. (See Art. 23.) Clothes Washer and Wringer. Art. 47: The simplest type of electric clothes washer and wringer may be mounted on the tubs and removed when not in use. Other types have all parts mounted on one stand which may be on roll- ers to bring it to the tubs on wash days and remove it at other times. Such a machine for a family of ?26 six would occupy a floor space of about 28 inches by 32 inches and the washing would be done better than by hand and with no danger of tearing laces and lingerie. Has switch on the machine and should connect to receptacle on wall. (See Laundry, p. 209.) Starch Cooker. Art. 48: A convenient and inexpensive appliance in the house laundry is an electrically heated pot for cooking starch. Should be connected to pilot switch and receptacle. (See Art. 18.) Sewing Machine Motor. Art. 49: Every home should have the sewing machine fitted with a motor which may be very small in size and can be arranged to start and stop by pressing a contractor with the foot. It is very inexpensive to operate and saves many a doctor's bill where much sewing is done. The motor may be no volts and should be connected to a base receptacle. Bath Room Heater. Art. 50: Heating rooms by electricity is not yet an economic fact, but for special cases where not in continual use, they are very convenient and not too expensive to operate. When taking a bath on a winter morning when the hot water is turned on an electric heater may also be turned on and by the time the tub is ready, the chill will be taken out of the air. For this purpose the heaters should have a capacity of four watts per cubic foot of room, al- though this is much greater than would be needed for continuous heating. These heaters should be on separate circuits and be supplied with combina- tion pilot switches and receptacles. (See Art. 18.) (See Bath Room, p. 213.) Other Bath Room Appliances. Art. 5 1 : Curling iron heaters may be mounted on the surface of the wall and are very small in size and consume current only when the iron is in- serted into the heater. Hot water cups or stoves are much used, take up little space and should be connected to a combination pilot switch and recep- tacle. (See Art. 18.) Entrance Ball Calls. Art. 52: The push button at the main entrance door should not ring on the annunciators, but should be a distinctive call, ringing a separate bell in kitchen or pantry. An extension bell should be placed in servant's room or corridor and a second extension may be placed in a sewing room that is much used. These extensions are controlled by small lever switches for cutting them off in time of sick- ness. The push button at rear entrance should ring a buzzer in the kitchen, but without the extensions. Bell Annunciators. Art. 53 : An annunciator should be placed in the kitchen with bell different in sound from adjacent bells and fitted with an indicating drop from each of the rooms, porches and baths in the house. A second annunciator is often placed in servants' corridor and a third annunciator may be placed in the sewing room. These two or three annunciators ring and indicate simultaneously for each call and are connected to- Mi gether by two or three wires more than the total number of calls or drops on each. When a call is answered from any annunciator, a push at bottom of the annunciator resets all* the annunciators, thus letting others know that the call is being attended to. Wall Pushes. Art. 54: Wall pushes are placed in the door trims of the various rooms, porches, bath, etc., and connected to the nearest annunciator. Bath room pushes are sometimes placed over tub rather than at the door. Table Pushes. Art. 55 : In some rooms such as the living room, it is often desirable to have a table push on a flex- ible cord connected to a floor receptacle. These portable pushes are usually connected to the same wires as the wall push in such rooms. In case of the dining room, the table push rings a separate buzzer in the pantry while the wall push rings the annunciator. Bed Pushes. Art. 56: Portable push buttons are frequently located at beds and they connect to the same wires as the wall pushes. (See Art. 196.) When the mistress of the house has a special maid, her bed portable push is usually connected to a buzzer in the maid's room. Battery and Cabinet. Art. 57 : The bell system may be operated from six to eight cells of dry battery, placed in a cabinet which may be located in the cellar. It is often well to use these batteries in duplicate with a throw- over switch so that while one set is being replaced or renewed, the other set is in use. (See Cellar, p. 208.) i Bell Ringing Transformer Art. 58: Where alternating current is used for lighting, the bell system can be operated by a small bell ringing transformer which may be placed in the cellar and connected to one of the lighting cir- cuits. These transformers may also be used for house intercommunicating telephone ringing, when the telephones are on metallic circuit. They cannot be used for telephone talking, which requires bat- tery or direct current. (See Cellar, p. 208.) Public Telephone. Art. 59: It is quite usual to put conduits in a residence for use of the Public Telephone Co. and thus keep their wires out of sight. A Public Tele- phone outlet may be placed in the kitchen or pantry with extensions to living room, owner's bedroom and to still other points if desired. A 24-inch con- duit is ample for the above equipment. "Dim-a-lite" Art. 60: A "Dim-a-lite" lamp socket, which en- ables an incandescent lamp to be turned down to a dim light, should be placed on one of the fixtures or portables in every bedroom, hall and bath room. List of Current-Consuming Devices Art. 6 1 : Time and additional work, and conse- quent expense, to all concerned, may be saved if the 880 house owner, at the start, is presented with a com- plete list of devices, for possible use in the various rooms of his -house, that he may check off just what he may need. Without such a list, which follows, many devices, later on, may suggest themselves, as needs demand them, and additional outlets may' have to be pro- vided, and larger conductors may have to be installed to take care of them. No one has ever complained of too many outlets after they are once installed. Halls. Vacuum cleaner Fan motor Electric Talking Machine Electric piano Table lamp Sewing machine Dim-a-lite Parlor or Reception Room. Outlets Table lamps Vacuum cleaner Fan motor Electric piano Electric Talking Machine Kitchen Electric Irons Washing machine Electric stoves Electric Tea kettle Disc stoves Frying pans Glue pot Soldering iron Radiant Grill Toaster Vacuum cleaner Fan motor Coffee grinder Meat chopper Bread mixer Egg beater . Silver polisher Knife grinder Dining Room Toaster Chafing Dish Coffee Percolator Tea kettle Cigar lighter Fan motor Hot water heater Radiant Grill Luminous Radiator Vacuum cleaner Samovar 281 Sitting Rdom or Library Table or Desk Lamp Vacuum cleaner Fan motor Cigar lighter Sewing machine Small pression iron Luminous radiator Bedroom or Boudoir Luminous radiator Vacuum cleaner Curling iron Water heater Bed pan Fan motor Reading lamp at head of bed Ozonator for sickness Hair dryer Massage vibrator Baby milk warmer Dim-a-lite Nursery Laundry Washing machine Irons Fan motor Laundry machine Vacuum cleaner Cellar Work Shop Grinder Glue pot Soldering iron Breast drill Small motor for operating tools Portable for cleaning heater Electric toys Vacuum cleaner Luminous radiator Vacuum cleaner of extra strenfc Ozonator Fan motor Electric Talking Machine Baby milk warmer Bath Room Luminous radiator Vacuum cleaner Shaving mug Curling iron Water heater Hair dryer Massage vibrator Dim-a-lite Girl's Room Vacuum cleaner Bed pad Fan motor Curling iron Hair dryer Garage Several outlets for portables Luminous radiator, if not heate: Glue pot Spidering iron Fire pumps Small motor for tools Portable drill Grinding machine Buffing machine Charging batteries Vacuum cleaner Stables Clippers Electric milkers Churns Grind stones Vacuum cleaner for currying Offices Vacuum cleaner Luminous radiator Cigar lighter Hot water heater Table or desk lamp Fan motor STANDARD SYMBOLS FOR WIRING PLANS As adopted and recommended by The National Electrical Con- tractors Association of the United States and The American Institute of Architects yjx Ceiling Outlet; Electric only. Numeral in center indicates number of >3< Standard 16 C. P. Incandescent Lamps. ^4 Ceiling Outlet; Combination. #j indicates 4-16 C. P. Standard Incandes- >A<2 cent Lamps and 2 Gas Burners. Iff If gas only. i>5< Bracket Outlet; Electric only. Numeral in center indicates number of t>< Standard 16 C. P. Incandescent Lamps. Bracket Outlet; Combination. % indicates 4-16 C. P. Standard Incandes- cent Lamps and 2 Gas Burners. 1$ If gas only. U , Wall or Baseboard Receptacle Outlet. Numeral in center indicates num- ri&l ber of Standard 16 C. P. Incandescent Lamps. M Floor Outlet. Numeral in center indicates number of Standard 16 C. P. Incandescent Lamps. ~3@ Outlet for Outdoor Standard or Pedestal; Electric only. Numeral indicates number of Standard 16 C. P. Lamps. X?( Outlet for Outdoor Standard or Pedestal; Combination. % indicates 6-16 XX6 . C. P. Standard Incandescent Lamps; 6 Gas Burners. o Drop Cord Outlet. () One Light Outlet, for Lamp Receptacle. (J Arc Lamp Outlet. /*v Special Outlet, for Lighting, Heating and Power Current, as described in W Specifications. COO Ceiling Fan Outlet. S 1 S. P. Switch Outlet. S' D. P. Switch Outlet. S s 3-Way Switch Outlet. S 4 4-Way Switch Outlet. S Automatic Door Switch Outlet. S' Electrolier Switch Outlet. Show as many . Symbols as there are Switches. Or in case of a very large group of Switches, indicate number of Switches by a Roman numeral, thus: S 1 XII, meaning 12 Single Pole Switches. Describe Type of Switch in Specifica- tions, that is, Flush or Surface, Push Button or Snap. B Meter Outlet. J Distribution Panel. Junction or Pull Box. Motor Outlet; Numeral in center indicates Horse-Power. Motor Control Outlet. =< O >r Transformer. Main or Feeder run concealed under Floor. < Main or Feeder run concealed under Floor above. Main or Feeder run exposed. Branch Circuit run concealed under Floor. - Branch Circuit run concealed under Floor above. ------ Branch Circuit run exposed. 28S STANDARD SYMBOLS (Continued) ~ -_ Pole Line. Riser. {3 Telephone Outlet; Private Service. N Telephone Outlet; Public Service. Q Bell Outlet. CV Buzzer Outlet. B2: Push Button Outlet; Numeral indicates number of Pushes. ~^ Annunciator; Numeral indicates number of Points. 4 Speaking Tube. - Watchman Clock Outlet. J Watchman Station Outlet. Master Time Clock Outlet. P Secondary Time Clock Outlet. [J] Door Opener. O Special Outlet, for Signal Systems, as described in Specifications. |||||| Battery Outlet. 1 Circuit for Clock, Telephone, Bell or other Service, run under Floor, - 1 concealed. ( Kind of Service wanted ascertained by Symbol to which line connects. (Circuit for Clock, Telephone, Bell or other Service, run under Floor 1 above, concealed. ( Kind of Service wanted ascertained by Symbol to which line connects. NOTE If other than Standard 25-watt Incandescent lamps are desired, Specifications should describe capacity of lamp to be used. Standard Wiring Symbols. Art. 62: Owners, architects and contractors would save much time and misunderstanding by familiarizing themselves with, and using, the stand- ard symbols as recommended by The National Elec- trical Contractors' Association and The American Institute of Architects, when indicating on plans just what is desired in the way of outlets, fixtures, receptacles etc., etc., as as given on pages 233-234. 284 MISCELLANEOUS. DEFINITIONS OF ELECTRICAL UNITS. All electrical units are derived from the follow- ing mechanical units: The Centimeter is the unit of length, and equals 3937 inch, or .000000001 of a quadrant of the earth. The Gram is the unit of mass, and is equal to 15432 grains, the mass of a cubic centimeter of water at 4 C. The Second is the unit of time and is the time of one swing of a pendulum, swinging 86464.09 times per day, or the i/864OOth part of a mean solar day. The Volt is the unit of electro-motive force [E]. Electromotive force, which is the force that moves electricity, is usually written E. M. F. (in formulae E) and various writers use it to express potential, difference of potential, electric pressure and electric force. One volt will force an ampere of current through one ohm of resistance. Its value is purely arbi- trary, but fixed. The Ohm is the unit of resistance [R] and it is equal to the resistance of a column of pure mer- cury i square millimeter in section and 106.3 centi- meters long at the temperature of melting ice. One ohm is that resistance through which one ampere of current will flow at a pressure of one volt of E. M. F. The Megohm = 1,000,000 ohms. 235 The Ampere is the unit of current strength [C]. Its value may be defined as that quantity of elec- tricity which flows through one ohm of resistance when impelled by one volt of E. M. F. One ampere of current flowing through a bath will deposit 0.017253 grain of silver or 0.004085 grain of copper per second. The Coulomb is the unit of quantity [Q], and is the quantity of electricity passing per second, when the current is one ampere. The Farad is the unit of capacity [,K], and is capacity that will contain one coulomb at a poten- tial of one volt. A condenser of one farad capacity, if charged to two volts, will contain two coulombs; if to 100 volts, 100 coulombs, etc. The Microfarad [mid] = one millionth of a farad. The Joule is the unit of work [W]. It is the work done or heat generated, by a watt in a sec- ond. It is equal to .7373 foot-pound. The Watt is the unit of electrical power [P], is the energy contained in a current of one ampere with an electromotive force of one volt. 746 watts = one horsepower. A current of 7.46 amperes at TOO volts will do the work of the one horsepower. A Horse-Power in a steam engine or other mover is 550 Ibs. raised one foot per second, or 33,000 Ibs. one foot per minute. 236 The Kilowatt [kw] equals to 1,000 watts. Tlie E. M. F. is distributed according to the re- sistance of the various parts of the circuit, except where there is counter E. M. F. Counter E. M. F. is like back pressure in hy- draulics. Thus, to find the available E. M. F., or the resulting current against a resistance where there is a counter E. M. F., the counter E. M. F. must be deducted. For example : Suppose a stor- age battery with a resistance of .02 ohm and a C. E. M. F. of 15 volts, and you wish to charge it with a dynamo which gives an E. M. F. of 20 volts at the battery binding posts. There are 20 15 = 5 volts working through a resistance of .02 of an ohm with consequently a current of 250 amperes. The impressed voltage is, however, 20 volts, and not 5 volts, and the power is 20 X 250 = 5000 watts, and not 5 X 250 = 1250 watts, as might per- haps be supposed. It is obvious that the C. E. M. F. has acted as a true resistance. In the above case 5 :X 250 = 1250 watts were wasted in over- coming the resistance of the storage battery and the remaining 3750 watts were stored up in the chem- ical changes which they brought about in the active material of the storage battery. Hii = Thousandths of an inch. d 2 = circular mils. The Circular Mil is now generally used as the unit of area when considering the cross-section of electric conductors, the resistance being inversely, and weight of copper directly, proportion to the circular mils. SS7 General Formulae Ohms Law (Direct Current.) C. = current in amperes. E. :=, electromotive force in volts. R = resistance in ohms. W. energy in watts. E. E. C. = E. = C.R. R. = R. C. E 2 C E. = W. W. = - C 2 R. = W. R W. = H.P. W. ==- 746 X H.P. 746 Formulae giving the volts or amperes necessary for a given horsepower on circuits of constant cur- rent, and constant potential, respectively: 746 X H.P. E. C. ;X K. 746 X H.P. C. = E. X K. E. = potential of circuit. C. = amperes. K. = efficiency of machine. H.P. = horsepower. General Formulae for Direct Current Light and Power Wiring. When possible use the table on page 8 1 for conveniences, c.m. = circular mils. (See page 91). 238 d. = length of wire, in feet, on one side of circuit. n. = number of lamps in multiple, c. current in amperes per lamp (see p. 166). v. = volts lost in lines (see pp. 25 and 81). r. resistance per foot of wire to be used. 10.8 ohms resistance of one foot of commercial copper wire having a diameter of one mil and a temperature of 75 Fahrenheit. It is an easy matter to find any of the above values by the following formulae for direct current: 10.8 X 2d. :X n. X c. c.m. = v. 10.8 X 2d. X n. :X c. c.m. X v. V. : C. = c.m. 10.8 X 2d. X n. c.m. X v. c.m. X v. n. 2d. = 10.8 'X 2d. X c. 10.8 X c. X n. v. n. X c. X 2d. v. v. = n. X c. X 2d. X r. c. = 2d. X n. X r. V. V. 2 d. c. X 2d. Xr. n. X c. X r. 239 Lull. Equivalent Value In Other 1 H. P. 746 watts. .846 K. W. 33,000 ft.-lbs. per minute. 550 ft.-lbs. per second. 2,645 heat-units per hour. 42.4 keat-units per minute. .707 heat-unit per second. .175 Ib. carbon oxidized per hr. 2.64 Ibs. water evaporated per hour from and at 212 F. 1 H. P. Hour 746 K. W. hours. 1,980,000 ft.-lbs. . 2,545 heat-units. 273,740 k. g. m. .175 Ib. carbon oxidized with perfect efficiency. 2.64 Ibs. water evaporated from and at 212 F. 17.00 Ibs. water raised from 62 to 212 F. 1 Kilo- watt 1,000 watts. 1.34 H. P. 2,654,200 ft. -Ibs. per hour. 44,240 ft.-lbs. per minute. 737.3 ft-lbs. per second. 3,412 heat-units per hour. 56.9 heat-units per minute. .948 heat-unit per second. .2275 Ib. carbon oxidized per hour. 3.53 Ibs. water evaporated per hour from and at 212 F. 1 Watt per sq. in. 8.19 ^heat units per sq. ft. per minute. 6,871 ft.-lbs. per sq. ft. per minute. .198 H. P. per sq. ft. 1 Kilo- gram Metre 7.288 ft.-lbs. .00000365 H. P. hour. .00000272 K. W. hour. .0093 heat-units. l Ib. Wat- er Evapo- rated from and at 212 F. .283 K. W. hour. .879 H. P. hour. 965.7 heat-units. 103,900 k. g. m. 1,019,000 joules. 751,800 ft.-lbs. .0664 Ib. of carbon oxidized. 140 Unit. Equivalent Value in Otner Unit*. 1 Heat- unit < I Heat f unit per sq. ft. =1 per mm. 1,055 watt seconds. 778 ft.-lbs. 107.6 .000293 K. W. hour. .000398 H. P. hour. .0000688 Ib. carbon oxidized. .001036 Ibs. water evaporated from and at 212 F. .122 watts per sq. in. .0176 K. W. per sq. ft. .0286 H. P. per sq. ft- l W*t == 1 joule per second. .00184 H. P. 3,412 heat-units per hour. .7373 ft.-lb. .0035 Ib water evaporated per hour. 44.24 ft.-lbs. per minute. 1 K. W. . Hour =at 1,000 watt hours. 1.34 H. P. hours. 2,664,200 ft.-lbs. 3,600,000 joules. 8,412 heat-units. 367,000 kilogram metres. ,235 Ib. carbon oxidized with perfect efficiency. 3.53 Ibs water evaporated from and at 212 F. 11.75 Ibs. of water raised from 62" to 212 F. 1 Joule =- 1 watt second. .000000278 K. W. hour. .102 k. g. m. .0009477 heat-units. .7378 ft.-lb. 1 ft.-lb. 1.356 joules. .1383 k. g. m. .000000377 K. W. hours. .001285 heat-units. 0000005 H. P. hour. 1 Ib. Car- bon Oxi- dized =. with Per- fect Ef- ficiency. 14,544 heat units. 1.11 Ib. anthracite coal ox. 2.5 Ibs. dry wood oxidized. 21 cu. ft. illuminating gas. 4.26 K. W. hours. 5.71 H. P. hours. 11,315,000 ft.-lbs. 15 Ibs. of water evaporated from and at 212 F. 141 e* - i i I i i lilts!*** S>l8*fet-' P 1. 8. ^COrHi-l S g 5 i Stf 3 s s a 1.^ 1 S S i 3 s j.aS 5 S Ir i-t >O t- i-t t CO '1 1 1 - t^owt^ooo-^^cjiftMioia tilsssssslsss 1 s to (O 00 243 V*P. *P*V9B2E^ I 99* 3! * a 3 -5 3 !9 oo-* rHi-io S55lcoeocoS P 3o W &S3 ooo o o o o o o o o o o o o oo o o o o o < ^tii ill i i s 5 S s * * * * ^ ** " ^ * * * ! Ei j S p ^^ oo>ooooooooooooooi0oooieoo > W tio oob-ooiOfHoocoo>wo-*coo52oS8eo I < eo IH c* CO JJ-2 > M e 5 "Si; p^i oQ.. oooooooooooooooooooiotoe O J? '~ Ous OOOOOOOOO 00 OOC4IO<0 kaoot>(0>a< ^eo eo c* 243 r^ ^ s I M**iMMOOl ala OlOUJOOOO^C* _ .- ^,rHg 'O^eOeOOilMNIMrH Q l I* 1 1 * - M^OWOOOlM^OOO 844 CO W CO >Q 04 rH 10 t- 9 W r-t r-l t- r* r-t rH IO t> CO t- CO OJ O4 NoSOOOOOOOOOOOOOOOOOOOOOrHC.00*OtO -000000000000000000, C/J-OOOOOOOOOOOOOOOOOOO C->oooooooooooooooooo OUiOIQOOOiOOUiOiQOlQOiQOlO ot^iococsooi--t-y.3 257.6 319.5 253.3 200.9 11 040. 8758 . 6946. 10 180 8070. 6400. 9103. 7219. 5725. 3 4 5 229.4 204.3 181.9 159.3 126.4 100.2 5508. 4368. 3464. 5075. 4025. 3192. 4540. 3600. 2855. 6 7 8 162.0 144.3 128.5 79.46 63.02 49.98 2747. 2179. 1728. 2531. 2007. 1592. 2264. 1796. 1424. 9 10 11 114.4 101.9 90.74 39.63 31.43 24.92 1370. 1087. 861.7 1262. 1001. 794.0 1129. 895.6 710.2 12 13 14 80.81 71.96 64.08 19.77 15.68 12.43 683.3 541.9 429.8 629.6 499.3 396.0 563.2 446.7 354.2 15 16 17 57.07 50.82 45.26 9.858 7.818 6.200 340.8 270.3 214.3 314.0 249.0 197.5 280.9 222.8 176.7 18 19 20 40.30 35.89 31.96 4.917 3.899 3.092 170.0 134.8 106.9 156.6 124.2 98. % 50 140.1 111.1 88.11 21 22 23 28.46 25.35 22.57 2.452 1.945 1.542 84.78 67.23 53.32 78.11 61.95 49.13 69.87 55.41 43.94 24 25 26 20.10 17.90 15.94 1.223 0.9699 .7692 42.28 88.53 26.59 38.96 30 . 90 24.50 34.85 27.64 21.92 27 28 29 14.20 12.64 11.26 .6100 .4837 .3836 21.09 16.72 13.26 19.43 15.41 12.22 17.38 13.78 10.93 30 31 32 10.03 8.928 7.950 .3042 .2413 .1913 10.52 8.341 6.614 9.691 7.685 6.095 8.669 6.875 5.452 33 34 35 7.080 6 . 305 5.615 .1517 .1203 .095 42 5.245 4.160 3.299 4.833 3.833 3.040 4.323 3.429 2.719 * Length at 20 C of a wire whose resistance is 1 ohm at the stated temperatures. (Bureau of Standards). 247 WIRE TABLE, STANDARD ANNEALED COPPER. CONTINUED. Gage No. B. &S. Diameter in Mils at 20 C Ohms per Pound C (=32 F) 20 C (=68 F) 50 C (=122 F) 0000 000 00 460.0 409.6 364.8 0.000 070 51 .000 1121 .000 1783 0.000 076 52 .000 1217 .000 1935 0.000 085 54 .000 1360 .000 2163 1 2 324.9 289.3 257.6 .000 2835 .000 4507 .000 7166 .000 3076 .000 4891 .000 7778 .000 3439 .000 5468 .000 8695 3 4 5 229.4 204.3 181.9 .001 140 .001 812 .002 881 .001 237 .001 966 .003 127 .001 383 .002 198 .003 495 6 7 8 162.0 144.3 128.5 .004 581 .007 284 .011 58 .004 972 .007 905 .012 57 .005 558 .008 838 .014 05 9 10 11 114.4 101.9 90.74 .018 42 .029 28 .046 56 .019 99 .031 78 .050 53 .022 34 .035 53 .056 49 12 13 14 80.81 71.96 64.08 .074 04 .1177 .1872 .080 35 .1278 .2032 .089 83 .1428 .2271 15 16 17 57.07 50.82 45.26 .2976 .4733 .7525 .3230 .5136 .8167 .3611 .5742 .9130 18 19 20 40.30 35.89 31.96 1.197 1.903 3.025 1.299 2.065 3.283 1.452 2.308 3.670 21 22 23 28.46 25.35 22.57 4.810 7.649 12.16 5.221 8.301 13.20 ' 5.836 9.280 14.76 24 25 26 20.10 17.90 15.94 19.34 30.75 48.89 20.99 33.37 53.06 23.46 37.31 59.32 27 28 29 14.20 12.64 11.26 77.74 123.6 196.6 84.37 134.2 213.3 94.32 150.0 238.5 CO 31 32 10.03 8.928 7.950 312.5 497.0 790.2 339.2 539.3 857.6 379.2 602.9 958.7 33 34 35 7.080 6.305 5.615 1256. 1998. 3177. 1364. 2168. 3448. 1524. 2424. 3854. (Bureau of Standards) 248 WIRE TABLE, STANDARD ANNEALED COPPER CONTINUED Gage No. B. &S. Diameter in Mils at 20 C Pounds per Ohm C (=32 F) 20 C (=68 F) 50 C (=122 F) 0000 000 00 460.0 409.6 364.8 14 180. 8920. 5610. 13 070. 8219. 5169. 11 690. 7352. 4624. C, 1 2 324.9 289.3 257.6 3528. 2219. 1395. 3251. 2044. 1286. 2908. 1829. 1150. 3 4 5 229.4 204.3 181.9 877.6 551.9 347.1 .808.6 508.5 319.8 723.3 454.9 286.1 6 7 8 162.0 144.3 128.5 218.3 137.3 86.34 201.1 126.5 79.55 179.9 113.2 71.16 10 11 114.4 101.9 90.74 54.30 34.15 21.48 50.03 31.47 19.79 44.75 28.15 17.70 12 13 14 80.81 71.96 64.08 13.51 8.495 5.342 12.45 7.827 4.922 11.13 7.001 4.403 15 16 17 57.07 50.82 45.26 3.360 2.113 1.329 3.096 1.947 1.224 2.769 1.742 1.095 18 19 20 40.30 35.89 31.96 0.8357 .5256 .3306 0.7700 .4843 .3046 0.6888 .4332 .2725 21 22 23 28.46 25.35 22.57 .2079 .1307 .08222 .1915 .1205 .075 76 .1713 .1078 .067 77 24 25 26 20.10 17.90 15.94 .051 71 .032 52 .02045 .047 65 .029 97 .018 85 .042 62 .026 80 .016 86 27 f)Q 29 14.20 12.64 11.26 .012 86 .008 090 .005 088 Oil 85 .007 454 .004 688 ,010 60 .006 668' .004 193 30 31 32 10.03 8.928 7.950 .003 200 .002 012 .001 266 .002 948 .001 854 .001 166 .002 637 .001 659 .001 043 33 34 35 7.080 6.305 5.615 .000 7959 .000 5005 .000 3148 .000 7333 .000 4612 .000 2901 .000 6560 .000 4126 .000 2595 (Bureau of Standards) 240 f| j gg^-S^ooto L o o w^ti *ooo6^i*o6to^'cs^#ioo*tQ*o"ooo*oo H CQU t-lrHN^OOtOtQoOOOoOi-ltOOSeOtaioO fe ^ i 3 i & 8 * fc *' * s g> ^ O 10 10 10 fc t-4r-(C^i^rH^gOTH^eO s "Siiiils s S s * SSio:sss " | 000000000000000000000 Q ri g, ^g D t- 00 O r-l c* o e oj eo eo eo to to t- co o> o 260 i-< 00 ~ O co N >n O 't O O * W - co OMH coO * O r^ in O O u-, O> W !>. O *n ' ' M M M c5 N coco^Or^O CO c O 4 O M rj- h. inco CO N co f-OO O N n 'H'J o9 O co O coO O O COM "-" ' 5 ''jadd 2 'S 5 'g'jaddoQ 'O 'M 'a UOJJ p 3 ZtUBA T co i^ m r^ m r^ m in M M cioi co^inOco O too O*O co H- pi ^^ ' * M OCO CO CM M M ^" OOO O ("* CM W O CO 1^ O oi uSco* ci rio'co coooco r~-t-^o t-i M I-H M w M co rf o r^> o coco O "! W CO O uojj '^ *3 co O^ N m ^f Oco mO^-O O ^J~O cor** rf co co O iJ M JR PIO coco r^o r-^mM comco co^TtMcoO mcoc c* COO N M COO OO COOCOO 'O 'AV ' UOJ M 1-1 Nr-cocoOco mo O"~>"^ \ON r < "ico r^r^.oi^.o mOO c* N M Or^Oinrl-COCOM M HI >H 'A\ '9 PIO Oco incow Ocoo ^CON O MO Oco r^O in m ri- rt to co ._ . O ^ Oco O co O mco T^ o co in co N uico o .2 tJ A\ H OcomcOMOcoO^cONO Ooo r-o m -<4- o t^co OO 251 o^-vno r>.co O ( V Length of Belting for Various Purposis. ID 2 . Open belting: L = -- S. + 2C. 2 L = Length of belt. S = Sum of pulley diameters. C Distance between centers of pulleys. D = Difference of pulley diameters. TT 3.141592, or, for practical purposes, 3.1416. For calculating the length of belting approxi- mately, add one-half the circumference of each pul- ley to twice the distance between centers of the pulleys. To find the horsepower strength of double leather belting when: d. = diameter of small pulley in inches. r. = revolutions of small pulley per minute. b. breadth of belting in inches. H.P. horsepower to be transmitted. dXrXb H.P. = - "Double" belting is expected to transmit twice that of "single" belting, and "light double" one and one-half times that of "single." Strength of wrought iron or steel Shafting. (Formula as used by Pencoyd Iron Works.) for bare shafts. or H. 1>.= _ _ or d = V P- f or shafts carrying pulleys, etc., K. 252 Rd* or H.P. = 70 i = \/ 720 d 2 for bare shafts, or d = *v -i- 720 3 or i = V 140 d 2 for shafts carrying pulleys, etc.. 2 or d = 140 H.P. = horse-power transmitted, d diameter shaft in inches. R = revolutions per minute. 1 = length between supports in feet. To find the horse-power of engines: in which: H.P. = indicated horse-power. Ps = travel of piston in feet per minute. A = area of piston in square inches. M. E. P. = mean effective pressure in pounds per square inch. Ip = initial pressure, and: 34Xlp (a) M. E. P. = at 1 A cut off. 57 nXlp (b) M. E. P. = at y 2 cut off. 13 An application of these formulae in an appropri- ate example may be considered in the following problem : 253 It is desired to determine the I. H. P. of an en- gine whose cylinder is 10 inches in diameter and whose stroke is 12 inches, operating at 300 revolu- tions per minute, the initial steam pressure being 100 pounds per square inch, cutting off at y$ and l /2 stroke, respectively: 34 X Ip 34 X ioo (a) M.E.P. = = 59.65 at # 57 57 cut off. nXlp 34 X ioo (b) M.E.P. = - - = 84.6 at y 2 13 13 cut off. n A = X diameter 2 = .7854 X io 2 = 78.54 square 4 inches. Ps = .2 feet per revolution and 30 revolutions per minute = 600 feet per minute. Ps X A X M. E. P. I. H. P. at y 4 cut off = - 33,000 600 X 78.54 X 59-65 = 85.18 33,000 Ps X A X M. E. P. I. H. P. at y s cut off = = 33,000 600 X 78.54 X 84.6 = 120.8 33>ooo 254 To find the horse-power of a pulley: Multiply the circumference of the pulley in feet by the revolutions per minute, and the product thus obtained by the width of the belt in inches, and di- vide the result by 600. This Tule is founded on the fact that good, ordi- nary, single leather belting, with a tension of fifty- five pounds per inch width, will require fifty square feet of belt surface passing over the pulley per min- ute for one horsepower. Fifty square feet per minute is equal to a belt one inch wide running 600 feet per minute. To find the speed of a belt, multiply the circum- ference of the driving pulley in feet by the revolu- tions per minute. Belts should always be run with the grain side next to the pulley. Rule for Determining the Size of Pulley D Diameter of driver, or number of teeth in pinion. d Diameter o f driven, or number of teeth in gear. Rev. Revolutions per minute of driver, rev. Revolutions per minute of driven. d ;X rev. d X rev. D = - Rev. = - D D X Rev. rev. = d To find the speed of the belt in feet per minute, multiply the circumference of the pulley in feet by the number of revolutions per minute. For best re- sults, the belt speed should be from 3,500 to 4,500 feet per minute. 255 Resuscitation From Electric Shock. As recommended by The National Electric Light Association. Follow these instructions even if the victim appears dead. I. Immediately Break the Circuit. With a single quick motion, free the victim from FIG. i INSPIRATION; PRESSURE OFF. the current. Use any dry non-conductor (clothing, rope, board) to move either the victim or the wire. Beware of using metal or any moist material. While freeing the victim from the live conductor have every effort also made to shut off the current quickly. 256 II. Instantly Attend to the Victim's Breathing. As soon as the victim is clear of the conductor, rapidly feel with your finger in his mouth and throat and remove any foreign body (tobacco, false teeth, etc.). Then begin artificial respiration at once. Do not stop to loosen the victim's clothing now; every moment of delay is serious. Proceed as follows: (a) Lay the subject on his belly, with arms ex- tended as straight forward as possible and with face to one side, so that nose and mouth are free for breathing (see Fig. i). Let an assistant draw for- ward the subject's tongue. (b) Kneel straddling the subject's thighs, and facing his head; rest the palms of your hands on the loins (on the muscles of the small of the back), with fingers spread over the lowest ribs, as in Fig. i. (c) With arms held straight, swing forward slowly so that the weight of your body is gradually, but not violently, brought to bear upon the subject (see Fig. 2). This act should take from two to three seconds. (d) Then immediately swing backward so as to remove the pressure, thus returnig to the position shown in Fig. i. (e) Repeat deliberately twelve to fifteen times a minute the swinging forward and back a complete respiration in four or five seconds. (f) As soon as this artificial respiration has been started, and while it is being continued, an assistant should looseh any tight clothing about the subject's neck, chest, or waist. 257 2. Continue the artificial respiration (if neces sary, two hours or longer), without interruption until natural breathing is restored, or until a physi- cian arrives. If natural breathing stops after being restored, use artificial respiration again. c. Do not give any liquid by mouth until the sub- ject is fully conscious. 4. Give the subject fresh air, but keep him warm. III. Send for Nearest Doctor as Soon as Acci- dent is Discovered. Switchboard and Electrical Fires A one-quart liquid gas fire extinguisher, called Pyrene, has now been on the market for approxi- mately eight years. Experimental and acceptance tests made by the largest electric light, power, rail- road and transit companies and by the Underwrit- ers' Laboratories, Inc., indicate that it is of great value to the electrical industry. At several tests made, short circuit electrical arcs larger than any that had ever before been intention ally produced, were successfully handled by Pyrene The extinguisher is small and light, working on the principle of a double-acting syringe, can be con- veniently located and is easily transported from one point to another. As the liquid will not freeze at fifty degrees below zero, it can be left in exposed places during the winter. No periodic recharging is required, although they are refillable after use. Pyrene is an absolute non-conductor of electric current, therefore perfectly safe to use. 258 INDEX TO CONTENTS. Approval of Apparatus and Supplies 162 Approved Apparatus, Makers 268-71 Arc Lamps on Constant Potential Circuits. . 155 Attendance 14 Auto-Starters 18 Batteries, Storage, Installation 14 Bearings, Care of 39 Belts, Operation of 40 Brushes, Generator and Motor 36 Brushes, Sparking 41 Cabinets and Cut-out Boxes 122 Cables, Armored, Installation 135 Cable, Flexible, for Flatirons 117 Candle Power 164 Canopy Insulators 151 Circuit Breakers, Construction of 104 Circuit Breakers, for Generators 5 Circuits, Branch and Tap, Protection 102 Cleats, Porcelain 133 Coils, Economy and Compensator 155 Commutators, Care of 37 Conduit, Flexible, Metallic 146 Conduits, Metal, Rigid, Construction 143 Conduits, Metal, Rigid, Installation 138 Conduit Work, Wires to Use 129 "Condulets" 139 Cross Arms, 70 Current Supply, A. C. or D. C 185 Cut-outs, Automatic 100 259 Cut-outs, Enclosed Fuse 109 Cut-outs, Fuses, Mounting of 105 Cut-outs, Plug 109 Cut-outs, Switches and Circuit Breakers... 95 Decorative Lighting 159 Definitions, Units, Terms, etc 235 Devices, Current Consuming 221-232 Equalizers, Generators 29 Extra High Potential System, over 3,500 Volts 160 Fire Extinguishers . . 13 Fires, Switchboard and Electrical 258 Flexible Cord, Protection of 155 Flexible Cord, Where Used 154 Flexible Tubing, Construction 134 Fixtures, Installation '. 148 Fixture Wires 150 Fuses, Enclosed, Approved Makers in Fuses, Enclosed, Caution About Refilling.. in Fuses, Enclosed, Construction of no Fuses, Enclosed, Dimensions 113 Fuses, Link 101 Fuses, Rated Capacity, Motors 103 Generators, Installation 3-7 Generators, Foundations 4 Generators, and Motors, General Instruction 26-42 Generators, Locating Trouble 31 Generators, Parallel Operation 29 Generators, Shutting Down 33 Generators, Starting 31 Generators, Windings, Types 26 Generators, Reversing Rotation 31 260 Ground Connections 57 Ground Detectors 6 1 Ground Detectors, Diagrams 75 Grounding Generators Frames 4 Grounding Low Potential Circuits 57 Guard Arms 49 Guard Irons 71 Guard Wires 66 Guys 7 1 Heaters, Electric, Installation 1 16 High Potential Systems, 550-3500 Volts. ... 159 House Mains 191 House Wiring 179-232 Illumination, Salculation, Formulae 176 Illumination, Definition 166 Illumination, Direct 171 Illumination, Efficiency 173 Illumination, for Various Uses 173 Illumination, Indirect 171 Illumination, Semi-Indirect 172 Illumination, Show- Window 175 Inspection, Electrical 163 Insulation Resistance, Ground Detectors. ... 13 Insulators, Petticoat 49~5i Insulators, Suspension Type 161 Joints, Insulating 151 Joints, Solderless 50 Knobs and Cleats 78 Knobs, Split 133 Knobs, Tubes and Cleats, Construction .... 133 Knob and Tube Works, Concealed 131 Laboratories, Testing, Underwriters 162 sei Lamps, Incandescent, Data 165-7 Lamps, Inc., Gas Filled, Installation 156 Lamps, Mazda, Comparative Sizes 169 Lamps, Mercury Vapor, Construction 156 Lamps, Mercury Vapor, Data 167 Lamps, Variation with Voltage 167 Light and Illumination 165-177 Light, Method of Producing 165 Lightning Arresters, Ground Wires 12 Lightning Arresters, on Poles 59 Lightning Arresters, Station 1 1 Link Fuse Cut-outs 106 Low Potential Systems, 550 Volts and Less. 118 Motors and Generators, General Instructions 26-42 Motors, Current Required D. C 23-24 Motors, Installation 14 Motors, Installation Diagrams 43~47 Motors, on Wood Floors 19 Motors, Protection of 17 Motors, Size of Fuses Required 23 Motors, Starting and Stopping 20-34 Motors, Windings, Types 28 Moulding, Metal, Construction 129 Moulding, Metal, Installation 146 Moulding, Wooden, Construction 128 Moulding Work (Wood or Metal) 127 Name Plates 6 Oily Waste 14 Outlet, Junction and Flush Switch Boxes. . . 123 Panel Boards and Cabinets, Construction. . . 125 Panel Boards, Construction of 124 Poles and Cross Arms Construction 74 262 Poles, Data Tables 72-73 Poles, for Light and Power Lines 67-71 Pole Holes 69 Poles, Painting of 69 Poles, Weights, Sizes, Etc 70 Receptacles 102 Resistance, "Megger" Method 62 Resistance of Wiring Installations. . . 157 Responsibility, for Wiring 163 Roof Structures 49 & 53 Rubber Covered Wires, Makers of 77 Service Blocks 50 Service Heads or Caps 52 Service, Obtaining of 179 Shock, Electric, Resuscitation 256 Sockets and Receptacles 152 Sockets, Double-Ended 153' Sockets, in Dangerous Places 151 Splicing, Wires and Cables 50 Switches, Flush and Surface, Wiring 218-219 Switches, Knife and Snap, Installation.... 114 Switches, Service 107 Switchboards, Installation of 8-n Switches, Snap, Construction of 120 Telegraph and Telephone Wires 54 Transformers, Installation 55 Transformers, Oil and Air Cooled 159 Transformers, Support of 60 Tree Wiring 50 Underwriters' Laboratories 162 Volts Lost, Table 25 Waterproof Covers 6 263 Wire Gauge 82 Wires, A. C. on Poles 71 Wires, Carrying Capacity, Table 91 Wires, Equivalent Cress Sections 92 Wires, Fixture 149 Wires, Fixture, Protection of 104 Wires, for Grounding, Size 137 Wires, for Outside Work 63 Wires, Installation, General, Inside 89 Wires, Rubber Covered 76 Wires, Service and Line 48 Wires, Service, Installation 52 Wires, Slow Burning 77 Wires, Space Between, Outside 48 Wires, Stranded 79 Wires, Tensile Strength, Copper 93 Wires, Tie 48 Wires, Underground 95 Wires, Weatherproof 78 Wiring, i-Phase 2 Wire . . . 88 Wiring, i-Phase 3 Wire 89 Wiring, i-Phase 4 Wire 89 Wiring, 2-Phase 3 Wire 86 Wiring, 2-Phase 4 Wire 88 Wiring, 3-Phase 3 Wire 83 Wiring, 3-Phase 4 Wire 88 Wiring Calculations, A. C 83-89 Wiring, for 5,000 Volts or Over 63 Wiring, for Burglar Lights 222 Wiring, from Generators 7-8 Wiring, in Attics and Roof Spaces 120 Wiring, in Damp Places 119 264 Wiring, in Plaster 1 18 Wiring, Inside, General Rules 76 Wiring, Open Work, Cleats and Knobs .... 120 Wiring, Protection on Sidewalls 119 Wiring, Series Arc Lamps 96 Wriing, Series Incandescent 99 Wiring, Special, Damp Places 99 Wires, Support of in Conduits 130 Wiring Table, with Examples 79 FORMULAE. To Find : Belting, Proper Length 252 Belting, Horse-power Strength 252 Engines, Steam, Horse-power 2 53~4 Gears, Proper Size 255 General Wiring, D. C 238 Horse-power, Electrical 238 Illumination 177 Lamp Efficiency 177 Lighting System, Efficiency 177 Motors, Size of Wire Required D. C 21 Motors, Current Required D. C 23 Motors and Generators, Horse-power. D. C. 27 Ohms Law 238 Pulleys, Horse-power of 255 Pulleys, Proper Size 255 Shafting, Steel, Strength of 252 Size of Wire for A. C. Systems 83-89 Size of Wire for D. C. Systems 238-9 265 TABLES. Amperes per Horse-power, Motors , . . 24 Amperes per Motor, A. C 84 Cables, Carrying Capacity and Dimensions. . gi Conduit, Flexible Metallic, Data 146 Conduit, Rigid, Threads per Inch 144 Conduits, Rigid, No. of Wires Inside 141-142 Conduit, Rigid, Weight per 10 Ft. Length. . 145 Definitions, Units 235-241 Devices, Current Using, for Domestic Use. . 231 Fuses, Enclosed, Approved Makes 1 1 1 Fuses, Enclosed, Standard Dimensions. ... 113-114 Fuses, Enclosed, Time to "Blow" no Fuses, Plug or Cartridge, Volts and Amp. . 109 Fuses, Link, Break Distances 107 Fuses, Sizes for Motors 23 Illumination, Amount for Different Uses. . . 173 Insulation Resistance, Completed Jobs 157 Insulators, Knobs and Cleats, Dimensions. . 121 Lamps, Cooper-Hewitt, Data 167 Lamps, Mazda, Data 166-167 Lamps, Mazda, C. P. Variations 167 Motor, Current Rating , 16 & 18 Motor Efficiencies, D. C 22 Poles, Cedar, Dimensions 70 Pole Line Data 73-74 Reflectors, Light Through Various Types. . 171 Size of Wire, 3-Phase 3- Wire 85 Siz,e of Wire, 2-Phase, 3-Wire 87 Sockets, Dimensions, Classes 153 Symbols, for Architects and Contractors .... 233-4 Units, Equivalent Values 241 266 Volts Lost at Different % Drop 25 Wires, Bare Copper, Tensile Strength 92 Wires and Cables, Insulated, Weights 91 Wires, Carrying Capacity, Rubber Covered and Weatherproof 91 Wires, Cir. Mils and Mils 91 Wires, in Conduit Risers, Support 130 Wires, Equivalent Cross Sections 92 Wires, Fixture, Carrying Capacity 150 Wires, Insulated, Solid and Stranded, Data. 242-5 Wires, Insulation Thickness 76 & 78 Wires, Iron, Steel, Copper, Comparative. ... 251 Wire, Magnet, Fine, Wt. and Res 250 Wire, Res., Weights, Etc., Bureau of Stand.. 246-9 Wires, Rubber Covered, Makers 77 Wires, Rubber Covered and Weatherproof, Data 91 Wiring for Light and Power, D. C 81 267 CLASSIFIED INDEX MANUFACTURERS OF OFFICIALLY APPROVED APPARATUS AND SUPPLIES (See pages 271 and 272 for Addresses) ADJUSTERS, LAMP CORD McGill Mfg. Co. Trumbull Electric Mfg. Co. AMMETERS AND VOLTMETERS General Electric Co. Hoyt Elecl. Inst. Co. L. M. Pignolet Westinghouse Elec. & Mfg. Co. ASBESTOS H. W. Johns-Manville Co. ATTACHMENT PLUGS Bryant Electric Co. Cutler-Hammer Mfg. Co. General Electric Co. Trumbull Elec. Mfg. Co. AUTO-STARTERS Cutler-Hammer Mfg. Co. General Electric Co. Westinghouse Elec. & Mfg. Co. BOLTS, EXPANSION U. S. Expansion Bolt Co. BUSHINGS, PORCELAIN General Electric Co. CABINETS Frank Adam Electric Co. Bryant Electric Co. Crouse-Hinds Co. Detroit Fuse & Mfg. Co. General Electric Co. Post-Glover Electric Co. Sprague Elec. Wks. of G. E. Co. Trumbull Elec. Mfg. Co. CABLES, ARMORED National Metal Molding Co. Safety-Armorite Conduit Co. Sprague Elec. Wks. of G. E. Co. Standard Underground Cable Co. Trumbull Elec. Mfg. Co. Western Conduit Co. CANOPY INSULATORS General Electric Co. The Macallen Co. CAPS, SERVICE Gillette-Vebber Co. Crouse-Hinds Co. . Co. CIRCUIT BREAKERS Cutler-Hammer Mfg. Co. Cutter Electric & Mfg. Co. General Electric Co. Westinghouse Elec. & Mfg CLAMPS, INSULATOR Clark Electric Mfg. Co. CLEATS, & KNOBS, PORCELAIN Cook Pottery Co. Findlay Elec. Porcelain Mfg. Co. General Electric Co. COMPOUNDS, INSULATING H. W. Johns-Manville Co. Standard Underground Cable Co. CONDUIT, FLEXIBLE, NON- METALLIC Alphaduct Company American Circular Loom Co. American Conduit Mfg. Co. National Metal Molding Co. Tubular Woven Fabric Co. CONDUIT, FLEXIBLE STEEL National Metal Molding Co. Safety-Armorite Conduit Co. Sprague Elec. Wks. of G. E. Co. Trumbull Elec. Mfg. Co. CONDUIT, RIGID METAL American Circular Loom Co. American Conduit Mfg. Co. Clifton Mfg. Co. National Metal Molding Co. Safety-Armorite Conduit Co. Sprague Elec. Wks. of G. E. Co. Western Conduit Co. CONDUIT BOXES Crouse-Hinds Co. Chicago Fuse Mfg. Co. Gillette-Vibber Co. National Metal Molding Co. Sprague Elec. Wks. of G. E. Co. "CONDULETS" Crouse-Hinds Co. CONNECTORS, SOLDERLESS Dossert & Company CURRENT TAPS Bryant Electric Co. General Electric Co. CUT-OUT BASES (For Edison Plug Type Fmses) Bryant Electric Co. General Electric Co. Trumbull Elec. Mfg. Co. Westinghouse Elec. & Mfr. Co. CUT-OUT BASES (For inclosed fuse*) BryL/it Electric Co. Chicago Fuse Mfg. Co. U & W Fuse Co. General Electric Co. H. W. Johns-Manville Co. Trumbull Elec. Mfg. Co. Westinghouse Elec.* & Mfg. Co. DECORATIVE LIGHTING Elblight Co. of America DRILLS ("Star," for Brick and Stone) tJ. S. Expansion Bolt Co EXTINGUISHERS, FIRE Pyrene Manufacturing Co. FIXTURES, ELECTRIC Phoenix Glass Co. Post-Glover Electric Co. New York Electric Lamp Co. Reflectolyte Co. FLEXIBLE CORDS (See Wires) FUSES, ENCLOSED Atlas Selling Agency (Six-in-One) Bryant Electric Co. Chicago Fuse Mfg. Co. Detroit Fuse & Mfg. Co. D & W Fuse Co. General Electric Co. H. W. Johns-Manville Co. Killark Electric Mfg. Co. Westinghouse Elec. & Mfg. Co. FUSES, PLUG TYPE, EDISON Atlas Selling Agency (Six-in-One) Bryant Electric Co. Chicago Fuse Mfg. Co. D & W Fuse Co. General Electric Co. H. W. Johns-Manville Co. FUSES, OPEN LINK Chicago Fuse Mfg. Co. General Electric Co. Walker Electric Co. Westinghouse Elec. & Mfg. Co. GAUGES, WIRE Novelty Electric Co. GENERATORS (See Motora) GROUND CLAMPS General Electric Co. Gillette- Vibber Co. Hart Mfg. Co. Novelty Electric Co. Sprague Elec. Wks. of G. E. Co HANGER BOARDS, ARC Bryant Electric Co. General Electric Co. HEATERS, ELECTRIC (Soldering and Flat Irons) Cutler-Hammer Mfg. Co. General Electric Co. Westinghouse Elec. & Mfg. Co INSULATING JOINTS The Macallen Co. Trumbull Elec. & Mfg. Co. INSULATORS, POLE LINE Hemingray Glass Co. Fred. M. Locke KNOBS & CLEATS, PORCELAIN Cook Pottery Co. Findlay Elec. Porcelain Mfg. Co. General Electric Co. LAMP GUARDS McGill Mfg. Co. LAMPS, INCANDESCENT Buckeye Electric Division General Electric Co. Lux Mfg. Co. National Lamp Wks. of G. E. Co. New York Elect. Lamp Co. Westinghouse Lamp Co. LAMPS, MERCURY VAPOR Cooper Hewitt Elec. Co. LIGHTNING ARRESTERS Electric Service Supplies Co. General Electric Co. Westinghouse Elec. & Mfg. Co. "MEGGERS" (For Measuring Resistance) James G. Biddle METERS, WATT General Electric Co. Westinghouse Elec. & Mfg. Co. MOTORS Century Electric Co. Emerson Elec. Mfg. Co. General Electric Co. Robbins & Myers Co. Sprague Elec. Wks. of G. E. Co Wagner Elec. Mfg. Co. Westinghouse Elec. & Mfg. Co. MOTORS, FAN (See Motors) MOULDING, METAL American Circular Loom Co. American Conduit Mfg. Co. National Metal Molding Co. PANEL BOARDS Frank Adam Electric Co. Grouse-Hinds Co. Bryant Electric Co. General Electric Co. Post-Glover Electric Co. Sprague Elec. Wks. of G. E. Co Trumbull Elec. Mfg. Co. PLUGS, ATTACHMENT Bryant Electric Co. Cutler-Hammer Mfg. Co. General Electric Co. Trumbull Electric Mfg. Co. RECEPTACLES Bryant Electric Co. The Cutter Co. General Electric Co. Trumbull Elec. Mfg. Co. REFLECTORS, SHADES National Metal Stamping & Mfg. Co. H. W. Johns-Manville Co. Reflectolyte Co. RHEOSTATS Cutler-Hammer Mfg. Co. General Electric Co. Sprague Elec. Wks. of G. E. Co. Westinghouse Elec. & Mfg. Co. ROSETTES Bryant Electric Co. General Electric Co. Trumbull Elec. Mfg. Co. SOCKETS, STANDARD Bryant Electric Co. General Electric Co. SOCKETS, PORCELAIN Bryant Electric Co. Cutler-Hammer Mfg. Co. General Electric Co. SOCKETS, WEATHERPROOF Bryant Electric Co. Crouse-Hinds Co. General Electric Co. H. W. Johns-Manville Co. Trumbull Elec. Mfg. Co. SOLDERING FLUX Burnley Battery & Mfg. Co. M. W. Dunton Co. SWITCHBOARDS (See Switches, Knife) SWITCH BOXES Bryant Electric Co. Chicago Fuse Mfg. Co. Crouse-Hinds Co. Detroit Fuse & Mfg. Co. General Electric Co. Hart Mfg. Co. H. W. Johns-Manville Co. Sprague Elec. Wks. of G. E. Co. SWITCHES, KNIFE Frank Adam Electric Co. Bryant Electric Co. Crouse-Hinds Co. General Electric Co. Post-Glover Electric Co. Trumbull Elec. Mfg. Co. Walker Electric Co. Westinghouse Elec. & Mfg. Co. SWITCHES, OIL BREAK General Electric Co. Westinghouse Elec. & Mfg. Co SWITCHES, SNAP Bryant Electric Co. Cutler-Hammer Mfg. Co. General Electric Co. Trumbull Elec. & Mfg. Co. SWITCHES, FLUSH, PUSH Bryant Electric Co. Cutler-Hammer Mfg. Co. Cutter Elecl. & Mfg. Co. General Electric Co. Hart Mfg. Co. Trumbull Elec. Mfg. Co. SWITCHES, FLUSH, ROTARY Bryant Electric Co. General Electric Co. Hart Mfg. Co. SWITCHES, FLUSH, TOGGLE Newton Manufacturing Co. TAPE, FRICTION, INSULATING Clifton Mfg. Co. M. W. Dunton Co. H. W. Johns-Manville Co. The Okonite Co. Standard Underground Cable Co. TOGGLES U. S. Expansion Bolt Co. TRANSFORMERS, LIGHT AND POWER General Electric Co. Wagner Elec. Mfg. Co. Westinghouse Elec. Mfg. Co. TRANSFORMERS, BELL RINGING General Electric Co. Westinghouse Elec. & Mfg. Co. WIRE, ASBESTOS COVERED D & W Fuse Co. WIRE, BARE, COPPER American Brass Co. Phillips Ins. Wire Co. John A. Roebling's Sons Co. Standard Underground Cable Co. WIRE, MAGNET (See Wire, Rubber Covered) WIRE, RUBBER COVERED American Electrical Works Atlantic Ins. Wire & Cable Co. Belden Mfg. Co. Bishop Gutta-Percha Co. Detroit Ins. Wire Co. General Electric Co. B. F. Goodrich Co. Habirshaw Elec. Cable Co. Indiana Rubber & Ins. Wire Co. Kerite Ins. Wire & Cable Co. Lowell Ins. Wire Co. National India Rubber Co. The Okonite Co. Phillips Ins. Wire Co. John A. Roebling's Sons Co. Rome Wire Co. Simplex Wire & Cable Co. Standard Underground Cable Co. WIRE, FLEXIBLE CORD (See Wire, Rubber Covered) WIRE, SLOW-BURNING American Brass Co. American Electrical Works Chicago Ins. Wire Co. General Electric Co. Phillips Ins. Wire Co. John A. Roebling's Sons Co. Standard Underground Cable Co. WIRE, SLOW-BURNING WEATH- ERPROOF Chicago Ins. Wire Co. General Electric Co. Standard Underground Cable Co. WIRE, WEATHERPROOF American Brass Co. American Electrical Works Chicago Ins. Wire Co. General Electric Co. National India Rubber Co. Phillips Ins. Wire Co. John A. Roebling's Sons Co. Simplex Wire & Cable Co. Standard Underground Cable Co. WIRE, RESISTANCE Driver-Harris Wire Co. List of Manufacturers of Standard Apparatus and Supplies Only Apparatus and Supplies that are officially approved, or per- mitted to be used, by the National Board of Fire Under- writers will be accepted in the following pages. ADA'M ELECTRIC CO., FRANK 288 ALPHADUCT CO 332 AMERICAN BRASS CO 320 AM. CIRCULAR LOOM CO 327 AMERICAN CONDUIT MFG. CO 274-C77 AMERICAN ELECTRICAL WORKS 309 ATLANTIC INS. WIRE & CABLE CO 304 ATLAS SELLING AGENCY 342 BELDEN MFG. CO 317 BIDDLE, JAMES G 343 BISHOP GUTTA-PERCHA CO. 302 BRYANT ELECTRIC CO 286 BUCKEYE LAMPS 296 BURNLEY BATTERY & MFG. CO 356 CENTURY ELECTRIC CO 354 CHICAGO FUSE MFG. CO 339 CHICAGO INS. WIRE & MFG. CO 316 CLARK ELECTRIC MFG. CO 347 CLIFTON MFG. CO 328 COOK POTTERY CO 351 COOPER-HEWITT ELECTRIC CO 297 GROUSE-HINDS CO 335 CUTLER-HAMMER MFG. CO .-, 273 CUTTER CO., THE ..... . !! 282-283 D. & W. FUSE CO 318 271 DETROIT FUSE & MFG. CO 338 DETROIT INSULATED WIRE CO.., 314 DOSSERT & CO 321 DRIVER-HARRIS WIRE CO 319 DUNTON CO., M. W 357 ELECTRIC VEHICLE HAND-BOOK 359 ELBLIGHT CO. OF AMERICA 298 ELECTRIC SERVICE SUPPLIES CO 291 EMERSON ELECTRIC MFG. CO 355 FINDLAY ELEC. PORCELAIN MFG. CO.... 350 GENERAL ELECTRIC CO . 278-279 GILLETTE- VIBBER CO 337 B. F. GOODRICH CO 315 HABIRSHAW ELECTRIC CABLE CO 305 HART MFG. CO 284 HEMINGRAY GLASS CO 346 HOYT ELECL. INST. CO 345 INDIANA RUBBER & INS. WIRE CO 312 JOHNS-MANVILLE CO., H. W 341 KERITE INS. WIRE & CABLE CO 300 KILLARK ELECTRIC MFG. CO 340 LOCKE, FRED M 348 LOWELL INS. WIRE CO 308 LUX MFG. CO 295 MACALLEN CO., THE 280-281 McGILL MFG. CO 299 NATIONAL INDIA RUBBER CO 307 NATIONAL LAMP WORKS OF G. E. CO-. 294 NATIONAL METAL MOLDING CO 326 NATIONAL METAL STAMPING & MFG. CO 358 NEW YORK ELECTRIC LAMP CO 324 NEWTON MFG. CO 285 NOVELTY ELECTRIC CO 336 OKONITE CO., THE 301 PHILLIPS INS. WIRE CO 306 PHOENIX GLASS CO 323 PIGNOLET, L. M 344 POST-GLOVER ELECTRIC CO 289 PYRENE MFG. CO 360 REFLECTOLYTE CO 322 ROBBINS & MYERS CO 352 ROEBLING'S SON?' CO., JOHN A 303 ROME WIRE CO 311 SAFETY- ARMORITE CONDUIT CO 334 SIMPLEX WIRE & CABLE CO 310 SPRAGUE ELECTRIC WORKS OF G. E. CO 330-331 STANDARD UNDERGROUND CABLE CO 313 TRUMBULL ELEC. MFG. CO 287 TUBULAR WOVEN FABRIC CO 333 UNITED ELEC. LT. & POWER CO 349 U. S. EXPANSION BOLT CO 325 WAGNER ELECTRIC MFG. CO 353 WALKER ELECTRIC CO 290 WESTERN CONDUIT CO 3'29 WESTINGHOUSE ELECTRIC & MFG. CO 292 WESTINGHOUSE LAMP CO 293 WOOLLEY, W. DOUGLAS 340 272 CUTLER-HAMMER MOTOR CONTROLLERS Hand Operated and Automatic Types Hand Operated Type Motor Starter with No - Voltage and Atttomatic Starter. Overload Release. Cutler-Hammer Starters and Controllers are made for both direct and alternating current motors. When installing motors tell us what you wish to accomplish and we will send bulletin describing just the apparatus you need. C-H SOCKETS AND SWITCHES C-H 7110 New No. 7500 No. 7007 Push Button Brass Shell "Acorn" Brass Surface Switches Push Button Socket Shell Pendent The C-H line of specialties includes Porcelain and Brass Shell Pendent Switches, Sockets, Surface Switches, Flush Switches, Fix- ture Canopy and Candelabra Switches. Door Switches, besides a complete line of Attachment Plugs and Attachment Plug Receptacles. Ask for Push Button Specialty Catalog. THE CUTLER-HAMMER MFG. CO., Milwaukee Largest Manufacturers of Electric Controlling Devices in the World NEW YORK BOSTON PITTSBURGH Hudson Terminal Columbian Life Bldg. Farmers' Bank Bldg. CHICAGO PHILADELPHIA CLEVELAND Peoples Gas Bldg. Commonwealth Bldg. Guardian Bldg. CINCINNATI, Gwynne Bldg. PACIFIC COAST AGENTS: H. B. Squires, 579 Howard St., San Francisco ; Los Angeles, San Fernando Bldg. ; Seattle, Wash. 271 WIREMOLD- No. 500 Wiremold The New And Different Metal Molding WIREMOLD does not come apart base and capping are per- manently assembled at the factory. WIREMOLD is two-wire size just big enough for easy fishing of a pair of 14's or 12's. WIREMOLD ''fishes," it goes up in one piece and in many other ways works like conduit. WIREMOLD 'has just a few simple fittings many of them standardized to work with things you always have on hand, like sockets for example. WIREMOLD comes in ten-foot lengths and complete with one coupling to each length another one of the ways in which it resembles conduit. WIREMOLD is manufactured only by The American Conduit Manufacturing Company at PITTSBURGH Fig. 1 Fig. 2 Fig. 3 Wiremold, like rigid conduit, is furnished with one coupling to each length. , To assemble, first shove the coupling forward and fasten to surface with a No. 8 flat head wood screw, as in Fig. i above, second start the end of the next length over coupling, as in Fig. 2, and third close up as in Fig. 3, -WIREMOLD- 274 WIREMOLD Fig. 1 Fig. 2 Fig. 3 Fig. 4 Base plates of all "Wiremold" fittings are provided with coupling tongues, as can be seen from the broken edge view of a tee base in Fig. i and of an outlet box .base in Fig. 3 above. In coupling "Wiremold" to fittings it is therefore only necessary to shove the grooved edges of the molding over these tongues as in Figs. 2. and 4. No. 511 90 Flat Elbow Non-Splice Type No. 512 45 Flat Elbow Non-Splice Type No. 513 90 Flat Elbow Splice Type No. 515 Plain Tee No. 514 45 Flat Elbow Splice Type WIREMOLD 275 WIREMOLD- No. 517 Internal Elbow No. 522 Cord Rosette No. 531 Blank Cover For Nos. 532-533 No. 525 Receptacle Base No. 532 2Y 2 " Outlet Box No. 538 Fixture Box No. 518 External Elbow No. 523 Fixture Rosette No. 533 3" Outlet Box No. 537 Extension Box WIREMOLD- 27 WIREMOLD- No. 581 y 3 " BOX Connector No. 588 Open Work Coupling No. 582 y 2 " Conduit Coupling No. 584 y 2 " Elbow Conduit Coupling No. 583 y 2 " Elbow Box Connector No. Flush Switch Box No. 551 Flush Switch Coupling Plate No. 561 Push Switch Cover No. 571 Standard Switch Cover . WIREMOLD- 277 A Device for Every Use Acorn Sockets Adapters Bayonet Base Candelabra, Medium Screw Base Angle Receptacles and Sockets Arj Lamp Celling Boards Attaching Plugs and Separable Re- ceptacles Miniature, Separable, Swivel Automobile Fuses and Cutouts, Hand Lamp, Switches, Wiring Supplies Boards Arc Lamp Ceiling, Pilot Lamp Connector Boxes, Cutout Buzzer Alternating Current, Combined Switch and Buzzer Candelabra Adapters, Receptacles, Sockets Candle Sockets Caps, Attaching Plug Car Wiring Receptacles Casings, Fuse Plug Celling Boards, Arc Lamp Celling Rosettes Celling Switches Clamp Insulators Clamps, Terminal Ground Clips, Fue Combined Socket and Attaching Plug, Switch and Attaching Plug, Switch and Buzzer, Switches and Cutouts Conduit Box Receptacles Condulet Receptacles, Switches Connector Boards, Pilot Lamp Copper Cable Terminals Cord Connectors Cutouts Electrolier, Enclosed Fuse, in Iron Boxes and Plug GENERAL ELECTRIC COMPANY Decorative Sockets Door Switches Double-Catch Sockets Electrolier Cutouts, Sockets, Switches Enclosed Fuses Enclosed Fuse Cutouts Entrance Switches Fan Motor Switches Flush Receptacles and Plates, Switchet, and Plates Fluted -Catch Receptacles, Pull Switches, Socket Fuse Wire Fuses Automobile, Enclosed, Glass Tube. Link, Plug GECO Flush Switches GECO Rosettes Ground Clamps Guards, Portable Lamp Insulator Clamp, Racks Keys Socket, Switch Lamp Guards, Portable Lever Switches D-12, Miniature. Motor Starting, Punched Clip, Quick Break Lock Attachments Locking Receptacles Sockets, Switches Machine Shop Receptacle Metal Shell Receptacle* Miniature Attaching Plugs, Lever Switches Receptacles, Snap Switches Sockets Momentary Contact Switches Motor Control Switches, Starting Switch 278 GENERAL ELECTRIC COMPANY Moulded Material Sockets Mult I -Catch Receptacles, Sockets Multiple Receptacles Outlet Box Receptacles Panel Board Switches Pendent Switches Plates Flush Receptacle, Flush Switch Plug Cutouts Plugs Attaching, Fuse, Separable Porcelain Cleats, Insulators, Knobs, Receptacles, Sockets Specialties, Switches Pull Sockets Pull Switches Punched Clip Lever Switches Push Button Switches Rack Insulators Racks, Insulator Receptacles Candelabra, Car, Conduit Box, Condulet, Flush, Fluted -Catch, Locking, Machine Shop, Metal Shell, Miniature, Mogul, Multi -Catch, Multiple, Outlet Box, Porcelain, Separable, Series, Sign Rings, Socket Rosettes Rotary Flush Switches Separable Receptacles and Attaching Plugs Scries Receptacles, Sockets Shadeholders, "Uno" Sign Receptacles Snap Switches Accessories, Snap Switch and Buz- zer, Snap Switch and Cutouts, Handles, Tubular Socket Keys, Plugs and Bushings, Rings Sockets Acorn, Aluminum Shell, Bracket, Candelabra, Candle, Decorative, Double- Catch, Electrolier, Fluted-Cateh, Hard Rubber, Key, 660 -Watt, Keyless, 600 Volt, Locking, Miniature, Mogul, Moulded, Multi- Catch, Porcelain, Pull, Pull 660-Watt, Series, Special, Streethood, Three-Way, Weatherproof, "9386" Type Special Sockets Specialties, Porcelain Stroethood Sockets Sub-bases Swlt hes and Plug Cutouts Automobile, Ceiling, Door, Elec- trolier, Entrance, Fan Motor, Flush Push Button, Flush Rotary. Lever, Locking, Momentary Con- tact, Motor Control, Motor Start- ing, Panel Board Type, Pendent, Plates Porcelain, Push Button, Snap Swivel Attaching Plug Swivel Attaching Plug and Socket Terminal Ground Clamps Three- Heat Connector Plug, Recep- tacles "Uno" Shadeholders Weatherproof Attaching Plugs and Sockets Sold by Distributors in All Large Cities 6674 MACALLEN ARMORED INSULATING JOINTS This ARMORED Joint is the result of over twenty years' experience in the manufacture of Insulating Joints. It has the greatest mechanical and electrical strength, and is the most compact joint ever made. These joints will be regularly inspected and labeled under the supervision of the Under- writers' Laboratories, Inc., under the direction of the National Board of Fire Underwriters. The Macallen Company Macallen & Foundry Streets Boston, Mass. Catalogues and Price Lists Furnished Upon Application. 280 MACALLEN Canopy Insulators Patented July 13, 1897. Regularly inspected and labeled under the su- pervision of the Underwriters' Laboratories, Inc., under the direction of the National Board of Fire Underwriters. They are designed to go between the canopy and the wall or ceiling, where combination or straight electric fixtures are installed in buildings that are constructed with metallic lathing, or where there are metal ceilings or walls used. They are made of a special compound that is thoroughly waterproof, strong, durable, and of the highest insulating qualities. We manufacture these insulators to fit all standard sizes of canopies. The Macallen Company Macallen & Foundry Streets Boston, Mass. Catalogues and Price Lists Furnished Upon Application. 281 I-T-E Circuit Breakers for every service The next time a fuse blows replace it with an I-T-E Circuit Breaker The Cutter Co. PHILADELPHIA 282 Flush* Plugs, Screw Plugs and Flush Switches The Cutter Co. PHILADELPHIA 283 A TRADE MARK and AN IDEA In the manufacture of all "DIAMOND H" products, one idea has always pre- dominated. That idea can be expressed fundamentally in three words '.Thor- oughness, Quality, Service Thorough- ness is a fundamental of "DIAMOND H" policy, because thoroughness in de- sign, materials and construction can alone produce quality. Quality is a "DIA- MOND H" fundamental,' because noth- ing but quality can guarantee service. Service is the "DlAMpND H" ideal, be- cause nothing but service-giving capacity can create a permanent and growing business. In the "DIAMOND H" Trade Mark, this Company has aimed to sym- bolize the utmost of value to the buyer. How well we have succeeded is best testified to by the fact that a product bearing a at once, and has been for over twenty years, as the best in its field. '"DIAMOND H" Switches, Receptacles, Remote Control Switches and Hotel Door Switches. THE HART MANUFACTURING COMPANY HARTFORD, CONN. 284 NEWTON TOGGLE SWITCHES A distinct advance over all previous practice is represented in these switches, in which a lever movement replaces push button or key movement. The Newton Flush Toggle Switch plate is only */$ the size of the ordinary switch plate, has no fastening screws, is furnished in a variety of handsome styles and finishes. The Newton Surface Toggle Switch is handsome in appearance, and is self- indicating without any marker or dial. The Newton Toggle mechanism is durable and simple, the make-and- break quick and positive. Newton Toggle Switches are becoming the standards for all high-class work. NEWTON MANUFACTURING CO. LYNBROOK, NEW YORK Newton Toggle Switches are officially ap- proved. Send for descriptive pamphlet giv- ing styles, fin- i she s and prices. Dis- counts quoted on request. 885 SMRWN REG. U.S. PAT. OFF. The Real STANDARD Line of INTERCHANGEABLE Plugs and Receptacles The Spartan Interchangeable Line provides over Five Hun- dred (500) different combina- tions, meeting practically every requirement for residence, hotel, industrial, office, amuse- ment and display service. 31 Different Receptacles 12 Different Caps (plugs) provide for your needs in the simplest way. Simplify your work and eliminate the neces- sity for handling many different lines. Regular caps are reversible in all Receptacles. Polarity (non- reversible) Caps fit same re- ceptacles but unique design of blades prevents reversal of polarity. Ask for our catalogue giving full details of the Spartan line and the complete line of Bryant wiring devices. Above are shown the six caps (reversible style) and three of the 31 Different Receptacles of the Spartan Standard line. THE BRYANT ELECTRIC COMPANY BRIDGEPORT, CONN. NEWYORK CHICAGO SAN FRANCISCO 286 "CIRCLE T" TRUMBULL SAFETY PANELS Showing Fuses Inner door open, fuses locked NO LIVE PARTS Door Within a Door This type of panel is equipped with push switches and plug fuse receptacles only. Base is moulded heat proof composition, with a backing of "%" "Transite," insulation resistance being much higher than any grade of slate or marble, and non-absorptive. All copper bars are enclosed between the base and back. The main lugs are covered by a removable moulded section. This panel can be furnished in a regular cabinet, but where access to the fuses is to be limited to but certain persons, it can be furnished in a cabinet having a door within a door. The door over the fuses to be locked, the inner door furnished with a catch only or lock if desired. THE TRUMBULL ELEC. MFG. CO. PLAINVILLE, CONN. 287 PANEL BOARDS AND STEEL CABINETS METER CONTROL PANELS s w i T C H E S Our Cabinets and Panel Boards fill all the re- quirements as shown on page 125 of this issue o( Standard Wiring. We also manufacture SAFETY type panels and cabinets. Our Catalog sent on request. FRANK ADAM ELECTRIC CO. ST. LOUIS, MO., U. S. A. 288 The Post-Glover Electric Co. CINCINNATI :-: :-: OHIO Manufacturers of Switch Boards Standard and Special Boards for direct and alternating current. Panel Boards For 125, 125 to 250 and 250 volts for 2 to 2 wire, 3 to 2 wire and 3 to 3 wire sys- tems, designed for open link fuses, N. E. C. S. enclosed fuses or plug fuses, with or without switches in mains. Approved by Underwriters. Cabinets, Flush or Surface types, constructed of steel or wood with or without wiring compartments, with wood or steel trims and with or without glass paneled doors. Approved. Knife Switches Type A 125, 250 and 600 volts front or back connected, with or without fuse con- nections, 30 to 5,000 amperes, latest de- signs. Special switches. Approved by Underwriters. We also manufacture a quality line of lighting fixtures. Write for catalogues and prices. Panel Boards Knife Switches and Switchboard Accessories Walker Electric Company PHILADELPHIA 290 YOUR ONLY PRICE FOR SAFETY Type CE-2 PC Arrester Type CE-2 Station Arrester The circuit breaker used in combination with a small air gap distance and a low series resistance h as given Carton-Daniels Lightning Arresters their well known characteristics of efficiency and durability. The air gaps mean protection to your electrical apparatus be- cause they arc over and discharge potentials Out slightly higher than normal. The low series resistance will eliminate surges, winking lights and other voltage disturbances on your circuits, because it limits the flow of line current following the lightning discharge to ground to a moderate value about 10 amperes. The circuit breaker will eliminate grounds and short-circuits on your lines, because it cuts off this flow of line current to ground. You can get complete lightning protection only from an arrester combining these three essential functions. An installation of Carton-Daniels is your only price for Safety. Write for catalog. ELECTRIC SERVICE SUPPLIES CO. Railway Material and Electrical Supplies PHILADELPHIA, NEW YORK, CHICAGO, - - 17th and Cambria Sts. - - Hudson Terminal 417 So. Dearborn St. 291 New Westinghouse Switchboard Details Bus Support with corrugated insulator 69 Universal Mounting Bracket Bus Support with corrugated insulator 70 Mounting Bracket for Oil Circuit Bus Support with corrugated insulator Breakers Bus Support with corrugated insulator 71 Mounting Bracket for Current Bus Support with corrugated insulator Transformers Bus Support with corrugated insulator 72 Mounting Bracket for Current Bus Support with corrugated insulator Transformers Insulator, Corrugated Porcelain Bus- Strap Support Bus-Bar Bracket Bus-Bar Bracket Bus- Strap Support Bus -Strap Support Bus- Rod Bracket and Supports Bus -Rod Bracket and Supports Bus- Rod Bracket and Supports Bus- Rod Bracket and Supports Insulator, Plain Porcelain Bus -Rod Bracket and Supports Bus-Rod Bracket and Supports Bus- Strap Bracket Bus- Strap Bracket Bus-Wire Bracket Bus- Wire Bracket Bus-Bar Clamps Bus-Bar Clamps Bus-Bar Clamps Bus-Bar Terminal Bus-Bar Terminal Terminal iTniversal Auxiliary Bracket Universal Mounting Bracket Universal Mounting Strap 74 Pipe Mounting Bracket 77 I-Beam Clamps 78 I-Beam Clamps 80 Pipe Conduit Clamps 81 Pipe Bracket 83 Pipe Saddle Clamps 84 Clamp 85 Clamp 88 Pipe End 89 Pipe End 90 Pipe Brace and Clamp 93 Wall Brace with Angular Adjust- ment 94 Wall Brace with Angular Adjust- ment 95 Wall Brace with Angular Adjust- ment 96 Wall Brace wifli Angular Adjust- ment 98 Barrier Bracket for Pipe Mounting 99 Mounting Clamp Bracket 103 Mounting Clamp Bracket 106 Pipe Cross Clamp 107 Pipe Flange Clamp 10S Mounting Clamp Bracket 109 Mounting Clamp Bracket The whole line designed with particular attention to strength requirements necessitated by stations of present-day design and capacity. Write for Catalogue Section Z?.S'-1523. WESTINGHOUSE ELECTRIC AND MANUFACTURING CO. East Pittsburgh, Pa. 29S Back of this Lamp there is a guarantee of quality which is all that the most dis- criminating buyer can ask. a name that for thirty-six years has stood for the highest attainment in the art of lamp manufacture and is an absolute in- surance of satisfac- tory lamp service. If you buy lamps that are labeled "Westinghouse" you know that you are getting your 'money's worth and more. GUARANTEED BY THE NAME Westinghouse Lamp Company Atlanta Baltimore Boston Chicago Cincinnati Cleveland Columbus Dallas Denver Detroit Kansas City Los Angeles Milwaukee New Orleans New York Philadelphia Pittsburgh Portland St. Louis Salt Lake City San Francisco Syracuse Westinghouse Lamp Corporation. Export Sales Dept. 165 Broadway, New York City. For Canada Canadian Westinghouse Co., Limited, Hamilton, Out. NATIONAL MAZDA The Way to Better Light National MAZD/ Lamp quality i founded on th< technical k n o w 1 edge of experts. I is the sum tota result to date o years of researcl effort put forth bj the world's fore most lamp labor a tories. OF GENERAl ELECTRIC CO. NELA PARK CLEVELAND Licensed under General Electric Co. Patents ARGON and NITROGEN LAMPS ARE PARTICULARLY PROMI- NENT DUE TO THEIR HIGH ^ STANDARD OF QUALITY AND EFFICIENCY; AND THE GREAT VARIETY OF SIZES MANUFACTURED From the Smallest 40 watts 50 60 75 100 150 200 250 300 350 400 500 750 IOOO 1500 to the Largest " Lux Lamps Last Longest ' LUX MANUFACTURING CO. M' HOBOKEN, N. J. 295 Buckeye Mazda The Most Efficient Lamps Manufactured Today Bear the trade-mark "Mazda." Made in all sizes from 10 watt to 1,000 watt. Secure maximum efficiency by using "Buckeye Mazda Lamps" in every socket. Special lamps for special purposes. Our Engineering Dept. is at your services and will be glad to assist you in any lighting problems you may have. .*. The /. Buckeye Electric Division National Lamp Works of General Electric Co. Cleveland Chicago Pittsburgh Who? Who, are the largest users of artificial light at present ? i The automobile plants. 2 The munition manufacturers. 3 Machine tool builders. 4 Motion Picture Studios. . Who are using Cooper-Hewitt Lamps to secure "Better Than Daylight" conditions) i Btiick, Continental Motors, Dodge Bros., Ford, Hupp, Maxwell, Packard, Reo, Stude- baker, White, Willys-Overland and others. 2 American Locomotive, E. W. Bliss, Chicago Pneumatic Tool, Detroit Screw Works, Peters Cartridge Co., Remington Arms, U. S. Cartridge Co., Westinghouse Air Brake Co., Winchester Repeating Arms and others. 3 E. W. Bliss, Cincinnati Bick- ford, Cincinnati Ball Crank Co., Cincinnati Milling Ma- chine Co., Cincinnati Planer Co., Columbus Die & Tool Co., Erie Forge, Hamilton Machine Tool Co., Johnson & Jennings, R. K. LeBlond, Toledo Ma- chine & Tool Co. and others. 4 Biograph Co., Essanay, Fa- mous Players, Fox, George Kleine, Kalem, Metro, Mutual, N. Y. Motion Picture, Pathe, Universal, World and others. Cooper - Hewitt Electric Company General Offices and Works, 8th and Grand Streets, Hoboken, N. J. B..l.n Chk*| Cincinnati Cl.T.liiul Detroit Philadelphia Pittsburgh St. Loui, 297 ELBLIGHT LAMPS AND CABLES Make the Officially Approved System for Ail ELECTRICAL DECORATIONS. See Page 159 in This Issue A few of the beautiful effects produced by THE ELBLIGHT SYSTEM Easy to install, easy to take down. Economical and artistic for both Inside and Outside Effects. Sold or rented at attractive rates. Send for illustrated catalog and price lists. ELBLIGHT COMPANY OF AMERICA Electrical Decorators 133 West 24th Street NEW YORK 298 LOXON" LAMP GUARDS THE KEY TO SAFETY Two expensive ele- ments of loss face the lamp user. To stop breakage he must use a guard, to stop theft he must use a lock. A guard fastened with wire or set screw can- not stop a thief; nor can a patent socket prevent lamp breakage. The Loxon Lamp Guard, which locks the lamp into a socket with a key, does this double duty at single cost. Send for Catalog and Price on Our Com- plete Line Dreadnaught Portable Lamp Guard A very strong portable guard made of Bessemer steel, built to withstand hard usage and can be recommended to give unusual service. Has a porcelain keyless socket fitted with spring con- tact firmly embedded in handle. Takes a 6o-Watt Lamp. Metal part copper plated finish. Made in only one size and finish. McGILL MFG. CO. No. 2 Beach Street VALPARAISO INDIANA 299 Out of the experienced past, ifrtpthe exacting present, KERITE through morethari a half-century of success- fyl service, continues asthe standard by which engineering judgment measures msulatinlvalut NEW YORK CM,* 800 TRADE MARK. REG. U. S. PATENT OFFICE The STANDARD for Rubber Insulation OKONITE Insulated WIRES and CABLES are standard because of their unvarying reliability in service. CANDEE Pot Heads OKONITE Tape MANSON Tape Sole Manufacturers THE OKONITE COMPANY 253 Broadway, New York 801 Write Into Your Specifications Para Rubber Compound) Iron Armored Submarine Cable. Lead Covered Under- ground Cable. Aerial Cables. Flexible Cables. Special Cables, also. "Paraxel" is "The Leader" of All Rubber Insulated Wires Special Wire to any Specifications Bishop Gutta Percha Co. 420-430 E. 25th St., N. Y. City. Telephone 21 Madison Square. 102 RDEBL1ND WIRES and CABLES Aerial Cables Annunciator Wire Annunciator Cables Automobile Horn Cord Automobile Lighting Cables Automobile Starter Cables Automobile Charging Cables Automobile Ignition Cables Armature Coils Armature Leads Asbestos Braided Wire Brush Cables Border Light Cables Brewery Cord Battery Wire Bridle Wire Bare Copper Wire Bare Copper Strands Bare Braided Copper Copper Wire, Bare Copper Strands, Bare Gas Engine Cables Heater Cord Ignition Cables Interior Telephone Wire Insulating Paper Insulating Tape Jumper Wire Lamp Cord Lighting Cable, Automobile Locomotive Cables, Mine Moving Picture Cord Messenger Strand Mining Machine Cables Motor Lead Cable Magnet Wire Motor Boat Wires and Cables Motorcycle Wires and Cables Office Wire and Cables Oilproof Finishing Braids Power Cable, Rubber Insulated Power Cable, Cambric Insulated Charging Cable for Elec. Vehicles Power Cable, Paper Insulated Copper Clad, Rubber Insulated Packing House Cord Paraffine Wax Rubber Covered Wire, N. E. C. S. Rubber Tape Starter Cables Sweeper Cord Spider Wire Stage Cables Signal Wire and Cables Submarine Cable Switchboard Wire Switchboard Cords Switchboard Cable Slow Burning Wire Solenoids Copper Clad, Weatherproof Cambric Cables Canvasite Cord Control Cable for Elevators Car Wire and Cables Cotton Tubing or Sleeving Copper Sleeves Copper Bells Compound, Pothead No. 1 Compound, Splicing No. 2 Compound, Telephone No. 3 Drop Wire Deck Cables Electric Horn Cord Electric Vehicle, Charging Cables Secondary Spark Coils Electric Locomotive Cables Elevator Annunciator Cables Elevator Lighting Cables Elevator Control Cables Enameled Wire Fixture Wire Fireproof Wires Flameproof Wire Fire and Weatherproof Wire Field Coils Friction Tape Gas Fixture Wire Silk Tubing or Sleeving Telephone Cords Telephone Wire Telephone Cable, Pap?r Insulation Telephone Cable, Rub'r Insulation Tubing, Cotton and Silk Telegraph Wire Telegraph Cable, Paper Insulation Telegraph Cable, Rub'r Insulation Vacuum Cleaner Cord Vibrator Cord Weatherproof Wire JOHN A. ROEBLING'S SONS COMPANY TRENTON, N. J. 803 ATLANTIC WIRES AND CABLES RUBBER INSULATED NATIONAL ELECTRICAL CODE STANDARD Three brands that mark the maximum of quality and ser- vice in their re- spective grades of insulated wire. WRITE FOR OUR PRICE LIST AND DISCOUNTS Commercial Code ATLANTIC INSULATED WIRE & CABLE CO. Sales Office: 125 Cedar Street, New York Factory: Stamford, Ct. 304 Known and recognized all over the world as a standard - - proven by over 30 years of faith- ful service. Look for three blue threads parallel in braid HABIRSHAW "Proven by the test of time" Insulated Wire Obtainable in all large cities at the Western Electric^ Company Manufactured by THE HABIRSHAW ELECTRIC CABLE CO., Inc. New York City and Yonkers, N. Y. 305 * 306 Catalogue Mailed Free All conductors carefully tested N. I. R. HIGH GRADE Rubber Covered Wires and Cables FOR EVERY SERVICE Electric Light, Power, Railway Telephone and Signal NATIONAL BRAND Weatherproof and Slow Burning WIRES AND CABLES National Electrical Code Standard NATIONAL INDIA RUBBER COMPANY General Sales Office and Factory BRISTOL, R. I., U. S. A. New York 1790 Broadway Chicago San Francisco Clinton and Van Buren Sts. 579 Howard Street Boston, 201 Devonshire Street Seattle, 524 First Ave., South. 307 Rubber Covered Lamp Cords Automobile Cable Show Window Cords : Telephone Wire Lowell Insulated Wire Co. LOWELL, MASS. STAR BRAND WEATHERPROOF WIRE & CABLE PAPER INSULATED UNDERGROUND CABLE (Single, Duplex & Three Phase) TROLLEY WIRE (Round, Grooved or Figure 8) BARE COPPER WIRES & CABLES Magnet Wire (Cotton qr Asbestos) Americanite Rubber Covered Wire Incandescent Lamp Cord Galvanized Iron and Steel Wire and Strand AMERICAN ELECTRICAL WORKS PHILLIPSDALE, R. I. BOSTON CHICAGO CINCINNATI NEW YORK 176 Federal 1 12 W. Adams Traction Bldg. 165 Broadway SAN FRANCISCO SEATTLE 612 Howard St. 1002 First Ave. South 300 SIMPLEX WIRES AND CABLES RUBBER CAMBRIC PAPER SIMPLEX WIRE &CABIE@ MANUFACTURERS 2O1 DEVONSHIRE ST.. BOSTON CHICAGO SAN FRANCISCO Rome Wire Company ROME, N. Y. Our Specialties Rubber Covered Code Wire Lamp Cord Telephone Wire ROUND-SQUARE-FLAT MAGNET WIRE YOU GET OUR PERSONAL ATTENTION ON ALL ORDERS 811 INDIANA RUBBER AND INSULATED WIRE CO. Paranite Rubber Covered Wires and Cables IF irs P A K A nl I p irs RIGHT More Than Code Requires Underground, Aerial, Submarine and inside use Telephone, Telegraph and Fire Alarm Cables Factory and General Offices, Jonesboro, Ind. Chicago Office, 210 So. Desplaines St. Chicago, Illinois. Eastern Representatives, THOMAS & BETTS CO. 105 Hudson St., New York 312 AWARD RIBBON STANDARD Wires and Cables Bare Copper Wire Brass and Bronze Wire (Colonial Copper Clad) Magnet Wire Weatherproof Wire Rubber Insulated Wire Varnished Cambric Cable Fibre Lead Covered Cable Paper Lead Covered Cable Armored Cable Cable Accessories Cable Terminals Cable Junction Boxes "Ozite" Insulating Compounds Jointing Supplies Miscellaneous Accessories P r oduc^f re- Write our nearest office concerning MACHINERY ceived the high- est specific award granted Electric Wires, Cables and Ac- cessories. Boston New York Philadelphia Atlanta Washington your requirements. Standard Underground Cable Co. Pittsburgh, Pa. Pittsburgh Cleveland Chicago Detroit Minneapolis St. Louis Los Angeles Seattle Salt Lake City San Francisco For Canada : Standard Underground Cable Co. of Canada, Ltd., Hamilton, Ontario 313 NATIONAL ELECTRICAL CODE WIRE OF ALL KINDS "DETROIT" RUBBER COVERED WIRES Insulated Telephone Wires. " Ajax" Copper Clad Flame Proof Wire Standard Copper Clad Jumper Wire H. D. Copper Drop Wire Bridle Wire Interior Wire Automobile Wires. Charging Cable Starter Cable Ignition Wire Lighting Wire Horn Wire Miscellaneous Wires. Battery Wire Fixture Wire Border Light Cable Gas Engine Cable Brewery Cord Lamp Cord Canvasite Cord Mining Machine Cable Deck Cable Elevator Cable Door Bell Wire INSULATED WIRES FOR ALL ELECTRICAL USES. DETROIT INSULATED WIRE CO. Detroit, Mich. 314 Tests made by the Underwriters Laboratories of Chicago on DIAMOND Rubber Insulated WIRES and CABLES Braided and Lead Encased sliow no demerits for the last eighteen months. Unusual ? No. For years Diamond brand wires and cables have stood without demerits. They are absolutely the best rubber insulated wires and cables that our ex- perience compounding 156,000,000 pounds of rubber goods per year can make. Millions of feet are now in use. The number of users is steadily increasing and we attribute this success to one great, big fundamental quality. SAFE and ECONOMICAL For Electric Light and Power Plants, Manufacturers, Engineers, Contractors, Dealers, Telephone and Telegraph Companies, Rail- roads, Central Stations and Ship-chandlers, Diamond Quality Wires and Cables are good insurance. What are your specifications? Diamonds conform to the N. E. Code specifications. Also made to meet any special specifications or requirements. The B. F. Goodrich Company AKRON, OHIO. 315 ESTABLISHED 1885 " CHIC AGO BRAND " ELECTRICAL WIRES & CABLES EXPERIENCE - PROGRESS THIRTY-TWO YEARS CHICAGO INSULATED WIRE & MFG. CO. SALES OFFICE, MONADNOGK BUILDING, CHICAGO FACTORY, SYCAMORE, ILL. 316 One Chicago Contractor says "This Duplex with one Con- ductor white and one black saves me 25% on my wiring costs." Another "Finest Working Wire I ever used." TRADE MARK N. E. C. S. Rubber- Covered Wire & Cables Solid Conductor Single and Duplex Lamp Cord Telephone Wire Heater Cords Automobile, Ignition and Lighting Cable Annunciator Wire and Cables Office Wire Magnet Wire All Insulations Made in CHICAGO BELDEN MANUFACTURING COMPANY 2305 S. WESTERN AVE. CHICAGO 317 Deltabeston Wires MAGNET WIRE. Covered with pure asbestos fibre in a smooth flexible mass, which will not crack nor break, even when sharp bends are made. Tough, moisture-proof and indestructible under any commercial temperature. FIXTURE WIRE. For installations where temperature makes rubber covered wires impracticable, this smooth, flexible, tenacious asbestos fibre covering will give best protection and longest service. Especially adapted for wiring Type C Fixtures. FIXTURE WIRE. Same construction as the above, with the addition of a silk covering over the asbestos fibre to give a neat, attractive appearance where wiring of fixtures is exposed to view. Made in single, parallel and twisted pair conductors. HEATER CORD. Asbestos, insulated throughout; will not burn nor deteriorate like rubber. The special application of the .asbestos fibre re-enforces the strands of the conductor against their breaking and puncturing the insulation. The occurrence of short-, circuits is thereby eliminated and longer life obtained. STOVE WIRE. Furnishes perfect wiring for electric stoves and ranges, in and around ovens and boiler rooms. Insulated with espe- cially treated asbestos fibre and a tightly braided asbestos covering. MOVING PICTURE CABLE. A very flexible conductor haying a wall of asbestos fibre and a braided asbestos covering; moisture- proof; widely used where wires are subjected to high temperatures projectors, searchlights, railroad controllers, cranes, etc. Approved by the Underwriters' Laboratories, Inc. D& W Fuse Company Providence, R. I. 818 HARRISON; N.J. RESISTANCE ALLOYS Made right in the U. S. A.-- to best imported every way." ROUND OR \X7T1> T? BARE OR FLATTENED VV llvll/ INSULATED "NICHROME" For Electric Heaters "ADVANCE" For Controllers, Arc Lamps "CLIMAX" For Moving Picture Rheostats "No. 193 ALLOY" For Heavy Duty Rheostats "THERLO" For Instruments and Shunts A RESISTANCE WIRE FOR EVERY REQUIREMENT D. H. Quality Heater Cords "Make the slickest heater decidedly neater" Pure Nickel and Nickel Alloys Sheet Wire and Strip HARRISON, N.J 319 Wires and Cables BARE COPPER WIRE for Power Transmission, Telephone and Telegraph Lines FLAT COPPER WIRE for Armature and Field Coils TROLLEY WIRE Round, Grooved, Figure 8 and Special Patterns GERMAN SILVER WIRE for Resistance Purposes INSULATED WIRE "K.K." Weather-proof Line Wire Slow Burning Weather-proof Wire Magnet, Office and Annunciator Wire BARE TRANSMISSION CABLE WEATHER - PROOF STRANDED CABLE Prices Quoted Upon Application. The American Brass Co. ANSONIA BRASS & COPPER BRANCH Ansonia, Conn. BENEDICT & BURNHAM BRANCH Waterbury, Conn. DOSSERT CONNECTORS 2-Way Type A Showing Details. Dossert Connectors eliminate entirely the use of solder in making electrical connections and splices, and are approved for use without solder by the National Board of Fire Underwriters for all classes of wiring. By their use much labor is saved and splices obtained that will withstand any overload. Many careful tests show that a splice made by means of a Dossert Connector will not heat as much as. the cable which it connects when the cable is heavily overloaded. Type A Connectors are for use on. cables, stranded, or solid wires, rods and tubing. They are simple and effective, and by their use splices can be quickly made in condutcors of any size. Type A Connectors, however, should not be used on a cable that is to be subjected to heavy tensile strains. Type B Connectors are for use on stranded wires or cables only, and are designed to make a joint which will withstand heavy tensile strains. They are not made for wires smaller than No. 0. The Cable Tap is used to connect a branch wire, rod, or bleeder, to a main wire, rod or feeder. It not splice the main, but simply clamps on to it. Branch wire is connected to cable tap by means of a nut and sleeve as shown in Type A cut. With Dossert devices any combination of dif- ferent sizes of cables, stranded and solid wires, rods and tubing can be connected together. The cable tap will tap from any size main to any size branch. Terminal and switchboard lugs, front or back con- ected; angle and swivel lugs, insulated connec- tors; two-ways, 'three-ways, equalizers, cable anchors, reducers, elbows, Y's, serv- ice box lugs and plugs, grounding devices and stud connectors for threaded rods and flat strips or blocks made in every nec- essary size and form for all conceivable connections ranging from No. 14 to 2,- 500,000 C. M. conductors. Cable Tap Send for Tenth Year Catalogue Dossert & Company H. B. LOGAN, President 242 West 41st Street New York, N. Y. 321 REFLECTOLYTE :(Reg. U. S. Pat. Off.) MAKES DAY OF NIGHT Type C. F. unit of exceptional value, appear- ance and efficiency. A reflecting surface of a glasslike, non-porous enamel, insur- ing permanent, satisfactory, economical service. We also make Reflectolytes with Glass Reflectors. Send for Catalog. Manufactured by THE, REFLECTOLYTE CO. 914 PINE STREET ST. LOUIS, MO. PHENIXLITE The Semi-Indirect Light of High Efficiency \\l m\ i*i 11951 A Simple, Economical, Durable, practically Dustproof, absolutely Glareless Tungsten Arc, giving a large volume of illumination. Light is reflected from lower to upper reflector, thence outward and downward. Try it for better Illumination. Ask for Catalogue. THE PHOENIX GLASS COMPANY NEW YORK BOSTON CHICAGO PITTSBURG NYELCO STAR Semi-Indirect Unit The most efficient semi-indirect unit made. Scientifically designed to give most effective illumination wherever ni- trogen filled lamps are used. Very simple in construction. Can be installed by anyone. Ready to hang. List Price $2.50 Write for special discounts to Electrical Contractors and Electricians. NEW YORK ELECTRIC LAMP COMPANY Sales Department 38 PARK ROW NEW YORK CITY 324. EXPANSION BOLTS A Size and Style for Every Duty For Wood Screws (Nos. 5 to 18 Inclusive) For Lag Screws (#" to 1" Inclusive) ARROW SPRING TOGGLE QUICK AUTO- MATIC SURE SPRING in head automatically spreads wings as soon as toggle passes through hole. Arrow points on wings grip walls, in- sure instant bearing and prevent turning in hole. Toggle wings when opened and "set," clamp directly on threads of bolt, providing a positive nut-locking effect which prevents work from loosening under vibration, and supplying holding quality equal to strength of bolt itself. Write for Catalog and Samples. U. S. EXPANSION BOLT CO. 57 Duane St., New York. 325 "NATIONAL" Quality Products SHERARDUCT The rigid steel conduit with both interior and exterior surfaces protected with a non- corrosive zinc-steel alloy, further protected by coatings of a clear transparent acid and alkali proof enamel, baked on. ECONOMY Enameled Rigid Steel Conduit FLEXTUBE The Seamless Non-Metallic Flexible Con- duit with the inseparable "roller bearing" interior. FLEXSTEEL Flat Surfaced Flexible Metallic Conduit, Armored Conductors, Armored Lamp Cord, and a complete line of improved fittings. "NATIONAL" Metal Molding and Fittings Locknuts and Bushings Sherardized Stamped Steel Fixture Studs Outlet Boxes and Covers Solid Switch Boxes Wall Brackets Write for catalogue, samples or other desired information. National Melal Molding 6 PITTSBURGH Atlanta Chicago El Paso Portland Boston Denver New York Seattle Buffalo Detroit Philadelphia St. Louis Los Angeles Salt Lake City San Francisco 326 "XDUCT" GALVANIZED CONDUIT Easy-Bending Spellerized Steel Tube, Doubly Protected by Copper-Plating and Zinc- Coating. Clean Threads, Smooth Enameled Interior. "ELECTRODUCT ENAMELED CONDUIT Easy-Bending Spellerized Steel Tube, Protected by Coatings of Special Enamel. Smooth Interior. "LOOMFLEX" FLEXIBLE CONDUIT Seamless Interwoven Canvaslike Interior covered by a Light Cotton Braid. Clean to Handle. Easy to Cut and Fish. 'CIRCULAR LOOM' FLEXIBLE CONDUIT Fibre Spiral Interior, covered by Insulating Tape and a Heavy Woven Cotton Jacket American Circular Loom Co. Main Office: 90 West Street, New York SELLING AGENTS New York: R. B. Corey Co., 39 Cortlandt Street. Chicago : Geo. C. Richards, 557 W. Monroe St. San Francisco: L. E. Sperry, 629 Howard Street. Seattle : H. G. Behneman, Inc., 617 Fourth Ave. Los Angeles: R. B. Clapp, 626 San Fernando Bldg. Boston : C. Walter Jones, 16 Medford Street. 327 RIGID STEEL CONDUIT THE FINEST BLACK ENAMELED CONDUIT ON THE MARKET "BLACK" ENAMELED AND NO BETTER GALVANIZED CONDUIT MADE 'WHITE" GALVANIZED Friction Tape Splicing Compounds Armature Tapes CLIFTON MANUFACTURING CO. Jamaica Plain, BOSTON, MASS. Warehouses, Boston, New York, Buffalo, Chicago 328 The remarkable growth of demand for BUCKEYE CONDUIT and REALFLEX ARMORED CONDUCTOR is the best evidence of their quality and the advantages they offer to users. BUCKEYE Conduit is made from the best steel we can produce for that espe- cial purpose. It is made in the best manner and with the utmost care. REALFLEX is rapidly being recog- nized as the most flexible, durable and handsome of all armored conductors. You want the best. Try them. TheWesteraConduit Co. Youn^stown, Ohio. ^Subsidiary to The Youqgstown 5heet & Tube Co. TRADE MARK SPRAGUE C A B L E REGISTERED U.S.PAT. OFFICE And other conduit products of Sprague manufacture are the Standard Single Strip Flexible Conduit wmiwaakimn Greenfielduct Hot Galvanized Conduit Spragueduct Enameled Conduit Carried in Stock by Leading Distributors SPRAGUE ELECTRIC WORKS OF GENERAL ELECTRIC COMPANY Main Offices: 527-531 West 34th Street, New York, N. Y. Branch Offices in Principal Citie ; 330 SPRAGUE OUTLET BOXES Non- Ad j ustable Floor Box Outlet Switch and Junction Box 4 inches square, 1^ in. deep 3J4 inch Loom and Conduit Box Gang Switch Boxes For 5/2 inch or 24 inch Conduit Switch Boxes Outlets for Y 2 inch or ->4 in., only Interchangeable with Boxes and Covers of other manufacture Clean Cut Knockouts Carried in Stock by Leading Distributors SPRAGUE ELECTRIC WORKS OF GENERAL ELECTRIC COMPANY Main Offices: 527-531 West 34th Street, New York, N. Y. Branch Offices in Principal Cities 331 "Order by Name" ALPHADUCT Combines per- fect flexibility of conduit with strength and so- lidity of wall. Meets with in- stant approval of Architects, Engi- neers, Contrac- tors and Inspec- tors. Easiest to "Fish." Send for cata- ' ^^&^> "^ Try it and prove logue. *Scr!* it. THE HIGHEST ACHIEVEMENT IN THE ART OF INTERIOR CONDUIT CONSTRUCTION Inner lining of heavy canvas. Water-proof coat- ing. Hard fibre cord. All intersects filled with special compounds. Outer jacket. Outer coating, protection against dampness and abrasion. Finished Conduit. ALPHADUCT CO 36 CATOR AVE., ., JERSEY CITY, N. J. 333 DURADUCT REG. U. S. PAT. OFF. FLEXIBLE NON-METALLIC CONDUIT This is the only interwoven wall conduit be- cause it is the only single wall conduit. The "roller-bearing wireway" reduces friction in fishing 75%, saving time and labor. Of the highest grade only. Approved by Underwriters' Laboratories, Inc. Sold by live jobbers everywhere Tubular Woven Fabric Co. Mfrs., Pawtucket, R. I. A. HALL BERRY, General Sales Agent 97 Warren St., New York 9 S. Clinton St., Chicago CONDUIT WORK fLfODERN construction makes essential the use of an armor of metal protection to electric wires; mechanical injury during con- struction or after completion of the work causes such annoyance, expense and damage, that the first cost of a conduit system over knob and tube work, exposed wiring, molding or non-metallic tubing construction is now considered of no consequence when safety by metallic conduit protection is secured. FIRST IN PROTECTIVE QUALITIES IS "Galvaduct" ] "Loricated" [ Ri id conduits "S.-A.C. Co. Special"] "Sterling" Flexible Steel Conduit Metallic Flexible "Sterling" Steel Armored Conductor (All Patented) THEY ARE THE BEST Literature and samples upon request Safety-Armorite Conduit Company PITTSBURGH, PA. Rigid Conduit Agent NATIONAL TUBE CO. 334 Fused Ironclad Switches MK Series Type MKC (Door Open) Type MKC (Door Closed) All live metal parts are protected. Door to fuses cannot be opened when switch is closed. Switch can- not be closed when door is open. End plates are made with various sizes and ar- rangements of hubs to meet all conduit require- ments. rPMCh CROUSE-HlNDS COMPANY Ifelinl Syracuse, N. Y., U. S. A. Boston New York Cincinnati Chicago "Griptite" and "Flexclamp" GROUND CONNECTION CLAMPS Rigid and Flexible Conduit National Electrical Code Standard Patented Made of one piece of copper insuring perfect and permanent contact. Made for all Standard sizes of rigid and flex- ible metallic conduit. Pat. Pending "NECO" Wire Gauge Our IMPROVED "NECO" POCKET WIRE GAUGE, for meas- uring wire from No. 18 to No. 000 B. & S. Gauge. On the front is also given the carrying capacity of cop- per wire in amperes and on the re- verse side the approx. decimal equivalent of the various size wires. Mailed to any address in the United States or Canada upon re- ceipt of 60 cents in cash or money order. Manufactured by Novelty Electric Company Wholesale Electrical Supplies 50-52-54 North 4th St., PHILADELPHIA Agents for Okonite Wires and Cables Holtzer Cabot Motors Service Cap For service entrance work. Furnished with three hole two piece insulator. Seal furnished to close unused hole when used with but two wires. Brass Screws; gal- vanized finish. Insulators for sizes 1" and under, made of approved molded in- sulation; above 1" of porcelain. Can be applied after service is connected up by cutting out reduced section of frame with hacksaw. No. 6012 6034 6001 6114 6112 6002 6212 6003 Size y, inch y 4 inch 1 inch 1^ inch iy 2 inch 2 inch 2*/ 2 inch 3 inch List Prices. Unit Pkg. 10 10 Each $0.45 .50 .90 1.50 2.00 3.00 4.50 7.00 Terminal, Form'T For motor loop, meter loop and other inside work. A two-piece, cast iron terminal furnished with a three-hole, two- piece insulator. Seal fur- nished to close unused hole when used with but two wires. Galvanized finish. Insulators for sizes i" and under, made of molded insulation; for sizes above i"of porcelain. No. Size Unit Pkg. 10012 y 2 inch.. 10 10034 Y 4 inch.. 10 10001 1 inch.. 5 10114 1J4 inch.. 2 10112 l l /2 inch.. 2 10002 2 inch. 2 10212 2^ inch.. 1 10003 3 inch.. 1 337 Trade Reg. U. S. Mark Pat. Off. Electrical Safety "Square D" Steel Enclosed Service Switches and Distributing Cabinets A line of Installation and Service Devices Un- equalled in Excellence of Design and Finish, in Quality, in Safety of Operation and in Low Price. " SQUARE D" Features All live parts enclosed Control outside box Removable top and bottom end plates End plates interchangeable End Plates Standard Equipment Meter protective trim Meter trim and end plates inter- changeable Convenient knockouts Ground wire lugs Exclusive "locking off" device Roominess inside Connections easily made Not less than 30 Amp. capacity Made from 16 Ga. steel Corners electrically welded Finished in lustrous black enamel Switch and cutout mounted ready to install Satisfactory operation assured Prevents accidental contact with live parts Prevents tampering with service Approved by Underwriters' Labora- tories. Send for Bulletin 39 S.W. No. 5211E. With meter protective trim. Switch in "on" position, cabinet sealed. "ARKLESS" Fuses N.E.C.S. Only Guaranteed Mechanical Indicator Made All National Electrical Code Standard "ARKLESS" Fuses comply strictly with the requirements of the National Board of Fire Underwriters and are approved by the Underwriters' Laboratories after examination and test under the provisions of the National Electrical Code. We guarantee "ARKLESS" fuses to indicate, and will replace, free of charge, every "ARKLESS" fuse that fails to indicate when blown. Write for Bulletin 38 S. W. DETROIT FUSE & MFG. CO. Detroit, Mich. "Union" Fuses Much depends upon the Enclosed Fuse. It is usually the only Protection for apparatus of many times its own value. Its cost is slight compared with the value that it guards. Is it wise to experiment with fuses not proven to be reliable? "Union" Fuses have stood the test of time. They arc approved by the National Board of Fire Under- writers, are carried in stock by Jobbers in all Cities and the sizes, above 60 amperes, if returned to the factory, can be reloaded at a large saving to the user and are (( Approved." "Union" Cut-Outs, either in porcelain or slate, are carefully designed and well made. "Union" Outlet Boxes and Covers accommodate all regular wiring devices. "Union" Switch Boxes are the original and the most complete line. Write for Cat. No. 28. Chicago Fuse Mfg. Co, Chicago New York 339 Killark" Enclosed Fuses Accurately rated, carefully calibrated. Operate consistently and give dependable protection. "Electrolet" Conduit Fittings Inexpensive, convenient, easy to install and make the best looking job for Meter Loops. Motor Connections. Entrances to Buildings. Box Outlets. All Combination Wiring. Type <'A" Type "FB" Entrance Fitting The "FB" Entrance Fit- tings are reversible and may be installed either as Type "F" or Type "B" fittings. Electric Manufacturing Co. ST. LOUIS General Saks Representative W. DOUGLAS WOOLLEY 411 S. Jefferson Street CHICAGO 340 Each Service Connection is a separate counter over which the commodity you sell passes to the consumer and the meter, the cash register ! Does the switch and cutout and your service meter properly control the supply and measure the amount? What are you doing to Maintain and Ensure the Safety and Efficacy of the Service Connection : Prevent tampering with the meter and theft of un- metered current from your service : Simplify and facilitate the installation, connection and testing of your meter: Ensure positive interference-proof non-serving lock- off. Noark Universal Service and Meter Appliances provide in a single device Switch, Cutout, Meter and Service Protection, Meter Testing, Non-serving Lock- off, for any service condition ! The Universal Service Switch accomplishes in itself the results previously requiring several appliances, sur- passing all others in technical and economic features. Every central station operator concedes the need of a Safe, Tamper-proof Meter Testing Service Appliance, if it can be obtained at a per- missible price. Noark Universal Appliances meet that need: Thousands in use on the largest systems in the United States prove we have made good with others. Why not with you? Write for demonstration. H. W. JOHNS- MANVILLE CO. NEW YORK CITY Branches in 55 Large Cities 341 SIX IN ONE FUSE PLUG ACTUAL SIZE Six Fuses in one Plug made in amperages from 3 to 30 for 125 maxi- mum voltage. Fits standard installa- tion, self-contained, non-refillable. How It Operates yolving part of contains six chambers for six separate fuse wires. When one of the fuses burns out, all that is necessary is to pull slightly on this upper part, which stands under the pres- sure of the spring, and to turn the part to the right. The new fuse snaps in at once. The construction of the yUtULUBt throughout is substantial so that the finished device itself has the appearance of value, taking it immediately out of the class of the single plug fuse so cheap in construction and appearance. The materials used in its manufac- ture are carefully selected and the workmanship of every part is of the highest class. It is built for serv- ice and in appearance it compares with the ordinary single fuse plug as a fine Swiss timepiece compares with a dollar watch. ATLAS SELLING AGENCY, Inc. Sole Selling A e , n i, 450 Fourth Avenue, NEW YORK CITY 342 Test the Insulation Resistance of INTERIOR WIRING With a MEGGER It reads in ohms (no calculations being required) ; and is equipped in the same case with a hand-driven gen- erator, that supplies direct current of 100 volts or more, depending upon capacity of the instrument. Hundreds of Meggers are in service and we strongly recommend them to the attention of Fire Underwriters, Inspectors, Operating Engineers and Contractors. Our "Megger-method" is approved and largely used by the U. S. Government. Write for Pamphlet 847, "A Stitch in Time." JAMES G. RIDDLE Electrical Measuring Instruments 1211-13 ARCH STREET PHILADELPHIA 343 PIGNOLET INSTRUMENTS Awarded medal at 1 ACCURATE Awarded medal at the Panama-Pacific International Exposition San Francisco, 1915. COMPACT INEXPENSIVE Voltmeters, Ammeters and Volt-Ammeters PORTABLE AND SWITCHBOARD TYPES FOR ALTERNATING AND DIRECT CURRENT. OUR NEW MODEL P. The handiest Direct and Alternating Current Portable Meter made; 6" long, 5" wide, 3" deep, weight less than 3 Ibs. We also make several styles of miniature Meters ; 4^2'" long 3^4" wide, i^" deep, with an extra long scale per- mitting close readings. Send for complete Catalog and Directions for Testing. L. M. PIGNOLET Cor. Cortlandt and Washington Streets NEW YORK, N. Y. 844 Type 445 Voltmeters and Ammeters Size 4 x W The Hoyt line comprising Pocket Voltmeters, Ammeters and Voltam- meters, Miniature Switchboard Voltmeters and Ammeters, Switchboard Voltmeters and Ammeters, Portable Voltmeters and Amme- ters for direct current, and Switchboard Volt- meters and Ammeters for alternating current, offers a wide and comprehensive list from which to make your selection of measuring in- struments. Catalogue on request. Hoyt Electrical Instrument Works Penacook, N. H. 345 TRADE MARK No. 19, Deep Groove No. 71, High Voltage No. 2, Cable Double Petticoat. Triple Petticoat. Double Petticoat. For years the name "Hemingray" has been synonymous, not- only with "glass insulators," but with "good glass insulators." The Hemingray insulators have been and are good insulators, be- cause they have been and are of good design and material sub- jected to proper processes ' of manufacturing, including especially perfect annealing. In a glass insulator, "good design" means more than proper lines electrically, it means a design which so dis- tributes the material that good annealing is possible. Given such a design and a proper proportioning of materials (including not too much cullet), it is possible to obtain, and the Hemingray Glass Company does produce a completed insulator, every part of which is perfectly annealed. Thorough annealing is of supreme importance in a glass insulator, and faults which have been found against glass as a material for line insulators have been due to the past practice of some other manufacturers who not only have used improper annealing methods, or material which was practically incapable of being properly annealed, but also have accepted for manufacture certain designs of insulators which so distributed the material as to make proper annealing practically impossible, no matter what materials or methods were used. The HEMINGRAY GLASS COMPANY has followed as one of its first principles the practice of riot accepting for manufacture any design which their sixty-five years of experi- ence would indicate could not be properly and perfectly annealed. This is the prime reason for the uniform success o fthe Hemingray insulator; the reason for its superior mechanical quality of strength and capabilities to withstand the shocks of sudden blows or rapid and extreme temperature changes; the reason for its remarkable electrical qualities as a high voltage insulator. Insulators for Telephone, Telegraph, Light and Power HEMINGRAY GLASS CO. Established 1848 Incorporated 1870 COVINGTON, KY. Factories - - - - MUNCIE, INDIANA 346 Standard Fastenings For Standard Wiring See pages 48 and 65 of this issue TYPE A "CLARK" PRODUCTS Insulator Clamps A standard design for your special condition. Line Crossing Clamps Approved by Railroads, Telephone and Central Stations for High Tension Crossings. Seamless Copper Splicing Sleeves, Single Tube, make practically a welded joint and without the use of solder. Used on all important transmission lines. Descriptive Bulletins on request. Compan? 149 Broadway New York 347 POLE LINE INSULATORS Fred M. Locke's PATENT INSULATORS The cut shows 4 units of suspension type Boro- Porcelain Insulators. Boro-Porcelain Will meet all require- ments Lowest dielectric constant of any Insulator. Highest dielectric strength. Highest mechanical strength. Expansion co-efficient, i.e., 29 to 350 Digs. C. 0.0000032. Nothing can equal Boro- Porcelain. Insulators for high voltage transmission lines and con- denser work. Insulators may be had with a dielectric value of 2 or 3 to one over its flash- over. Remarkable for high fre- quency. Less units are required owing to its low electro- static capacity. Write for full information FRED M. LOCKE VICTOR, N. Y. 348 Mr. Manufacturer: Have you any new current consuming device that you would like to advertise to our consumers? We would be glad to enclose booklets, circulars or other advertising matter in our mail, outlining the usefulness and convenience of articles of this character. The United Electric Light & Power Co. General Offices: 130 East 15th Street, New York 349 THIS IS THE NEW "Buckeye" 'Trade Mark" Split- Knob Insulator Officially Approved for use in Knob and Tubework Described on Page 131 in this issue of "STANDARD* WIRING." It is the only knob with two available wire grooves and the interlocking feature, which keeps the pieces in place while being installed. Has liberal screw protection and may be installed with screws, or nails, where approved by inspectors. Note the triangular construction of the wire way, which grips the wire absolutely, without injuring insulation. This knob is strong and substantial; neat and compact in appearance ; and complies with the Underwriters' rules. Samples, Printed Matter and Discounts on request. IMPORTANT The undersigned are owners of the exclusive rights to manufacture and sell Inter-locking Reversible Buckeye Knobs described herein, under patent of John W. Moore, No. 1048850, dated Dec. 31, 1912, and under a patent pending. Any in- fringement of this knob by other manufacturers, dealers, or users will be vigorously prosecuted. THE FINDLAY ELECTRIC PORCELAIN CO. FINDLAY, OHIO 860 The Cook Wedge Split Insulator Two GROOVE for 10, 12, 14 Wire Makes Standard Wiring Easy Made of the Best Hard White Porcelain. No Burrs or Rough Edges to Cut Insulation, but Firmly Grips the Wire when Screwed in Place The Cap Needs no Centering. Once Used Never Replaced. Trial Orders Packed 500 in a box Now Furnished v ** Note that the Complete with Nail is not Nail and Leather t Weakened by * Nail Head Crimping Protected by U. S. Patents Ask Your Jobber or Write Us for Samples and Prices COOK POTTERY CO Trenton, N. J. SOLE MANUFACTURERS. 351 Bobbins & Myers Motors and Fans The R & M line of motors includes sizes from 1/40 to 25 horse- power, inclusive. For direct or alternating cur- rent circuits. In ad- dition to the standard frames, special frames can be furnished, adapt- ed to the particular re- 'quirements of any motor Type "K" Polyphase Motor, driven machine. Robbins & Myers Direct Current Generators are made in capacities ranging from T 4 to 10 kilowatts, in- clusive. They can be furnished with fly-wheel pulleys for service with gas engines. The Robbins & Myers line of Fans includes types and sizes for all services for operation on all direct and alter- nating current circuits. Bulletins on R & M Motors, Generators or Fans will be furnished on request. 12-Inch Oscillating Fan, Drawn Steel Frame. THE ROBBINS & MYERS CO. SPRINGFIELD, O. New York Philadelphia Cleveland Chicago St. Louis Boston Rochester Cincinnati San Francisco Motors Single-phase or Polyphase Started and Stopped with a Single-throw Switch. What could be more simple? Sim- plicity means dependability, the most important factor in motor purchases, and de- pendability means freedom from re- pairs and that is economy. Ask about Wagner, Quality BA & BW motors, Bulletins noLand mL. Manufacturing Company, Si. Louis, Mo. 383 353 ^ Eliminate voltage fluctuation caused by the starting of small motors- Many are installing fractional horse power Repulsion Start - Induction SINGLE PHASE MOTORS (1-10 to 1-4 H. P.) which start with considerably less than 3 times full load current and accelerate to full speed under full load in 2 to 10 seconds. This makes it possible to connect them to lighting- circuits using- fuses which will 1 really protect and which will still be of j sufficient capacity to insure their suc- cessful starting. OTHER SIZES UP TO 40 HORSE POWER THEY-KEEP-A -RUNNING CENTURY ELECTRIC COMPANY \ 19th, Pine to Olive Streets St. Louis, Mo., U.S. A. SALES OFFICES IN PRINCIPAL CITIES 248 l!nillll!l!llll[illlll!IIIIIHIIil[l!l!l!llllllli!llllin 354 Emerson Fans With the 5 -year Factory-to-user Guarantee For Alternating and Di- rect Currents. Sold by fifty leading jobbers. Fac- tory Stocks at St. Louis and New York City. Emerson Small Motors 2 H. P. and Less Split Phase Types. Repulsion -Start Types. Single and Multiphase Motors. - Direct Current Mo- tors. Large Stocks always on hand. Special types developed. We sell apparatus only to those buying for resale. The Emerson Electric Mfg. Co. 2032 Washington Av., St. Louis, Mo., 50 Church St., New York City 355 Get "BURNLEY" on the wire before you solder it. "Burnley" is the handy soldering paste that helps you out on an awkward job. You will like sURNLEV SOLDERING PASTE ATTERY & ! Western Electric COMPANY DISTRIBUTORS It is much like vaseline. It .sticks to the job and follows the heat spreads the solder evenly and quickly around the joint. "Burnley" comes in the following sizes : 2 oz., 4 oz., l / 2 lb., I lb., 5 lb., 10 Ib. The con- venient tin can't be spilled. You may hold the can upside down without losing a drop. No bottle to tip over or break just at the wrong time, non-corrosive it doesn't waste. Look for the yellow label. BURNLEY BATTERY & MFG. CO. NORTH EAST, PA. 356 Soldering EFFICIENCY The last word in soldering effi- ciency the accumulated knowl- edge and experiences of expert solderers compiled for the first time in convenient book form. Fully diagramed and illustrated so simple an amateur could understand it, so complete that the trained pro- fessional finds valuable suggestions on every page. PRICE COMPLETE O t ft Postpaid anywhere in the U.S.A. " V V "THE BEST SOLDERING PASTE IN THE WORLD' USED EXCLUSIVELY BY the U. S. Government on the telephone circuits of the Panama Canal, by 90% of the Electrical trade of New York and New England, and the leading Automobile Manufacturers in this country. PRICE LIST 2 cz. Cans, less than case lots 2 cz. " 3 doz?n (ons case) .... ,1 Ib. " !/2 " (one case) .... 10 Ib. " 25.lb..and 50 Ib. Cans .'... $0.25 each 2.00 doz. 1.00 Ib. 1.00 Ib. .90 Ib. Discount in less than cast lots, 40 per cent. Discount in case lots 50 per cent. Nokorode is more carefully compounded than 9/10 of druggists prescriptions. The smallest particle you can pick up on a pin contains all the elements of the flux. Nokorode is VERY economical to use and makes a perfect, lasting, non-corrosive joint every time. THE M.W. DUNTON Co. PROVIDENCE R. I., U.S. A Send For Catalogue Street Lighting Fixtures To the Trade We wish to make clear that these goods are manu- factured in our own plant. We are constantly adding new lines, and will appre- ciate any suggestions offer- ing improvements which may specially fit your re- quirements. Reflectors DEEP CONE SHALLOW CONE AND FLAT CRESCENT HALF REFLECTORS TIN OR ALUMINUM National Metal Stamping & Mfg. Co, Murray and Mulberry Sts. Newark, N. J. 358 "The Electric Vehicle Hand-Book" FOURTH EDITION H, G, GUSHING, Jr. Fellow Am. lust. Elec. Engrs., Publisher of "The Central Static n," and Author of "Standard Wir- ing," and FRANK W. SMITH Ex - president Electric Vehicle Association of America and Vice Pres. United Electric Light & Power Co., New York. 362 pages, fully illustrated, flexible cover, pocket sizes, Price $2.00 THE ONLY COMPLETE AND PRACTICAL BOOK ON THE OPERATION, CARE AND MAINTE- NANCE OF all classes OF ELECTRIC VEHICLES, their Storage Batteries, Motors^ Controllers, Tires and Accessories. Sent postpaid to any address on receipt of $2.00, by H. C, GUSHING, Jr. WORLD BLDG. NEW YORK, N. Y. 359 FIRE EXTINGUISHERS Safe on Electrical Fires Pyrene is a non-conductor. It can be used on the highest voltages without injury to operator. Does not deteriorate with age. Needs no re- charging until used No upkeep cost. Always ready for use. No "pumping up" first. Does not freeze at 50 degrees below zero; Fahr. Contains no acid, alkali or moisture. Kills fire from any cause instantly, can hurt noth- ing else. Pyrene is the only type of extinguisher that can be used effectively on gasoline, kerosene or other oils or acetylene gas fires. Inspected, Approved & Labeled by the Under- writers Laboratories, Inc. PYRENE MANUFACTURING COMPANY Makers of a Complete Line of Fire Appliances 52 Vanderbilt Avenue NEW YORK Branch Offices in all Principal Cities Atlanta, Ga., Denver, Omaha. . Baltimore, Detroit, Philadelphia, Birmingham, Ala., Grand Hapids, Mich., Phoenix, Boston, Indianapolis, Pittsburgh, Bridgeport Conn., Kansas City, Portland, Me., Buffalo, Los. Angeles Providence, R. I. Butte, Mont., Milwaukee, St. Louis, Charleston, VV. "Va., Nashville, St. Paul, Chicago, New Orleans, Salt Lake City, Cincinnati, Now York, San Francisco, Cleveland, Oklahoma City, Seattle. Dallas, THE PYRENE CO.. LTD., 19-21 Great Queen St., London, W. C. Distributors for Great Britain and the Continent THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW INITIAL FINE OF 25 CENTS WILL BE ASSESSED FOR FAILURE TO RETURN THIS BOOK ON THE DATE DUE. THE PENALTY WILL INCREASE TO 5O CENTS ON THE FOURTH DAY AND TO $1.OO ON THE SEVENTH DAY OVERDUE. 2AP'54HK DEC 12 t EC'D LD V 11 1956 FEB 1 1 1961 YA 0?!99 . 389475 UNIVERSITY OF CALIFORNIA LIBRARY