-NRLF STANDARD TABLES ELECTRIC WIREMEN. WITH INSTRUCTIONS FOR WIREMEN AND LINE- MEN, UNDERWRITERS' RULES, AND USEFUL FORMULA AND DATA. CHARLES M. DAVIS. FOURTH EDITION, THOROUGHLY REVISED AND EDITED BY W. D. WEAVER. NEW COPYRIGHT, 1893, THE W. J. JOHNSTON 167-176 TIMES BUILDING. PREFACE TO THIRD EDITION. THE revision of this popular work had just been commenced, when it was sadly interrupted by the death of Mr. Davis, and has been completed by other hands. Much that was alien to the purpose of the book has been discarded, and new material so extensively introduced as to render this a practically new work. The wiring tables have all been recalcu- lated on a uniform basis and arranged in a more convenient manner for practical use. The object has been to produce a book for wiremen thoroughly reliable and prac- tical in its data, and free from verbiage and padding. PREFACE TO FOURTH EDITION. THE new insurance rules of the Under- writers' International Electric Association, which havebeen generallyadopted through- out the United States, and will, it is thought, finally supersede all others, have been sub- stituted in the present edition. An important section has been expressly prepared for this edition on the calculation of alternating current wiring, which, for the first time, brings this subject within the reach of practical men. 3 NOTE. In order to still further improve future editions of this work, suggestions from those using it are cordially invited and will receive careful consideration. Address Publishing Department, THE VV. J. JOHNSTON Co., Ld., Times Building, New York. SIZES OF CONDUCTORS FOR IN CIRCUITS. The most accurate method of determin- ing the proper sizes of incandescent lamp conductors is to refer all measurements back to the dynamo, converter, or street tap. To illustrate, suppose we have an installa- tion of 150 lights, consisting of a feeder or dynamo main 20 feet long (to distributing point) and several mains A, B, andC, their lamps and lamp centres being respectively 60, 50, and 40 in number, and 38, 60, and 90 feet from the end of the feeder. Let us calculate the sizes of the feeder and one main, and of one branch having 12 lamps with centre 20 feet from the main, the branch starting 18 feet from the distribut- ing point. (See cut.) \~ --33- "E * 63 1 86 9 8 7 7 6 5 5 4 4 3 90 8 7 6 6 5 5 4 3 3 2 00' 100 7; o 6 5 5 4 3 3 2 2 000 1*1 0000 160 6 6 5 5 4 3 3 2 2 1 6 5 5 4 3 3 2 2 1 1 5 5 4 4 3 2 2 1 1 5 4 3 3 2 2 1 4 3 3 2 1 1 00 00 3 2 2 1 1 00 000 000 2 1 1 00 000 000 0000 1 I 1 0| 00 00 000 000 000 0000000 ooooloooo 0000 1 ! 00 CO 0000000 0000 1 00 00 000 0000000 00 00 0000000,0000 00 00 000 0000000 00 000 000 00000000 00 000 0000000 0000 00 00000000000 000 0000 0000 000 0000 3000 0000 WOO, KX)0 WIRING 75 NUMBER OF LAMPS. 16 C. P. LAMPS. Per cent of Loss. \% 2 3# 4 5f e 10* 20' 25' 30' 35' 40' 45' 50' ~ 11 1 2 2 5 16! 16 16 16 16 16 16 1 2 2 4 5i 10 10 10 10 16 16 16 16 1 3 4 6 15 16 16: 16 16 16 16 16 2 4 6 8 10 20 10 10 16 1$ 16 16 16 2 5 10 12 25 16 16 16 16 16 16 16 3 6 9 12 15 30 10 10 10 10 16 15 15 3 7 10 14 17 35 10' 16 10 10 15 15 14 4 8 12 10 20 40 16 16 16 15 15 14 ! 14 4 9 13 18 22 45 10 16 15 15 14 14 13 5 10 15 20 25 50 10 16 15 14 14 13 13 6 12 18 24 30 60 10 15| 14 14 13 12 12 7 14 21 28 35 70 15 14 14 13 12 12 11 8 16 24 32 40 80 14 14 1-3 12 12 11 11 9 18 27 30 45 90 14 19 12 12 11 11 10 10 20 30 40 50 100 14 13 12 11 11 10 10 12 25 37 50 62 125 18 12 11 10 10 9 9 15 30 45 60 75 150 12 11 10 10 9 9 8 j 17 35 52 70 87 175 11 10 10 9 9 8 j r l 20 40 60 80 100 200 11 10 <) 8 8 7 7 i 22 45 67 90 112 225 10 9 9 8 7i 7 25 27 50 75 55! 82 100 110 125 137 250 10 B Q 9 8 8 6 6 5 30 60| 90 120 150 8 8 7 7 6 5 5 32 65 97 130 162 g 8 7 5 5 35 70 105 140 175 8 7' 7 6 5 5 4 40 80 120 160 200 8 7 6 5 5 4 4 45 90 135 180 225 7 6 5 5 4! 4 3 50 100 150 200 250 M 6 5 4 4 3 3 55 110 165 220 6 5 5 4 3 3 2 60 120 180 240 5 4 4 3 a 2 65 130 195 5 5 4 3 3 2 j> 70 140 210 5 4 4 3 2 2 1 75 150 225 5 4 3 3 2, 1 1 j 16 TABLE II. VOLTS, B. & S. GAUGE. HEAT- ING LIMITS. II -| 60' 70' 80' 90' 100' 1 120' 140' 160' 180' 200' 5^ fc'J 16 16 16 16 16 16 16 16 16 16 16 6 16 16 16 16 16 16 15 15 14 14 14 13 16 16 16 15 15 14 14 13 12 12 12 20 10 27 16 15 14 14 14 13 19 12 11 11 8 34 15 14 13 13 13 12 11 11 10 10 7 40 14 14 13 12 12 11 10 10 9 9 6 44 5 61 14 13 12 12 11 10 10 9' 9 8 4 68 13 12 12 11 11 10 9 9 8 8 3 81 13 I 12 11 11 10 9 s 8 8 7 2 95 1 129 12 11 11 10 10 9 S 7 7 136 11 10 10 9 9 8 8 7 6 6 00 16? 11 10 9 9 8 7 6 6 5 000 197 0000 240 10 9 9 S 8r>' / 7 6 6 5 5 i) 9 8 8 7 7 6 5 4 4 9 8 8 7 5 5 4 4 8 7 6 6 5 5 4 3 a 7 7 6 6 5 4 4 3 3 5j 7 6 5 5 4 4 3 2 * 1 6 5 5 4 4 3 2 2 1 1 5 5 4 4 3 2 2 1 1 5 4 4 3 3 2 1 I 5 4 3 3 2 o 1 00 4 4 3 o 2 1 1 00! 00 '43 3 2 2 1 00 00 4 3 2 1 00 00 000 1 3 2 2 ] 1 00 00 000 000 i 2 2 1 1 oo ooo 0000000 I 2 1 1 00 ooo 1 ooooooo-oooo 2 1 1 1 00 00 00 00 000 ooooooojoooo oooooool 1 00 00 000 0000 0000 i 1 00 00 000 0000000 00 000 000 0000 0000 NUMBER OF LAMPS. 16 C. P. LAMPS. Per cent of Loss. 1% & 8* 4% 5* 1 10* '-. 25' 30' 35' 40' 45' 50' | 1 1 o 2 1 5 16 16 16 16 16 16 1 2 3 4 5 10 16 16 16 16 16 16 16 1 3 4 6 7 15 16 16 16 16 16, 16 16 2 4 6 8 10 20 16 16 16 16 16 16 16 5 71 10 25 16 16 16 16 16 16 16 3 6 9 12 15 30 16 16 16 16 16 16 16 3 7 10 14 17 35 16 16 16 16 16 16 16 4 8 12 16 20 40 16 16 16 16 16 16 16 4 9 13 18 45 16 16 16 16 16 16 16 5 10 15 20 25 50 16 16 16 16 16 16 16 6 12 18 24 30 60 16 16 16 16 16 15 15 7 14 21 28 35 70 16 16 16 16 15 15 14 8 16 24 32 40 80 16 16 16 15 15 14 14 18 27 36 45! 90 16 16 15 15 14i 14 13 10 20 30 40 50 100 16 16 15 14 14 13 13 12 25 37 50 62 125 16 15 14 18 13 12 12 15 30 45 60 75 150 15 14 13 18 12 11 11 17 35 52 70 87 175 14 14 13 12 11 11 11 20 40 60 80 100 200 14 13 12 12 11 10 10 22 45 67 90 112 2:25 13 12 12 11 10 10 9 25 50 75 100 125 250 18 12 111 11 10 9 9 27 55 82 110 137, 275 12 12 11 10 9 9 9 30 60 90 120 150 300 12 11 10 10 9 9 8 32 65 97 130 162 325 12 11 10 9 9 8 8 35 70 105 140 175 350 11 11 10 9 9 8 8 40 80 120 160 200 11 10 9 9 8 7 7 45 90 135 180 225 10 10 9 8 7 7 6 50 100 150 200 250 10 9 8 8 7 6 6 55 1101 155 220 275 9 9 8 7 6 6 5 60 120 180 240 300 9 8 7 7 6 6 5 65 130 195 260 325 9 8 7 6 6 5 5 70 140 210 280 350 9 8 7 6 5 5 4 75 150 225 300 8 7 6 6 5 5 4 18 TABLE III. VOLTS. ^ B. & S. GAUGE. \ HEAT- ING LIMITS. 1 5* c ~ z- 60' ro' 80' 90' 100' 120' 140' 160' 180' 200' 10 16 1G 16 16 16 16 16 16 10 16 10 16 16 16 16 16 16 16 16 16 16 14 20 16 16 16 16 16 16 16 16 15 15 12 30 10 40 16 16 16 16 16 16 15 15 14 14 S 50 16 16 16 16 16 15 14 14 13 13 ? 60 16 16 16 15 15 14 14 13 12 12 6 70 5 90 16 16 15 15 14 14 13 12 12 11 4 100 16 15 15 14 14 13 12 12 11 11 3 120 15 15 14 14 13 12 12 11 11 10 2 140 1 190 15 14 14 13 13 12 11 11 10 10 200 14 14 13 12 12 11 11 10 9 9 00 -,'40 14 13 12 12 11 11 10 9 U 9 000 290 0000 350 13 1-2 12 11 11 10 9 9 8 8 12 12 11 11 10 9 1) 8 8 r t 12 11 11 10 10 9 9 8 7 1 11 10 10 9 9 8 8 7 6 6 10 10 9 9 8 7 7 6 6 5 10 9 9 s 8 7 6 5 5 4 9 9 8 7 7 6 5 5 4 4 9 8 7 7 6 6 5 4 4 3 8 8 7 6 6 5 4 4 3 3 8 7 6 6 5 5 4 4 3 3 7 7 6 6 5 4 4 33 2 7 6 6 5 5 4 3 3 ~ 2 7 6 5 5 4 4 3 2 2 1 6 5 5 4 4 3 2 2 1 1 6 5 4 4 a 3 2 1 1 5 4 4 3 3 o 1 1 5 4 3 3 9 2 1 00 4 4 3 3 2 1 1 00 4 3 3 2 2 1 00 00 4 3 2 2 1 1 00 00 000 3 3 2 1 1 00 00 000 THREE-WIRE SYSTEM. NUMBER OF LAMPS. 16 C. P. LAMPS. Per cent of Loss. 1% 2* 3# \% 5# 20' 25' 30' 35' | 40' 45' ! 50' 2 5 7 10; 12 16 16 ~16~ 16 16 16 16 5 10 15 20 25 16 16 16 16 16 16 16 7 15 22 30 37 16 16 16 16 16 16 16 10 20 30 40 50 16 16 16 16 16 16 16 12 25 37 50 62 16 16 16 16 16 16 16 15 30 45 60 75 16 16 16 16 16 16 16 17 35 52 70 87 16 IP 16 16 16 U> 16 20 40 60 80; 100 16 16 16 16 16 16 16 22 45 67 90 1 112 16 16 16 16 16 16 15 85 50 75 100 125 16 16 16 16 16 15 15 27 55 82 110 137 16 16 16 16 16 15 15 30 60 90 U'O 150 16 16 16 16 15 15 14 32 65 97 130 162 16 16 16 15 15 15 14 35 70 105 140 175 16 16 16 15 15 14 14 40 80 120 160 200 16 16 15 14 14 13 13 45 90 135 180 225 16 16 15 14 14 13 13 50 100 150 200 250 16 15 14 13 13 12 12 55 110 165 220 275 15 15 14 13 13 li 12 60 120 180 240 300 15 14 13 13 12 11 11 65 130 195 260 325 15 14 13 13 12 11 11 70 140 210 280 350 14 14 13 12 11 11 11 80 160 240 320 ! 400 14 13 12 12 11 10 10 90 180 270 360! 450 13 12 12 11 10 10 9 100 200 300! 400 500 13 12 11 11 10 9 9 112 225 337 450 562 13 12 11 10 10 9 9 125 250 375 500 625 12 11 11 10 9 9 8 137 275 412 550 687 12 11 10 10 B 9 8 150 300 450 600 750 11 10 9 9 9 8 8 175 350 525 700 11 10 9 9 8 7 7 200 400 600 10 9 8 8 6 6 225 450 675 10 9 8 7 6 6 250 500 750 9 8 7 7 6 6 5 300 | GOO 8 1 6 6 5 4 TABLE IV. LAMPS. THREE-WIRE SYSTEM. B. & S. GAUGE. HE ii LllM II C^ -AT- s'G [ITS. t 6 a fc J 60' TO' ' 80' 90' 100' 120' 140' 160' 180' 200' 16 16 16 16 16 16 16 16 16 16 16 20 16 16 16 16 16 16 16 16 16 15 14 40 16 16 16 16 16 16 15 15 15 14 12 60 10 80 16 16 16 16 16 15 14 14 13 13 8 100 16 16 16 15 15 14 14 13 13 12 7 120 16 16 15 15 14 H 13 13 12 11 6 140 5 180 16 15 ; 15 14 14 13 13 12 12 11 4 200 15 14 ! 14 13 13 12 , 11 11 10 10 3 240 15 14 ! 14 13 13 12 12 11 11 10 2 280 1 380 14 14 13 13 12 12 11 11 10 9 400 14 14 13 13 12 11 11 10 10 9 00 480 14 13 13 12 12 11 10 10 9 9 000 580 0000 roo 13 13 12 12 11 10 10 9 9 8 13 13 12 11 11 10 10 9 9 8 12 11 11 10 10 9 9 8 8 7 12 11 11 10 10 9 9 8 8 7 11 10 10 9 9 8 8 7 7 6 11 11 10 9 9 8 8 7 7 6 10 10 9 9 8 7 7 6 6 5 10 10 9 9 8 7 7 6 " 6 5 10 9 9 8 8 7 6 5 5 4 9 9 8 7 7 6 5 5 4 4 9 8 7 7 6 6 5 4 4 3 8 8 7 6 6 5 4 4 3 3 8 8 7 6 6 5 4 4 3 3 8 7 6 6 5 5 4 3 3 2 7 7 6 5 5 4 3 3 3 2 f 6 6 5 5 4 3 2 2 1 6 5 5 4 4 3 2 2 1 1 5 A 4 3 3 2 1 1 00 5 4 4 3 3 2 1 1 00 4 4 3 2 2 1 1 000 3 3 2 1 1 00 00 000 B. & S. GAUGE, Percent Loss. Amperes 0 3840 5065 4015 3200 3800 3010 2400 3040 2410 1920 2430 1930 1535 2025 1605 1280 1520 1210 960 1215 965 770 3040 2420 1920 25:35 2015 1600 1900 1510 1200 1520 1210 960 1215 970 770 1010 805 640 760 605 610 Io20 1280 960 1270 1005 800 950 755 600 760 605 480 610 760 605 480 630 500 400 475 375 TABLE ODD VOLTAGES AND Percent column. 50 VOLTS. 55 \% ' 2% 8* 4^' 5JJ 1* 2% 50-volt table 75 ' k ' . 110 " " Per cent column . 1.0 2.0 2.2 4.5 4,8. 9.6 ! 3.0 6.7 14.4 4.0 9.0 19.2 5.0 12.2 24.0 .8 1.8 4.0 "IT? 8.0 2.4 5.6 12.0 70 VOLTS. 75 1* 2% a* 4^ 5* 1$ 2$ 3* 50- volt table... 75 " " no " ;.;:: Per cent column. .5 1.2 2.5 1.0 5.0 1.5 3.4 7.5 2.0 4.6 10.0 2 5 5.'7 12.5 .4 1.0 2.1 9 2.0 4.2 1.3 3.0 6.3 !H) VOLTS. 95 1% 2# 3# 4% 5% \% 3* 3^ 50-volt table lib " " .*;;.*. Per cent column. .3 L5 .6 1.4 3.0 .9 2 1 4^5 1.2 2.8 6.0 1.5 3.5 7.5 .3 .6 1.3 .5 1.2 2 7 .8 2.0 4.0 110 VOLTS. 115 W 2* 3^ 4% 5* \% 2% & 50-volt table 75 " - . 110 " . . .2 A 1.0 .4 .9 2.0 1^4 3.0 .8 1.8 4.0 1.0 23 5.0 .2 A .9 A .8 1.8 6 1.3 2 7 By means of the above table, Tables I'- ll I can be used for any voltage or per- centage of loss with an accuracy within the limits of practice. For example, suppose the wiring is to be for 90 volts with 2% per cent loss. Referring to the body of the go-volt section, we find the nearest percentage of loss given is 2.1$; then 28 VIII. PERCENTAGES. VOLTS. 60 VOLTS. 65 VOLTS. 3.3 7.4 1(5.0 Dfc 4.1 9.3 20.0 w l'.5 3.4 3* 1.4 3.1 6.7 4.7 10.0 2.8 6.2 13.4 5* 3.5 7.8 16.8 \% .6 1.3 2.8 1.2 2.6 4.7 3* 1.8 3 9 8.6 5^2 11.5 5* To 6.5 13.3 VOL rs. & 80 VOLTS. 85 VOLTS. \% 2% 3* 4% 5* \% 2% 3* ^4* 5* 1.8 4.0 8.4 2.2 5.0 10.5 .4 .8 1.9 .8 1.6 3.8 1.2 2.4 5.7 1.6 3.2 7.6 2.0 4.1 9.5 .3 .8 i:5 1.0 2.3 5.1 1.4 3.1 6.8 1.7 4.0 8.5 VOLTS. 100 VOLTS. 105 VOLTS. 4% 5% \% 2% 3% 4% 5* 1* 2* 3* 4% 5* 1.0 2.5 5.4 1 3 3.1 6.7 .2 .5 1.2 .5 1.1 2.4 3.6 1.0 2.2 4.8 1.2 2.8 6.0 .2 .5 1.1 .4 1.0 2.2 ila 3.3 .9 2.0 4.4 1.2 2.5 5.5 VOL 4% 8 TS. 1 120 VOLTS. 125 VOLTS. W a 2% 3% .3 .5 7 8 \% 9 3# _. 4% 5* R 1.7 3.6 2.1 4.5 !8 .8 1.2 1.6 2.0 1.7 2.5 3.3 4.2 .4 .8 .7' 1.0 1.5 2.2 1 4 3.0 1.8 3.8 following the horizontal and vertical columns in turn we find that this corresponds to the 75- volt table, using the 3^ column of that table. That is, wiring for 75 volts with 3$ loss is the same as wiring for 90 volts with 2% loss. Similarly, we find that for a loss of .6$ with no volts we may use the 3^ column of the 50- volt table. 29 TABLE IX. DIMENSIONS AND RESISTANCES OF COPPER WIRE. i 9) -T 1 fe J, Jl | 3 a| l.J| i* S . E . 2 * -2 8 .2 s a ^ |X |ir is fe aj * S 2| S 5 < " o a>! _g i ^ fc 1 1 a rf 5 i 0000 .46000 211600 166190 .051288 .27080 11.68 107 21< 000 .40964167805 131790 .064672 .34147 10.405 85.02^ 00 .3648 133079 104520 .081549 .43058 6.266 67.43] .32495 105592 82932 .1027 .54223 8.254 53.501 1 .28930 83694 65733 .129668 .684627 7.348 42.401 2 .25763 66373 52130 .1635 .86328 6.544 33.631 3 .22942 52634 41339 .2062 1.08874 5.827 26.67C 4 .20431 41742 32784 .2599 1.37237 5.189 21.151 5 .18194 33102 25998 .32785 1.731048 4.621 16.77? 6 .16202 26250 20617 .41343 2.1829 4.115 13.301 7 .14428 20816 16349 .5213 2.7525 3.665 8 .12849 16509 12966 .65737 3.47091 3.264 S.'Sfr 9 .11443 13094 10284 .8288 4.37606 2.907 6.63." 10 .10189 10381 8153 1.0454 5.51971 2.588 5.26C 11 .09074 8234 6467 1.31801 6.9601 2.305 4.172 12 .08 81 6530 5129 1.6619 8.7748 2.053 3. 80S 13 .07196 5178 4067 2.09588 11.066 1.828 2.618 14 .06408 4107 8147 2.6424 13.87187 1.628 2.083 15 .05707 3257 2558 3.33205 17.5993 1.540 1.650 16 .05082 2583 2029 4.2007 22.17969 1.291 1.309 17 .04526 2048 1609 5.299078 27.9787 1.150 1.088 18 .04030 1624 1276 6.68258 35.2836 1.024 .822 19 .03539 1252 984 8.86814 45.7670 .899 .6346 20 .03196 1021 802 10.34128 54.6020 .812 .5176 TABLE X. EDISON SYSTEM, EDISON GAUGE. '&.. Jl* Diameter in mils. IN $*# Maximum Amperes. CO 1 1 * O *, I 3 1 P .0 * p. Li 1 s, 3 55 3000. 12.5 .0034976 .00908372 5 71 5000. 18.3 .0020986 .01513924 8 90 8000. 26.0 .0013118 .02422034 12 110 12000. 35.2 .0008746 .03632824 15 123 15000. 41.6 .0006997 .04540984 20 142 20000. 51.6 .0005247 .06054840 25 158 25000. 61.0 .0004188 .07568210 80 173 80000. 70.0 .0003498 .09081666 35 187 85000. 78.6 .0002999 .10595483 40 200 40000. 86.8 .0002624 .12108200 45 222 45000. 94.9 .0002332 .13622748 50 224 50000. 102.7 .0002099 .15135683 55 235 55000. 110.3 .0001908 .16650083 60 245 60000. 117.7 .0001749 .18162452 65 255 65000. 125.0 .0001615 .19677218 70 865 70000. 132.1 .0001499 .21190130 75 274 75000. 139.1 .0001399 .22704321 80 283 80000. 146.0 .0001312 .24217648 85 292 85000. 152.8 .0001235 .25730349 90 300 90000. 159.5 .0001166 .27243450 95 308 95000. 166.1 .0001105 .28758723 100 316 100000. 172.6 .0001049 .30270928 110 332 110000. 185.4 .0000954 .33299060 120 346 120000. 198.0 .0000845 .36326663 130 361 130000. 210.2 .0000807 .39352714 140 374 140000. 222.2 .0000750 .42379665 150 387 150000. 234.0 .0000700 .45406140 160 400 160000. 245.6 .0000656 .48432800 170 412 170000. 257.0 .0000617 .51462206 180 424 180000. 268.3 .0000583 .54488423 190 436 190000. 279.4 .0000552 .57513978 200 447 200000. 290.4 .0000525 .60542734 TABLE XI. DIFFERENT WIRE GAUGES IN USE IN THE UNITED STATES. Dimension* of Sizes, in Decimal Ports of an Inch. H ij American, or Brown & Sharpe. fa 11 QQ Washburn & Moen Mfg. Co. ! Worcest V, Ms. \ Trenton Iron \ Co. Trenton, N.J. 1 . s .?> j ^ <3 . Old English. vf jl ^s 000000 I .46 00001)0 00000 .43 .45 00000 0000 .&" 454 393 4 0000 000 .40964 .425 .362 .36 .3586 000 00 .3648 .38 .331 .33 .3282 .'.'.'.' 00 .32486 .34 .807 .305 .2994 1 .2893 .3 .283 .285 .2777 1 2 .25763 .284 .263 .265 .2591 2 8 1.22942 .259 .244 .245 .2401 8 4 . 20431 .238 .225 .225 .223 4 5 .18194 .22 .207 .205 .2047 5 6 .16202 .203 .192 .19 .1885 6 7 .14428 .18 .177 .175 .1758 7 8 .12849 .165 .162 .16 . 1605 . . . H 9 .11443 .148 .148 .145 .1471 .... g 10 . 10189 .134 .135 .13 .1351 10 11 .090742 .12 .12 . 1175 .1205J 11 12 .080808 .109 .105 . 105 . 1065 12 13 .071961 .095 .092 .0925 .0928 13 14 .064084 .083 .08 .08 .0816 .083 14 15 .057068 .072 .072 .07 .0726 .072 15 IB .05082 .065 .063 .061 .0627 .065 16 17 .045257 .058 .054 .0525 .0546 .058 17 18 .040303 .049 .047 .045 .0478 .049 18 19 .03589 .042 .041 .04 .0411 .04 19 20 .031961 .035 .035 .035 .0351 .035 20 21 .028462 .032 .032 .081 .0321 .0315 ! 21 22 .025347 .028 .028 .028 .029 .0295 22 23 .022571 .025 .025 .025 .0261 .027 23 24 .0201 .022 .23 .0225 .0231 .025 24 25 .0179 .02 .02 .02 .0212 .023 25 26 .01594 .018 .018 .018 .0194 .0205 26 27 .014195 .016 .017 .017 .0182 .01875 27 28 .012641 .014 .016 .016 .017 .0165 28 29 .011257 .013 .015 .015 .0163 .0155 29 30 .010025 .012 .014 .014 .0156 .01375 30 31 .008928 .01 .0185 .013 .0146 .01225 31 32 .00795 .009 .013 .012 .01861.01125 82 33 .00708 .008 .011 .011 .013 .01025 33 34 .006304 .007 .01 .01 .0118 .0095 34 35 .005614 .005 .0095 .0095 .0109 .009 35 36 .005 .004 .009 .009 .01 .0075 36 37 .004453 .0085 .0085 .0095 .0065 37 38 .003965 .008 .008 .009 .00575 38 39 .003531 .0075 .0075 .0083 .005 88 40 .003144 .007 .007 .0078 .0045 40 32 TABLE XII. BARE AND INSULATED WIRES. APPROXIMATE No. OF FEET PER POUND. 1 3 "z r ^\ S 9 c8 o - . 'S5.g si 5 03 ,1 GQ 55 l s ^ * $ . ."ti || 3 _ ;~ PQ S'g 5"* fl^ .S'S ^ 5 ti o^- ii 2 32 il 2 d a fc 5 O S tf 4 * 0000 1. 1. 1.5 1.56 000 1.5 1.4 1.9 1.97 00 2. 1.7 2 34 2.49 2.75 2.5 2.1 2.5 2.9 2.7 3.13 1 3.20 3.25 3.66 3.26 3.95 4. 4.25 3^37 4^5 4.54 4.27 4.99 3 5. 5.25 3.88 5.5 5.6 5. 6.29 4 5 6.25 8. 6.25 8. 4.68 6.75 7.1 5 64 8.33 8.7 5.9 7.4 7.93 10. 6 9.50 10. 6.67 10. 10.75 9. 12.61 7 12.5 12.25 8.73 12 5 13. 10. 15.9 8 14.5 14. 12.42 13.75 15.6 12.5 20.05 9 17. 16.3 18. 15.3 25.28 10 20. 17.9 19.75 22.7 18. 31.88 11 26. 27. 40.20 12 32. 27.21 25. 33.3 24. 50.69 13 38.5 63.91 14 45. 36.9 50. 49. 80.59 15 59. 101.63 16 70. 53.8 71.4 128.14 17 85. 161,59 18 90. 72.1 93. 203.76 19 111. 264.26 20 110. 82.5 133. 324.00 33 TABLE XIII. LIMITING CURRENTS FOR INTERIOR WIRING. (KENNELLY.) Applies to insulated copper house-wires of 98 per cent conductivity, carrying steady currents, and encased in wooden moulding. The rule followed is that the temperature elevation of any wire shall not, with the proposed current, exceed 18 F. or 10 C. Amperes. Number in B. & S. 1 Diameter in inches. Circular Mills. Amperes. Number in B.&S. Diameter in inches. Circular Mills. 1000 1.47 2160900 61 3 .2294 52634 900 1.37 1876900 52 4 .2043 41742 800 1.27 1612900 43 5 .1819 33102 700 1.16 1345600 36 6 .1620 26244 600 1.049 1100401 30 7 .1442 20822 550 .988 976144 25 8 .1284 16512 500 .928 861184 22 9 .1144 13110 475 .897 804609 18 10 .1019 10381 450 .865 748225 15 11 .0907 8226 425 .832 692224 12 12 .0808 6528 400 .800 640000 10.5 13 .0719 5184 375 .766 586756 9.0 14 .0641 4110 350 .732 535824 7.25 15 .0571 3260 325 .697 485809 6.00 16 .0508 2581 300 .060 435600 5.50 17 .0452 2044 275 .623 388129 4.00 18 .0403 1624 250 .585 342225 3.25 19 .0359 1253 225 .545 297025 2.75 20 .0319 1024 200 .504 254016 2.25 21 .0285 820 174 0000 .460 211(500 2.00 22 .0253 626 147 000 .4096 167805 1.75 23 .0226 510 124 00 .3648 133079 1.50 24 .0201 404 103 .3-249 105592 1.25 25 .0179 320 87 1 .2893 83694 1.00 26 .0159 254 73 2 .2576 66373 34 TABLE XIV. CURRENTS AND CORRESPONDING ELEVA- TIONS OF TEMPERATURE OF OPEN-AIR CONDUCTORS IN CALM WEATHER. (BLACK INSULATION.) (Compiled from Kennelly's Experiments.) Gauge B. & S. 9F. 18 F. 36 F. 72 F. 0000 250 345 480 680 000 210 295 405 565 00 175 245 350 480 145 205 290 400 1 125 175 250 345 2 105 150 210 290 3 90 125 175 240 4 75 110 150 210 5 65 90 125 175 6 55 75 105 145 7 50 65 95 125 8 40 55 80 110 10 30 45 60 80 12 25 30 45 60 14 20 25 35 45 16 15 20 25 ' 35 Rise in temperature at top of columns, amperes below. 35 m ?o i- oooso i-i o? so "* LO o j>xoi 1-1 1-1 1-1 1-1 T-l ?J C> 71 ?t OJ C ?J ?< r* ?{ S-* rf OO l ^ ?S3 ?ioi co i- oo oio^-H oicort* o as i- OOO5O 0- - ocoooo GOOOQO 000000 000000 000000 CO Tin 5Ol>OO OiOi-H OZSO^ OOl> 0, ,. 0~ 6 OOIOI OI OI OJ OI OI OI OI OI OI OI Oi OI pa Or-!N SO-^lO COI>QO OiO-i 36 8 6 3 fc- - * d .. - - _ d- - - ^ ^ ^ * - 8 OOOOOO 000000 000000 00 0000 -?>CO ^.CO te d- -. - * - - -. - 2T ' s I 55' * ?>co^ TABLE XVI. KESISTANCES. Material. Approximate Comparative Resistances. Resistance of 100 Feet of No. 20 (B & S.) Wire, in Ohms. Copper 1 1.016 Aluminum 1 8 1 82 Zinc 3 4 3.45 Platinum Iron 5.5 6 8.81 6 03 Nickel 7.6 7.68 Tin 8 8.12 Lead 12 12 1 German-silver . . . Antimony 13 21 13.6 Ferro-nickel Mercury 50 58 50.8 Bismuth Sulphuric acid... 80 2.6xlO GAUGES (B. & S.) OF DIFFERENT WIRES FUSED BY 100 AMPERES. (PREECE.) Copper, No. 17 Aluminum " 15 Platinum "13 German-silver, .... "13 Platinoid, "12 Iron, " 10 Tin, . " 6 Lead, ....... " 6 Tin-lead alloy, .... " 5 TABLE XVII. WEIGHT AND RESISTANCE OF GAL VAN IZED IEON WIRE PER MILE. (ROEBLINQ.) Gauge. B. &S. Weight per Mile. Resist- ance. Ohms. Gauge. B. & : S. Weight per Mile. Resist- ance. Ohms. 6 8 9 10 550 470 385 330 268 10 12.1 14.1 16.4 20 11 12 14 16 216 170 100 62 20 32.7 52.8 91.6 TABLE XVIII. TABLE OF RESISTANCES OF 18 PER CENT GERMAN-SILVER WIRE. (AMERICAN ELECTRICAL WORKS.) B. &S. Gauge. Ohms per 1000ft. Ohms perlb. 1 B. &S. Gauge. Ohms per 1000 ft. Ohms per Ib. No. 8 9 10 11.772 11.832 18.72 .23598 .37494 . 59652 No. 25 26 27 606.312 764.586 964.134 626.31 995.958 1583.622 11 12 13 23.598 29.754 37.512 .94842 1.50786 2.39778 28 29 30 1215.750 1533.00 1933.038 2518.075 4004.082 6368.356 14 15 16 47.304 59.65^ 75.222 3.8124 i 6.0624 9.639 31 32 33 2437. 23G 3073.77 3875.616 10119.978 16096.356 25589.628 17 18 19 94.842 119.61 155.106 15.327 24.3702 40.9896 34 35 36 4888.494 6163.974 7770.816 40712.76 64729.87 102876. -482 20 21 22 190.188 239.814 302.382 61.614 97.974 155.772 37 38 39 9797.166 12357.198 15570.828 163524.78 257764.68 409546.8 23 24 381.33 480.834 247.734 393.93 40 19653.57 652024.62 39 WHITE CEDAR POLES. (ELECTRICAL SUPPLY Co.) . xa 00 j 53 S^-oS 1*0 ** o,^u "S eS ^^2 S Size. ?3 tX cc ^w Size. 2.S? w Xq_, Oj aj'O 5^1 p, - o >> s ^^ g^oS p-l <* ^ 25', top 4" 25', 5" 160 200 170 150 35', top 7' 35', u 8' 650 -,oo 90 85 25', 6" 250 120 35', " 9' 850 70 25', 7" 325 100 40', " 6' 800 80 25', 8" 475 75 140', " 7' 900 75 25', 9" 550 60 40', " 8' 950 70 30', 5" 300 110 45', " 6' 1000 65 30', 6" 350 90 45', " 7' 1200 55 30', 7" 450 75 50', " 6' 1400 52 30', 8" 600 55 50', " 7' 1500 40 30', 9" 700 45 55', " 7' 1600 37 35', 6" 550 100 60', " 7' 1700 35 Green chestnut poles weigh about 50 per cent more than the above figures. Poles 40 ft. long and over require two cars. DIMENSIONS OF CROSS ARMS. Regular size, 3^ inches x 4^ inches, i-J- inch holes. Special size, 4 inches x 5 inches, i^-inch holes. 2-pin, 3 feet long; 4-pin, 4 or 5 feet long; 6-pin, 6 feet long. 40 CANDLE-POWEK OF ARC LAMPS. (ANTWERP ELECTRICAL EXPOSITION.) Amperes. a 'o > Maximum C.P. Horizontal C.P. Upper Hemi- sphere. Mean C. P. Lower Hemi- sphere. Mean C. P. Mean C. P. 3 1 4 37.2 390 74 17 119 136 157 46.2 1090 168 63 298 361 259 6.8 46 1240 240 65 320 385 313 8 46 1550 334 70 385 454 350 10 45.5 2070 421 102 640 750 491 LIGHT CUT OFF BY GLOBES. Clear glass 10 per cent Light ground glass 30 " " Heavy ground glass 45 to 50 " " Strong opals. ... 50 to 60 " " An incandescent lamp gives off from to T V the heat of an equivalent gas-jet. An arc lamp gives off from -$ to V as much heat as gas-jets producing an equal light. A 5-foot (16 c. p.) gas-jet vitiates as much air as four men. 1 Derivation 1 X 2 & : -5- ampere illion ohms illionth ohm t H- ohm ousandth amp T5 a X y 1 lomb -=- volt illionth farad : X ampere t X ampere X 1 t x colomb s oSS of: S gg "33 o <5 >rH >~ ^ OrH >" K* e of Unit. a || pere iampere JO o ad rofarad g 9 fc 1 oil 11 8 II Is fee o 1 T ? j g ^ P^ r- 1 T-t O *"* O 3 t^ '^ pi p K XX X X 02 ^ 1 S > o 1 ance. . . . i "fi X" . 1 W I 3 o 1 1 & 42 i_ 3 c' f O j_ o 1 S 1 .a i x + O O c c *> 02 O in "o C/3 rt p^ OQ 5_ "5 rz^ QJ 'tt o 53 'S *"* t ^(N u s ^ . 6 M ZJ H a i cc H Name of Uni b . II c 03 Q 03 *O Cxi "o I '35 capacity of S OJ *0 P ^ S 2 "o t/3 5 u c 3 w 3 C u! 5 H o w "o X5 CJ JD 03 4-l So VO cr o Cu I I cr a iistance O DH o OJ o3 JG to E _H C/3 "c 3 Q O S w "i 3 -K 03 '5 Self-induction Force 03 H t/3 W o c An AMPERE A MICROFAB k- 00 H .23 >< 43 TOOLS REQUIRED The following-named tools will probably be re- quired in constructing a plant for city or commercial lighting : (DAVIS.) Article. Size. Cost about Stubs' pliers, plain Sin. $2.00 3.00 8.00 2.25 2.50 4.80 6.00 6.00 .95 1.50 1.25 3.50 2.60 .90 .75 6.00 2.00 2.40 12.00 20.00 1.00 3.50 2.10 1.50 3.00 .80 1.25 .30 Climbers and straps Pulley -block and ecc. clamp ) To vNo 3 Come-along and strap Splicing clamps \ B.&S. Linemen's tool-bag and strap . ... Soldering furnace Gasoline blow -pipes . ... Soldering coppers 21b. 8ft. 7ft. 8ft. 7ft. 10 Ib. Pole -hole shovels Pole-hole spoon regular Octagon digging- bars Tamping-bars Crowbar Pick -axe Cant-hook 4ft. 16ft. 6ft. Pike-poles Pole-supporter Comb, pay-out reel and straps Nail-hammer 1 Ib. 6 in. 12 in. 26 in. 10 in. Sin. 12 in. 12 in. Linemen's broad hatchets Drawing-knives Hand-saw Ratchet-brace bits Screw-drivers Wrench Bastard file . . 44 APPROXIMATE LIST OF SUPPLIES REQUIRED IS INSTALLING 15 CITY LAMPfe AND 20 COM- MERCIAL LAMPS ON A FIVE-MILE CIRCUIT, SETTING POLES 132 FEET APART. (DAVIS.) Articles. Size or Diameter Price about. Quan- tity. Electric-light poles Electric-light poles 30ft., 6 in. 35 ft 7 in $2.40each 4 15 180 Electric-light poles ...... Cross arms, 4-pin. . 40ft., Tin. 4ft. 5.50 .30 40 200 Painted oak pins Hin. .02 800 Oak pins and bolts Irou break-arms Hin. .0? 24 25 Lag-screws and washers. Glass insulators D G * X 7 in. .04 74 400 850 Pole steps g. X 8 in. '.05 2500 Guy stranded cable Cross-arm brace & bolts. Line wire ... fin. 6 BS .071b. .20each 125 00 mi SOOlbs. 40 6 miles MATERIAL REQUIRED FOR CONNECTING IN LAMPS. (DAVIS.) Sleet-proof pulleys fO 75 each 30 Street-lamp cleats, iron.. .25 " 15 Arc-lamp cordage Suspension cable fin. i in 1.25hdft 02ift 25 3000ft Hard-rubber tube Soft-rubber tubing Arc cut-out f X I in. fin. l.SOlb. .20ft. 3 50 each 5 IDS. 200ft. 20 Porcelain insulators and screws 2 40 hd. 400 Oak brackets and spikes 2 50 " 150 45 HORSE POWER OF ENGINES. Commercial horse power rating of sim- ple high speed, single or double acting engines, based on 40 pounds mean indi- cated pressure with 80 pounds initial pres- sure. D diameter in inches ; S = stroke " " N = number of revolutions per minute. 80 pounds boiler pressure, H P * H - P - = 90 pounds boiler pressure, .. 5600 100 pounds boiler pressure, .. 5000 EXAMPLE. Diameter cylinder, 10 in. ; stroke, 10 in. ; revolutions per minute, 300. H. P. = 0JfJg)_?LI x 3 = 6 6300 at 80 pounds pressure. Similarly, H. P. = 53.5 at 90 pounds pressure. H.P. = 60 100 46 HORSE POWER OF BOILERS. The following commercial rating of boilers is based on heating surface, and on 80 pounds pressure and 40 pounds of water per indicated horse power. D diameter of boiler in inches ; d = " " tubes " " L length " " " feet; /= " " " inches, ;/ = number " " HORIZONTAL TUBULAR BOILERS. (To 200 H. P.) CASE I. L(D + nd) is less than 50000. H P _L(D+nd) 62 CASE 2. L(D + nd} is between 50000 and 70000. H P= ^ + '"0 55 CASE 3. L(D 4- nd) is over 70000. H P _ 50 EXAMPLE. Diameter boiler, 48 in.; length tubes, 14 ft. ; diameter tubes, 3 in. ; num- ber tubes, 52. _ 47 UPRIGHT TUBULAR BOILERS FULL LENGTH TUBES. (To 60 H. P.) l(D -h nd) H.P. = 620 EXAMPLE. Diameter, 36 in. ; length tubes, 51 in. ; diameter tubes, 2 in. ; num- ber tubes, 77. H p _. 5U36 + 77 x 2) = i 620 5 ' UPRIGHT TUBULAR BOILERS. SUB- MERGED TUBES. (To 60 H. P.) l(D 4- nd) H.P. = 500 EXAMPLE. Diameter boiler, 24 in.; length tubes, 30 in. ; diameter tubes, 2 in. ; num- ber tubes, 31. TT p _ 30(24 + 3i x 2) _ i~i. i . 5 500 NOTE. In" the above formulae for boilers, allowance has been made for the greater efficiency of heating surface exposed to direct radiation. 48 RULES FOR CALCULATING THE SPEED OF PULLEYS AND GEARS. To find the REVOLUTIONS of a DRIVEN shaft, multiply the diameter of the driving pulley by its speed in revolutions and di- vide by the diameter of the driven pulley. EXAMPLE. Engine pulley, 42 in.; en- gine revolutions, 240; dynamo pulley, 8 in. _ 42 x 240 Dynamo rev. = ~ = 1260. To find the DIAMETER of a DRIVEN pulley, multiply the diameter of the driv- ing pulley by its speed in revolutions and divide by the required speed of the driven shaft. EXAMPLE. Engine pulley, 66 in.; en- gine revolutions, 303 ; dynamo speed, 2000 rev. 66 x 303 Diam. dynamo pulley = = 10 in. 49 To find the DIAMETER of a DRIVING pulley, multiply the diameter of the driven pulley by its revolutions arid divide by the revolutions of the driving shaft. EXAMPLE. Dynamo revolutions, 1500; dynamo pulley, 10 in.; counter speed, 600 .... 10 x 1500 Diam. counter-driver = = 25 in. 600 Where a COUNTER is to be used, the problem is in two parts, the countershaft being first considered the driven and next the driver, or vice versa. The above rules can similarly be extended to any number of intermediate shafts or counters. EXAMPLE. Shafting pulley, 48 in.; shafting revolutions, 120; counter driven pulley, 12 in.; dynamo pulley, 8 in.; dy- namo revolutions, 1500. Required coun- ter driving pulley. 48 x 1 20 Counter rev. = = 480. 8 x 1 500 Diam. counter driver = g^ = 25 in. For GEARS, substitute the number of teeth in the above rules for the diameter in inches. 50 INSTRUCTIONS FOR AND LINEMEN. (JAS. I. AVER,) When cutting wire, grip the line with the cutting jaws of pliers and move up and down at right angles with the wire two or three times, so that you cut the insulation part of the way round on both sides ; then hold your pliers firmly bend the wire once or twice up and down with your left hand, and the wire will break. Never try to break the wire by twisting your pliers, unless you first move the line out of the cutting jaws. There is no excuse fof nicks in the cutting jaws of Stubs' pliers, and careful linemen rarely have it happen. In stripping the ends of wire to make a connection, always cut along the wire towards the end, in much the same man- ner as if whittling a stick. Never cut round the wire with the edge of the knife or pliers, excepting when cutting the wire. In making joints, be careful never to let the cutting jaws or edge of your tools "score " the wire. If you do, don't cover it up, but make a new joint. After a joint is made with not less than four turns each side of the connectors, dip or moisten with acid. If you are on the ground, dip the joint in melted solder and hold it there a few seconds, to thor- oughly heat the joint, then take it out. If well "tinned," dip it in water to remove any acid which may be on the ends of the wire near the insulation. If where you cannot dip the joint, but have to use the ladle, pour the solder frequently over the joint until it leaves a thin smooth coating on the wire. It is not properly done if the solder is in lumps or in a thick layer. If you are obliged to use a " blow-pot," hold the joint in the flame until the solder will easily melt when held against the wire after the flame is removed. When this is accomplished, apply the solder with the flame and not before. Solder is put on the joint to keep it from corroding, thereby insuring good contact where the two wires come to- gether, and is of no use if not well applied. After the joint is well cleaned of acid after being soldered, paint it thoroughly with insulating compound, then cover with a layer of tape, which you will start on one side of the joint against the insu- lation of the wire but not over it. Have 52 the first layer cover the joint and bare wire only. When this is done paint it ; then start back over the joint and tape until you have run over the line insulation about two inches, then wrap two layers, painting each when done. In wrapping tape, cover what you have laid half, or lap one half. After four layers are on paint the whole thoroughly. Whenever you find a break in the insu- lation on the line anywhere, paint it first, then tape and paint it. Don't forget this. No joints should be permitted to be made and left without being soldered. Never fail to put in " drip-loops " in line where entering building. In all electrical work, remember where insulation is desired it can never be too good, or when contact is desired you can never make it too good or strong. Always avoid temporary work. In making house connections, where wires enter building, have not less than six inches clearance from cornices of walls. All wiring running over cornices or other building projections should be protected with rubber tubing thoroughly taped and painted at the ends. Never let a wire, however well protected, come in contact with the outside portion of the building. 53 In placing tubing on wire, carefully paint and tape at the upper end, leaving the lower end open, so that moisture can escape if it should get hi; In placing converters and making con- nections to same, you should always leave the line connection where you branch to be made after all other work is completed. The primary fuses at the converter must be left out until the final line connections are completed* In making connections to constant potential (alternating or 5oo-volt) circuits, always finish one connection before break- ing the insulation on the other line. Re- member this : that you must have but one wire or joint bare at a time when working on the lines. After completing a converter connection and before closing line connections, care- fully paint the entire outfit (except glass insulators) with insulating paint. See that all wires leading out of con- verters and out of fuse-boxes are well taped and painted where they leave the converter; and all converters must be placed as far from doors, balconies, win- dows, and other openings, as possible, and sufficiently high above ground or roof, to prevent accidental contact; in other words, out of reach. 54 All secondary wires from the converter to house should be as well insulated and protected from grounds as if carrying high- pressure currents. In plugging brick or stone buildings, paint the plugs with insulating compound before driving them. All supports for converters and fuse- boxes placed on buildings must be well painted with insulating paint. In renewing fuses of secondary wires, be sure that the binding-post screws which hold the line wires are firmly set. Fuses are frequently blown by loose line con- ductors. When primary fuses are blown, examine converter for short circuit or leakage be- fore replacing them. When main- line secondary fuses are blown, test with the current on both legs for ground, if circuit is being used. If not, you may test with magneto bells, first re- moving both fuses on main block and testing wires to lamps only. In placing fuses in secondary circuits, always open the switch on the branch before fused, or turn the lamps "off" at sockets before replacing fuse. When replacing fuses, always test for 55 grounds or short circuits on lines where fuses are blown. Use your fuse test wire for all tests on secondaries, if testing with current. Where grounds are found, unless cleared by you, the branch grounded must be left cut out. When placing guard wires on street crossings, always use iron pins and glass insulators to attach both ends of guard wires to. Never tie on cross arm or pole, as in stormy weather, when they should be of use, they will thus become danger- ous. In working on lines all circuits must at all times be regarded as alive and grounded. With many wires, some of which may be carrying heavy currents, some using ground returns, the line you are on may "come alive " any time. Be careful. See that all tools are securely fastened in your belt when working on pole or lad- der, and in handling lines and wires on poles have a proper regard for the safety of those passing beneath. When working on poles always use your safety belt, as well as other desirable safety devices. It takes but little time to make yourself safe, and many weeks to mend a broken bone. 56 Never lay tools down when above the ground. In putting in jumpers, be careful that the loop of jumper does not lie on wiresN^elow and thus make a cross possible if the in- sulation does not hold. Always run wires in straight parallel lines, and make square turns where possi- ble. Twelve inches between wires is the proper space for arc-lighting circuits, where practicable. Never fasten a cut-out box against the wall. Always place glass or porcelain knobs between the box and wall. In tying in, never draw the tie wire so as to bend a kink in the line or cut through the insulation with the tie. A tie will properly hold the wire in place without drawing it so tight as to do either. In using pulley-blocks on the line, avoid the use of " come-alongs " when possible, by taking a series of half hitches, or mak- ing a " noose wrap " with a small line on the wire to hook the block to. If you do use "come-alongs," see that you do not score, cut, or kink the wire, and always paint and tape broken insulation. Groundmen are especially cautioned to watch the line in " paying out " and pre- vent " kinking." Should a short "kink" 57 get pulled into the line, cut it out rather than take the risk of breaking. Never use porcelain knobs where they will be exposed to moisture or the weather, and never use them anywhere else if glass can possibly be substituted. Porcelain knob circuit breakers may be used where necessary, provided not more than two lamps are on the loop. In mak- ing them, paint and insulate with tape the joints in connecting wire or loop. In removing lamps ordered out, always close the loop at the line where it was originally cut in and remove all dead wire. Never leave dead or unnecessary wire in circuit. Always use iron pins on arms where wires turn a corner or leave the line. Never screw an insulator on an iron pin or bracket very tightly, nor without first putting inside the glass a strip of paper folded twice or three times. This will pre- vent the glass being broken, as iron ex- pands with heat nearly twice as rapidly as glass, and unless there is room enough the difference in temperature between winter and summer will burst insulators in sum- mer that were placed in winter. RULES AND REQUIREMENTS FOR THE INSTALLATION OF ELECTRIC LIGHT AND POWER, AS REVISED AND CODIFIED BY TH E UNDERWRITERS' INTERNATIONAL ELECTRIC ASSOCIATION.* CLASS A. CENTRAL STATIONS. FOR LIGHT OR POWER. These Rules also apply to Dynamo Rooms in Isolated Plants, connected ivith or de- tached from buildings used for other pur- poses ; also to all varieties of apparatus therein of both high and low potential. I. GENERATORS a. Must be located in a dry place. b. Must be insulated on floors or base frames, which must be kept rilled to pre- vent absorption of moisture, and also kept clean and dry. * See Appendix for definitions of the word AP- PROVED and rules for the introduction of Automatic Fire Alarm Systems. 59 c. Must never be placed in a room where any hazardous process is carried on, nor in places where they would be exposed to inflammable gases or flyings or combusti- ble material. d. Must each be provided with a water- proof covering. 2. CAKE AND ATTENDANCE. A com- petent man must be kept on duty in the room where generators are operating. Oily waste must be kept in approved metal cans and removed daily. 3. CONDUCTORS from generators, switchboards, rheostats or other instru- ments, and thence to outside lines a. Must be in plain sight, and readily accessible. b. Must be wholly on non-combustible insulators, such as glass or porcelain. c. Must be separated from contact with floors, partitions, or walls through which they may pass by non-combustible insulat- ing tubes, such as glass or porcelain. d. Must be kept rigidly so far apart that they cannot come in contact. e. Must be covered with non-inflamma- ble insulating material sufficient to pre- vent accidental contact, except that " bus bars " may be made of bare metal. 60 f. Must have ample carrying capacity, to prevent heating. (See Capacity of Wires Table.) 4. SWITCHBOARDS a. Must be so placed as to reduce to a minimum the danger of communicating fire to adjacent combustible material. b. Must be accessible from all sides when the connections are on the back ; or may be placed against a brick or stone wall when the wiring is entirely on the face. c. Must be kept free from moisture. d. Must be made of non-combustible material, or of hard wood in skeleton form, filled to prevent absorption of moisture. e. Bus bars must be equipped in accord- ance with Rule 3 for placing conductors. 5. RESISTANCE BOXES AND EQUALIZERS a. Must be equipped with metal or other non-combustible frames. b. Must be placed on the switchboard, or, if not thereon, at a distance of a foot from combustible material, or separated therefrom by a non-inflammable, non-ab- sorptive, insulating material. 6. LIGHTNING ARRESTERS . Must be attached to each side of 61 every overhead circuit connected with the station. b. Must be mounted on non-combustible bases in plain sight on the switchboard, or in an equally accessible place, away from combustible material. c. Must be connected with at least two " earths " by separate wires, not smaller than No. 6 B. & S., which must not be connected to any pipe within the building. d. Must be so constructed as not to maintain an arc after the discharge has passed. 7. TESTING. a. All series and alternating circuits must be tested every two hours while in operation to discover any leakage to earth, abnormal in view of the potential and method of operation. b. All multiple-arc low-potential systems (300 volts or less) must be provided with an indicating or detective device, readily attachable, to afford easy means of testing where the station operates continuously. c. Data obtained from all tests must be preserved for examination by insurance inspectors. These rules on testing to be applied at such places as may be designated by the association having jurisdiction. 62 8. MOTORS- a. Must be wired under the same pre- cautions as with a current of the same volume and potential for lighting. The motor and resistance box must be pro- tected by a double-pole cut-out and con- trolled by a double-pole switch. b. Must be thoroughly insulated, mount- ed on rilled dry wood, be raised at least eight inches above the surrounding floor, be provided with pans to prevent oil from soaking into the floor, and must be kept clean. c. Must be covered with a waterproof cover when not in use, and, if deemed necessary by the Inspector, be enclosed in an approved case. 9. RESISTANCE BOXES a. Must be equipped with metal or other non-combustible frames. b. Must be placed on the switchboard or at a distance of a foot from combustible material, or separated therefrom by a non- inflammable, non - absorptive, insulating material. 63 CLASS B. ARC (SERIES) SYSTEMS. OVER 300 VOLTS. 10. OUTSIDE CONDUCTORS. All outside overhead conductors (including services) a. Must be covered with some approved insulating material, not easily abraded, firmly secured to properly insulated and substantially built supports, all tie wires having an insulation equal to that of the conductors they confine. b. Must be so placed that moisture can- not form a cross-connection between them, not less than a foot apart, and not in con- tact with any substance other than their insulating supports. c. Must be at least seven feet above the highest point of flat roofs and at least one foot above the ridge of pitched roofs over which they pass or to which they are attached. d. Must be protected by dead insulated guard irons or wires from possibility of contact with other conducting wires or substances to which current may leak. 64 Special precautions of this kind must be taken where sharp angles occur or where any wires might possibly come in contact with electric light or power wires. e. Must be provided with petticoat insu- lators of glass or porcelain. Porcelain knobs or cleats and rubber hooks will not be approved. f. Must be so spliced or joined as to be both mechanically and electrically secure without solder. The joints must then be soldered to insure preservation, and cov- ered with an insulation equal to that on the conductors. 11. SERVICE BLOCKS a. Must be covered over their entire surface with at least two coats of water- proof paint. b. Telegraph, telephone, and similar wires must not be placed on the same cross-arm with electric light or power wires. 12. ALL INTERIOR CONDUCTORS a. Must be covered where they enter buildings from outside terminal insulators to and through the walls with extra water- proof insulation, and must have drip loops outside. The hole through which the conductor passes must be bushed with waterproof and non-combustible insulat- ing tube or hard rubber tube, slanting up- 65 ward toward the inside. The tube must be sealed with tape, thoroughly painted, and securing the tube to the wire. b. Must be arranged to enter and leave the building through a double contact service switch, which will effectually close the main circuit and disconnect the inte- rior wires when it is turned "off." The switch must be so constructed that it shall be automatic in its action, not stopping between points when started, and prevent an arc between the points under all cir- cumstances ; it must indicate on inspec- tion whether the current be "on" or "off," and be mounted in a non-combustible case, and kept free from moisture and easy of access to police or firemen. c. Must be always in plain sight, and never encased, except when required by the Inspector. d. Must be covered in all cases with an approved non-combustible material that will adhere to the wire, not fray by fric- tion, and bear a temperature of 150 F. without softening. e. Must be supported on glass or porce- lain insulators, and kept rigidly at least eight inches from each other, except with- in the structure of lamps or on hanger boards, cut-out boxes, or the like, where less distance is necessary. 66 f. Must be separated from contact with walls, floors, timbers, or partitions through which they may pass by non-combustible insulating tube or hard-rubber tube. g. Must be so spliced or joined as to be both mechanically and electrically secure without solder. They must then be sol- dered to insure preservation, and covered with an insulation equal to that on the conductors. 13. AEG LAMPS in every case a. Must be carefully isolated from in- flammable material. b. Must be provided at all times with a glass globe surrounding the arc, securely fastened upon a closed base. No broken or cracked globes to be used. c. Must be provided with an approved hand switch, also an automatic switch, that will shunt the current around the carbons should they fail to feed properly. d. Must be provided with reliable stops to prevent carbons from falling out in case the clamps become loose. e. Must be carefully insulated from the circuit in all their exposed parts. f. Must be provided with a wire netting around the globe and an approved spark arrester above to prevent escape of sparks, melted copper or carbon, where readily 67 inflammable material is in the vicinity of the lamps. It is recommended that plain carbons, not copper-plated, be used for lamps in such places. g. Hanger-boards must be so constructed that all wires and current-carrying devices thereon shall be exposed to view, and thor- oughly insulated by being mounted on a water-proof, non-combustible substance. All switches attached to the same must be so constructed that they shall be automatic in their action, not stopping between points when started, and preventing an arc between points under all circumstances. 14. INCANDESCENT LAMPS IN SERIES CIR- CUITS HAVING A MAXIMUM POTENTIAL OF 300 VOLTS OR OVER a. Must be governed by the same rules as for arc lights, and each series lamp provided with an approved hand-spring switch and automatic cut-out. b. Must have each lamp suspended from a hanger-board by means of a rigid tube. c. No electro - magnetic device for switches and no system of multiple-series or series-multiple lighting will be approved. d. Under no circumstances can series lamps be attached to gas fixtures. 68 CLASS C. INCANDESCENT (LOW-PRESSURE) SYSTEMS. 300 VOLTS OR LESS. 15. OUTSIDE OVERHEAD CONDUCTORS a. Must be erected in accordance with the rules for arc (series) circuit conductors. b. Must be separated not less than 12 inches, and be provided with an approved fusible cut-out that will cut off the entire current as near as possible to the entrance to the building and inside the walls. 16. UNDERGROUND CONDUCTORS a. Must be protected against moisture and mechanical injury, and be removed at least two feet from combustible material when brought into a building but not con- nected with the interior conductors. b. Must have a switch and a cut-out for each wire between the underground con- ductors and the interior wiring when the two parts of the wiring are connected. These switches and fuses must be placed as near as possible to the end of the un- derground conduit and connected there- with by specially insulated conductors, kept apart not less than two and a half inches. c. Must not be so arranged as to shunt the current through a building aiound any catch-box. INSIDE WIRING GENEfcAL RULES. 17. At the entrance of every building there shall be an approved switch placed in the service conductors by which the current may be entirely cut off. 18. CONDUCTORS a. Must have an approved insulating covering, and must not be of sizes smaller than No. 14 B. & S., No. 16 B. W. G., or No. 4 E. S. G., except that, in conduit in- stalled under Rule 22, No. 16 B. & S., No. 18 B. W. G., or No. 4 E. S. G. may be used. b. Must be protected when passing through FLOORS, or through walls, parti- tions, timbers, etc., in places liable to be exposed to dampness by waterproof, non- combustible, insulating tubes, such as glass or porcelain. Must be protected when passing through walls, partitions, timbers, etc., in places not liable to be exposed to dampness by approved insulating bushings specially made for the purpose. c. Must be kept free from contact with gas, water, or other metallic piping, or any other conductors or conducting ma- terial which they may cross (except high potential conductors) by some continuous and firmly fixed non-conductor creating a 70 separation of at least one inch. Devia- tions from this rule may sometimes be allowed by special permission. \-^ ^ d. Must be so placed in crossing high potential conductors that there shall be a space of at least one foot at all points be- tween the high and low tension conduc- tors. e. Must be so placed in wet places that an air-space will be left between conduc- tors and pipes in crossing, and the former must be run in such a way that they can- not come in contact with the pipe acci- dentally. Wires should be run over all pipes upon which condensed moisture is likely to gather, or which by leaking might cause trouble on a circuit. INSIDE WIRING SPECIAL RULES. 19. WIRING NOT ENCASED IN MOULDING OR APPROVED CONDUIT a. Must be supported wholly on non- combustible insulators, constructed so as to prevent the insulating coverings of the wire from coming in contact with other substances than the insulating supports. b. Must be so arranged that wires of opposite polarity, with a difference of po- tential of 150 volts or less, will be kept apart at least two and one half inches. c. Must have the above distance in- creased proportionately where a higher voltage is used unless they are encased in moulding or approved conduit. d. Must not be laid in plaster, cement, or similar finish. e. Must never be fastened with staples. IN UNFINISHED LOFTS, BETWEEN FLOOR AND CEILINGS, IN PARTITIONS AND OTHER CONCEALED PLACES f. Must have at least one inch clear air- space surrounding them. g. Must be at least ten inches apart when possible, and should be run singly on separate timbers or studding. h. Wires run as above immediately un- der roofs, in proximity to water tanks or pipes, will be considered as exposed to moisture. /. Wires must not be fished for any great distance, and only in places where the Inspector can satisfy himself that the above rules have been complied with. j. Twin wires must never be employed in this class of concealed work. 20. MOULDINGS a. Must never be used in concealed work or in damp places. b. Must have at least two coats of water- proof paint or be impregnated with a moisture repellant. 72 c. Must be made of two pieces, a back- ing and capping, so constructed as to thoroughly encase the wire, and maintain a distance of one half-inch between con- ductors of opposite polarity, and afford suitable protection from abrasion. 21. SPECIAL WIRING, In breweries, packing-houses, stables, dye-houses, paper and pulp mills, or other buildings specially liable to moisture or acid, or other fumes liable to injure the wires or insulation, except where used for pendants, conductors a. Must be separated at least six inches. b. Must be provided with an approved waterproof covering. c. Must be carefully put up. d. Must be supported by glass or por- celain insulators. No switches or fusible cut-outs will be allowed where exposed to inflammable gases or dust, or to flyings of combustible material. e. Must be protected when passing through floors, walls, partitions, timbers, etc., by waterproof, non-combustible, in- sulating tubes, such as glass or porcelain. 22. INTERIOR CONDUITS* a. Must be continuous from one junc- * The object of a tube or conduit is to facilitate the insertion or extraction of the conductors, to protect them from mechanical injury, and, as far as possible, 73 tion box to another, or to fixtures, and must be of material that will resist the fusion of the wire or wires they contain, without igniting the conduit. b. Must not be of such material or con- struction that the insulation of the con- ducto'r will ultimately be injured or de- stroyed by the elements of the composi- tion. c. Must be first installed as a complete conduit system, without conductors, strings, or anything for the purpose of drawing in the conductors, and the con- ductors then to be pushed or fished in. The conductors must not be placed in po- sition until all mechanical work on the building has been, as far as possible, com- pleted. d. Must not be so placed as to be sub- ject to mechanical injury by saws, chisels, or nails. e. Must not be supplied with a twin conductor, or two separate conductors, in a single tube. f. Must have all ends closed with good adhesive material, either at junction boxes or elsewhere, whether such ends are con- from moisture. Tubes or conduits are to be considered merely as raceways, and are not to be relied on for in- sulation between wire and wire or between the wire and the ground. 74 cealed or exposed. Joints must be made air-tight and moisture-proof. g. Conduits must extend at least one inch beyond the finished surface of walls or ceilings until the mortar or other simi- lar material be entirely dry, when the pro- jection may be reduced to half an inch. 23. DOUBLE POLE SAFETY CUT-OUTS a. Must be in plain sight or enclosed in an approved box, readily accessible. b. Must be placed at every point where a change is made in the size of the wire (unless the cut-out in the larger wire will protect the smaller). c. Must be supported on bases of non- combustible, insulating, moisture-proof material. d. Must be supplied with a plug (or other device for enclosing the fusible strip or wire) made of incombustible and moist- ure-proof material, and so constructed that an arc cannot be maintained across its terminals by the fusing of the metal. e. Must be so placed that on any com- bination fixture no group of lamps requir- ing a current of six amperes or more shall be ultimately dependent upon one cut-out. Special permission may be given /;/ writ- ing by the Inspector for departure from this rule in case of large chandeliers. /. All cut-out blocks must be stamped 75 with their maximum safe carrying capacity in amperes, and when installed must be marked with the current they are intended to carry. 24. SAFETY FUSES a. Must all be stamped or otherwise marked with the number of amperes they will carry indefinitely without melting. b. Must have fusible wires or strips (where the plug or equivalent device is not used), with contact surfaces or tips of harder metal, soldered or otherwise, hav- ing perfect electrical connection with the fusible part of the strip. c. Must all be so proportioned to the conductors they are intended to protect that they will melt before the maximum safe carrying capacity of the wire is ex- ceeded. 25. TABLE OF CAPACITY OF WIRES It must be clearly understood that the size of the fuse depends upon the size of the smallest conductor it protects, and not upon the amount of current to be used on the circuit. Below is a table showing the safe carrying capacity of conductors of different sizes in Birmingham, Brown & Sharpe, and Edison gauges, which must be followed in the placing of interior con- ductors: 76 BROWN & SHARPS. BIRM [NGHAM. E ( No Uge Amperes. G No gC Amperes. oooo . . ..-.175 oooo. . i75 ooo. . i45 ooo.. 150 oo. . . 120 00. . 130 0. .. 100 o. . no 95 I. . 95 2 . . 70 2. . 85 3 .. .. 60 3 75 4 50 4-- 65 5 45 5 60 6... 35 6.. 50 7 3 7-- 45 8.. 25 8.. 35 . .... 20 0. . 30 2. . 15 2. . . . . . 20 4 . ... 10 4 15 6 . 5 6.. IO 8.. 3 8.. 5 20. . 3 Amp's. 200 .... ....175 180.... .. .160 140 ....135 no no 00.... 95 80.... ... 85 65 ... 75 50 .... .... 60 40... - ... 50 30 .... .... 40 25... 35 20 .... 30 12 .... 20 8 ... .... 15 5---- 10 3.... .... 5 2. . . . .... 3 26. SWITCHES a. Must be mounted on moisture-proof and non-combustible bases, such as slate or porcelain. b. Must be double-pole when the cir- cuits which they control supply more than six 16 candle-power lamps, or their equiv- alent. c. Must have a firm and secure contact, must make and break readily, and not stop when motion has once been imparted by the handle. d. Must have carrying capacity sufficient to prevent heating. 77 e. Must be placed in dry, accessible places, and be grouped as far as possible, being mounted when practicable upon slate or equally non-combustible back- boards. Jack-knife switches, whether pro- vided with friction or swing stops, must be so placed that gravity will tend to open rather than close the switch. 27. FIXTURE WORK. a. In all cases where conductors are concealed within or attached to gas fix- tures, the latter must be insulated from the gas-pipe system of the building by means of approved joints. The insulating material used in such joints must be of a substance not affected by gas, and that will not shrink or crack by variation in tem- perature. Insulating joints with soft rubber in their construction will not be approved. b. Supply conductors, and especially the splices to fixture wires, must be kept clear of the grounded part of gas-pipes, and where shells are used the latter must be constructed in a manner affording suffi- cient area to allow this requirement. c. When fixtures are wired outside, the conductors must be so secured as not to be cut or abraded by the pressure of the fastenings or motion of the fixture. 78 d. All conductors for fixture work must have a waterproof insulation that is dura- ble and not easily abraded, and must not in any case be smaller than No. 18 B. & S., No. 20 B. W. G., or No. 2 E. S. G. e. All burrs or fins must be removed before the conductors are drawn into a fixture. f. The tendency to condensation within the pipes should be guarded against by sealing the upper end of the fixture. g. No combination fixture in which the conductors are concealed in a space less than one-fourth inch between the inside pipe and the outside casing will be ap- proved. //. Each fixture must be tested for " con- tacts " between conductors and fixtures, for "short circuits," and for ground con- nections before the fixture is connected to its supply conductors. /. Ceiling blocks of fixtures should be made of insulating material ; if not, the wires in passing through the plate must be surrounded with hard-rubber tubing. 28. ARC LIGHTS ON LOW POTENTIAL CIR- CUITS a. Must be supplied by branch conduct- ors not smaller than No. 12 B. & S. gauge. 79 b. Must be connected with main con- ductors only through double-pole cut-outs. c. Must only be furnished with such resistances or regulators as are enclosed in non-combustible material, such resist- ances being treated as stoves. Incandescent lamps must not be used for resistance devices. d. Must be supplied with globes and protected as in the case of arc lights on high-potential circuits. 29. ELECTRIC GAS LIGHTING. Where electric gas-lighting is to be used on the same fixture with the electric light a. No part of the gas-piping or fixture shall be in electrical connection with the gas-lighting circuit. b. The wires used with the fixtures must have a non-inflammable insulation, or, where concealed between the pipe and shell of the fixture, the insulation must be such as requited for fixture wiring for the electric light. c. The whole installation must test free from "grounds." d. The two installations must test per- fectly free from connection with each other. 80 \o *t>* < V V, J'^Qfi 30. SOCKETS V(^ From the nature of the ques- tion, the decision as to what is an approved case must be left to the Inspector to deter- mine in each instance. RULE 10. OUTSIDE CONDUCTORS. Section a. Insulation that will be ap- proved for service wires must be solid, at least -^ of an inch in thickness, and cov- ered with a substantial braid. It must not readily carry fire, must show an insulating resistance of one megohm per mile after two weeks' submersion in water at 70 de- grees Fahrenheit, and three days' subrner- 91 sion in lime water, with a current of 550 volts and after three minutes, electrifica- tion. RULE 12. INTERIOR CONDUCTORS. Section d. Insulation that will be ap- proved for interior conductors must be solid, at least -%\ of an inch in thickness, and covered with a substantial braid. It must not readily carry fire, must show an insulating resistance of one megohm per mile after two weeks' submersion in water at 70 degrees Fahrenheit, and three days' submersion in lime-water, with a current of 550 volts and after three minutes' elec- trification. RULE 13. ARC LAMPS. Section c. The hand switch to be ap- proved, if placed anywhere except on the lamp itself, must comply with requirements for switches on hanger-boards as laid down in new Section (g) of Rule 13. RULE 13. ARC LAMPS. Section f. An approved spark arrester is one which will so close the upper orifice of the globe that it will be impossible for any sparks thrown off by the carbons to escape. RULE 15. OUTSIDE OVERHEAD CONDUCT- ORS. Section b. An approved fusible cut-out 92 must comply with the sections of Rules 23 and 24 describing fuses and cut-outs. RULE 17. The switch required by this rule to be approved must be double pole, must plainly indicate whether the current is " on " or "off," and must comply with Sections a, c, d t and e of Rule 26 relating to switches. RULE 18. CONDUCTORS. Section a. In so-called "concealed" wir- ing, moulding, and conduit work, and in places liable to be exposed to dampness, the insulating covering of the wire, to be approved, must be solid, at least -g of an inch in thickness, and covered with a sub- stantial braid. It must not readily carry fire, must show an insulating resistance of one megohm per mile after two weeks' submersion in water at 70 degrees Fahren- heit, and three days' submersion in lime- water, with a current of 550 volts and after three minutes' electrification. For work which is entirely exposed to view throughout the whole interior cir- " cults, and not liable to be exposed to dampness, a wire with an insulating cov- ering that will not support combustion, will resist abrasion, is at least -^ of an inch in thickness, and thoroughly impregnated with a moisture repellent, will be approved. 93 RULE 18. CONDUCTORS. Section b. Second paragraph. Except for FLOORS, and for places liable to be exposed to dampness, Glass, Porcelain^ metal-sheathed Interior Conduit, and Vulca Tube, when made especially for bushings, will be approved. The two last named will not be approved If cut from the usual lengths of tube made for conduit work, nor when made without a head or flange on one end. RULE 21. SPECIAL WIRING. Section b. The insulating covering of the wire to be approved under this section must be solid, at least -^ of an inch in thickness, and covered with a substantial braid. It must not readily carry fire, must show an insulating resistance of one meg- ohm per mile after two weeks' submersion in water at 70 degrees Fahrenheit, and three days' submersion in lime-water with a current of 550 volts after three minutes' electrification, and must also withstand a satisfactory test against such chemical compounds or mixtures as it will be liable to be subjected to in the risk under con- sideration. RULE 23. DOUBLE POLE SAFETY CUT-OUTS. Section a. To be approved, boxes must be constructed, and cut-outs arranged, whether in a box or not, so as to obviate any danger of the melted fuse metal com- 94 ing in contact with any substance which might be ignited thereby. RULE 27. FIXTURE WORK. Section a. Insulating joints to be ap- proved must be entirely made of material that will resist the action of illuminating gases, and will not give way or soften under the heat of an ordinary gas flame. They shall be so arranged that a deposit of moisture will not destroy the insulating effect, and shall have an insulating resist- ance of 250,000 ohms between the gas-pipe attachments, and be sufficiently strong to resist the strain they will be liable to in attachment. RULE 37. POWER STATIONS. Section a. Automatic circuit-breakers should be submitted to the Committee for approval before being used. RULE 43. STORAGE OR PRIMARY BAT- TERIES. Section b. Insulators for mounting sec- ondary batteries to be approved must be non-combustible, such as glass, or thor- oughly vitrified and glazed porcelain. 95 Recommendations of the Electrical Com- mittee as to approval of certain wires and materials, and the interpretation of certain rules. RULE 4. SWITCH-BOARDS. Section a. Special attention is called to the fact that switch-boards should not be built down to the floor, nor up to the ceil- ing, but a space of at least eighteen inches or two feet, should be left between the floor and the board, and between the ceil- ing and the board, in order to prevent fire from communicating from the switch- board to the floor or ceiling, and also to p'revent the forming of a partially con- cealed space very liable to be used for storage of rubbish and oily waste. RULE 5 RESISTANCE BOXES. Section a. The word " frame" in this section relates to the entire case and sur- rounding of the rheostat, and not alone to the upholding supports. RULE 9. RESISTANCE BOXES. Section a. The word " frame" in this section relates to the entire case and sur- rounding of the rheostat, and not alone to the upholding supports. CLASS B. It is the sense of the Electrical Com- mittee that any circuit attached to any 96 machine or combination of machines, which develop over 300 volts difference of potential between any two wires, shall be considered as a high potential circuit and coming under that class, unless an ap- proved transforming device is used, which cuts the difference of potential down to less than 300 volts. RULE 10. OUTSIDE CONDUCTORS. Section/. It is the sense of the Electri- cal Committee that all joints must be soldered, even if made with the Mclntyre or any other patent splicing device. This ruling applies to joints and splices in all classes of wiring covered by these Rules. RULE 15. OUTSIDE OVERHEAD CONDUCT- ORS. Section b. The cut-out required by.this section must be placed so as to protect the switch required by Rule 17. RULE 16. UNDERGROUND CONDUCTORS. Section b. The cut-out required by this section must be placed so as to protect the switch. RULE 22. INTERIOR CONDUITS. It is recommended that the American Circular Loom Co. Tube, the metal- sheathed Interior Conduit Tube, and the Vulca Tube be approved for the class of work called for in this rule. 97 MATERIALS. The following are given as a list of non- combustible, non - absorptive, insulating materials, and are listed here for the bene- fit of those who might consider hard rub- ber, fiber, wood, and the like, as fulfilling the above requirements. Any other sub- stance which it is claimed should be ac- cepted, must be forwarded for testing be- fore being put on the market. 1. Thoroughly vitrified and glazed Por- celain. 2. Glass. 3. Slate without metal veins, 4. Pure Sheet Mica. 5. Marble (filled). 6. Lava (certain kinds of). WIRES. The following is a list of wires which have been tested by the Committee and found to comply with the requirements for an approved insulation under Rule 10 (a), Rule 12 (d), and Rule 18 (a). Americanite. Bishop. Canvasite. Clark. Edison Machine. Grimshaw (white core), Habirshaw (red core). 98 Kerite. National India Rubber Co. (N. I. R.). Okonite. Paranite. Raven Core. c , . r i . i ^ Requa white core. ) Safety Insulated ( Safety black core. > Salamander (rubber covered). Simplex (caoutchouc). None of the above wires to be used unless protected with a substantial braided outer covering. Rules Recommended by the Electrical Committee for the Introduction of Automatic Fire-alarm Systems. THERMOSTATS must be placed 1. Not more than 15 feet apart. 2. Not more than 10 feet from any side of any-room. 3. Not more than 5 feet from any side of any room having window's or similar openings. 4. In every room in the building which is separated by partitions running from the floor to the ceiling. 5. At the top of each elevator well and hoistway in the building. 6. In any particular places required by the Inspector of the Association. 7. In buildings of so-called bay construc- tion, so that there shall be a line in each bay, unless the thermostats are placed on a level with the lower side of the timbers forming the bays. WIRES INSIDE BUILDINGS 1. Must be equivalent in conductivity and tensile strength to No. 18 B. & S. copper wire, 2. Must have an approved insulating covering. 3. Unless encased in metal pipes, ap- 100 proved tubing, or thoroughly filled mould- ing, must be run in plain sight and sup- ported entirely on non-combustible insula- tors. 4. Must be protected from abrasion and from accidental contact with other con- ductors. WIRES OUTSIDE BUILDINGS 1. Must be equivalent in conductivity and tensile strength to No. 12 galvanized iron wire. 2. Must have an approved insulating covering. 3. Must have their routes recorded by plans filed at the Central station of the alarm company operating them. 4. Must be provided near the point of entrance to the building with some protec- tive device, which will operate to shunt the inside wires and apparatus in case of a dangerous rise of potential, and will open the circuit and arrest an abnormal current flow. MANUAL ALARMS Must be located near all main and floor exits. ALARM GONGS Must be installed in all buildings having a watchman. 101 IN SYSTEMS OPERATING WITHOUT A CENTRAL STATION there shall be 1. An annuuciator on the outside of each risk. 2. A gong not less than seven inches in diameter on the outside of each risk. 3. Some means by which the entire sys- tem can be tested daily, and also some method by which any trouble which may arise will be located by this test. 4. At least two outside connections, besides the gong on the outside of the building itself. As a general rule these should be selected from the following list, taking the first two that are possible in any particular risk : (/?) The nearest fire department house where there are permanent men stationed. (b) The house of the owner, or some responsible employee of the risk equipped, which must be within rea- sonable distance of the risk. (c) The house of some other party as described in Section (b). (d) In some of the larger cities with paid city fire-departments the first connection alone may be accepted. 5. A metallic circuit for the whole system. 102 NOTE. It will be seen that the above rules do not in any way relate to what systems shall be approved. The Com- mittee have not yet found it possible to enter into this subject, or to formulate detailed rules as to what a system shall accomplish or how it shall do it, or what the construction of the thermostats and other apparatus should be. These rules simply relate to how a sys- tem which has been approved by any Board or Association should be installed so as to secure the best and most permanent effi- ciency from such system, regardless of the merits or demerits of the svstem itself. 103 ALTERNATING CURRENT WIRING. THE following tables, calculated from Kennelly's formula, give the increase of drop due to impedance in circuits carry- ing alternating currents. Each table is for a different frequency, as given : the first vertical column of a table gives the gauge of wire, the hori- zontal column at the top the distance apart of the two wires of a circuit, and the other columns the coefficients by which the drop due to a continuous current should be multiplied to find the true drop if an alternating current is used. To lower the drop due to impedance it will be seen that large wires should be avoided. In inside work, particularly, a considerable saving of copper may often be made by dividing the feeders or mains into several circuits. The following method will enable the tables to be applied with an approximation sufficiently close for practical purposes : i By means of one of the formulas on pages n, 12, and 13 calculate, for the given lamps, amperes, or horse-power, the size of the wire (in circular mils) as if a continuous current were to be used, 104 and from Table IX. find the nearest corresponding B. & S. gauge number. 2 Enter with the gauge thus found that one of the following tables which cor- responds with the periodicity used and take out the corresponding co- efficient. 3 Multiply the original circular mils by this coefficient and find the correspond- ing gauge again from Table IX. 4 Repeat the operation of 2. 5 Multiply the original circular mils by this second coefficient and proceed otherwise as in 3. EXAMPLE. Amperes, 20; volts, 1000; drop, 5 per cent ; distance, 4000 feet ; peri- odicity, 130; distance of wires apart, 18 inches. i From formula (2), page 11, 2i$oLC 2150 x 4000 x 20 A = E~ -rin^ =344 or about No. 5 B. cS: S. gauge. 2" Referring to Table XXIII., we get the coefficient 1.38. 3 34400 x 1.38 = 47472 cir. mils, or be- tween gauges 3 and 4. 4 Referring to Table XXIII., we find the corresponding coefficient to be about 1.44. 105 5 344oo x 144 = 49536, or about gauge No. 3. If thought necessary a third or fourth approximation may be made by repeating the operations indicated in 4 and 5. The above rules and the tables apply to alternating currents that can be repre- sented by simple sine waves (sinusoids). If the current waves are of more complex type, the drop due to impedance will be increased. The above values are there- fore minimum values. The tables are based on the assumption that the current density in a conductor remains uniform. 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O ~f- X <.' x tr s i> i> CO O rf CO : 1-1 -r rt ct 01 01 TH THTHTH TH ogo 8^S S^g O ^CO(M 01 01 TH THTHTH ^ : ^ ggg ctgS ss^ TH 01 L^ 01 L^ 00 t- OS CO OI TH TH TH rooioi 01 TH r-irHrH ^ : & 2 O , |S O rHOl III 5OOO DIAGRAMS. e I. Two-wire incandescent system. II. Three-wire III. IV. Alternating system. V. Incandescent system, usual. VI. Arc and incandescent series system, little used. VII. Arc and incandescent series and incandescent multiple, little used. VIII. Arc system. IX. Series-wound dynamo (arc). X. Shunt-wound dynamo (incan- descent or arc). XL Compound-wound dynamo. XII. Alternating system. XIII. Closed and open circuit arma- tures. XIV. Siemens, Gramme, and alter nator windings. I. X X X X X a/ III. 00- IV, V. MULTIPLE SERIES VII. IX. X. T XI. \ \ V \ xn [ CONVERTERS VY VY upp uX/ XIII. INDEX. PAGE Alternating current wiring rules and tables . ........ 107 Boilers, horse-power of ...................... ....... 47 Circuits, incandescent, rules for ...................... 5 Closet system of wiring ............................... 9 Copper wire, bare, dimensions, etc .............. ...... 30 11 insulated, weight of , etc ............... 33 Cross-arms, dimensions of ........................... 40 Electrical units ............ ......................... 42 Engines, horse-power of .............................. 46 Equivalents of wires (for cabling, etc.) ........... . . 36 Formulae for wiring Fusing points of variou sing points of various wires Gas jets, air vitiated by ........................... . . 41 Gauges, comparison of ............................... 32 Edison ----- .................................. 31 Gears, rules for calculating ......................... 50 German-silver wire, resistance of .................... 39 Globes, light cut off by .............................. 41 Heating limits, interior wires ............... ....... 34 exterior lines ....................... 35 Horse-power of boilers ............................... 47 " engines ............... . ............. 46 Incandescent circuits, rules for ................... 5 Instructions for wiremen and linemen ............... 51 Iron wire, resistance and weight of .................. 39 Lamp centres defined ................................ 8 Lamps, arc, candle-power of .......... . ............. 41 1 heat from ........................... 41 " incandescent, heat from ..................... 41 Material for installing arc lamps ................... 45 Poles, w r eight and dimensions of ......... . ........... 40 Pulleys, rules for calculating ................... ____ 49 Resistance of copper wire ............................ 30 " different materials ................... 38 " " German silver wire .................... 39 " " iron wire ................... ........ 39 Underwriters' rules ................................ 59 Supplies for installing arc lamps. ................. 45 Tools for installing city plant ....................... 44 Tree system of wiring ................................ 9 Units, electrical ..................................... 42 Voltmeters, connecting up ........................... 10 Wiring formulae ..... .............................. 11 table, 50 volts .............. ......... ........ 14 " 75 " ................................. 16 4 110 " ................................ 18 * 220 " ............................. 20 ' 500 " ............... ................. 22 ' 1000 ** ................................ 24 * 2000 " ................................ 26 ' three- wire system . . ..................... 20 ' odd voltages ......... . . ................. 28 " percentages ......... . .............. 29 128 IF YOU WISH TO KNOW The latest and best work or works on the principles and theory of Electricity, or relating to any par- ticular application of Electricity, THE ELEC- TRICAL WORLD will be pleased to promptly fur- nish the information, personally or by letter, free of charge. 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Annual subscription $3.00 Johnston's Electrical and Street Railway Directory. Published annually 5.00 The Telegraph in America. By JAS. D. REID. 894 royal octavo pages, illustrated. Russia 7.00 Dictionary of Electrical Words, Terms and Phrases. By E. J. HOUSTON, A.M. Second Edi- tion. 562 double-column octavo pages, 570 illus. . . 5.00 The Electric Motor and its Applications. By T. C. MARTIN and Jos. WETZLER. With an appen- dix on the Development of the Electric Motor since 1888, by Dr. Louis BELL. 815 pages, 353 illustrations. 3.00 The Electric Railway in Theory and Practice. By O. T. CROSBY and Dr. Louis BELL. Second edition. 416 pages, 182 illustrations 2.50 Alternating- Currents. An Analytical and Graphical Treatment for Students and Engineers. By F. BEDELL, Ph.D., and A. C. CRKHORK, Ph.D. Second edition. 325 pages, 112 illustrations 2.50 Principles of Dynamo-Electric Machines and Practical Directions for Designing and Construct- ing Dynamos. By CARL HERING. Seventh thou- sand. 279 pages, 59 illustrations 2.50 Continuous-Current Dynamos and Motors. An Elementary Treatise for Students. By FRANK P. Cox, B.S. 271 pages, 83 illustrations 2.00 Electric-Lighting: Specifications for the Use of Engineers and Architects. By E. A. MERRILL. 175 pages 1.50 The Quadruples. By WM. MAYER, Jr.. and MINOR M. DAVIS. With Chapters on the Dynamo in Relation to the Quadruples, the Wheatstone Auto- matic Telegraph, etc. 126 pages, 63 illustrations. . 1.50 The Elements of Static Electricity, with Full Descriptions of the Holtz and Topler Machines. By PHILIP ATKINSON, Ph.D. 228 pages, 64 illus 1.50 Lightning; Flashes. A Volume of Short, Bright and Crisp Electrical Stories and Sketches. 160 pages, copiously illustrated 1-50 A Practical Treatise on Lightning Protec- tion. By H. W. SPANG. 180 pages, 28 illustrations. 1.50 A Practical Treatise on Lightning Conduc- tors. By H. W. SPANG. 48 pages, 10 illus 75 Electricity and Magnetism. Being a Series of Advanced Primers. By E. J. HOUSTON, A.M. 300 pages, 11G illustrations $1.00 Electrical Measurements, and Other Ad- vanced Primers of Electricity. By E. J. HOUSTON, A.M. 429 pages, 169 illustrations 1.00 The Electrical Transmission of Intelligence, and Other Advanced Primers of Electric- ity. By E. J. HOUSTON, A.M. 330 pages, 88 illus.. 1.00 Alternating Currents of Electricity, their Generation, Measurement, Distribution and Appli- cation. By GISBERT KAPP. 166 pages, 38 illus ... 1. 00 Recent Progress in Electric Railways. Being a Summary of Current Advance in Electric Rail- way Construction, Operation, Appliances, etc. Compiled by CARL HERING. 386 pages, 120 illus.. . 1.00 Reference Book of Tables and Formulae for Electric Street Railway Engineers. By E. MERRILL 1.00 Original Papers on Dynamo Machinery and Allied Subjects. By JOHN HOPKINSON, F.R.S. 249 pages, 90 illustrations 1.00 Universal Wiring Computer for Determining the Sizes of Wires for Incandescent Electric-Lamp Leads without Calculation, with Some Notes on Wiring, etc. By CARL HERING. 44 pages 1.00 Dynamo and Motor Building for Amateurs. With Working Drawings. By C. D. PARKHURST... 1.00 Experiments with Alternating Currents of High Potential and High Frequency. By NIKOLA TESLA. 146 pages, 30 illustrations 1.00 Lectures 011 the Electromagnet. By Prof. SIL- VANUS P.THOMPSON. 287 pages, 75 illustrations. .. 1.00 Electricity at the Paris Exposition of 1889. ^ By CARL'HERING. 250 pages, 62 illustrations J&00 Practical Information for Telephonists. By T. D. LOCKWOOD. 192 pages 1.00 Wheeler's Chart of Wire Gauges 1.00 Davis' Standard Tables for Electric Wire- men 1.00 Proceedings of the National Conference of Electricians. 300 pages, 23 illustrations T5 Wired Love : A Romance of Dots and Dashes. 256 pages 75 Tables of Equivalents of Units of Measure- ment, By CARL HERING 50 THE W. J, JOHNSTON COMPANY, Ltd., 41 Park Row (Times Building), New York. SECOND EDITION, JUST ISSUED. Revised. Enlarged. Entirely Rewritten. A Dictionary of ELECTRICAL WORDS, TERMS AND PHRASES. By EDWIN J. HOUSTON, A.M. 562 Large Octavo Pages. 570 Illustrations. Price, $5.00. Some idea of the scope of this timely and impor- tant work, and of the immense amount of labor in- volved in it, may be formed when it is stated that it contains definitions of about 5,000 DISTINCT WORDS, TERMS OR PHRASES. The Dictionary is not a mere word book. The words, terms and phrases are invariably followed by a short, concise definition, giving the sense in which they are correctly employed and a general statement of the principles of electrical science on which the definition is founded. As one feature, an elaborate system of cross references has been adopted, so that it is as easy to find the definitions as the words, and aliases are readily detected and traced. The typography is excellent, being large and bold, and so arranged that each word catches the eye at a glance by standing out in sharp relief from the page. Published and for sale, at wholesale and retail, by The W. J. JOHNSTON COMPANY, Ltd., TIMES BUILDING, NEW YORK. ELECTRICITY AND MAGNETISM: A Series of Advanced Primers. By Prof, EDWIN J. HOUSTON, AUTHOR OF A Dictionary of Electrical Words, Terms and Phrases, Cloth. 306Pages, 116 Illustrations. Price, 1.00. Prof. Houston's Primers of Electricity written in 1884 enjoyed a wide circulation, not only in the United States but in Europe, and for some time have been out of print. Owing to the great prog- ress in electricity since that date the author has been led to prepare an entirely new series of primers, but of a mpre advanced character in con- sonance with the advanced general knowledge of electricity. Electricians will find these primers of marked interest from their lucid explanations of principles, and the general public will in them find an easily read and agreeable introduction to a fascinating subject. CONTENTS. I. Effects of Electric Charge. II. Insulators and Con- ductors. III. Effects of an Electric Discharge. IV. Electric Sources. V. Electro-receptive Devices. VI. Electric Current. VII. Electric Units. VIII. Electric Work and Power. IX. Varieties of Electric Circuits. X. Magnetism. XI. Magnetic Induction. XII. The- ories of Magnetism. XIII. Phenomena of the Earth's Magnetism. XIV. Electro-Magnets. XV. Electrostatic Induction. XVI. Frictional and Influence Machines. XVII. Atmospheric Electricity. XVIII. Voltaic Cells. XIX. Review, Primer of Primers. Published and for sale, at wholesale and retail, by The W. J. JOHNSTON COMPANY, Ltd., TIMES BUILDING, NEW YORK. JUST PUBLISHED. THE ELECTRIC RAILWAY In Theory and Practice. By O. T. CROSBY and Dr. LOUIS BELL. 400 Octavo Pages. 179 Illustrations. Price, $2.*>0, This is the first Systematic Treatise that has been pub- lished on the Electric Railway, and it is intended to cover the General Principles of Design, Construction and Operation. TABLE OF CONTENTS. Chapter I. General Electrical Theory. II. Prime Movers. III. Motors and Car Equipment. IV. The Line. V. Track, Car Mouses, Snow Machines. VI. The Station. VII. The Efficiency of Electric Traction. VIII. Storage Battery Traction. IX. Miscellaneous Methods of Electric Traction. X. High Speed Service. XI. Commercial Considerations. XII. Historical Notes. APPENDICES. Appendix A. Electric Railway vs. Telephone De- cisions. B. Instructions to Linemen. " C. Engineer's Log Book. " D. Classification of Expenditures of Electric Street Railways. " E. Concerning Lightning Protection, by Prof. Elihu Thomson. Published and for sale^ at wholesale and retail, by The W. J. JOHNSTON COMPANY, Ltd., TIMES BUILDING, NEW YORK. THE ELECTRIC MOTOR AND ITS APPLICATIONS. By T. C. MARTIN and JOSEPH W.ETZLER. WITH AN APPENDIX BRINGING THE BOOK DOWN TO DATE, BY DR. LOUIS BELL. 325 Large Quarto Pages and 354 Illustrations. Price, postage prepaid to any part of the world, $3.00. This timely work is the first American Book on Electric Motors, and the only book in any lan- guage dealing exclusively and fully with the modern Electric Motor in all its various practical applications. The book is a handsome quarto, the page being of the same size as Dredge's large work on " Electric Illumination." and many of the cuts are full page. No effort has been spared to make the book complete to date, and it will prove invaluable to every one interested in the progress and develop- ment of the Electric Motor or the Electrical Trans- mission of Energy. Mailed prepaid to any address on receipt of the price by the Publishers, The W. J. JOHNSTON COMPANY, Ltd., TIMES BUILDING, NEW YORK. AN IMPORTANT NEW BOOK. ALTERNATING CURRENTS. An Analytical and Graphical Treatment for Students and Engineers. FREDERICK BEDELL, Ph.D,, and A, C, CREHORE, Ph.D, Cor, Univ, Uniform in size and style with " The Electric Railway in Theory and Practice, 11 by O. T. Crosby and Dr. Louis Bell. Cloth. 350 Pages and 11 '2 Illustrations. Price, $2.50, While there are many monographs and special treatises on alternating currents, they are either fragmentary or special in character, or couched in mathematical language requiring a special mathe- matical education to interpret. In this volume the theory of alternating currents is, for the first time, treated in a connected and logical manner, and in mathematical language familiar to the ordinary mathematical public, while the graphical extension can be followed by those not having a special knowledge of mathe- matics. Some parts of this volume have been published in separate papers, and from the cordial welcome they received, it is believed that the present work will fill a distinct want in an important branch of electrical science. Mailed prepaid to any address on receipt of the price by the Publishers, The W. J. JOHNSTON COMPANY, Ltd., TIMES BUILDING, NEW YORK. PRINCIPLES OF DYNAMO-ELECTRIC MACHINES AND Practical Directions for Designing and Constructing Dynamos. By CARL. HERING. Sixth Thousand. 279pp. 59 Illustrations. Price, $2.50 CONTENTS. Review of Electrical Units and Fundamental Laws. Fundamental Principles of Dynamos and Motors. Magnetism and Electromagnetic Induction. Generation of Electromotive Force in Dynamos. Armatures. Calculation of Armatures. Field Magnet Frames. Field Magnet Coils. Regulation of Machines. Examining Machines. Practical Deductions from the Franklin Institute Tests of Dynamos. The So-called " Dead Wire" on Gramme Arma- tures. Explorations of Magnetic Fields Surrounding Dynamos. Systems of Cylinder- Armature Windings. Table of Equivalents of Units of Measurements. Mailed prepaid to ony address on receipt of the price by the Publishers, The W. J. JOHNSTON COMPANY, Ltd., TIMES BUILDING, NEW YORK. ELECTRIC LIGHTING SPECIFICATIONS FOR THE USE OF Engineers and Architects. By E. A. MERRILL. loth. 170 Pages. Price, including Postage, $1.50. The author has drawn up a set of specifications covering the various classes of lighting installa- tions, which will serve as forms for any special type or character of plant, ind which are at the same time full enough to cover the ordinary instal- lation of electrical apparatus and '.\ectric light wir- ing. The book will prove especially useful to architects and engineers who desire a full knowl- edge of the necessary requirements of the various classes of electrical installations in order to meet the demands of the insurance inspectors and the conditions of safety. The latest rules are given of the (i) National Electric Light Association, (2) National Board of Fire Underwriters, (3) New England Insurance* Exchange. Mailed prepaid to any address en feceipt of the price by the Publishers, The W. J. JOHNSTON COMPANY, Ltd., TIMilS BUILDING, NEW YORK. EXPERIflENTS WITH ALTERNATE CURRENTS Of High Potential and High Frequency. By NIKOLA TESLA. 156 Pages, with Portrait and 35 Illus. Cloth. $1.00. This book gives in full Mr. Tesla's important lecture before the London Institution of Electrical Engineers, which embodies the results of years of patient study and investigation on Mr. Tesla's par- of the phenomena of Alternating Currents of Enort mously High Frequency and Electromotive Force. EVERY ELECTRICIAN, ELECTRICAL ENGINEER OR STUDENT OF ELECTRIC- AL PHENOMENA WHO MAKES ANY PRE- TENSIONS TO THOROUGH ACQUAINT- ANCE WITH RECENT PROGRESS IN THIS IMPORTANT FIELD OF RESEARCH WHICH MR. TESLA HAS SO ABLY DE VELOPED MUST READ AND REREAD THIS LECTURE. The book is well illustrated with 35 cuts of Mr. Tesla's experimental apparatus, and contains in addition a biographical sketch, accompanied by a full-page portrait, which forms a fitting frontispiece to a lecture which created such widespread interest. Mailed prepaid to any address on receipt of the price by the Publishers, The W. J. JOHNSTON COMPANY, Ltd., TIMES BUILDING, NEW YORK. RECENT PROGRESS IN ELECTRIC RAILWAYS BEING A SUMMARY OF CURRENT PROGRESS IN ELECTRIC RAILWAY CONSTRUCTION, OPERATION, SYSTEMS, MACHINERY, APPLIANCES, ETC. COMPILED 11 V 380 Pages and 120 Illustrations. Cloth. Price, $1.00. This volume contains a classified summary of the recent literature on this active and promising branch of electrical progress, with descriptions of new apparatus and devices of general interest. CONTENTS. Chapter I. Historical. Chapter II. Develop- ment and Statistics. Chapter III. Construction and Operation. Chapter IV. Cost of Construc- tion and Operation. Chapter V. Overhead Wire Surface Roads. Chapter VI. Conduit and Surface Conductor Roads. Chapter VII. Storage Battery Roads. Chapter VIII. Underground Tunnel Roads. Chapter IX. High Speed Interurban Railroads Chapter X. Miscellaneous Systems. Chapter XI. Generators, Motors and Trucks. Chapter XII. Accessories. Mailed prepaid to any address on receipt of the Price by the Publishers, The W. J. JOHNSTON COMPANY, Ltd., TIMES BUILDING, NEW YORK. ORIGINAL PAPERS DYNAMO MACHINERY AND ALLIED SUBJECTS. By JOHN HOPKINSON, F.E.S. Uniform in size, style and price with Thompson's Lectures on the Electromagnet. Cloth. 257 Pages. 98 Illustrations. Price, $1.00. This collection of papers includes all written on electro-technical subjects by the distinguished author, most of which have been epochal in their character and results. The papers are arranged according to subject. Five papers relate wholly or in part to the contin- uous current dynamo ; four are on converters and one each on the theory of alternating current machines and on the application of electricity to light-houses. In the words of the author, " The motive of this publication has been that I have understood that one or two of these papers are out of print and not so accessible to American readers as an author who very greatly values the good opinion of American electrical engineers would desire." Mailed prepaid to any address on receipt of the price by the Publishers, The W. J. JOHNSTON COMPANY, Ltd., TIMES BUILDING, NEW YORK. THE ELECTROHAGNET. r-Y Prof, SILVANUS P, THOMPSON, D,Sc, f B,A M M.I.E.E, A full theoretical and practical account of the proper- ties and peculiarities of electromagnets, together with complete instructions for designing magnets to serve any specific purpose. Published with the express consent and careful revision of the author. Cloth. 280 Pages. 75 Illustrations. Price, $1.00. LECTURE I.: Introductory ; Historical Sketch ; Gener- alities Concerning Electromagnets ; Typical Forms ; Po- Jarity ; Uses in General ; The Properties of Iron ; Methods of Measuring Permeability ; Traction Methods ; Curves of Magnetization and Permeability ; The Law of the Electro- magnet ; Hysteresis; Fallacies and Facts about Electro- magnets. LECTURE II,: General Principles of Design and Construction ; Principle of the Magnetic Circuit. LECTURE III.: Special Designs ; Winding of the Copper ; Windings for Constant Pressure and for Constant Current ; Miscel- laneous Rules about Winding ; Specifications for Electro- magnets ; Amateur Rules about Resistance of Electromag- net and Battery ; Forms of Electromagnets ; Effect of Size of Coils ; Effect of Position of Coils ; Effect of Shape of Section ; Effect of Distance between Poles ; Researches of Prof. Hughes; Position and Form of Armature, Pole- Pieces on Horseshoe Magnets ; Contrast between Electro- magnets and Permanent Magnets ; Electromagnets for Maximum Traction ; Electromagnets for Maximum Range of Attraction ; Electromagnets of Minimum Weight ; A Useful Guiding Principle ; Electromagnets for Use with Alternating Currents ; Electromagnets for Quickest Ac- tion ; Connecting Coils for Quickest Action; Battery- Grouping ff r Quickest Action ; Short Cores vs. Long Cores. LECTURE IV.: Electromagnetism, etc. Mailed prepaid to any address on receipt of the price by the Publishers, The W. J. JOHNSTON COMPANY, Ltd., TIMES BUILDING, NEW YORK. THEQUADRUPLEX. BY WM, MAVER, Jr., and MINOR M, DAVIS, With Chapters on The Dynamo-Electric Machine in Relation to the Quadruplex. The Practical Work- ing of the Quadruplex. Telegraph Repeaters and the Wheatstone Automatic Telegraph. By WM. MAVER, Jr. Cloth. 126 Pages. 63 Illustrations. Price, $l.oO. CONTENTS. Development of the Quadruplex. Introduction and Explanatory. The Transmitter, Rheostat and the Condenser. Stearns Duplex. Instruments of the Polar Duplex. The Polar Duplex. The Quadruplex. The Dynamo-Electric Machine in relation to ihe Quad. The Practical Working of the Quadruplex. Telegraph Repeaters. The Wheatstone Automatic Telegraph. This book is written in plain, simple and explicit language, and is within the ready comprehension of all. The illustrations are numerous, and with their aid the reader can at once grasp, menta/iy, the operation of the Quadruplex. The book is handsomely printed on fine paper and substantially bound. Every Telegrapher and every Electrician should have a copy. Mailed prepaid to any address on receipt of the prtte by the Publishers, The W. J. JOHNSTON COMPANY, Ltd., TIMES BUILDING, NEW YORK. ELEMENTS OF STATIC ELECTRICITY, With full description of the Holtz and To'pler flachines and their mode of operation. By PHILIP ATKINSON, A.M., Ph.D. Cloth, 12mo. 2-28 Pages. 4 Illustrations. Price, $1.50. The author of this treatise has made a special study of Static Electricity, and is an acknowledged master of the subject. The book embodies the result of much original investigation and experi- ment, which Dr. Atkinson's long experience as a teacher enables him to describe in clear and inter- esting language, devoid of technicalities. The principles of electricity are presented un- trammeled, as far as possible, by mathematical formulae, so as to meet the requirements of a large class who have not the time or opportunity to mas- ter the intricacies of formulae, which are usually so perplexing to all but expert mathematicians. The views expressed in the book are the result of many years' experience in the class room, the lee ture room and the laboratory, and were adopted only after the most rigid test of actual and oft- repeated experiment by the author. Mailed prepaid to any address on receipt of the price by the Publishers, The W. J. JOHNSTON COMPANY, Ltd., TIMES BUILDING, NEW YORK. TH UNIVERSAL WIRING COMPUTER. By CARL HEBING, Author of " Principles of Dynamo-Electric Machines," " Magnet Winding,' 1 etc. Convenient Size for the Pocket. Cloth. Price, $1.00. Gives the sizes of wires directly in circular mils or in gauge numbers, for any make of lamp (or any horse power of current), for any loss, for any number of lamps, and at any distances, without cal- culations, for mu Ice or knowledge of mathematics. It is the equivalent of a complete set of tables for all practical cases, with the advantage over these of being much simpler, more compact and handy than such a cumbersome and bulky set of tables would be. It gives the result in as little time as it would otherwise take to write down the figures to perform the calculation. The book includes also an illustrated article giv- ing general hints on wiring and a set of original Useful Auxiliary Tables, such as for heating limits, weights of insulation, power reductions, composite wires of large sections, weights and resistances, wire gauges, etc. flailed postpaid to any address on receipt of the price by the Publishers. The W. J. JOHNSTON COMPANY, Ltd., TIMES BUILDING, NEW YORK. Practical Information for Telephonists, By T. D. LOCKWOOD, ELECTRICIAN AMERICAN BELL TELEPHONE COMPANY. 12nio. 192 Pages. Cloth. Price, $1.00. CONTENTS. Historical Sketch of Electricity from 600 B.C. to 1882 A.D. Facts and Figures about the Speaking Telephone. How to Build a Short Telegraph or Telephone Line. The Earth and Its Relation to Telephonic Systems of Communication. The Magneto-Telephone What it is, How it is Made, and How it Should be Handled. The Blake Transmitter. Disturbances Experienced on Telephone Lines. The Telephone Switch- Board. A Chronological Sketch of the Magneto-Bell, and How to Become Acquainted with it. Telephone Transmitter Batteries. Lightning Its Action upon Telephone Apparatus How to Prevent or Reduce Troubles Aris- ing Therefrom. The Telephone Inspector. The Telephone Inspector His Daily Work. The Inspector on Detective Duty. The Daily Routine of the Telephone Inspector. Individual Calls for Telephone Lines. Telephone Wires versus Electric Light W T ires. Electric Bell Construction, Part I. Electric Bell Construction, Part II. Housetop Lines, Pole Lines and Aerial Cables. Anticipations of Great Discoveries and Inventions. Published and for sale, at wholesale and retail, by The W. J. JOHNSTON COMPANY, Ltd., TIMES BUILDING, NEW YORK. TABLES OF EQUIVALENTS OF UNITS OF MEASUREMENT. BY CARL HERING, Author of " Principles of Dynamo Electric Machines," etc. Bound in Flexible Covers. Price, 50 Cents. Electrical measures being based upon the metric system, these tables have been carefully calculated to express the various values met with in electrical literature in their English equivalents. CHART OF WIRE GAUGES. By S. S. WHEELER, Electrical Expert, New York Board of Electrical Control. Engraved on fine plate paper, and suitable for framing, Price, - - $1.00. By means of the engraved curves on this chart of the various wire gauges of the world, the size of wire corresponding to any number, or the equiva- lent number of another gauge, can be determined at a glance. Mailed prepaid to any address on receipt of the price by the Publishers, The W. J. JOHNSTON COMPANY, Ltd., TIMES BUILDING, NEW YORK. PROCEEDINGS OF T1IK National Conference of Electricians AT PHILADELPHIA. Cloth. 800 Pages. 23 Illustrations. Price, 75 Cents. The conference of electricians held in connection with the International Electrical Exhibition, at Philadelphia, in 1884, was a notable gathering, and the discussions of the eminent American and English electricians who were present on that im- portant occasion will always have an authoritative value. Among those who took part in the Conference and whose views and opinions are preserved in this volume were Sir Wm. Thomson (now Lord Kel- vin), Prof. Rowland, Prof. S. P. Thompson, Elihu Thomson, W. H. Preece, Prof. Forbes, Pro'. Newcomb, F. J. Sprague, and many others of eminence in the scientific and practical world. Mailed prepaid to any address on receipt of the price by the Publishers, The W. J. JOHNSTON COMPANY, Ltd., TIMES BUILDING, NEW YORK, A BOOK FOR THE LIGHTER MOMENTS. Lightning Flashes /. and .'. .*. Electric Dashes. A Volume of Choice Telegraphic and Electrical Literature, Humor, Fun, "Wit and Wisdom. Cloth. Profusely Illustrated. 160 Large, Double Column Paa;es. Price, $1.50. "Lightning Flashes" is principally made up of short, bright, crisp, ably-written stories and sketches from the pens of the foremost writers in the ranks of telegraphic and electrical literature, as well as of several writers of prominence outside of the business. Among the latter are included Mr. Charles Barnard and the late Benson J. Lossing, LL.D. The article by Dr. Lossing, on Professor Morse, is a valuable contribution to the history of the telegraph, and the other articles, grave and gay in turn, in some cases illustrated by the authors, make this a work of interest to the general reading public as well as to electricians. Mailed prepaid to any address on receipt of the price by the Publishers, The W. J. JOHNSTON COMPANY, Ltd., TIMES BUILDING, NEW YORK. :RIRST WIRED LOVE: A ROMANCE OF DOTS AND DASHES. By ELLA CHEEVER THAYER. Fourth Edition. loth. 25 Pages. Price, 75 Cents. A good book to make you forget business and care, and leave pleasant memories behind it. Chicago Inter- Ocean. A capital love story, the affection having its origin in telegraphic communications between two operators unknown to each other, fifty miles or so apart. Boston Commonwealth* The book is written in an easy, off-hand style, pervaded with quiet humor, and its sentimental portions contain some suggestions of wisdom that are expressed with great force, beauty and origi- nality. Boston Herald. The love-making which goes on is done over telegraphic wires, and there is plenty of humor and a dash of mystery about the story which makes it refreshing reading. The heroine is a telegraphic operator, and the way in which her acquaintance over the wires with a fellow-operator ripens into something more than friendship is very pleasantly told. Boston Journal. Mailed prepaid to any address on receipt of the price by the Publishers, The W. J. JOHNSTON COMPANY, Ltd., TIMES BUILDING, NEW YORK. JOH NSTO N'S Electrical and Street Railway DIRKC TORY. CONTAINING LISTS OF CENTRAL ELECTRIC LIGHT STATIONS, ISOLATED PLANTS. ELECTRIC MINING PLANTS, STREET RAILWAY COMPANIES (Electric, Horse, and Cable). WITH DETAILED INFORMATION REGARDING EACH. ALSO LISTS OF ELECTRICAL AND STREET RAILWAY- MANUFACTURERS AND SUPPLY DEALERS, ELECTRICIANS, ETC. PUBLISHED ANNUALLY. H Substantially bound in Cloth, - Price, $5.00. The great facilities possessed by THE ELECTRICAL WORLD for obtaining information in every branch covered by the Directory, added to the special facilities of the Directory department itself, guar- antee that this work will ALWAYS be the MOST COMPLETE, the MOST RELIABLE and the MOST VALUABLE of any work of the kind EVER ISSUED. Mailed postpaid to any address on receipt of the price by the Publishers, The W. J. JOHNSTON COMPANY, Ltd., TIMES BUILDING, NEW YORK. The Pioneer Electrical Journal of America. READ WHEREVER THE ENGLISH LANGUAGE IS SPOKEN. The Electrical World IS THE Largest, Most Handsomely Illustrated, and Widest Circulated Electrical Journal in the World. It should be read not only by every ambitious electrician anxious to rise in his profession, but by every intelligent American. The paper is ably edited and noted for explain- ing electrical principles and describing new inven- tions and discoveries in simple and easy language, devoid of technicalities.- It also gives promptly the most complete news from all parts of the world, relating to the different applications of electricity. Subscription, including Postage in the U. S., Canada, or Mexico, $8.00 A losir. May be ordered of any Newsdealer at 10 cents a week. ' (J* The W. J. JOHNSTON COMPANY, Ltd., TIMES BUILDING, NEW YORK. YA 0220 YA 02201; THE UNIVERSITY OF CALIFORNIA LIBRj