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 UNIVERSITY OF CALIFORNIA 
 AT LOS ANGELES
 
 WIRE 
 
 Electrical 
 
 JOHN A. ROBBING'S SONS Co. 
 
 TRENTON, N. J. 
 
 117-119 Liberty street, 171-173 Lake street, 
 
 NEW YORK. CHICAGO. 
 
 32 South Water street, 25-27 Fremont street, 
 
 CLEVELAND. SAN FRANCISCO. 
 
 f 
 
 (grantt $re0s,
 
 COPYRIGHTED, 1897, 
 BY 
 
 JOHN A. ROEBLING'S SONS CO. 
 
 All rights reserved. 

 
 TK 
 
 PREFATORY. 
 
 THE OBJECT of this book is to give in a convenient 
 form the properties and dimensions of bare and 
 insulated wires and cables used in electrical construction. 
 No attempt has been made to describe the uses of wire in 
 any of the applications of electricity. To go into this 
 would require that the whole field of electrical engineer- 
 ing be covered. 
 
 It is believed that some of the matter is new. All of 
 the tables have been very carefully computed, and are 
 believed to be correct. 
 
 In nearly all cases the formulae and constants used in 
 computing tables are given, so that the user can deter- 
 mine at once the basis from which the table was calcu- 
 lated. A considerable amount of work has been done in 
 testing samples to determine the proper constants. In 
 many cases this has taken more time than the actual 
 preparation of the tables. 
 
 It is hoped that the work will be acceptable to the 
 users of electrical wires, and that some of the labor 
 involved in the preparation of these tables will be saved 
 to those using the book. 
 
 JOHN A. ROEBLING'S SONS Co. 
 TRENTON, N. J., May, 1897. 
 
 249 
 
 210987
 
 TABLE OF CONTENTS. 
 
 MEASURES AND THEIK EQUIVALENTS : PAGE. 
 
 Measures of length 1 
 
 Measures of area 2 
 
 Measures of volume 3 
 
 Measures of weight 4 
 
 Measures of work 5 
 
 Measures of pressure 6 
 
 Decimal equivalents of parts of an Inch 7 
 
 Wire gauges in mils 8 
 
 Wire gauges in millimeters 9 
 
 Tables of specific gravities : 
 
 Metals 10 
 
 Liquids 11 
 
 Gases 11 
 
 Weights of substances 12 
 
 The comparison of thermometers : 
 
 Fahrenheit to Centigrade 13 
 
 Centigrade to Fahrenheit 13 
 
 Electrical units 14-15 
 
 COPPER WIRE: 
 
 Formulae and explanations 16-17 
 
 Matthiessen's standard 17 
 
 Temperature coefficients 18 
 
 Properties of copper wire weights, resistances, etc. 
 English system : 
 
 Brown & Sharpe gauge 19 
 
 Birmingham wire gauge 20 
 
 New British standard gauge 21 
 
 Metric system : 
 
 Brown & Sharpe gauge 22 
 
 Weights of all gauges 23 
 
 Hard-drawn copper wire : 
 
 British Post-office specifications 24 
 
 Telephone specifications 25 
 
 Tensile strength of copper wire 26 
 
 Bi-metallic wire 27 
 
 Strands of copper wire : 
 
 Formulae and explanations. 28 
 
 Diameters and properties 29 
 
 Diameters of wires in strands 30-31 
 
 Numbers of wires in strands .... 32-33
 
 TABLE OP CONTENTS. 
 
 IRON WIRE: PAGE. 
 
 Formulae and explanations 34 
 
 Properties of iron wire weights, strength, resistances, etc., 35 
 Specifications : 
 
 Western Union Telegraph company 36 
 
 British Post-office 37 
 
 Strands : 
 
 Formulae and explanations 38 
 
 Properties of galvanized steel wire strands weights 
 
 and breaking strength 38 
 
 Supporting capacity of galvanized strands 39 
 
 CURRENTS : 
 
 Fusing effects : 
 
 Diameters of wires. 40 
 
 Current required 41 
 
 Heating effects : 
 
 References and explanations 42 
 
 Carrying capacity : 
 
 Insurance rules 43 
 
 Insulated wires in mouldings 44 
 
 Wires indoors 45 
 
 Wires outdoors 46 
 
 SPANS : 
 
 Formulae and explanations 47-49 
 
 Specifications 48 
 
 Strains at centers of spans 50-52 
 
 Total lengths of wires in spans 54-55 
 
 Deflections in spans at various temperatures 53 
 
 DESCRIPTION OF THE ROEBLING ELECTRIC WIRES : 
 
 Weatherproof wires 56-57 
 
 Rubber wires 58-69 
 
 Magnet wire 60-61 
 
 German silver wire ,62 
 
 Office wires 63 
 
 Cables : 
 
 Power cables 64-65 
 
 Telephone cables 66-67 
 
 Telegraph cables 68-69 
 
 Aerial cables 70-71 
 
 Submarine cables. 72
 
 JOHN A. ROEBLING S SONS CO. 
 
 !i 
 
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 JOHN A. ROEBLING'S SONS co. 7 
 
 DECIMAL EQUIVALENTS OF PARTS OF 
 
 AN INCH. 
 
 leths. 
 
 32ds. 
 
 64ths. 
 
 Mils. 
 
 16ths. 
 
 32ds. 
 
 64ths. 
 
 Mils. 
 
 
 1 
 
 1 
 2 
 
 15.625 
 31.25 
 
 
 17 
 
 33 
 34 
 
 515.625 
 531.25 
 
 
 
 3 
 
 46.875 
 
 
 
 35 
 
 546.875 
 
 i 
 
 2 
 
 4 
 
 62.5 
 
 9 
 
 18 
 
 36 
 
 562.5 
 
 
 
 5 
 
 78.125 
 
 
 
 37 
 
 578.125 
 
 
 3 
 
 6 
 
 93.75 
 
 
 19 
 
 38 
 
 593.75 
 
 
 
 7 
 
 109.375 
 
 
 
 39 
 
 609.375 
 
 2 
 
 4 
 
 8 
 
 125. 
 
 10 
 
 20 
 
 40 
 
 625. 
 
 
 
 9 
 
 140.625 
 
 
 
 41 
 
 640.625 
 
 
 5 
 
 10 
 
 156.25 
 
 
 21 
 
 42 
 
 656.25 
 
 
 
 11 
 
 171.875 
 
 
 
 43 
 
 671.875 
 
 3 
 
 6 
 
 12 
 
 187.5 
 
 11 
 
 22 
 
 44 
 
 687.5 
 
 
 
 13 
 
 203.125 
 
 
 
 45 
 
 703.125 
 
 
 7 
 
 14 
 
 218.75 
 
 
 23 
 
 46 
 
 718.75 
 
 
 
 15 
 
 234.375 
 
 
 
 47 
 
 734.375 
 
 4 
 
 8 
 
 16 
 
 250. 
 
 12 
 
 24 
 
 48 
 
 750. 
 
 
 
 17 
 
 265.625 
 
 
 
 49 
 
 765.625 
 
 
 9 
 
 18 
 
 281.25 
 
 
 25 
 
 50 
 
 781.25 
 
 
 
 19 
 
 296.875 
 
 
 
 51 
 
 796.875 
 
 5 
 
 10 
 
 20 
 
 312.5 
 
 13 
 
 26 
 
 52 
 
 812.5 
 
 
 
 21 
 
 328.125 
 
 
 
 53 
 
 828.125 
 
 
 11 
 
 22 
 
 343.75 
 
 
 27 
 
 54 
 
 843.75 
 
 
 
 23 
 
 359.375 
 
 
 
 55 
 
 859.375 
 
 6 
 
 12 
 
 24 
 
 375. 
 
 14 
 
 28 
 
 56 
 
 875. 
 
 
 
 25 
 
 390.625 
 
 
 
 57 
 
 890.625 
 
 
 13 
 
 26 
 
 406.25 
 
 
 29 
 
 58 
 
 906.25 
 
 
 
 27 
 
 421.875 
 
 
 
 59 
 
 921.875 
 
 7 
 
 14 
 
 28 
 
 437.5 
 
 15 
 
 30 
 
 60 
 
 937.5 
 
 
 
 29 
 
 453.125 
 
 
 
 61 
 
 953.125 
 
 
 15 
 
 30 
 
 468.75 
 
 
 31 
 
 62 
 
 968.75 
 
 
 
 31 
 
 484.375 
 
 
 
 63 
 
 984.375 
 
 8 
 
 16 
 
 32 
 
 500. 
 
 16 
 
 32 
 
 64 
 
 1000. 

 
 8 JOHN A. ROEBLING'S SONS co. 
 
 WIRE GAUGES IN MILS. 
 
 Numbers. 
 
 Roebling. 
 
 Brown 
 & 
 Sharpe. 
 
 Birmingham 
 or 
 Stubs. 
 
 New British 
 standard. 
 
 000000 
 00000 
 0000 
 000 
 00 
 
 460. 
 430. 
 
 362'. 
 331. 
 
 
 
 464. 
 432. 
 400. 
 372. 
 348. 
 
 460. 
 409.6 
 364.8 
 
 454. 
 425. 
 380. 
 
 
 
 1 
 
 2 
 3 
 - 4 
 
 307. 
 283. 
 263. 
 244. 
 225. 
 
 324.9 
 289.3 
 257.6 
 229.4 
 204.3 
 
 340. 
 300. 
 284. 
 259. 
 238. 
 
 324. 
 300. 
 276. 
 252. 
 232. 
 
 5 
 6 
 7 
 8 
 9 
 
 207. 
 192. 
 177. 
 162. 
 148. 
 
 181.9 
 162. 
 144.3 
 128.5 
 114.4 
 
 220. 
 203. 
 180. 
 165. 
 148. 
 
 212. 
 192. 
 176. 
 160. 
 144. 
 
 10 
 11 
 12 
 13 
 14 
 
 135. 
 120. 
 105. 
 92. 
 80. 
 
 101.9 
 90.74 
 80.81 
 71.96 
 64.08 
 
 134. 
 120. 
 109. 
 95. 
 83. 
 
 128. 
 116. 
 104. 
 92. 
 80. 
 
 15 
 16 
 17 
 18 
 19 
 
 72. 
 63. 
 
 54. 
 47. 
 41. 
 
 57.07 
 50.82 
 45.26 
 40.3 
 35.89 
 
 72. 
 65. 
 58. 
 49. 
 42. 
 
 72. 
 64. 
 56. 
 48. 
 40. 
 
 20 
 21 
 22 
 23 
 24 
 
 35. 
 32. 
 28. 
 25. 
 
 23. 
 
 31.96 
 28.46 
 25.35 
 22.57 
 20.1 
 
 35. 
 
 28! 
 25. 
 22. 
 
 36. 
 
 32. 
 28. 
 24. 
 22. 
 
 25 
 
 26 
 27 
 28 
 29 
 
 20. 
 
 18. 
 17. 
 16. 
 15. 
 
 17.9 
 15.94 
 14.2 
 12.64 
 11.26 
 
 20. 
 18. 
 16. 
 14. 
 13. 
 
 20. 
 18. 
 16.4 
 14.8 
 13.6 
 
 30 
 
 31 
 32 
 33 
 34 
 
 14. 
 13.5 
 13. 
 11. 
 10. 
 
 10.03 
 8.93 
 7.95 
 7.08 
 6.3 
 
 12. 
 
 10. 
 9. 
 
 8. 
 7. 
 
 12.4 
 11.6 
 10.8 
 10. 
 9.2 
 
 35 
 36 
 
 9.5 
 9. 
 
 5.62 
 5. 
 
 5. 
 4. 
 
 8.4 
 7.6 

 
 JOHN A. ROEBLING'S SONS co. 9 
 
 WIRE GAUGES IN MILLIMETERS. 
 
 Numbers. Roebling. 
 
 Brown 
 & 
 Sharpe. 
 
 Birmingham 
 or 
 
 Stubs. 
 
 New British 
 standard. 
 
 000000 
 00000 
 0000 
 000 
 00 
 
 11.683 
 10.921 
 9.982 
 9.195 
 8.407 
 
 il.683 
 10.404 
 9.266 
 
 11.531 
 10.794 
 9.652 
 
 11.785 
 10.972 
 10.16 
 9.448 
 8.839 
 
 
 
 1 
 
 3 
 4 
 
 7.798 
 7.188 
 6.68 
 6.198 
 5.715 
 
 8.251 
 7.348 
 6.544 
 5.827 
 5.19 
 
 8.636 
 7.62 
 7.213 
 6.579 
 6.045 
 
 8.229 
 7.62 
 7.01 
 6.401 
 5.893 
 
 5 
 
 7 
 8 
 9 
 
 5.257 
 4.877 
 4.496 
 4.115 
 3.759 
 
 4.621 
 4.115 
 3.665 
 3.263 
 2.906 
 
 5.588 
 5.156 
 4.572 
 4.191 
 3.759 
 
 5.385 
 4.877 
 4.47 
 4.064 
 3.657 
 
 10 
 
 11 
 12 
 13 
 14 
 
 3.429 
 3.048 
 2.667 
 2.337 
 2.032 
 
 2.588 
 2.305 
 2.052 
 1.828 
 1.628 
 
 3.404 
 3.048 
 2.768 
 2.413 
 2.108 
 
 3.251 
 2.947 
 2641 
 2.337 
 2.032 
 
 15 
 16 
 17 
 18 
 19 
 
 1.829 
 1.6 
 1.372 
 1.194 
 1.041 
 
 1.449 
 1.291 
 1.15 
 1.024 
 .9116 
 
 1.829 
 . 1.651 
 1.473 
 1.245 
 1.067 
 
 1.829 
 1.626 
 1.422 
 1.219 
 1.016 
 
 20 
 
 21 
 22 
 23 
 24 
 
 .889 
 .8128 
 .7112 
 .635 
 .5842 
 
 .8118 
 .7229 
 .6438 
 .5733 
 .5105 
 
 !8128 
 .711 2 
 .635 
 .5588 
 
 .9144 
 .812 8 
 .7112 
 .6096 
 .5588 
 
 25 
 
 26 
 27 
 28 
 29 
 
 .508 
 .4572 
 .4318 
 .4064 
 .381 
 
 .4546 
 .4049 
 .3605 
 .3211 
 .2859 
 
 .508 
 .4572 
 .4064 
 .3556 
 .3302 
 
 .508 
 .4572 
 .4166 
 .3759 
 .3454 
 
 30 
 
 31 
 32 
 33 
 34 
 
 .3556 
 .3429 
 .3302 
 .2794 
 .254 
 
 .2545 
 .226 7 
 .2019 
 .1798 
 .1601 
 
 .3048 
 .254 
 .2286 
 .2032 
 .1778 
 
 .315 
 .2946 
 .274 3 
 .254 
 .2337 
 
 35 
 
 36 
 
 .2413 
 .2286 
 
 .1426 
 .127 
 
 .127 
 .1016 
 
 .2134 
 .193 

 
 10 JOHN A. ROEBLING'S SONS co. 
 
 TABLES OP SPECIFIC GRAVITIES. 
 
 Metals. 
 
 Names of metals. 
 
 Specific 
 graTity. 
 
 Weights 
 per cubic 
 foot. 
 
 Specific 
 heat. 
 
 Melting 
 point in 
 degrees 
 Fahr- 
 enheit. 
 
 Aluminum, cast 
 " hammered. 
 
 2.5 1 
 2.67 1 
 6.702* 
 5.763" 
 4. 3 
 
 156.06 
 166.67 
 418.37 
 359.76 
 249.7 
 
 .2143 
 
 .0508 
 
 .0814 
 
 "sib" 
 
 365. 
 
 Arsenic 
 
 
 
 Bismuth 
 Cadmium 
 
 9.822" 
 8.604 6 
 1.566* 
 7.3" 
 8.6 
 
 613.14 
 537.1 
 97.76 
 455.7 
 536.86 
 
 .0308 
 .0567 
 
 .107'" 
 
 497. 
 500. 
 
 Calcium 
 Chromium 
 Cobalt 
 
 
 8.895' 
 8.878" 
 8.788" 
 8.946 3 8 
 8.958 7" 
 
 555.27 
 554.21 
 548.59 
 558.47 
 559.25 
 
 .0951 
 
 19%. 
 
 ( xw er lle - d -;::::;::::::::::. 
 
 drawn 
 ' hammered 
 
 ' pressed 
 
 ' electrolytic 
 Gold 
 
 8.931 9 
 8.914" 
 19.258" 
 7.483" 
 7.79 
 
 55752 
 556.46 
 1 202.18 
 467.18 
 486.29 
 
 .0324 
 .13 
 .113 
 
 2"6l6.' 
 2786. 
 3286. 
 
 
 " wrought 
 
 Steel 
 
 7.85 
 11445 10 
 2.24 11 
 6.9 1 " 
 13.568 1S 
 
 490.03 
 714.45 
 139.83 
 430.73 
 846.98 
 
 .116 
 .0314 
 .2499 
 .114 
 .0319 
 
 3286. 
 612. 
 
 sbbb! 
 
 -38. 
 
 Lead 
 
 Manganese 
 
 
 Nickel 
 
 7.832 
 20.3" 
 .865" 
 10. 522 " 
 .972 1 * 
 
 488.91 
 1 267.22 
 54. 
 656.84 
 60.68 
 
 .1091 
 .0324 
 .1696 
 .057 
 .2934 
 
 2800. 
 3286. 
 136. 
 1873. 
 194. 
 
 Potassium 
 
 Silver 
 
 Sodium 
 
 Gt 
 
 2.504* 
 7.291' 
 6.861" 
 
 156.31 
 455.14 
 428.29 
 
 
 
 Tin 
 Zinc 
 
 .056 2 
 .0955 
 
 442. 
 773. 
 
 
 . Wohler. 8. Brezenius. 
 . Brisson. 9. Marchand & Scheerer. 
 . Clarke. 10. Musschenbroek. 
 . Matthiessen. 11. Playfair & Joule. 
 . Stromeyer. 12. Bergman. 
 . Bunsen. 13. Watts' Dictionary. 
 7. Hatchett. 14. Gay-Lussac A Thenard.
 
 JOHN A. ROEBLING'S SONS co. 11 
 
 TABLES OF SPECIFIC GRAVITIES.-(Cbn<.) 
 Liquids. 
 
 Names of liquids. 
 
 Specific gravity. 
 
 Temperatures. 
 
 Alcohol 
 
 0.815 71 
 0.883 
 1.491 
 1.293 1 
 0.720 4 
 
 At 50 F. 
 At 59 F. 
 At 62.6 F. 
 At 32 F. 
 At 60.8 F. 
 
 
 
 Carbon bisulphide 
 Ether 
 
 
 
 1.2636 
 1.27 
 13.596 
 1.552 
 0.855 to 0.864 
 
 At 59 F. 
 
 At 32 F. 
 At 59 F. 
 At 68 F. 
 
 Hydrochloric acid 
 Mercury 
 Nitric acid 
 
 
 
 0.94 
 0.915 
 1.854 
 
 At 32 F. 
 
 Olive oil 
 
 
 
 Gases. 
 
 Names of gases. 
 
 At C. and 760 
 mm. pressure 
 compared to water. 
 
 At C. and 760 
 mm. pressure 
 compared to air. 
 
 Air 
 
 0.001 292 8 
 0.001 429 3 
 0.001 255 7 
 0.000 089 54 
 0.001 976 7 
 
 1. 
 1.10563 
 0.971 37 
 0.069 26 
 1.5291 
 
 Nitrogen 
 Hydrogen 
 Carbonic dioxide 
 
 Mixed gases from electro- 1 
 lysis of water / 
 
 0.0005361 
 
 0.414 72 
 0.623 
 
 

 
 JOHN A. HOBBLING 8 SONS CO. 
 
 WEIGHTS OF SUBSTANCES. 
 
 Names of substances. 
 
 Average weights 
 
 per cubic foot. 
 
 Pounds. 
 
 Asphaltum 87. 
 
 Brick, common, hard 125. 
 
 Brickwork, pressed brick 140. 
 
 " ordinary 112. 
 
 Coal, anthracite, solid, of Pennsylvania 93. 
 
 " broken, loose 54. 
 
 " bituminous, solid 84. 
 
 broken, loose 49. 
 
 Coke, loose, of good coal 62. 
 
 Cork 12.4 
 
 Earth, common loam, dry, loose 76. 
 
 " " " " moderately rammed 95. 
 
 " as a soft, flowing mud 108. 
 
 Gneiss, common 168. 
 
 Granite 170. 
 
 Glass, Crown 168.5 
 
 " flint 218.3 
 
 Ice at 0C 57.2 
 
 Lime, thoroughly shaken 75. 
 
 Masonry, of granite or limestone, well dressed 165. 
 
 Mortar, hardened 103. 
 
 Mud, dry, close 80 to 1 
 
 Quartz 165.4 
 
 Sulphur 131. 
 
 Wax 58.7 
 
 Wood, ebony 74.9 
 
 " birch 43.7 
 
 " oak 46.8 
 
 " pine 31.2 
 
 Water at 32 F 62.418 
 
 39.1 F 62.425 
 
 50 F 62.409 
 
 60 F 62 367 
 
 70 F 62.302 
 
 80 F 62.218 
 
 90 F 62.119
 
 JOHN A. ROEBLING'S SONS co 
 
 13 
 
 THE COMPARISON OF THERMOMETERS. 
 
 
 
 
 Fahrenheit to Centigrade. 
 
 
 
 
 
 
 (t F. 32) X I = Degrees C. 
 
 
 
 ^ 
 
 . 
 
 ^ 
 
 . 
 
 ^ 
 
 . 
 
 j 
 
 6 
 
 I 
 
 . 
 
 
 1 
 
 *3 
 
 1 
 
 1 
 
 1 
 
 
 
 1 
 
 1 
 
 .1 
 
 I 
 
 
 
 3 
 
 I 
 
 s 
 
 S 
 
 1 
 
 I 
 
 50 
 
 10. 
 
 61 
 
 16.1 
 
 72 
 
 22.2 
 
 83 
 
 28.3 
 
 94 
 
 34.4 
 
 51 
 
 10.6 
 
 62 
 
 16.7 
 
 73 
 
 22.8 
 
 84 
 
 28 
 
 9 
 
 95 
 
 35. 
 
 52 
 
 11.1 
 
 M 
 
 17.2 
 
 74 
 
 23.3 
 
 85 
 
 2V 
 
 4 
 
 96 
 
 35.6 
 
 53 
 
 11.7 
 
 64 
 
 17.8 
 
 75 
 
 23.9 
 
 86 
 
 :;< 
 
 
 97 
 
 36.1 
 
 54 
 
 12.2 
 
 65 
 
 18.3 
 
 76 
 
 24.4 
 
 87 
 
 30.6 
 
 98 
 
 36.7 
 
 55 
 
 12.8 
 
 H 
 
 18.9 
 
 77 
 
 25. 
 
 8H 
 
 31 
 
 1 
 
 99 
 
 37.2 
 
 56 
 
 13.3 
 
 87 
 
 19.4 
 
 78 
 
 25.6 
 
 
 31 
 
 7 
 
 100 
 
 37.8 
 
 57 
 
 13.9 
 
 68 
 
 20. 
 
 79 
 
 26.1 
 
 90 
 
 32.2 
 
 
 
 58 
 
 14.4 
 
 69 
 
 20.6 
 
 80 
 
 26.7 
 
 91 
 
 32 
 
 8 
 
 
 
 59 
 
 15. 
 
 70 
 
 21.1 
 
 81 
 
 27.2 
 
 9?, 
 
 35 
 
 3 
 
 
 
 60 
 
 15.6 
 
 71 
 
 21.7 
 
 82 
 
 27.8 
 
 93 
 
 33.9 
 
 
 
 
 
 
 Centigrade to Fahrenheit. 
 
 
 
 
 
 
 1 1 C + 32 = Degrees F. 
 
 
 
 g 
 
 a 
 ?, 
 
 
 I 
 
 1 
 
 1 
 
 1 
 
 I 
 1 
 
 1 
 
 s 
 
 t 
 
 
 I 
 
 1 
 
 1 
 
 1 
 
 I 
 
 10 
 
 50. 
 
 
 18 
 
 64.4 
 
 26 
 
 78.8 
 
 
 34 
 
 93.2 
 
 11 
 
 51. 
 
 S 
 
 19 
 
 66.2 
 
 27 
 
 80.6 
 
 
 35 
 
 95. 
 
 12 
 
 53. 
 
 1 
 
 20 
 
 68. 
 
 28 
 
 82.4 
 
 
 36 
 
 96.8 
 
 13 
 
 55.4 
 
 21 
 
 69.8 
 
 29 
 
 84.2 
 
 
 37 
 
 98.6 
 
 14 
 
 57.2 
 
 22 
 
 71.6 
 
 30 
 
 86. 
 
 
 38 
 
 100.4 
 
 15 
 
 59. 
 
 
 23 
 
 73.4 
 
 31 
 
 87.8 
 
 
 39 
 
 102.2 
 
 16 
 
 60. 
 
 s 
 
 24 
 
 75.2 
 
 32 
 
 89.6 
 
 
 40 
 
 104. 
 
 17 
 
 62.6 
 
 25 77. 
 
 33 
 
 91.4 
 
 
 

 
 JOHN A. ROEBLING S SONS CO. 
 
 ELECTRICAL UNITS. 
 
 Final and official recommendation of the Chamber of Dele- 
 gates of the International Electrical Congress, 
 held at Chicago, 1893. 
 
 Resolved, That the several governments represented by 
 the delegates of this International Congress of Elec- 
 tricians be, and they are hereby, recommended to 
 formally adopt as legal units of electrical measure the 
 following: As a unit of resistance, the international ohm, 
 which is based upon the ohm equal to 10 9 units of resist- 
 ance of the C. G. S. system of electro-magnetic units, and 
 is represented by the resistance offered to an unvarying 
 electric current by a column of mercury at the tempera- 
 ture of melting ice 14.452 1 grams in mass, of a constant 
 cross-sectional area and of the length of 106.3 centimeters. 
 
 As a unit of current, the international ampere, which is 
 one-tenth of the unit of current of the C. G. S. system of 
 electro-magnetic units, and which is represented suffi- 
 ciently well for practical use by the unvarying current 
 which, when passed through a solution of nitrate of 
 silver in water, and in accordance with accompanying 
 specifications, 1 deposits silver at the rate of 0.001 118 of 
 a gram per second. 
 
 1. In the following specification the term silver voltameter means 
 the arrangement of apparatus by means of which an electric current 
 is passed through a solution of nitrate of silver in water. The silver 
 voltameter measures the total electrical quantity which has passed 
 during the time of the experiment, and by noting this time the 
 time average of the current, or, if the current has been kept con- 
 stant, the current itself can be deduced. 
 
 In employing the silver voltameter to measure currents of about 
 one ampere, the following arrangements should be adopted : 
 
 The kathode on which the silver is to be deposited should take 
 the form of a platinum bowl not less than 10 centimeters in diameter 
 and from 4 to 5 centimeters in depth. 
 
 The anode should be a plate of pure silver, some 30 square centi- 
 meters in area and 2 or 3 millimeters in thickness. 
 
 This is supported horizontally in the liquid near the top of the 
 solution by a platinum wire passed through holes in the plate at 
 opposite corners. To prevent the disintegrated silver which is 
 formed on the anode from falling onto the kathode, the anode 
 should be wrapped around with pure filter paper, secured at the back 
 with sealing wax. 
 
 The liquid should consist of a neutral solution of pure silver nitrate, 
 containing about 15 parts by weight of the nitrate to 85 parts of water. 
 
 The resistance of the voltameter changes somewhat as the current
 
 JOHN A. ROEBLING'S SONS co. 15 
 
 As a unit of electro-motive force, the international volt, 
 which is the electro-motive force that, steadily applied 
 to a conductor whose resistance is one international 
 ohm, will produce a current of one international ampere, 
 and which is represented sufficiently well for practical 
 use by yftf of the electro-motive force between the poles 
 or electrodes of the voltaic cell known as Clark's cell, 
 at a temperature of 15 C., and prepared in the manner 
 described in the accompanying specification. 2 
 
 As a unit of quantity, the international coulomb, which 
 is the quantity of electricity transferred by a current of 
 one international ampere in one second. 
 
 As a unit of capacity, the international farad, which is 
 the capacity of a condenser charged to a potential of one 
 international volt by one international coulomb of 
 electricity. 
 
 As a unit of work, the joule, which is equal to 10 7 units 
 of work in the C. G. S. system,-and which is represented 
 sufficiently well for practical use by the energy expended 
 in one second by an international ampere in an interna- 
 tional ohm. 
 
 As a unit of power, the watt, which is equal to 10 7 
 units of power in the C. G. S. system, and which is repre- 
 sented sufficiently well for practical use by work done at 
 the rate of one joule per second. 
 
 As the unit of induction, the henry, which is the 
 induction in a circuit when the electro-motive force 
 induced in this circuit is one international volt, while 
 the inducing current varies at the rate of one ampere 
 per second. 
 
 passes. To prevent these changes having too great an effect on the 
 current, some resistance besides that of the voltameter should be 
 inserted in the circuit. The total metallic resistance of the circuit 
 should not be less than 10 ohms. 
 
 2. A committee, consisting of Messrs. Helmholtz, Ayrton and Car- 
 hart, was appointed to prepare specifications for the Clark's cell. 
 Their report has not yet been received.
 
 16 JOHN A. ROEBLING'S SONS co. 
 
 COPPER WIRE. 
 
 IN THE following tables of copper wire the value of 
 the mil-foot is taken as the standard. 
 
 The temperature coefficient is interpolated for 60 F. 
 and 75 F. from the values given in the second table. 
 
 In the table for B. & S. G., the actual sizes to which 
 wire is drawn, are used. 
 
 In many cases the nearest whole number of pounds is 
 taken when the variation is less than that found in actual 
 weights of drawn wire. 
 
 In computing the weights, the specific gravity of copper 
 is taken at 8.89, water being at its greatest density 62.425 
 pounds per cubic foot. 
 
 International ohms are used, unless the kind of unit 
 is specifically stated. 
 
 The following formulae were used : 
 
 Resistance per 1 000 feet at 60 F. = IPJ 
 
 Resistance per 1 000 feet at 75 F. = 
 Weight per 1 000 feet = .003 027 X d a . 
 Weight per mile = .015 983 X d. 
 
 The following data and formulae may be useful : 
 
 One B. A. unit = .988 9 legal ohms = .986 6 International ohms. 
 One legal ohm = 1.011 22 B. A. units = .997 67 International ohms. 
 One International ohm = 1.013 58 B. A. units = 1.002 33 legal ohms. 
 One cubic foot of copper weighs 555 pounds. 
 One cubic inch of copper weighs .321 2 pounds. 
 
 Resistance per 1 000 feet at 60 F. = _ 
 
 Q-l Q/VJ 
 
 Resistance per 1 000 feet at 75 F. = weight per 
 
 If a copper wire of length 1, diameter d, and weight wi 
 has a resistance R at temperature t, then its conductivity
 
 JOHN A. ROEBLING'S SONS co. 
 
 by diameter is given by the first formula, and by weight 
 
 by the second. 
 
 C = - Rt=?^ 
 
 , bl'e n blc 
 
 Here, a is the resistance of a mil-foot in same units as 
 R, k is the temperature coefficient for t Centigrade, and 
 b is the resistance of one meter-gram at temperature t 
 and in same units as R. 
 
 When 1 is in meters and w in grams, c = 1. 
 When 1 is in feet and w in grams, c = .092 9. 
 When 1 is in feet and w in pounds, c = .000 204 8. 
 
 Mile-ohm = weight per mile X resistance per mile. 
 
 Mile-ohm at 60 = 859, International ohms. 
 Mile-ohm at 60 = 868.9, B. A. units. 
 Mile-ohm at 60 = 861, Legal ohms. 
 
 The following tables are taken from the report of the 
 Standard Wiring Table Committee, published in the 
 report of the meeting of the American Institute of Elec- 
 trical Engineers, held January 17, 1893 : 
 
 MATTHIESSEN'S STANDARD. 
 
 (Recommended by the Committee). 
 
 Equivalent length of a 
 square mm. 
 
 B. A 
 
 units. 
 
 Legal ohms. 
 
 Interna- 
 tional ohms. 
 
 mercury column. 
 
 104.8 cms. 
 
 106.0 cms. 
 
 106.3 cms. 
 
 Resistance at C. of Mat- 
 thiessen's Standard 
 Meter-gram soft copper 
 Meter-millimeter soft cop- 
 per 
 
 .14365 
 .020 57 
 
 .142 06 
 .02035 
 
 .14173 
 020 3 
 
 Cubic centimeter soft cop- 
 
 000 001 616 
 
 000 001 598 
 
 000 001 594 
 
 Mil-foot soft copper 
 
 9.72 
 
 9.612 
 
 9.59
 
 18 JOHN A. ROEBLING'S SONS co. 
 
 TEMPERATURE COEFFICIENTS. 
 
 Table of temperature variations in the resistance of pure 
 soft copper according to Matthlessen's 
 standard and formula;. 
 
 Temperature in 
 degrees Centi- 
 grade. 
 
 Temperature 
 coefficient of 
 resistance. 
 
 Logarithm. 
 
 Matthiessen meter-gram standard 
 resistance. 
 
 B. A. 
 
 units. 
 
 Legal 
 ohms. 
 
 Interna- 
 tional 
 ohms. 
 
 
 
 1 
 2 
 3 
 4 
 
 1. 
 
 1.003 876 
 1.007 764 
 1.011 66 
 1.015 58 
 
 0. 
 0.001 680 1 
 0.003 358 8 
 0.005 036 2 
 0.006 712 1 
 
 0.14365 
 0.144 21 
 0.144 77 
 0.145 33 
 0.145 89 
 
 0.14206 
 0.142 61 
 0.143 17 
 0.143 72 
 0.14427 
 
 0.141 73 
 0.142 28 
 0.142 83 
 0.143 38 
 0.143 94 
 
 5 
 6 
 7 
 8 
 9 
 
 1.019 5 
 1.023 43 
 1.027 38 
 1.031 34 
 1.035 31 
 
 0.008 386 4 
 0.010 059 3 
 0.011 730 7 
 0.013 400 3 
 0.015 068 3 
 
 0.146 45 
 0.147 02 
 0.147 59 
 0.148 15 
 0.14873 
 
 0.144 83 
 0.145 39 
 0.145 95 
 0.14651 
 0.147 08 
 
 0.144 49 
 0.14505 
 0.145 61 
 0.146 17 
 0.146 73 
 
 10 
 11 
 12 
 13 
 14 
 
 1.039 29 
 1.04328 
 1.04728 
 1.051 29 
 1.055 32 
 
 0.016 734 6 
 0.018 399 3 
 0.020 062 1 
 0.021 723 
 0.023 382 1 
 
 0.149 3 
 
 149 87 
 0.15045 
 0.151 02 
 0.151 6 
 
 0.147 64 
 0.14821 
 0.148 78 
 0.149 35 
 0.149 92 
 
 0.147 3 
 0.147 86 
 0.14843 
 0.149 
 0.149 57 
 
 15 
 16 
 
 17 
 18 
 19 
 
 1.059 35 
 1.063 39 
 1.067 45 
 1.071 52 
 1.075 59 
 
 0.025 039 
 0.026 694 
 0.028348 
 0.029 999 
 0.803 164 
 
 0.152 18 
 0.152 77 
 0.153 34 
 0.15393 
 0.154 51 
 
 0.15049 
 0.151 07 
 0.151 64 
 0.152 22 
 0.152 8 
 
 0.150 14 
 0.150 71 
 0.151 29 
 0.151 86 
 0.152 44 
 
 20 
 21 
 22 
 
 24 
 
 1.079 68 
 1.083 78 
 1.087 88 
 1.092 
 109612 
 
 0.033 294 
 0.034 939 
 0.036 581 
 0.038 222 
 0.039 859 
 
 0.1551 
 0.155 69 
 0.156 28 
 0.156 87 
 0.157 46 
 
 0.15338 
 0.15396 
 0.154 55 
 0.15513 
 0.155 72 
 
 0.153 02 
 0.153 6 
 0.154 18 
 0.154 77 
 0.155 35 
 
 25 
 26 
 27 
 28 
 29 
 
 ' 1.100 26 
 1.104 4 
 1.10856 
 1.112 72 
 1.11689 
 
 0.041 494 
 0.043 127 
 0.044 758 
 0.046385 
 0.048 Oil 
 
 0.15806 
 0.158 65 
 0.159 25 
 0.159 85 
 0.16044 
 
 0.156 31 
 0.156 89 
 0.157 48 
 0.15808 
 0.158 67 
 
 0.15594 
 0.156 53 
 0.157 11 
 0.157 7 
 0.1583 
 
 30 
 
 40 
 50 
 60 
 70 
 
 1.121 07 
 1.16332 
 1.206 25 
 1.24965 
 1.293 27 
 
 0.049633 
 0.065699 
 0.081 436 
 0.096 787 
 0.111 687 
 
 0.16105 
 0.167 11 
 0.173 28 
 0.17952 
 0.185 78 
 
 0.15926 
 0.16526 
 0.171 36 
 0.177 53 
 0.183 72 
 
 0.15889 
 0.16488 
 0.17095 
 0.177 11 
 0.183 29 
 
 80 
 90 
 100 
 
 1.336 81 
 1.379 95 
 1 422 31 
 
 0.126 069 
 0.139 863 
 0.152 995 
 
 u!92 04 
 0.198 23 
 0.204 32 
 
 0.18991 1 0.18946 
 0.19604 0.19558 
 0.202 06 0.201 58 

 
 JOHN A. ROEBLING'S SONS co. 19 
 
 PROPERTIES OF COPPER WIRE. 
 
 English system Brown & Sharpe gauge. 
 
 1 
 
 jq 
 
 f| 
 
 JM 
 
 la 
 
 P 
 
 Areas in 
 circular mils. 
 C. M. = d". 
 
 Weights. 
 
 Resistances per 1 000 
 feet in International 
 ohms. 
 
 1000 
 feet. 
 
 Mile. 
 
 At60F. 
 
 At 75 F. 
 
 0000 
 000 
 00 
 
 1 
 
 460. 
 410. 
 365. 
 325. 
 289. 
 
 211600. 
 168 100. 
 133 225. 
 105625. 
 83 521. 
 
 641. 
 509. 
 403. 
 320. 
 253. 
 
 3382. 
 2687. 
 2129. 
 1688. 
 1335. 
 
 .04811 
 .06066 
 .076 42 
 .09639 
 .1219 
 
 .04966 
 .06251 
 .078 87 
 .09948 
 .1258 
 
 2 
 3 
 4 
 5 
 6 
 
 T~ 
 
 8 
 9 
 10 
 11 
 
 258. 
 229. 
 204. 
 182. 
 162. 
 
 66564. 
 52441. 
 41 616. 
 83 124. 
 26244. 
 
 202. 
 159. 
 126. 
 100. 
 79. 
 
 1064. 
 838. 
 665. 
 529. 
 419. 
 
 .1529 
 .1941 
 .2446 
 .3074 
 .3879 
 
 .1579 
 .2004 
 .2525 
 .317 2 
 .4004 
 
 144. 
 128. 
 114. 
 102. 
 91. 
 
 20736. 
 16384. 
 129%. 
 10404. 
 8281. 
 
 50'. 
 39. 
 32. 
 25. 
 
 331. 
 262. 
 208. 
 166. 
 132. 
 
 .491 
 .6214 
 .7834 
 .9785 
 1.229 
 
 .5067 
 .6413 
 .8085 
 1.01 
 1.269 
 
 12 
 13 
 14 
 15 
 16 
 
 81. 
 72. 
 64. 
 57. 
 51. 
 
 6561. 
 51S4. 
 4096. 
 3249. 
 2601. 
 
 20. 
 15.7 
 12.4 
 9.8 
 7.9 
 
 105. 
 83. 
 65. 
 52. 
 42. 
 
 1.552 
 1.964 
 2.485 
 3.133 
 3.914 
 
 1.601 
 2.027 
 2.565 
 3.234 
 4.04 
 
 17 
 18 
 19 
 20 
 21 
 
 45. 
 40. 
 36. 
 32. 
 
 28.5 
 
 2025. 
 1600. 
 1296. 
 1Q24. 
 812.3 
 
 6.1 
 
 4.8 
 3.9 
 3.1 
 2.5 
 
 32. 
 
 25.6 
 20.7 
 16.4 
 13. 
 
 5.028 
 6.363 
 7.855 
 9.942 
 12.53 
 
 5.189 
 6.567 
 8.108 
 10.26 
 12.94 
 
 22 
 23 
 24 
 25 
 26 
 
 25.3 
 22.6 
 20.1 
 17.9 
 15.9 
 
 640.1 
 510.8 
 404. 
 320.4 
 252.8 
 
 1.9 
 
 1.5 
 1.2 
 .97 
 .77 
 
 10.2 
 8.2 
 65 
 5.1 
 4. 
 
 15.9 
 19.93 
 25.2 
 31.77 
 40.27 
 
 16.41 
 20.57 
 26.01 
 32.79 
 41.56 
 
 27 
 
 28 
 29 
 30 
 31 
 
 14.2 
 12.6 
 11.3 
 10. 
 8.9 
 
 201.6 
 158.8 
 127.7 
 100. 
 79.2 
 
 .61 
 .48 
 .39 
 .3 
 .24 
 
 3.2 
 2.5 
 2. 
 1.6 
 1.27 
 
 50.49 
 64.13 
 79.73 
 101.8 
 128.5 
 
 52.11 
 66.18 
 82.29 
 105.1 
 132.7 
 
 32 
 33 
 34 
 35 
 36 
 
 8. 
 7.1 
 6.3 
 5.6 
 5. 
 
 64. 
 50.4 
 39.7 
 31.4 
 
 25. 
 
 .19 
 .15 
 .12 
 .095 
 .076 
 
 1.02 
 .81 
 .63 
 .5 
 .4 
 
 159.1 
 202. 
 256.5 
 324.6 
 407.2 
 
 164.2 
 208.4 
 264.7 
 335.1 
 420.3 

 
 20 JOHN A. ROEBLING'S SONS co. 
 
 PROPERTIES OF COPPER WIRE.-(Con/.) 
 English system Birmingham wire gauge. 
 
 K 
 
 Diameters in 
 mils. 
 
 Areas in 
 circular mils. 
 C. M. =d. 
 
 Weights. 
 
 Resistances per 1 000 
 feet in International 
 ohms. 
 
 1000 
 feet. 
 
 Mile. 
 
 At60F. 
 
 At 75 F. 
 
 0000 454. 
 000 425. 
 00 380. 
 340. 
 1 300. 
 
 206 116. ' 624. 
 180 625. ! 547. 
 144 400. 1 437. 
 115 600. 350. 
 90 000. 272. 
 
 3294. 
 
 2887. 
 2308. 
 1847. 
 1438. 
 
 .04939 
 .05636 
 .0705 
 .08807 
 .1131 
 
 .05098 
 .05817 
 .07277 
 .09089 
 .1167 
 
 2 
 3 
 4 
 5 
 6 
 
 284. 
 259. 
 238. 
 220. 
 203. 
 
 80656. 
 67081. 
 56644. 
 48400. 
 41209. 
 
 244. 
 203. 
 171. 
 146. 
 125. 
 
 1289. 
 1072. 
 905. 
 773. 
 659. 
 
 .1262 
 .1518 
 .1797 
 .2103 
 .2471 
 
 .1303 
 .1566 
 .1855 
 .2171 
 .255 
 
 7 180. 
 8 165. 
 9 148. 
 10 ' 134. 
 11 120. 
 
 32400. 
 27225. 
 21904. 
 17 956. 
 14400. 
 
 98. 
 82. 
 66. 
 54. 
 44. 
 
 518. 
 435. 
 350. 
 287. 
 230. 
 
 .3142 
 .3739 
 .4648 
 .567 
 .707 
 
 .3243 
 .3859 
 .4797 
 .5852 
 .7297 
 
 13 
 14 
 15 
 16 
 
 109. 
 95. 
 83. 
 72. 
 65. 
 
 11881. 
 9025. 
 6889. 
 5184. 
 4225. 
 
 36. 
 27.3 
 20.8 
 15.7 
 12.8 
 
 190. 
 144. 
 110. 
 83. 
 68. 
 
 .8569 
 1.128 
 1.478 
 1.964 
 2.41 
 
 .8844 
 1.164 
 1.525 
 2.027 
 2.487 
 
 17 58. 
 18 49. 
 19 42. 
 IM 35. 
 21 32. 
 
 3364. 
 
 2401. 
 1764. 
 1225. 
 1024. 
 
 10.2 
 7.3 
 53 
 3.7 
 3.1 
 
 54 
 
 38.4 
 28.2 
 19.6 
 16.4 
 
 3.026 
 4.24 
 5.771 
 . 8.311 
 9.942 
 
 12.99 
 16.29 
 21.03 
 25.45 
 31.42 
 
 3.123 
 4.376 
 5.957 
 8.577 
 1026 
 
 2l> 28. 
 23 25. 
 24 22. 
 25 20. 
 26 18. 
 
 784. 
 625. 
 484. 
 400. 
 324. 
 
 2.4 
 1.9 
 1.5 
 
 M 
 
 12.5 
 10. 
 7.7 
 6.4 
 52 
 
 13.4 
 16.81 
 21.71 
 26.27 
 32.43 
 
 27 
 28 
 29 
 30 
 31 
 
 16. 
 14. 
 13. 
 12. 
 10. 
 
 256. 
 196. 
 169. 
 144. 
 100. 
 
 .77 
 .59 
 .51 
 .44 
 .3 
 
 4.1 
 
 3.1 
 2.7 ! 
 2.3 , 
 1.6 
 
 uf~ 
 
 1.02 
 .78 
 .4 
 .256 
 
 39.77 
 51.94 
 60.24 
 70.7 
 
 10S. 
 
 41.04 
 53.61 
 62.17 
 72.97 
 105.1 
 
 32 
 33 
 34 
 35 
 36 
 
 9. 
 8. 
 
 7. 
 5. 
 4. 
 
 81. 
 64. 
 49. 
 
 25. 
 16. 
 
 .25 
 .19 
 .15 
 .075 
 .048 
 
 125.7 
 159.1 
 207.8 
 407.2 
 636.3 
 
 129.7 
 164.2 
 214.4 
 420.3 
 656.7 

 
 JOHN A. ROEBLING'S SONS co. 21 
 
 PROPERTIES OF COPPER WIRE.-(Om*.) 
 English system New British standard gauge. 
 
 fc 
 
 Diameters in 
 mils. 
 
 Areas in 
 Circular mils. 
 C M. = d. 
 
 Weights. 
 
 Resistances per 1 000 
 feet in International 
 ohms. 
 
 1000 
 feet. 
 
 Mile. 
 
 At60F. 
 
 At 75 F. 
 
 000000 
 00000 
 0000 
 000 
 00 
 
 464. 
 432. 
 400. 
 372. 
 348. 
 
 215296. 
 186 624. 
 160000. 
 138384. 
 121 104. 
 
 652. 
 565. 
 484. 
 419. 
 367. 
 
 3441. 
 
 2983. 
 2557. 
 2212. 
 1935. 
 
 .04729 
 .05455 
 .06363 
 .073 57 
 . .08407 
 
 .0488 
 .0563 
 .06567 
 .075 93 
 .08676 
 
 
 
 1 
 
 2 
 3 
 4 
 
 324. 
 300. 
 276. 
 252. 
 232. 
 
 104 976. 
 90000. 
 76 176. 
 63504. 
 53824. 
 
 318. 
 272. 
 231. 
 192. 
 163. 
 
 1678. 
 1438. 
 1217. 
 1015. 
 860. 
 
 .9698 
 .1131 
 .1336 
 .1603 
 .1892 
 
 .10009 
 .1167 
 .1379 
 .1655 
 .195 2 
 
 5 
 6 
 7 
 8 
 9 
 
 212. 
 192. 
 176. 
 160. 
 144. 
 
 44944. 
 36864. 
 30976. 
 25600. 
 20736. 
 
 136. 
 112. 
 94. 
 77. 
 63. 
 
 718. 
 589. 
 495. 
 409. 
 331. 
 
 .2265 
 .2762 
 .3287 
 .3977 
 .491 
 
 .2338 
 
 !3392 
 .4104 
 .5067 
 
 10 
 11 
 12 
 13 
 14 
 
 128. 
 116. 
 104. 
 92. 
 80. 
 
 16384. 
 13456. 
 10 816. 
 8464. 
 6400. 
 
 60. 
 
 41. 
 33. 
 25.6 
 19.4 
 
 262, 
 215. 
 173. 
 135. 
 102. 
 
 .6214 
 .7566 
 .9413 
 1.203 
 1.591 
 
 .6413 
 .7809 
 .9715 
 1.241 
 1.642 
 
 15 
 16 
 17 
 18 
 19 
 
 72. 
 64. 
 56. 
 48. 
 40. 
 
 5184. 
 40%. 
 3136. 
 2304. 
 1600. 
 
 15.7 
 12.4 
 9.5 
 
 7. 
 4.8 
 
 83. 
 65. 
 50. 
 36.8 
 25.6 
 
 1.964 
 2.486 
 8.246 
 4.419 
 6.363 
 
 2.027 
 2.565 
 3.351 
 4.561 
 6.567 
 
 20 
 21 
 22 
 23 
 24 
 
 36. 
 32. 
 28. 
 24. 
 22. 
 
 1296. 
 1024. 
 784. 
 576. 
 484. 
 
 3.9 
 3.1 
 2.4 
 1.7 
 1.5 
 
 20.7 
 16.4 
 12.5 
 9.2 
 7.7 
 
 7.855 
 9.942 
 12.99 
 17.67 
 21.03 
 
 8.108 
 10.26 
 13.4 
 18.24 
 21.71 
 
 25 
 26 
 27 
 28 
 
 29 
 
 20. 
 18. 
 16.4 
 14.8 
 13.6 
 
 400. 
 324. 
 269. 
 219. 
 185. 
 
 1.2 
 .98 
 .81 
 .66 
 .56 
 
 6.4 
 5.2 
 4.3 
 3.5 
 3. 
 
 25.45 
 31.42 
 37.85 
 46.48 
 55.04 
 
 26.27 
 32.43 
 39.07 
 47.97 
 56.81 
 
 30 
 31 
 32 
 33 
 34 
 
 12.4 
 11.6 
 10.8 
 10. 
 9.2 
 
 153.8 
 134.6 
 116.6 
 100. 
 84.6 
 
 .47 
 .41 
 .35 
 .3 
 .26 
 
 2.5 
 2.15 
 1.86 
 1.6 
 1.35 
 
 66.21 
 75.66 
 87.28 
 101.8 
 OM 
 
 68.34 
 78.09 
 90.08 
 105.1 
 124.1 
 
 35 | 8.4 
 36 1 7.6 
 
 70.6 
 57.8 
 
 .21 
 .17 
 
 1.13 
 .92 
 
 144.3 
 176.3 
 
 148.9 
 181.9 

 
 22 JOHN A. ROEBLING'S SONS co. 
 
 PROPERTIES OF COPPER WIEE. (Con*.) 
 Metric system Brown & Sliarpe gauge. 
 
 Numbers. 
 
 Diameters in 
 millimeters. 
 
 Areas in 
 square 
 millimeters. 
 
 fl 
 
 $ 
 
 hi 
 ill 
 
 i 33 
 
 Resistances per kilo- 
 meter in Interna- 
 tional ohms. 
 
 At 60 F. 
 
 At 75 F. 
 
 0000 
 000 
 00 
 
 1 
 
 11.683 
 10.404 
 9.266 
 8.251 
 7.848 
 
 107.2 
 85.01 
 67.43 
 53.47 
 42.41 
 
 954.3 
 
 756.8 
 600.2 
 480.4 
 377.4 
 
 .1578 
 .1987 
 .2507 
 .3162 
 .3999 
 
 .1629 
 .2051 
 .2588 
 .3264 
 .4127 
 
 2 
 3 
 4 
 5 
 6 
 
 6.544 
 5.827 
 5.19 
 4.621 
 4.115 
 
 33.63 
 26.67 
 21.16 
 16.77 
 13.3 
 
 299.3 
 237.4 
 188.3 
 149.3 
 118.4 
 
 .5018 
 .6369 
 .8026 
 1.009 
 1.273 
 
 .5179 
 .6574 
 .8284 
 1.041 
 1.314 
 
 8 
 9 
 10 
 11 
 
 3.665 
 3.263 
 2.906 
 2.588 
 2.305 
 
 10.55 
 8.362 
 6.633 
 5.26 
 4.173 
 
 93.9 
 74.5 
 59. 
 
 46.8 
 37.1 
 
 1.611 
 2.039 
 2.57 
 3.21 
 4.033 
 
 1.662 
 2.104 
 2.653 
 3.313 
 4.163 
 
 12 
 13 
 14 
 15 
 16 
 
 2.052 
 
 1.828 
 1.628 
 1.449 
 1.291 
 
 3.307 
 2.625 
 2.082 
 1,649 
 1.309 
 
 29.5 
 23.4 
 18.5 
 14.7 
 11.7 
 
 5.091 
 6.443 
 8.155 
 10.28 
 12.84 
 
 5.253 
 6.65 
 8.416 
 10.61 
 18.28 
 
 17 
 18 
 19 
 20 
 21 
 
 1.15 
 1.024 
 .9116 
 .8118 
 .7229 
 
 1.039 
 .8236 
 .6527 
 .5176 
 .4104 
 
 ~3255 
 .2581 
 .2047 
 .1623 
 .1288 
 
 9.23 
 7.32 
 5.8 
 4.61 
 3.65 
 
 2^89 
 2.16 
 1.82 
 1.44 
 1.15 
 
 16.5 
 20.88 
 25.77 
 32.62 
 41.11 
 
 17.02 
 21.55 
 26.6 
 33.66 
 42.45 
 
 22 
 23 
 2.4 
 25 
 26 
 
 27~ 
 28 
 29 
 30 
 31 
 
 .6438 
 .5733 
 .5105 
 .4546 
 .4049 
 
 52.16 
 65.39 
 82.68 
 104.2 
 132.1 
 
 53.84 
 67.49 
 
 107i6 
 136.3 
 
 .3605 
 .3211 
 .2859 
 .2545 
 .2267 
 
 .1021 
 .081 
 .0642 
 .0509 
 .0404 
 
 .908 
 .72 
 .572 
 .452 
 JG9 
 
 165.1 
 210.4 
 261.6 
 334. 
 21. 
 
 171. 
 217.1 
 270. 
 344.8 
 435.4 
 
 32 
 
 33 
 34 
 35 
 36 
 
 .2019 
 .1798 
 .1601 
 .1426 
 .127 
 
 .032 
 .0254 
 .0201 
 .016 
 .0127 
 
 .284 
 .226 
 .179 
 .141 
 .113 
 
 522. 
 662.7 
 841.5 
 1065. 
 1336. 
 
 538.7 
 683.7 
 
 1099! 
 1379. 

 
 JOHN A. ROEBLING'S SONS co. 23 
 
 WEIGHTS OF COPPER WIRE. 
 
 Metric system per kilometer, in kilograms. 
 
 Numbers. 
 
 Roebling. 
 
 Brown 
 
 & 
 Sharpe. 
 
 Birmingham 
 or 
 Stubs. 
 
 New British 
 standard. 
 
 000000 
 00 000 
 0000 
 000 
 00 
 
 954.3 
 
 833.9 
 696.5 
 591. 
 494.1 
 
 
 
 970.9 
 841.6 
 721.5 
 624. 
 546.2 
 
 9J54'.3" 
 756.8 
 600.2 
 
 929.4" 
 814.5 
 651.3 
 
 
 
 1 
 
 2 
 3 
 4 
 
 425.1 
 361.2 
 311.9 
 268.5 
 228.3 
 
 480.4 
 377.4 
 299.3 
 237.4 
 188.3 
 
 521.3 
 405.8 
 363.3 
 302.6 
 255.3 
 
 473.4 
 405.8 
 343.5 
 286.3 
 242.7 
 
 5 
 
 6 
 7 
 8 
 9 
 
 193.2 
 166.2 
 141.3 
 
 118.3 
 98.8 
 
 149.3 
 118.4 
 93.9 
 74.5 
 59. 
 
 218.3 
 185.9 
 146.1 
 
 122.8 
 98.8 
 
 202.7 
 166.2 
 139.7 
 1154 
 93.5 
 
 10 
 11 
 12 
 13 
 14 
 
 82.2 
 64.9 
 49.9 
 38.2 
 28.9 
 
 46.8 
 37.1 
 29.5 
 23.4 
 18.5 
 
 81. 
 64.9 
 53.6 
 39.8 
 31.1 
 
 73.9 
 60.7 
 48.8 
 38.2 
 2S.9 
 
 15 
 
 16 
 17 
 18 
 19 
 
 23.4 
 17.9 
 13.2 
 
 9.96 
 7.58 
 
 14.7 
 11.7 
 9.23 
 7.32 
 5.8 
 
 23.4 
 191 
 15.2 
 10.8 
 7.95 
 
 23.4 
 18.5 
 14.1. 
 10.4 
 
 7.22 
 
 20 
 21 
 
 22 
 23 
 24 
 
 5.52 
 4.61 
 3.54 
 2.81 
 2.38 
 
 4.61 
 3.65 
 2.89 
 2.16 
 1.82 
 
 5.52 
 4.62 
 3.54 
 2.81 
 2.19 
 
 5.85 
 4.61 
 3.54 
 2.59 
 2.19 
 
 25 
 
 26 
 27 
 28 
 29 
 
 1.8 
 1.46 
 1.3 
 1.15 
 1.02 
 
 1.44 
 1.15 
 .908 
 .72 
 .572 
 
 1.8 
 1.46 
 1.16 
 
 .884 
 .762 
 
 1.8 
 1.46 
 1.21 
 .988 
 .833 
 
 30 
 
 31 
 32 
 33 
 34 
 
 .884 
 .822 
 .762 
 .544 
 .451 
 
 .452 
 .359 
 .284 
 .226 
 .179 
 
 .649 
 .451 
 .365 
 .289 
 .22 
 
 .694 
 .607 
 .525 
 .451 
 
 !81 
 
 35 
 36 
 
 .406 
 .365 
 
 .141 
 .113 
 
 .113 
 .071 
 
 .319 
 
 .26 

 
 24 
 
 JOHN A. ROEBLING'S SONS CO. 
 
 HARD-DRAWN COPPER WIRE. 
 
 British Post-office specifications. 
 
 Diameters. 
 
 226 
 1% 
 160^ 
 
 220.% 
 
 191 
 
 155% 
 
 110% 
 78 2 
 
 Weights per mile. 
 
 K'-'O 
 6U 
 
 -11U 
 
 102>i 
 
 2400 
 1800 
 
 650 
 490 
 
 ;o 
 
 1.098 
 1.464 
 2.195 
 
 4.391 
 5.855 
 8.782 
 
 "The wire shall be capable of being wrapped in six 
 turns around wire of its own diameter, unwrapped and 
 again wrapped in six turns around wire of its own diam- 
 eter in the same direction as the first wrapping, witliout 
 breaking; and shall be also capable of bearing the 
 number of twists set down in the table, without 
 breaking. 
 
 " The twist-test will be made as follows : The wire will 
 be gripped by two vises, one of which will be made to 
 revolve at a speed not exceeding one revolution per 
 second. The twists thus given to the wire will be reck- 
 oned by means of an ink mark which forms a spiral on 
 the wire during torsion, the full number of twists to be 
 visible between the vises." 
 
 According to the above table, the mile-ohm of copper 
 required is 878 pounds. This corresponds to a conduc- 
 tivity of 96.6 per cent., taking the value of the mile-ohm 
 of 100 per cent, copper as 859.
 
 JOHN A. ROEBLING'S SONS co. 25 
 
 HARD -DRAWN COPPER WIRE. (Continued.) 
 Telephone specifications. 
 
 laaj A0 m noti 1 - o> -* * 
 -B3uop 'juaa aaj 
 
 
 
 
 saqoui 
 xts ui SISIAIJ, 
 
 S55 
 
 Conduc- 
 tivity. 
 
 innui}U{K 
 
 ggsg 
 
 paipnb9H 
 
 sssss 
 
 Weights of 
 coils. 
 
 uratmnTK 
 
 g S g 8 I 
 
 mnra{xiJK 2 2 2 S 
 
 1 
 
 | 
 
 1 
 
 qom 
 aawnbs aaj 
 
 S 3 3 
 
 uinuitnjui 
 
 Hmov 
 
 !! 
 
 pannbaa 
 
 imov 
 
 si 
 
 Weights per mile. 
 
 rannnaiK 
 
 |||s 
 
 'ninmix'8j>j 
 
 t~ r- .0 
 
 3SS e 
 
 psjinban 
 
 i|sls 
 
 Diameters in mils. 
 
 nmramiK 
 
 sis?s 
 
 'uitiniixiij^ 
 
 i||d 
 
 p8JTnb8 H 
 
 S 3 5 83 
 
 
 
 K 
 
 j o o d d 
 d M ' w ai aa 
 
 ^ -3 -8 8 
 
 ^ K M fq 
 oc Jl S ! 3
 
 26 JOHN A 
 
 ROEBLING'S SONS co. 
 
 TENSILE STRENGTH OF COPPER WIRE. 
 
 
 Breaking weight. 
 Pounds. 
 
 
 Breaking weight. 
 Pounds. 
 
 Numbers, 
 
 
 
 Numbers, 
 
 
 B. & 8. G. 
 
 
 
 B. & S. G. 
 
 
 
 Hard- 
 
 An- 
 
 
 Hard- 
 
 An- 
 
 
 drawn. 
 
 nealed. 
 
 
 drawn. 
 
 nealed. 
 
 0000 
 
 8310 
 
 5650 
 
 9 
 
 617 
 
 349 
 
 000 
 
 6580 
 
 4480 
 
 10 
 
 489 
 
 277 
 
 00 
 
 5226 
 
 3553 
 
 11 
 
 388 
 
 219 
 
 
 
 4558 
 
 2818 
 
 12 
 
 307 
 
 174 
 
 1 
 
 3746 
 
 2234 
 
 13 
 
 244 
 
 138 
 
 2 
 
 3127 
 
 1772 
 
 14 
 
 193 
 
 109 
 
 3 
 
 2480 
 
 1405 
 
 15 
 
 153 
 
 87 
 
 4 
 
 1967 
 
 1114 
 
 16 
 
 133 
 
 69 
 
 5 
 
 1559 
 
 883 
 
 17 
 
 97 
 
 55 
 
 6 
 
 1237 
 
 700 
 
 18 
 
 77 
 
 43 
 
 7 
 
 980 
 
 555 
 
 19 
 
 61 
 
 34 
 
 8 
 
 778 
 
 440 
 
 20 
 
 48 
 
 27 
 
 The strength of soft copper wire varies from 32 000 to 
 
 36000 pounds per square inch, and of hard copper wire 
 
 from 45 000 to 68 000 pounds per square inch, according to 
 
 the degree of hardness. 
 
 The above table 
 
 is calculated for 34000 pounds for 
 
 soft wire and 60000 pounds for hard wire, except for 
 
 some of the larger sizes, where the breaking weight per 
 
 square inch is taken at 50000 pounds for 0000, 000 and 
 
 00, 55 000 for 0, and 
 
 57000 pounds for 1.
 
 JOHN A. ROEBLING'S SONS co. 27 
 
 BI-METALLIC WIRE. 
 
 Numbers, 
 B. & 8. G. 
 
 Diameters 
 in mils. 
 
 Weights per 
 mile. 
 Pounds. 
 
 Breaking weight. 
 Pounds. 
 
 0000 
 
 460 
 
 3200 
 
 10500' 
 
 000 
 
 410 
 
 2537 
 
 8600 
 
 00 
 
 365 
 
 2022 
 
 7000 
 
 
 
 325 
 
 1620 
 
 5700 
 
 1 
 
 289 
 
 1264 
 
 4600 
 
 2 
 
 25? 
 
 1003 
 
 3800 
 
 3 
 
 229 
 
 797 
 
 3200 
 
 4 
 
 204 
 
 629 
 
 2600 
 
 5 
 
 182 
 
 490 
 
 1790 
 
 6 
 
 162 
 
 398 
 
 1500 
 
 7 
 
 144 
 
 314 
 
 1210 
 
 8 
 
 128 
 
 246 
 
 1020 
 
 9 
 
 114 
 
 203 
 
 850 
 
 10 
 
 102 
 
 157 
 
 660 
 
 11 
 
 91 
 
 127 
 
 520 
 
 12 
 
 81 
 
 100 
 
 410 
 
 14 
 
 64 
 
 63 
 
 260 
 
 16 
 
 51 
 
 40 
 
 160 
 
 18 
 
 40 
 
 25 
 
 100 
 
 This wire consists of a steel center with a cover of 
 
 copper. Its conductivity is about 65 per cent, of that of 
 
 pure copper. The percentage of copper and steel may 
 
 vary a trifle, hence the strength and weight must be ap- 
 
 proximate.
 
 28 JOHN A. ROKBMNG'S SONS co. 
 
 STRANDS OF COPPER WIRE. 
 
 COPPER WIRES are laid up into concentric strands 
 or into ropes of seven strands. A rope of seven 
 strands each composed of seven wires, is called a seven 
 by seven rope, and is usually written 7x7. The number 
 of wires that can be made into a strand is limited by the 
 capacity of the stranding machinery. Two hundred 
 wires is the usual limit of a concentric strand, and one 
 hundred and thirty-three wires of a rope. 
 
 In a strand of circular milage, C. M., composed of n 
 wires of diameter d, with a weight per 1 000 feet w, then 
 we have 
 
 O. M. = d*xn. 
 
 w = . 00305 XC.M. 
 
 The weights of strands are calculated about one per 
 cent, heavier than a solid wire of the same circular 
 milage, while the resistance is calculated for the solid 
 wire. 
 
 In specifying how a strand shall be made, the number 
 of wires to be used or the diameter of each wire may be 
 given. In the first case the wire usually has to be 
 specially drawn, and this will delay an order, especially 
 a small order, unduly. It is, therefore, better to specify 
 the size wires B. &. S. G., of which the strand is to be 
 made. 
 
 The diameter of a strand may be calculated by multi- 
 plying the diameter of one wire by the factors given in 
 the table at the bottom of the opposite page, according 
 to the number of wires composing the strand.
 
 JOHN A. ROEBLING'S SONS co. 29 
 
 STRANDS OF COPPER WIRE. 
 Diameters and properties. 
 
 Numbers, 
 B. & S. G. 
 
 Circular 
 mils. 
 
 Diameters. 
 
 Weights. 
 
 : * 
 
 Si 
 
 M 
 
 Decimal 
 parts of 
 inch. 
 
 Nearest 
 32d. 
 
 1000 
 feet. 
 
 Mile. 
 
 
 1 000000 
 950000 
 900000 
 850000 
 
 801) 000 
 
 1.152 
 1.125 
 1.092 
 1.062 
 1.035 
 
 Ufa 
 
 l 
 1* 
 
 It's 
 1& 
 
 3050 
 2898 
 2745 
 2593 
 2440 
 
 16104 
 15299 
 14 494 
 13688 
 12883 
 
 .010 51 
 .01106 
 .011 67 
 .012 36 
 .013 13 
 
 ::::::: 
 
 750000 
 700000 
 650000 
 600000 
 550000 
 
 .999 
 .963 
 
 .927 
 .891 
 .855 
 
 1 
 
 H 
 
 U 
 
 I 
 
 2288 
 2135 
 1983 
 1830 
 1678 
 
 12078 
 11 273 
 10468 
 9662 
 8857 
 
 .014 01 
 .015 01 
 -.016 17 
 .017 51 
 .0191 
 
 ::::::: 
 
 500000 
 450000 
 400000 
 350000 
 300000 
 
 .819 
 
 .770 
 .728 
 .679 
 .630 
 
 H 
 
 8 
 
 H 
 
 % 
 
 1525 
 1373 
 1220 
 1068 
 915 
 
 8052 
 7247 
 6442 
 5636 
 4831 
 
 .02101 
 .02335 
 .02627 
 .03002 
 .03502 
 
 0000 
 
 000 
 00 
 
 
 250000 
 211 600 
 168100 
 133 225 
 105 625 
 
 83521 
 66564 
 52441 
 41616 
 
 .590 
 .530 
 
 .470 
 .420 
 .375 
 
 tt 
 
 1! 
 
 
 762 
 645 
 513 
 406 
 322 
 
 4026 
 3405 
 2709 
 2144 
 1700 
 
 .042 03 
 .04966 
 .06251 
 .078 87 
 .09948 
 
 1 
 
 2 
 3 
 
 4 
 
 .330 
 
 291 
 .261 
 .231 
 
 H 
 A 
 
 & 
 * 
 
 255 
 203 
 160 
 127 
 
 1346 
 1072 
 845 
 671 
 
 .1258 
 .157 9 
 .2004 
 .2525 
 
 
 NU wl b r e e^ of Factors. 
 
 Numbers of 
 wires. 
 
 Factors. 
 
 3 1% 
 7 3 
 12 4fc 
 19 5 
 27 6>i 
 
 75 
 91 
 108 
 127 
 147 
 
 MJ< 
 
 11 
 
 UK 
 
 13 
 
 MK 
 
 37 7 
 
 48 8X 
 61 9 
 7x7 9 
 7x19 15 
 
 169 
 192 
 217 
 
 15 
 
 iK 
 
 17 

 
 30 
 
 JOHN A. ROEBLING'S SONS co. 
 
 05 0> 05051^ 
 
 
 505 lOr-J CO tO to 10 ,H * 
 
 ?S2SS SSSS^?j S 
 
 li 
 
 

 
 JOHN A. ROEBLING'S SONS co. 31 
 
 I 
 
 35285 1 s;_ __, , 
 
 : ** 
 
 I 
 
 I aJda&fii I SaSSd I 1S5S3 
 
 s 
 
 1 
 ^ 
 
 ' giigjg 
 ss JisiS 
 
 | & ggjjg 1 -" 
 
 a ^S^iiiJSS 
 
 lOrHOSlOOO -(<-<Jiifll> I OC< 
 
 3 52g ISSSSSS' trfM*lH 
 
 t-t-t-0> MOOrHUS OS<
 
 32 
 
 JOHN A. ROEBLING S SONS CO. 
 
 
 
 
 ittti 
 
 gglii iiiii i 
 
 <0 -.COS CO ! I>r-l0 .TJ. 
 
 110 I 0> 
 
 i I 
 
 iiil ilili SPSS N 
 
 > .**:-! 
 
 iiiii
 
 JOHN A. ROEBLING'S SONS co. 33 
 
 
 
 mass s* 
 
 IS S< 
 
 SSSS^S 
 
 o'sva 888 
 
 INOOSMr-l-* 
 
 <Ho6.riM<N rn 
 
 c5e^<Nrt rJ :
 
 34 JOHN A. ROEBLING'S SONS co. 
 
 IRON WIRE. 
 
 IN COMPARING tables of the weights of Galvanized 
 Iron Wire it was found that the weights of the 
 various sizes were not consistent with each other in the 
 same table, and that no two tables seemed to agree in 
 regard to the specific gravity of the material. 
 
 This table is calculated from the formula, weight per 
 mile = D 2 X .013 9, which seems to be the most likely 
 value for galvanized iron wire. This corresponds with 
 a specific gravity of 7.73, and a weight per cubic foot 
 of 483 pounds. 
 
 Steel wire is slightly heavier, and it is probable the 
 constant in the above formula should be .014 for galva- 
 nized steel wire. 
 
 The following average values of the mile-ohm were 
 used in calculating the resistance per mile at 68 F., the 
 International ohm being the unit : 
 
 Kind of material. Minimum. Maximum. Average. 
 E. B. B., , 4500 4800 4700 
 
 B. B., 5300 6000 5500 
 
 Steel, 6000 7000 6500 
 
 The breaking weight of any wire equals its weight per 
 mile multiplied by 3 for E. B. B., 3.3 for B. B., or 3.7 for 
 steel, all annealed and galvanized. This corresponds to 
 53 100 pounds, 58 410 pounds, and 65 490 pounds per 
 square inch, respectively. 
 
 The strength of steel wire varies from 50 000 pounds 
 per square inch to over 300 000 pounds, according to the 
 kind of material and its treatment. 
 
 By taking 100 000 pounds per square inch as the break- 
 ing strain of steel wire, the breaking strain of any other 
 wire may easily be computed from the table. For a wire 
 of 80 000 pounds per square inch breaking strain, take 
 eight-tenths of the tabulated breaking strain for that 
 size wire at 100 000 pounds per square inch given in the 
 table.
 
 JOHN A. ROEBLING'S SONS co. 35 
 
 GALVANIZED IRON WIRE. 
 
 
 
 Weights. 
 Pounds. 
 
 h^ Resistance per mile 
 Pounds in ohms - 
 
 P 
 
 oi a 
 5 
 
 1000 
 feet. 
 
 One 
 mile. 
 
 Iron. 
 
 Steel. 
 
 E. B. B. 
 
 B. B. 
 
 Steel. 
 
 
 340 
 
 304 
 
 1607 
 
 4821 
 
 9079 
 
 2.93 
 
 3.42 
 
 4.05 
 
 300 
 
 237 
 
 1251 
 
 3753 
 
 7068 
 
 3.76 
 
 4.4 | 5.2 
 
 
 284 
 
 212 
 
 1121 
 
 3363 
 
 6335 
 
 4.19 
 
 4.91 
 
 5.8 
 
 
 259 
 
 177 
 
 932 
 
 2796 
 
 5268 
 
 5.04 
 
 5.9 
 
 6.97 
 
 
 288 
 
 149 
 
 787 
 
 2361 
 
 4449 
 
 5.97 
 
 6.99 
 
 8.26 
 
 
 220 
 
 127 
 
 673 
 
 2019 
 
 3801 
 
 6.99 
 
 8.18 
 
 9.66 
 
 203 
 
 109 
 
 573 
 
 1719 
 
 3237 
 
 ' 8.21 
 
 9.6 
 
 11.35 
 
 7 180 
 
 85 
 
 450 
 
 1350 
 
 2545 
 
 10.14 
 
 12.21 
 
 14.43 
 
 8 ! 165 
 
 72 
 
 378 
 
 1134 
 
 2138 
 
 12.42 
 
 14.53 
 
 17.18 
 
 9 
 
 148 
 
 58 
 
 305 
 
 915 
 
 1720 
 
 15.44 
 
 18.06 
 
 21.35 
 
 10 
 
 134 
 
 47 
 
 250 
 
 750 
 
 1410 
 
 1883 
 
 22.04 
 
 26.04 
 
 11 
 
 120 
 
 38 
 
 200 
 
 600 
 
 1131 
 
 23.48 
 
 27.48 
 
 32.47 
 
 12 
 
 109 
 
 31 
 
 165 
 
 495 
 
 933 
 
 28.46 
 
 33.3 
 
 39.36 
 
 13 
 
 95 
 
 24 
 
 125 
 
 375 
 
 709 
 
 37.47 
 
 43.85 
 
 51.82 
 
 14 
 
 83 
 
 18 
 
 96 
 
 288 
 
 541 
 
 49.08 
 
 57.44 
 
 67.88 
 
 15 
 
 72 
 
 13.7 
 
 72 
 
 216 
 
 407 
 
 65.23 
 
 76.33 
 
 90.21 
 
 16 
 
 65 
 
 11.1 
 
 59 
 
 177 
 
 332 
 
 80.03 
 
 93.66 
 
 110.7 
 
 17 
 
 58 
 
 8.9 
 
 47 
 
 141 
 
 264 
 
 100.5 
 
 120.4 
 
 139. 
 
 18 49 
 
 6.3 
 
 33 
 
 99 
 
 189 
 
 140.8 
 
 164.8 
 
 194.8 

 
 36 JOHN A. ROEBLING'S SONS co. 
 
 GALVANIZED IRON TELEGRAPH WIRE. 
 
 Western Union Telegraph company's specifications. 
 
 (Condensed). 
 
 " 1. The wire to be soft and pliable, and capable of elon- 
 gating 15 per cent, without breaking, after being galva- 
 nized. 
 
 "2. Great tensile strength is not required, but the wire 
 must not break under a less strain than two and one- 
 half times its weight in pounds per mile. 
 
 " 3. Tests for ductility will be made as follows : The 
 piece of wire will be gripped by two vises, 6 inches apart, 
 and twisted. The full number of twists must be dis- 
 tinctly visible between the vises on the 6-inch piece. 
 The number of twists in a piece of 6 inches in length not 
 to be under 15. 
 
 " 4. The weight per mile for the different gauge wires to 
 be : for No. 4, 730 K>s. ; No. 6, 540 K>s. ; No. 8, 380 R>s. ; No. 
 9, 320 ft>s. ; No. 10, *250 K>s., or, as near these figures as 
 practicable. 
 
 " 5. The electrical resistance of the wire in ohms per 
 mile, at a temperature of 68 Fahrenheit, must not exceed 
 the quotient arising from the dividing the constant num- 
 ber 4 800 by the weight of the wire in pounds per mile. 
 The coefficient .003 will be allowed for each degree Fah- 
 renheit in reducing to standard temperature. 
 
 " 6. The wire must be well galvanized, and capable of 
 standing the following tests: The wire will be plunged 
 into a saturated solution of sulphate of copper, and per- 
 mitted to remain one minute, and then wiped clean. 
 This process will be performed four times. If the wire 
 appears black after the fourth immersion, it shows that 
 the zinc has not been all removed, and that the galva- 
 nizing is well done ; but if it has a copper color, the iron 
 is exposed, showing that the zinc is too thin."
 
 JOHN A. KOKBLING'S SONS co. 37 
 
 GALVANIZED IRON TELEGRAPH WIRE. 
 
 British Post-office specifications. 
 
 sraqo IBUOIJ 
 -BIU8JUI -j 069 
 JB azis pxeptiBis jo 
 
 sisas 
 
 I'll'f* II 
 
 Strength and ductility. 
 
 saqom 
 
 XJS Ul SJStMJ, 
 
 SSK2S 
 
 "^(^"tf^cSaJS 
 t a 5 _ a 25 C J 
 
 nuqj 
 seal ?oji 
 jqSiaAV 
 
 81181 
 
 "The wire shall be well galvanized with zinc spelter, and this will be tested by an oflRcer' appointed b 
 General to inspect and test the wire, and hereinafter called the Inspecting Officer, taking samples from a 
 and plunging them into a saturated solution of sulphate of copper, at 60 F., and allowing them to remain i 
 one minute, when they are to be withdrawn and wiped clean. The galvanizing shall admit of this proces 
 performed with each sample without there being, as there would bo if the coating of zinc were too thin, 
 dish deposit of metallic copper on the wire. Samples taken from pieces of the 800-ft. wire shall also bear 
 bar 2% inches in diameter without any signs appearing of the zinc cracking or peeling off; the 600-ft. wi 
 bear bending around a bar 1% inches in diameter; the 450-ft. and 400-lb. wire around a bar 2 inches in d 
 200-ft. wire around a bar 1% inches in diameter." 
 The mile-ohm is 5 323. 
 
 XtS UI SJSIMJ, 
 
 SSS8S 
 
 unqj 
 
 8881 50 M 
 
 81al 
 
 soqoui 
 
 S , SS8 
 
 spnnoj 
 uinui'iujK 
 
 ! 
 
 Weights per mile. 
 Pounds. 
 
 UUUHIUJK 
 
 gssss 
 
 ' 
 
 S86S8 
 
 
 
 1ISS1 
 
 
 Diameters in mils. 
 
 umtnmiK 
 
 a 
 
 
 
 sssss 
 
 paatnbaa 
 
 sga 
 
 210987
 
 38 
 
 JOHN A. ROEBLING'S SONS co. 
 
 GALVANIZED SUPPORTING STRANDS. 
 
 What weight per foot will a half-inch ordinary strand 
 support if the strain is one-half the breaking weight, the 
 span 120 feet, and the deflection .01 of the span or 1.2 
 
 One-half the breaking weight of a half-inch ordinary 
 galvanized strand is 4 160 pounds. The value of S for 
 above span and deflection, table page 50, is 1 500.2. 
 Dividing 4 160 by 1 500.2 we find the total weight per foot 
 to be 2.773 pounds. Deducting from this the weight per 
 foot of the half-inch galvanized strand we have 2.263 
 pounds as the weight per foot of cable that this strand 
 will support. While it is true that a factor of safety of 
 two in this work is too small, yet the cables help in a 
 great measure to carry their own weight. It is believed 
 that galvanized strands will easily carry the loads indi- 
 cated on page 39. 
 
 This strand is composed of seven wires, twisted 
 together into a single strand. 
 
 Diameters in 
 32ds of an 
 inch. 
 
 Weights per 100 
 Pounds. 
 
 Estimated breaking strength. 
 Pounds. 
 
 Ordinary. 
 
 Special. 
 
 16 
 15 
 14 
 12 
 10 
 
 51 
 48 
 37 
 30 
 21 
 
 8320 
 7500 
 6000 
 4700 
 3300 
 
 16640 
 
 15000 
 12000 
 9400 
 6600 
 
 9 
 
 8 
 7 
 6 
 5 
 
 18 
 UK 
 8% 
 6% 
 
 t% 
 
 2600 
 1750 
 1300 
 1000 
 700 
 
 5200 
 3500 
 2600 
 2000 
 1400 
 
 4 
 3 
 
 y/* 
 
 2 
 
 375 
 320 
 
 750 
 640
 
 JOHN A. ROEBLING'S SONS co. 39 
 
 SUPPORTING CAPACITY OF GALVANIZED 
 
 STRANDS. 
 
 Ordinary. 
 
 | 
 
 Spans in feet. 
 
 "Serf 
 
 
 
 
 
 
 
 
 
 
 ES 
 
 100 
 
 110 
 
 120 
 
 125 
 
 130 
 
 140 
 
 150 
 
 175 
 
 200 
 
 \\l 
 
 |ft 
 
 
 
 
 
 
 
 
 
 
 Weights of 1 000 feet of cable. Pounds. 
 
 16 
 
 2818 
 
 2516 
 
 2263 
 
 2152 
 
 2050 
 
 1867 
 
 1709 
 
 1391 
 
 1154 
 
 15. 
 
 2520 
 
 2247 
 
 2020 
 
 1920 
 
 1827 
 
 1663 
 
 1520 
 
 1234 
 
 1130 
 
 14 
 
 2030 
 
 1812 
 
 1630 
 
 1550 
 
 1476 
 
 1344 
 
 1230 
 
 1001 
 
 900 
 
 12 
 
 1580 
 
 1409 
 
 1266 
 
 1204 
 
 1146 
 
 1043 
 
 953 
 
 774 
 
 640 
 
 10 
 
 1110 
 
 899 
 
 890 
 
 846 
 
 805 
 
 733 
 
 670 
 
 544 
 
 450 
 
 9 
 
 860 
 
 765 
 
 680 
 
 652 
 
 620 
 
 563 
 
 513 
 
 414 
 
 340 
 
 8 
 
 585 
 
 521 
 
 468 
 
 445 
 
 423 
 
 385 
 
 352 
 
 285 
 
 235 
 
 7 
 
 433 
 
 385 
 
 346 
 
 329 
 
 313 
 
 284 
 
 260 
 
 210 
 
 172 
 
 6 
 
 337 
 
 300 
 
 270 
 
 257 
 
 245 
 
 223 
 
 204 
 
 165 
 
 137 
 
 Special. 
 
 | 
 
 Spans in feet. 
 
 -g 
 
 
 
 
 
 
 
 
 
 
 f"l a 
 
 100 
 
 110 
 
 120 
 
 125 
 
 130 
 
 140 
 
 150 
 
 175 
 
 200 
 
 3- 
 
 
 
 
 
 
 
 
 
 
 III 
 
 Q 
 
 
 
 
 
 
 
 
 
 
 Weights of 1 000 feet of cable. Pounds. 
 
 16 
 
 6146 
 
 5482 
 
 5036 
 
 4814 
 
 4510 
 
 4244 
 
 3928 
 
 3292 
 
 2818 
 
 15 
 
 5520 
 
 4974 
 
 4520 
 
 4320 
 
 4134 
 
 3808 
 
 3520 
 
 2948 
 
 2520 
 
 14 
 
 4430 
 
 3994 
 
 3630 
 
 3470 
 
 3322 
 
 305^ 
 
 2830 
 
 2372 
 
 2030 
 
 12 
 
 3460 
 
 3118 
 
 2832 
 
 2708 
 
 2592 
 
 238? 
 
 2 206 
 
 1848 
 
 1580 
 
 10 
 
 2430 
 
 2008 
 
 1990 
 
 1902 
 
 1820 
 
 1676 
 
 1550 
 
 1298 
 
 1110 
 
 9 
 
 1900 
 
 1710 
 
 1540 
 
 1484 
 
 1420 
 
 1306 
 
 1206 
 
 1008 
 
 860 
 
 8 
 
 1285 
 
 1157 
 
 1051 
 
 1005 
 
 961 
 
 885 
 
 819 
 
 685 
 
 585 
 
 7 
 
 953 
 
 857 
 
 778 
 
 745 
 
 712 
 
 655 
 
 607 
 
 507 
 
 473 
 
 6 
 
 737 
 
 663 
 
 603 
 
 577 
 
 553 
 
 509 
 
 472 
 
 393 
 
 337 
 
 Dip = .01 of span. 
 
 Factor of safety of two.
 
 40 JOHN A. ROEBLING'S SONS co. 
 
 CURRENTS/ 
 
 FUSING EFFECTS OF CURRENTS. 
 
 Table giving the diameters 
 
 of wires of various materials 
 
 which will be fused by 
 
 a current of given strength. 
 
 W. H. PBEECE, F.R.S. 
 
 I 
 
 1 
 
 Diameters in inches. 
 
 
 
 
 . 
 
 
 
 
 . 
 
 I 
 
 
 
 
 f 
 
 
 
 
 & 
 
 a 
 
 J 
 
 9 
 
 g~j 
 
 o 
 
 & 
 
 g 
 
 g 
 
 *s 
 
 g 
 
 1 
 
 || 
 
 11 
 
 1! 
 
 B 03 
 
 ll 
 
 |1 
 
 
 I" 
 
 cbi 
 
 ll 
 
 o 
 
 O 
 
 ^ 
 
 K 
 
 
 M 
 
 
 EH 
 
 H 
 
 J 
 
 l 
 
 0.002 1 
 
 0.0026 
 
 0.0033 
 
 0.003 3 
 
 0.0035 
 
 0.0047 
 
 0.0072 
 
 0.008 3 
 
 0.0081 
 
 2 0.003 4 
 
 0.004 1 
 
 0.005 3 
 
 0.005 3 
 
 0.005 6 ! 0.00741 0.0113! 0.0132 
 
 0.012 8 
 
 3 0.0044 
 
 0.005 4 
 
 0.007 
 
 0.0069 
 
 0.00741 0.009 71 '0.014 9 0.0173 0.0168 
 
 4l 0.0053 
 
 0.0065 
 
 0.008 4 
 
 0.0084 
 
 0.0089 0.0117 0.0181 
 
 0.021 i 0.0203 
 
 5 1| 0.0062 
 
 0.0076 
 
 0.0098 
 
 0.0097 
 
 0.010 4j 0.013 6 : 0.021 
 
 0.0243 
 
 0.0236 
 
 
 
 
 
 
 
 
 
 
 10' 0.0098 
 
 0.012 
 
 0.015 5 
 
 0.015 4 
 
 0.0164 
 
 0.021 6 
 
 0.0334 
 
 0.038 6 
 
 0.037 5 
 
 15; 0.0129 
 
 0.015 8 
 
 0.020 3 
 
 0.020 2 
 
 0.0215' 0.0283 
 
 0.0437 
 
 0.050 6 
 
 0.049 1 
 
 20 0.015 6 
 
 0.019 1 
 
 0.024 6 
 
 0.024 5 
 
 0.0261; 0.0343 
 
 0.052 9 
 
 0.061 3 
 
 0.059 5 
 
 25 0.0181 
 
 0.022 2 
 
 0.028 6 
 
 0.0284 
 
 0.0303 0.0398 
 
 0.061 4 
 
 0.071 1 
 
 0.069 
 
 30j 0.0205 
 
 0.025 
 
 0.032 3 
 
 0.032 
 
 0.034 2j 0.045 
 
 0.0694 
 
 0.080 3 
 
 0.077 9 
 
 35! 0.0227 
 
 0.027 7 
 
 0.0358 
 
 0.035 6 
 
 0.037 9 
 
 0.0498 
 
 0.076 9 
 
 0.089 
 
 0.0864 
 
 40 
 45 
 
 0.024 8 
 0.026 8 
 
 0.030 3 
 0.032 8 
 
 0.039 1 
 0.0423 
 
 0.0388 
 0.042 
 
 0.0414 
 0.044 8 
 
 0.0545 
 0.0589 
 
 0.084 
 0.090 9 
 
 0.097 3 
 0.105 2 
 
 0.094 4 
 0.102 1 
 
 50 
 
 0.0288 
 
 0.035 2 
 
 0.045 4 
 
 0.045 
 
 0.048 
 
 0.0632 
 
 0.0975 
 
 0.1129 
 
 0.1095 
 
 60 
 
 0.032 5 
 
 0.039 7 
 
 0.051 3 
 
 0.050 9 
 
 0.0542 
 
 0.071 4 
 
 0.110 1 
 
 0.127 5 
 
 0.1237 
 
 70 
 80! 
 
 0.036 
 0.039 4 
 
 0.044 
 
 0.048 1 
 
 0.056 8 
 0.062 1 
 
 00564 
 0.061 6 
 
 0.0601 
 0.0657 
 
 0.079 1 
 0.0864 
 
 0.122 
 0.133 4 
 
 0.141 3 
 
 0.154 4 
 
 0.137 1 
 0.1499 
 
 90! 0.0426 
 lOO 1 ! 0.045 7 
 
 0.052 
 0.055 8 
 
 0.*72 0.0667 
 0.072 1 0.071 5 
 
 0.071 1 
 0.076 2 
 
 00935 
 0.1003 
 
 0.1443 0.167 1| 0.1621 
 0.1548 0.1792 0.1739 
 
 120 ! 0.051 6 
 
 0.063 
 
 0.081 4 1 0.0808 
 
 0.0861 
 
 0.1133 
 
 0.174 8 1 0.2024 0.1964 
 
 HO! 
 
 0.057 2 
 
 0.069 8 1 0.0902! 0.0,95 
 
 0.0954 
 
 0.125 5 
 
 0.1937 0.2243 0.2176 
 
 160; 
 
 0.0625 0.0763 0.0986 0.0978 
 
 0.1043 0.1372 0.2118 0.2452 0.2379 
 
 180 0.0676 0.0826 0.1066 0.1058: 0.1128' 0.1484 0.2291 0.2652 0.2573 
 200| 0.0725 0.08MJ 0.1144; 0.1135 0.121 1 0.1592 0.2-157 0.2845! 0.276 
 
 225J 0.0784 0.0958 0.123 7 1 0.1228 
 
 0.1309 
 
 0.1722 02658, 0.30771 0.2986 
 
 250 
 
 0.0841 
 
 0.1028 
 
 0.1327 0.1317 
 
 0.1404 
 
 0.1848 0.2851 0330 l' 0.320 3 
 
 275 
 
 0.0897 
 
 0.1095 
 
 0.1414 0.1404 
 
 0.14971 0.19691 0.3038 
 
 ().:;.,! 8 
 
 0.3417 
 
 300 
 
 0.095 
 
 0.116 1 
 
 0.1498 0.1487 
 
 0.1586 0.2086 0.322 
 
 0.372 8 
 
 0.361 7 

 
 JOHN A. ROEBLING'S SONS co. 
 
 41 
 
 .) 
 nd 
 
 61 
 
 ^SS 
 
 IM CO O<C 
 
 isss 
 
 
 
 
 
 m 
 ve 
 
 fr 
 n 
 
 ld 
 t 
 
 its, can be tak 
 t-out or fuse, 
 
 relia 
 hich 
 
 ts, 
 m 
 bet 
 
 " 
 ie 
 l 

 
 42 JOHN A. ROEBLING'S SONS co. 
 
 HEATING EFFECTS OF CURRENTS. 
 
 A REPORT read before the Edison Convention, at 
 Niagara Falls, August, 1889, by A. E. Kennelly, 
 gives complete formulae and tables based on experi- 
 mental data, showing the heating effects of electric 
 currents. This report was published in the Electrical 
 World, beginning with the edition of November 23, 
 1889. 
 
 The tables in this book are taken from curves con- 
 structed from data given in the above report. 
 
 The table page 43 gives the rules of the various insur- 
 ance companies, together with one column giving the 
 current whose double would cause a rise of 40 C. This 
 is the safe carrying capacity recommended in Kennelly 's 
 report. 
 
 The table page 44 gives the diameters of various wires 
 and the current they will carry with a specified rise in 
 temperature. The wires are insulated, and the condi- 
 tions are similar to those met with in house wiring in 
 mouldings or conduits. 
 
 The table page 45 is computed for bare wires suspended 
 indoors, and gives the current carried with the corres- 
 ponding rise in temperature. 
 
 The table page 46 is computed for outdoor wires, not 
 insulated. 
 
 In these tables all wires are solid. 
 
 Insulation increases the current a wire will carry with 
 a given rise in temperature, because the radiating surface 
 is increased, and for the same reason a strand will carry a 
 larger current than a solid wire. 
 
 One square inch of bright copper radiates .003 9 watts 
 per degree Centigrade rise in temperature, and one 
 square inch of blackened copper, .009 watts, under the 
 same conditions. Convection seems to be dependent 
 only on length, and may be taken at .053 watts per foot 
 per degree Centigrade rise.
 
 JOHN A. KOEBLING'S SONS co. 43 
 
 HEATING EFFECTS OF CURRENTS. 
 
 Insurance rules for carrying capacity of wires. 
 
 
 *! 
 
 t| 
 
 ft 
 
 
 
 h 
 
 umbers, B. & S. G. 
 
 irrent, the double 
 which will cause a 
 of 72 F. 
 
 ational Electric Lij 
 association. 
 
 National Board 
 of Fire Under- 
 writers. 
 
 ssociated Factory 
 Mutual Insurance 
 company. 
 
 si's 
 
 fi! 
 Sffl 
 
 ssw 
 
 Con- 
 cealed 
 work. 
 
 Open 
 work. 
 
 K 
 
 5 
 
 fc 
 
 
 
 
 
 E 
 
 0000 
 
 174 
 
 175 
 
 218 
 
 312 
 
 175 
 
 
 000 
 
 146 
 
 145 
 
 181 
 
 262 
 
 145 
 
 
 
 00 
 
 123 
 
 120 
 
 150 
 
 220 
 
 120 
 
 105 
 
 
 
 103 
 
 100 
 
 125 
 
 185 
 
 100 
 
 83 
 
 1 
 
 88 
 
 95 
 
 105 
 
 156 
 
 85 
 
 66 
 
 2 
 
 73 
 
 70 
 
 88 
 
 131 
 
 70 
 
 52 
 
 3 
 
 61 
 
 60 
 
 75 
 
 110 
 
 60 
 
 41 
 
 4 
 
 52 
 
 50 
 
 63 
 
 92 
 
 50 
 
 33 
 
 5 
 
 43 
 
 45 
 
 53 
 
 77 
 
 45 
 
 26 
 
 6 
 
 36 
 
 35 
 
 45 
 
 65 
 
 35 
 
 21 
 
 7 
 
 31 
 
 30 
 
 
 
 
 
 30 
 
 16 
 
 8 
 
 26 
 
 25 
 
 33 
 
 46 
 
 25 
 
 13 
 
 10 
 
 18 
 
 20 
 
 25 
 
 32 
 
 20 
 
 8 
 
 12 
 
 13 
 
 15 
 
 17 
 
 23 
 
 15 
 
 5 
 
 14 
 
 9 
 
 10 
 
 12 
 
 16 
 
 10 
 
 3 
 
 16 
 
 6 
 
 5 
 
 6 
 
 8 
 
 5 
 
 2 
 
 18 
 
 5 
 
 
 
 3 
 
 5 
 
 3 
 
 1 

 
 44 JOHN A. KOEBLING'S SONS co. 
 
 HEATING EFFECTS OF CURRENTS.-(Cton<.) 
 
 Carrying capacity of insulated wires in mouldings. 
 
 (Kennelly's formula.) 
 
 
 Rise in temperature in degrees Centigrade. 
 
 i 
 
 5 
 
 10 
 
 15 20 
 
 30 
 
 40 
 
 50 
 
 60 
 
 70 
 
 a 
 
 < 
 
 Diameters of wires in mils. 
 
 300 
 
 
 
 
 
 446 
 
 411 
 
 386 
 
 367 
 
 354 
 
 280 
 
 
 
 
 
 427 
 
 393 
 
 
 350 
 
 
 260 
 
 
 
 
 450 
 
 409 
 
 375 
 
 352 
 
 333 
 
 321 
 
 240 
 
 
 
 
 430 
 
 390 
 
 356 
 
 333 
 
 315 
 
 304 
 
 220 
 
 
 
 
 
 436" 
 
 408 
 
 370 
 
 337 
 
 315 
 
 298 
 
 285 
 
 200 
 
 
 448 
 
 414 
 
 386 
 
 350 
 
 317 
 
 295 
 
 280 
 
 268 
 
 190 
 
 
 437 
 
 403 
 
 375 
 
 339 
 
 308 
 
 286 
 
 270 
 
 258 
 
 180 
 
 
 425 
 
 391 
 
 364 
 
 328 
 
 298 
 
 277 
 
 260 
 
 249 
 
 170 
 
 
 411 
 
 378 
 
 352 
 
 317 
 
 287 
 
 266 
 
 250 
 
 239 
 
 ICO 
 
 
 398 
 
 364 
 
 340 
 
 305 
 
 276 
 
 256 
 
 241 
 
 229 
 
 150 
 
 445 
 
 383 
 
 351 
 
 326 
 
 293 
 
 265 
 
 244 
 
 230 
 
 218 
 
 140 
 
 431 
 
 370 
 
 338 
 
 312 
 
 281 
 
 253 
 
 232 
 
 220 
 
 206 
 
 130 
 
 417 
 
 354 
 
 322 
 
 300 
 
 
 240 
 
 220 
 
 208 
 
 195 
 
 120 
 
 400 
 
 339 
 
 308 
 
 285 
 
 255 
 
 228 
 
 208 
 
 195 
 
 182 
 
 110 
 
 383 
 
 322 
 
 292 
 
 270 
 
 240 
 
 214 
 
 195 
 
 182 
 
 170 
 
 100 
 
 362 
 
 302 
 
 276 
 
 253 
 
 223 
 
 200 
 
 182 
 
 168 
 
 158 
 
 90 
 
 343 
 
 284 
 
 259 
 
 237 
 
 208 
 
 185 
 
 168 
 
 154 
 
 143 
 
 80 
 
 322 
 
 264 
 
 240 
 
 218 
 
 192 
 
 169 
 
 153 
 
 139 
 
 130 
 
 70 
 
 300 
 
 242 
 
 220 
 
 198 
 
 174 
 
 152 
 
 139 
 
 123 
 
 116 
 
 60 
 
 275 
 
 220 
 
 195 
 
 175 
 
 155 
 
 135 
 
 122 
 
 108 
 
 101 
 
 60 
 
 250 
 
 195 
 
 175 
 
 152 
 
 132 
 
 118 
 
 104 
 
 91 
 
 86 
 
 40 
 
 217 
 
 169 
 
 144 
 
 128 
 
 110 
 
 95 
 
 85 
 
 75 
 
 70 
 
 30 
 
 178 
 
 136 
 
 115 
 
 100 
 
 85 
 
 73 
 
 66 
 
 58 
 
 54 
 
 20 
 
 132 
 
 100 
 
 71 
 
 
 59 
 
 50 45 
 
 40 
 
 37 
 
 10 
 
 78 
 
 58 
 
 42 
 
 35 
 
 30 : 
 
 

 
 JOHN A. ROEBLING'S SONS co. 45 
 
 HEATING EFFECTS OF CURRENTS. (Gmt.) 
 Bare copper in still air. 
 
 8 
 <! 
 
 Rise in temperature, degrees Centigrade. 
 
 10 
 
 20 
 
 40 
 
 80 
 
 1 
 
 I 
 
 tl 
 fl 
 
 1 
 
 I 
 
 jj 
 
 3 
 
 . s 
 
 1 
 M 
 
 Jj] 
 1 
 
 3 
 
 Diameters of wires in mils. 
 
 1000 
 950 
 900 
 850 
 800 
 
 
 
 
 
 
 
 
 
 968 
 930 
 893 
 858 
 823 
 
 911 
 
 878 
 844 
 809 
 771 
 
 750 
 723 
 695 
 666 
 638 
 
 610 
 580 
 550 
 518 
 503 
 
 
 
 
 
 
 
 
 1000 
 
 750 
 700 
 650 
 600 
 575 
 
 ...... 
 
 :::: 
 
 ::::: 
 
 960 
 910 
 858 
 833 
 
 950 
 
 900 
 850 
 800 
 775 
 
 785 
 748 
 708 
 668 
 648 
 
 784 
 
 696 
 660 
 621 
 603 
 
 650 
 525 
 500 
 475 
 450 
 
 
 
 995 
 978 
 960 
 925 
 
 895 
 
 980 
 948 
 913 
 880 
 843 
 
 808 
 780 
 751 
 723 
 696 
 
 750 
 725 
 700 
 675 
 648 
 
 628 
 607 
 584 
 563 
 541 
 
 520 
 498 
 475 
 452 
 428 
 
 583 
 563 
 543 
 . 523 
 501 
 
 488 
 461 
 455 
 439 
 421 
 
 425 
 400 
 375 
 350 
 325 
 
 1000 
 950 
 900 
 850 
 
 860 
 820 
 783 
 745 
 
 708 
 
 808 
 770 
 731 
 690 
 654 
 
 669 
 641 
 612 
 581 
 550 
 
 620 
 592 
 564 
 536 
 506 
 
 479 
 457 
 435 
 413 
 390 
 
 406 
 387 
 369 
 350 
 331 
 
 300 
 275 
 250 
 225 
 200 
 
 800 
 750 
 6% 
 642 
 586 
 
 668 
 628 
 586 
 545 
 500 
 
 615 
 575 
 534 
 494 
 453 
 
 519 
 487 
 453 
 419 
 384 
 
 475 
 444 
 412 
 379 
 345 
 
 403 
 377 
 351 
 323 
 
 2% 
 
 366 
 341 
 
 317 
 291 
 265 
 
 312 
 292 
 272 
 252 
 229 
 
 208 
 194 
 161 
 135 
 123 
 
 112 
 100 
 87 
 74 
 61 
 
 is~ 
 
 36 
 24 
 
 175 
 150 
 125 
 100 
 90 
 
 80 
 70 
 60 
 50 
 40 
 
 30 
 20 
 10 
 
 530 
 470 
 408 
 343 
 315 
 
 454 
 404 
 352 
 300 
 
 272 
 
 406 
 360 
 308 
 258 
 237 
 
 349 
 311 
 270 
 226 
 208 
 
 310 
 274 
 235 
 195 
 178 
 
 266 
 226 
 206 
 170 
 158 
 
 239 
 210 
 182 
 150 
 137 
 
 286 
 259 
 226 
 191 
 156 
 
 246 
 220 
 194 
 167 
 140 
 
 214 
 190 
 167 
 142 
 117 
 
 1% 
 170 
 150 
 130 
 108 
 
 161 
 143 
 125 
 106 
 86 
 
 143 
 
 127 
 - 112 
 95 
 
 78 
 
 124 
 110 
 97 
 82 
 68 
 
 120 
 
 82 
 40 
 
 111 
 
 76 
 
 90 
 63 
 37 
 
 85 
 60 
 35 
 
 66 
 45 
 30 
 
 60 
 
 44 
 28 
 
 54 
 40 
 26 

 
 46 JOHN A. ROEBLING'S SONS co. 
 
 HEATING EFFECTS OF CURRENTS.-(Om<.) 
 Bare copper suspended outdoors. 
 
 Amperes. 
 
 Rise in temperature, degrees Centigrade. 
 
 5 
 
 10 
 
 20 
 
 40 
 
 ! 
 
 1 
 
 
 
 A 
 
 
 
 
 1 
 
 
 
 x 
 
 1 
 
 g 
 
 Diameters of wires in mils. 
 
 1000 
 950 
 900 
 850 
 800 
 
 963 
 916 
 
 869 
 845 
 
 ;; 
 
 962 
 9'J8 
 894 
 
 839 
 
 932 
 897 
 865 
 843 
 810 
 
 771 
 744 
 715 
 689 
 672 
 
 745 
 720 
 692 
 665 
 649 
 
 595 
 574 
 550 
 537 
 
 ~615 
 491 
 467 
 442 
 
 129 
 
 594 
 572 
 552 
 530 
 512 
 
 750 
 700 
 650 
 600 
 575 
 
 ~550~ 
 525 
 500 
 475 
 450 
 
 975 
 
 933 
 
 837 
 813 
 
 804 
 767 
 729 
 690 
 671 
 
 775 
 739 
 703 
 665 
 647 
 
 643 
 613 
 
 582 
 554 
 538 
 
 6JO 
 591 
 561 
 532 
 517 
 
 496 
 
 472 
 449 
 426 
 414 
 
 820 
 795 
 770 
 745. 
 719 
 
 789 
 764 
 740 
 719 
 693 
 
 650 
 630 
 610 
 589 
 
 627 
 609 
 589 
 569 
 548 
 
 522 
 506 
 489 
 473 
 453 
 
 501 
 487 
 470 
 455 
 438 
 
 417 
 404 
 390 
 377 
 363 
 
 402 
 
 389 
 376 
 363 
 
 :;:,<! 
 
 425 
 400 
 375 
 350 
 325 
 
 690 
 661 
 632 
 601 
 571 
 
 667 
 638 
 610 
 581 
 552 
 
 546 
 524 
 502 
 478 
 453 
 
 526 
 504 
 484 
 462 
 439 
 
 436 
 418 
 399 
 380 
 362 
 
 422 
 406 
 377 
 360 
 342 
 
 349 
 334 
 319 
 304 
 
 289 
 
 336 
 322 
 309 
 295 
 279 
 
 264 
 
 249 
 222 
 215 
 198 
 
 300 
 
 275 
 250 
 225 
 200 
 
 540 
 509 
 477 
 445 
 410 
 
 522 
 492 
 460 
 430 
 399 
 
 428 
 404 
 378 
 351 
 324 
 
 415 
 392 
 367 
 343 
 316 
 
 342 
 321 
 300 
 280 
 259 
 
 326 
 309 
 
 290 
 270 
 250 
 
 273 
 
 257 
 240 
 223 
 205 
 
 175 373 
 150 1 334 
 125 II 295 
 100 1 254 
 90 l| 236 
 
 365 
 329 
 290 
 248 
 230 
 
 296 
 267 
 235 
 
 202 
 
 186 
 
 289 
 258 
 226 
 193 
 178 
 
 235 
 211 
 
 185 
 157 
 145 
 
 227 
 202 
 177 
 152 
 140 
 
 IN, 
 166 
 145 
 123 
 114 
 
 180 
 161 
 144 
 120 
 111 
 
 102~ 
 91 
 80 
 70 
 59 
 
 ~~45~ 
 30 
 14 
 
 80 
 70 
 60 
 50 
 40 
 
 216 
 198 
 177 
 155 
 130 
 
 212 
 192 
 170* 
 147 
 124 
 
 171 
 155 
 137 
 119 
 100 
 
 164 
 150 
 132 
 115 
 96 
 
 132 
 
 120 
 107 
 92 
 
 77 
 
 128 
 116 
 104 
 87 
 73 
 
 104 
 94 
 83 
 72 
 62 
 
 30 
 20 
 10 
 
 104 
 73 
 40 
 
 100 
 70 
 38 
 
 78 
 54 
 
 27 
 
 75 
 53 
 26 
 
 61 
 
 43 
 20 
 
 58 
 40 
 18 
 
 50 
 
 34 
 16 

 
 JOHN A. ROEBLING'S SONS co. 47 
 
 SPANS. 
 
 THE formulae used in calculating these tables of 
 lengths and strains in spans of wire are those 
 of a catenary of small deflection. They are given in 
 Weisbach's Mechanics of Engineering, page 297, (seventh 
 American edition, translated by Eckley B. Coxe, A. M.) 
 
 In these tables the horizontal strain at the center of 
 the span is given. The strain at any other point equals 
 the strain at the center plus the weight of a length of 
 the wire equal to the perpendicular distance of that 
 point from the lowest point of the wire in the span. 
 For ordinary spans this is negligible. For any given 
 wire the longest possible span is one where the deflec- 
 tion is about one-third of the span. 
 
 The effects of temperature on the strains of wires in 
 spans is at first sight so great as to render the other con- 
 siderations of little importance. The table, page 53, is 
 calculated on the assumption that the supports of the 
 spans are perfectly rigid under all conditions of strain 
 and that the wire is inelastic. This is never true in 
 practice. The changes in direction in a pole line afford 
 a chance for the strains, due to a shortening of the wire 
 by a fall in temperature, to be taken up by a bending of 
 the supports. 
 
 If the elastic limit of hard-drawn copper wire of 
 60 000 pounds breaking strain be taken at 20 000 pounds, 
 then S will equal 20 000 divided by 3.85, the weight of a ' 
 piece of copper one foot long and one square inch in 
 section. This makes S equal 5 195. Looking at the 
 table of values of S, page 50, this value for a span of 130 
 feet comes between a deflection of .003 and .004. In the 
 same way the allowable deflection for any other span of 
 hard-drawn copper could be found or for any other 
 material by substituting the proper terms for the elastic 
 limit and the weight per foot given above.
 
 48 
 
 JOHN A. ROEBLING S SONS CO. 
 
 The following gives the practice of some of the tele- 
 graph and telephone companies in their line construc- 
 tion : 
 
 SPECIFICATIONS FOR STANDARD 
 CONSTRUCTION OF HARD-DRAWN COPPER. 
 
 erature 
 degrees 
 renheit. 
 
 30 
 
 10 
 
 10 
 
 30 
 
 Spans in feet. 
 
 Sag in inches. 
 
 ft 
 
 9 
 
 j* 
 
 For spans between 400 and 600 feet, the dip shall be 
 l-40th of the span. 
 
 For spans between 600 and 1 000 feet, the dip shall be 
 l-30th of the span. 
 
 Another company uses 40 poles to the mile, and in the 
 East allows three-inch dip at center of spans. In the 
 West, where the variation of temperature is greater, 10 
 inches dip is allowed in summer, and 8 inches in the 
 winter. This construction applies to both copper and 
 iron wire, and has been found by actual experience to 
 give satisfactory results. 
 
 The following formulae were used in calculating the 
 tables : 
 
 (1) S X W = horizontal strain on wire at center of span 
 
 (2)
 
 _ 349 _ 
 
 JOHN A. ROEBLING'S SONS co. 49 
 
 In these formulae 
 
 y = one-half span. 
 1 = one-half length of wire in span. 
 x = deflection at center in same units as y. 
 w = weight per foot of wire. 
 
 Suppose we have a span of 200 feet of hard-drawn cop- 
 per wire weighing one pound to 10 feet, and a deflection 
 of two feet or .01 of the span. 
 
 (2) 
 
 (.1, 
 
 In calculating the table, page 53, the deflection of the 
 line was determined at 10 F. by formula 4, the value 
 of S being 30 000 divided by 3.85 or 7 792. For the other 
 temperatures the length of the wire was calculated from 
 the following formula: 
 
 Length = 1 (l + .000 009 3 1). 
 
 Here t is the difference in temperature in degrees 
 Fahrenheit. 
 
 By formula 5 the deflection corresponding to the new 
 length was found. 
 
 The coefficients of linear expansion for each degree 
 Fahrenheit are as follows : 
 
 Copper, .0000093. 
 Iron, .000 006 8. 
 Lead, .000 016.
 
 50 
 
 JOHN A. ROEBLING'S SONS co. 
 
 
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 JOHN A. ROEBLING'S SONS co. 53 
 
 TEMPERATURE EFFECTS IN SPANS. 
 
 
 
 Temperature in degrees Fahrenheit. 
 
 Spans in 
 fVet. 
 
 -10 
 
 30 
 
 40 
 
 50 
 
 60 
 
 70 
 
 80 
 
 90 
 
 100 
 
 
 Deflections in inches. 
 
 50 
 
 .5 
 
 6 
 
 8 
 
 9 
 
 9 
 
 10 
 
 11 
 
 11 
 
 12 
 
 no 
 
 .7 
 
 8 
 
 10 
 
 11 
 
 11 
 
 12 
 
 13 
 
 13 
 
 14 
 
 70 
 
 1. 
 
 10 
 
 11 
 
 12 
 
 13 
 
 14 
 
 15 
 
 15 
 
 17 
 
 80 
 
 1.2 
 
 11 
 
 13 
 
 14 
 
 15 
 
 16 
 
 17 
 
 18 
 
 19 
 
 90 
 
 1.6 
 
 13 
 
 14 
 
 16 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 100 
 
 1.9 
 
 14 
 
 16 
 
 17 
 
 19 
 
 20 
 
 21 
 
 23 
 
 24 
 
 110 
 
 2.3 
 
 16 
 
 18 
 
 19 
 
 21 
 
 22 
 
 24 
 
 25 
 
 26 
 
 120 
 
 2.8 
 
 17 
 
 19 
 
 21 
 
 22 
 
 24 
 
 26 
 
 27 
 
 28 
 
 130 
 
 3.2 
 
 19 
 
 a 
 
 23 
 
 25 
 
 26 
 
 28 
 
 29 
 
 31 
 
 140 
 
 8.7 
 
 20 
 
 23 
 
 25 
 
 27 
 
 28 
 
 30 
 
 32 
 
 33 
 
 10 
 
 4.8 
 
 22 
 
 24 
 
 26 
 
 28 
 
 30 
 
 32 
 
 34 
 
 36 
 
 160 
 
 4.9 
 
 23 
 
 26 
 
 28 
 
 30 
 
 32 
 
 34 
 
 36 
 
 38 
 
 170 
 
 5.5 
 
 25 
 
 28 
 
 30 
 
 32 
 
 35 
 
 37 
 
 38 
 
 40 
 
 180 
 
 6.2 
 
 26 
 
 29 
 
 32 
 
 34 
 
 37 
 
 39 
 
 41 
 
 43 
 
 190 
 
 7. 
 
 28 
 
 31 
 
 34 
 
 36 
 
 39 
 
 41 
 
 43 
 
 45 
 
 200 
 
 7.7 
 
 31 
 
 33 
 
 36 
 
 38 
 
 41 
 
 43 
 
 45 
 
 48 
 
 Hard-drawn copper wire, 60 000 pounds strength per 
 
 square inch. 
 
 Strain 
 
 at 10 F., 30000 pounds per square inch.
 
 54 JOHN A. ROEBLING'S SONS co. 
 
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 JOHN A. HOBBLING S SONS CO. 
 
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 JOHN A. ROEBLING'S SONS co. 
 
 WEATHERPROOF WIRE. 
 
 Our Weatherproof wire is put on reels in long lengths, 
 and has a hard, smooth finish, presenting the least pos- 
 sible chance for adherence of ice and snow. We keep in 
 stock all sizes given in the accompanying table, to 000 
 B. & S., in both double and triple braid. 
 
 In the Stranded wires, we keep only the most com- 
 monly used sizes. We make this Feed Wire Strand 
 either concentric or cable-laid, as desired. 
 
 FIRE AND WEATHERPROOF WIRE. 
 
 For interior work, we manufacture a Fire and Weather- 
 proof insulation. Full information concerning weights, 
 diameters and prices furnished on application. 
 
 UNDERWRITERS' WIRE. 
 
 Underwriters' wire seems to be used chiefly for inside 
 work. Its weight is about the same as double-braid 
 Weatherproof. 
 
 WEATHERPROOF IRON WIRE. 
 
 We keep in stock 10, 12 and 14 B. W. G., both double 
 and triple braid. 
 
 Numbers, 
 B. W. G. 
 
 Weights per mile. 
 Pounds. 
 
 Lengths in 
 coils. 
 Miles. 
 
 Double braid. 
 
 Triple braid. 
 
 4 
 6 
 8 
 9 
 
 10 
 
 12 
 14 
 
 997 
 713 
 483 
 403 
 
 1102 
 773 
 548 
 
 464 
 
 | 
 
 350 
 240 
 150 
 
 410 
 
 265 
 176 
 
 | 
 
 y*
 
 JOHN A. ROEBLING'S 
 
 SONS CO. 
 
 57 
 
 WEATHERPROOF 
 
 WIRE. 
 
 
 .6 
 
 BGG 
 
 t 
 
 Double braid. 
 
 Triple braid. 
 
 Approxi- 
 mate 
 weights. 
 Pounds. 
 
 Outside 
 diameters 
 in 32ds 
 inch. 
 
 Weights. 
 Pounds. 
 
 Ouiside 
 diameters 
 in 32ds 
 inch. 
 
 Weights. 
 Pounds. 
 
 1000 
 feet. 
 
 Mile. 
 
 1000 
 feet. 
 
 Mile. 
 
 Reel. 
 
 Coil. 
 
 0000 
 000 
 00 
 
 20 
 18 
 17 
 16 
 15 
 
 716 
 575 
 
 465 
 375 
 285 
 
 3781 
 3036 
 2455 
 1980 
 1505 
 
 24 
 22 
 18 
 17 
 16 
 
 775 
 630 
 490 
 400 
 306 
 
 4092 
 3326 
 2587 
 2112 
 1616 
 
 2000 
 2000 
 500 
 500 
 500 
 
 250 
 250 
 250 
 250 
 250 
 
 250 
 250 
 125 
 130 
 140 
 
 2 
 
 5 
 6 
 
 14 
 13 
 11 
 10 
 9 
 
 245 
 190 
 152 
 120 
 98 
 
 1294 
 1003 
 803 
 634 
 518 
 
 15 
 14 
 12 
 11 
 10 
 
 268 
 210 
 164 
 145 
 112 
 
 1415 
 1109 
 
 766 
 591 
 
 500 
 500 
 
 250 
 260 
 275 
 
 10 
 12 
 
 u 
 u 
 
 8 
 7 
 6 
 5 
 . 4 
 
 66 
 45 
 30 
 20 
 14 
 
 349 
 238 
 158 
 106 
 
 74 
 
 9 
 
 g 
 7 
 6 
 5 
 
 78 
 55 
 35 
 26 
 20 
 
 412 
 290 
 185 
 137 
 106 
 
 200 
 200 
 
 100 
 100 
 25 
 25 
 25 
 
 25 
 
 18 
 
 3 
 
 10 
 
 
 53 4 
 
 16 
 
 85 
 
 
 
 STRANDED WEATHERPROOF FEED WIRE. 
 
 Circular 
 mils. 
 
 Outside 
 diameters. 
 Inches. 
 
 Weights. 
 Pounds. 
 
 Approxi- 
 mate 
 length 
 on reels. 
 Feet. 
 
 1 000 feet. 
 
 Mile. 
 
 1000000 
 900000 
 800000 
 750000 
 700000 
 
 1 
 
 3550 
 3215 
 2880 
 2713 
 2545 
 
 18744 
 16975 
 15206 
 14325 
 13438 
 
 800 
 800 
 850 
 850 
 900 
 
 650000 
 600000 
 550000 
 500000 
 450000 
 
 1 
 
 2378 
 2210 
 2043 
 1875 
 1703 
 
 12556 
 11668 
 10787 
 9900 
 8992 
 
 i'OO 
 1000 
 1 200 
 1320 
 1400 
 
 400000 
 350000 
 300 000 
 250 000 
 
 I 1 
 
 ii 
 
 
 1530 
 1358 
 1 J85 
 1012 
 
 
 8078 
 7170 
 6257 
 
 1450 
 1 500 
 1600 
 1600 
 
 The table is calculated for concentric strands. Rope-laid strands 
 are larger.
 
 58 JOHN A. ROEBLING'S SONS co. 
 
 RUBBER WIRE. 
 
 WE MANUFACTURE rubber insulated wires for all 
 purposes, including wires and cables for aerial, 
 underground, and submarine use. The copper conductor 
 is tinned, and then covered with a cement of pure 
 rubber, which causes the succeeding coat of rubber to 
 adhere firmly to the wire. This layer consists of white 
 rubber without sulphur. Over this is a layer of vulcan- 
 ized rubber, and the whole is covered with a finishing 
 braid of cotton saturated with a Weatherproof com- 
 pound, which protects the rubber from mechanical in- 
 jury, and from the action of the air. A poor quality of 
 rubber insulation is inferior to Weatherproof, and we 
 would recommend our Fire and Weatherproof insulation 
 for inside work, rather than an inferior rubber wire. 
 
 A good rubber wire should have its conductor central, 
 the insulation should adhere firmly to the wire, it should 
 not crack or become brittle after use, and it should show, 
 after immersion in water for twenty-four hours, the same 
 insulation resistance per mile as when tested after being 
 first put in water. The absolute number of megohms 
 per mile depends on the age of the rubber used, together 
 with other details of manufacture, and is not always a 
 sure guide to the quality of the insulation. Uniformity 
 of insulation among several coils of wire made at the 
 same time, or among the various conductors of a cable, 
 is a much more valuable aid in detecting a poor piece of 
 wire, as in this case an insulation lower than the average 
 shows a local defect, which, in time, will be likely to 
 cause trouble.
 
 JOHN A. ROEBLING'S SONS co. 59 
 
 CRESCENT RUBBER WIRE 
 
 Stranded conductors. 
 
 Num- 
 bers, 
 B. & S. G. 
 
 Circular 
 mils. 
 
 Outside 
 diam- 
 eters. 
 Inches. 
 
 Weights 
 per 1 000 
 feet. 
 Pounds. 
 
 Sizes of wires in 
 strands. B. & 8. G. 
 
 Regular. 
 
 Flexible. 
 
 ::::::: 
 
 1000000 
 900000 
 800000 
 700000 
 600000 
 
 1* 
 
 IH 
 i* 
 i* 
 i* 
 
 3690 
 3370 
 3020 
 2685 
 2345 
 
 8 
 8 
 8 
 10 
 10 
 
 12 
 12 
 12 
 12 
 12 
 
 :::: 
 
 500000 
 450000 
 400000 
 350000 
 300000 
 
 1A 
 I* 
 
 i 
 
 * 
 % 
 
 1885 
 1723 
 1560 
 1378 
 1155 
 
 10 
 10 
 10 
 10 
 10 
 
 14 
 14 
 14 
 14 
 14 
 
 0000 
 
 000 
 00 
 
 250000 
 
 H 
 H 
 
 9 
 H 
 
 995 
 866 
 725 
 613 
 
 10 
 10 
 10 
 
 11 
 
 14 
 15 
 15 
 15 
 
 
 Numbers, 
 B. & S. G. 
 
 Outside diameters in 
 32ds of an inch. 
 
 Weights 
 per 1000 
 feet. 
 Pounds. 
 
 Sizes of wirps in 
 strand. B. & S. G. 
 
 Solid. 
 
 Stranded. 
 
 Regular. 
 
 Flexible. 
 
 
 1 
 2 
 3 
 
 18 
 16 
 14 
 13 
 12 
 
 20 
 18 
 15 
 14 
 13 
 
 393 
 309 
 
 244 
 198 
 
 12 
 12 
 12 
 13 
 14 
 
 16 
 16 
 18 
 18 
 20 
 
 5 
 
 ! 
 
 10 
 12 
 
 11 
 10 
 9 
 8 
 7 
 
 12 
 11 
 10 
 8 
 7 
 
 168 
 146 
 106 
 77 
 55 
 
 15 
 16 
 18 
 20 
 20 
 
 20 
 20 
 22 
 25 
 25 
 
 14 
 16 
 18 
 
 6 
 
 5 
 4 
 
 6 
 5 
 4 
 
 85 
 
 25 
 20 
 
 21 
 23 
 25 
 
 25 
 25 
 25 

 
 JOHN A. HOBBLING S SONS CO. 
 
 MAGNET WIRE. 
 
 THE BARE COPPER intended for Magnet wire is 
 specially drawn and annealed, great care being 
 taken to have it true to gauge, and soft. 
 
 A difference from the standard, of one mil, is allowed 
 on sizes larger than No. 10 B. & S. G. ; from No. 10 to 
 No. 14, three-fourths of a mil variation is allowed, and 
 any wire smaller than No. 14, one-half a mil variation is 
 allowed. 
 
 The insulation is smooth and uniform, and is kept 
 true to gauge to within one mil of the required 
 diameter. 
 
 We manufacture any special kind of Magnet wire 
 required, flats, squares and strands. 
 
 We understand that a No. 6 B. & R. square Magnet 
 wire measures 162x162 mils. 
 
 Flats are designated by their width and thickness. 
 Thus a flat Magnet wire 340 mils wide and 40 mils thick 
 would be designated as a 340x40 flat Magnet wire. 
 
 Strands can be furnished of any size, insulated with 
 double or triple windings of cotton, or any combination 
 of braids and windings that may be desired.
 
 JOHN A. ROEBLING'S SONS co. 61 
 
 MAGNET WIEE. 
 
 Numbers, 
 B. & S. G. 
 
 Diameter 
 drawn. 
 Mils. 
 
 Outside diameters. 
 Mils. 
 
 Approxi- 
 mate 
 weights on 
 reels. 
 
 
 
 
 
 Double. 
 
 Single. 
 
 Pounds. 
 
 
 
 325 
 
 343 
 
 337 
 
 200 
 
 1 
 
 289 
 
 307 
 
 301 
 
 200 
 
 2 
 
 258 
 
 276 
 
 270 
 
 200 
 
 3 
 
 229 
 
 247 
 
 241 
 
 200 
 
 4 
 
 204 
 
 222 
 
 216 
 
 200 
 
 5 
 
 182 
 
 200 
 
 194 
 
 200 
 
 6 
 
 162 
 
 178 
 
 172 
 
 200 
 
 7 
 
 144 
 
 160 
 
 154 
 
 200 
 
 8 
 
 128 
 
 142 
 
 137 
 
 200 
 
 9 
 
 114 
 
 126 
 
 122 
 
 200 
 
 10 
 
 102 
 
 112 
 
 108 
 
 200 
 
 11 
 
 91 
 
 101 
 
 97 
 
 200 
 
 12 
 
 81 
 
 91 
 
 87 
 
 200 
 
 13 
 
 72 
 
 81 
 
 78 
 
 160 
 
 14 
 
 64 
 
 73 
 
 70 
 
 160 
 
 15 
 
 57 
 
 66 
 
 63 
 
 50 
 
 16 
 
 51 
 
 60 
 
 57 
 
 50 
 
 17 
 
 45 
 
 54 
 
 51 
 
 50 
 
 18 
 
 40 
 
 49 46 
 
 50 
 
 19 
 
 36 
 
 45 
 
 42 
 
 50 

 
 62 
 
 JOHN A. ROEBLING'S SONS co. 
 
 GERMAN SILVER WIRE. 
 
 Numbers, 
 B. & S. G. 
 
 Resistance per 1 000 
 feet. 
 
 CJ 
 CaJ 
 
 t 
 
 Resistance per 1 000 
 feet 
 
 18 per 
 centum. 
 
 30 per 
 centum. 
 
 18 per 
 centum. 
 
 30 per 
 centum. 
 
 6 
 7 
 8 
 9 
 10 
 
 7.20 
 9.12 
 11.54 
 14.55 
 1&18 
 
 11.21 
 14.18 
 17.95 
 22.63 
 28.28 
 
 22 
 23 
 24 
 25 
 26 
 
 295.38 
 370.26 
 468.18 
 590.22 
 748.08 
 
 459.48 
 575.96 
 728.28 
 918.12 
 1163.68 
 
 11 
 
 12 
 13 
 14 
 15 
 
 22.84 
 28.81 
 36.48 
 46.17 
 58.21 
 
 35.53 
 44.82 
 56.75 
 71.82 
 90.55 
 
 27 
 28 
 29 
 30 
 31 
 
 937.98 
 1 191.24 
 1481.22 
 1 891.8 
 2388.6 
 
 1459.08 
 1853.04 
 2 304.12 
 2942.8 
 3 715.6 
 
 16 
 
 17 
 18 
 19 
 20 
 
 72.72 
 93.40 
 118.20 
 145.94 
 184.68 
 
 113.12 
 145.29 
 183.87 
 227.02 
 287.28 
 
 32 
 33 
 34 
 35 
 36 
 
 2955.6 
 3 751.2 
 4764.6 
 6 031.8 
 7565.4 
 
 4 597.6 
 5835.2 
 7 411.6 
 9382.8 
 11 768.4 
 
 21 
 
 232.92 
 
 362.32 
 
 
 
 
 The resistance of German silver wire varies according 
 to the method of manufacture and the materials used. 
 
 From actual tests on wire with eighteen per centum of 
 nickel, extending over ten years, it seems that eighteen 
 times the resistance of copper, at 75 F., represents very 
 closely the resistance of this alloy. This value is rather 
 under than over the average results of the tests. 
 
 For the thirty per centum alloy, we have to depend on 
 the results of a single series of tests, and while the results 
 are believed to be correct, they are not as reliable as 
 those given for the eighteen per centum German silver 
 wire. We take the resistance of the thirty per centum 
 alloy at twenty-eight times the resistance of copper, at 
 75. 
 
 The International ohm is taken as the unit of resist-
 
 JOHN A. ROEBLING S SONS CO. 
 
 OFFICE WIRES. 
 
 Office wire is usually made with a wind and a braid of cotton 
 saturated with paraffine. It is sometimes required with a 
 double braid or triple braid of cotton. The most common 
 colors are red and white. Any combination of colors dan be 
 furnished. 
 
 Damp-proof Office wire has the inside wind saturated with 
 black Weatherproof compound, while the outside finish is the 
 same as ordinary Office wire. 
 
 Annunciator wire has a covering consisting of two wraps of 
 cotton saturated with paraffine. The outer covering is made 
 in solid colors or combination of two colors. - 
 
 Double conductors for house wiring are of various kinds. 
 
 Two conductors twisted together, without any outside cover, 
 form a convenient method of wiring for bells, telephones, etc. 
 These conductors maybe 18 B. & S., with double braid Weather- 
 proof or with Annunciator insulation. 
 
 Two-conductor Office wire may be two Office wires laid side 
 by side and covered with a two-colored Office braid, or it may 
 consist of two Annunciator wires so insulated. 
 
 Weatherproof cables consist of 18 B. & S. G. Annunciator 
 wires, twisted into a cable and covered with rubber tape and a 
 braid of cotton saturated with Weatherproof insulation. They 
 weigh about ten pounds per 1 000 feet per conductor. For work 
 inside building, in dry places, the rubber tape may be omitted, 
 and the finishing braid made any color to correspond with the 
 woodwork. 
 
 Lamp cord is furnished in silk or cotton insulation. Green 
 and yellow is the standard color combination. 
 
 Numbers, 
 B. & 8. G. 
 
 Weights per 1 000 feet. 
 
 Sizes of Lamp cord. 
 
 Office 
 wire. 
 
 Annunciator 
 wire. 
 
 Silk. 
 
 Cotton. 
 
 14 
 
 Ifr 
 18 
 20 
 
 17 
 12 
 9 
 7 
 
 15 
 10 
 7 
 *X 
 
 X 
 
 S 
 
 y 
 
 A 
 
 I 
 
 A
 
 64 JOHN A. ROEBLING'S SONS co. 
 
 POWER CABLES. 
 
 WE MANUFACTURE power and electric-light 
 cables, with jute, paper or rubber insulation. 
 The thickness and kind of insulation depend on the use 
 for which the cable is intended. The table of diameters 
 and weights is based on T \ insulation on a side, and is 
 approximately correct for any kind of insulation. 
 
 Specifications for Underground Cable of 600 000 C. M. 
 
 1. COPPER CONDUCTOR. 
 
 The conductor shall consist of 47 wires, each 104 mils in 
 diameter, and shall weigh not less than 1.525 pounds per foot. 
 The copper used shall have a conductivity of not less than 98 
 per cent. 
 
 2. INSULATION. 
 
 The insulation shall consist of paper not less than / 8 thick, 
 and shall form a wall of uniform thickness around the con- 
 ductor. 
 
 3. SHEATH. 
 
 The insulated conductor shall be enclosed in a pipe composed 
 of lead and tin. The amount of tin shall not be less than 2.9 
 per cent. The pipe shall be formed around the core, and shall 
 be free from holes or other defects, and of uniform thickness 
 and composition. 
 
 4. INSULATION RESISTANCE. 
 
 The insulation resistance shall be not less than 300 megohms 
 per mile, at 60 F.
 
 JOHN A. ROEBLING'S SONS co. 
 
 65 
 
 POWER CABLES. 
 
 
 
 Outside 
 
 Weights, 
 
 Numbers, 
 B. & 8. G. 
 
 Circular mils. 
 
 diameters. 
 Inches. 
 
 1 000 feet. 
 Pounds. 
 
 
 
 1000000 
 
 1 
 
 6685 
 
 
 
 900000 
 
 m 
 
 6228 
 
 
 800000 
 
 i& 
 
 5773 
 
 
 
 750000 
 
 1% 
 
 5543 
 
 
 
 700000 
 
 m 
 
 5315 
 
 
 
 650000 
 
 i* 
 
 5088 
 
 
 600000 
 
 in 
 
 4857 
 
 
 
 550000 
 
 m 
 
 4630 
 
 
 
 500000 
 
 t& 
 
 4278 
 
 
 
 450000 
 
 1% 
 
 3923 
 
 
 400000 
 
 i 
 
 3619 
 
 
 
 350000 
 
 IA 
 
 3416 
 
 
 
 300000 
 
 15* 
 
 3060 
 
 
 
 250000 
 
 ift 
 
 2732 
 
 0000 
 
 211600 
 
 IA 
 
 2533 
 
 000 
 
 168100 
 
 IA 
 
 2300 
 
 00 
 
 133225 
 
 i 
 
 2021 
 
 
 
 105 625 
 
 u 
 
 1772 
 
 1 
 
 83521 
 
 i 
 
 1633 
 
 2 
 
 66564 
 
 % 
 
 1482 
 
 3 
 
 52441 
 
 u 
 
 1360 
 
 4 
 
 41 616 
 
 % 
 
 1251 
 
 6 
 
 26244 
 
 H 
 
 1046
 
 JOHN A. ROEBLING'S SONS co. 
 
 TELEPHONE CABLES. 
 
 Lead-encased for underground or aerial use. 
 
 THE INSULATION of these cables is dry paper. 
 We manufacture several styles of 19 B. & S. G., 20 
 B. & S. G., and 22 B. & S. G., according to the use for 
 which they are intended. The most common size is 19 
 B. & S. G. We also supply terminals and hangers. To 
 determine the size supporting strand to use with these 
 cables, consult tables page 39. 
 
 Specifications for Telephone Cables. 
 
 1. CONDUCTORS. 
 
 Each conductor shall be .035 89 inches in diameter, (19 B. & S. 
 G.,) and have a conductivity of 98 per cent, of that of pure 
 soft copper. 
 
 2. CORE. 
 
 The conductor shall be insulated, twisted in pairs, the length 
 of the twist not to exceed three inches, and formed into a core 
 arranged in reverse layers. 
 
 3. SHEATH. 
 
 The core shall be enclosed in a pipe composed of lead and 
 tin, the amount of the tin shall be not less than 2A per cent. 
 The pipe shall be formed around the core, and shall be free 
 from holes or other defects, and of uniform thickness and 
 composition. 
 
 4. ELECTROSTATIC CAPACITY. 
 
 The average electrostatic capacity shall not exceed .080 of a 
 microfarad per mile, each wire being measured against all the 
 rest and a sheath grounded ; the electrostatic capacity of any 
 wires so measured shall not exceed .085 of a microfarad per 
 mile. 
 
 5. INSULATION RESISTANCE. 
 
 Each wire shall show an insulation of not less than 500 meg- 
 ohms per mile, at 60 F., when laid, spliced and connected to 
 terminal ready for use ; each wire being measured against all 
 the rest and sheath grounded. 
 
 6. CONDUCTOR RESISTANCE. 
 
 Each conductor shall have a resistance of not more than 47 
 B. A. ohms, at 60 F., for each mile of cable, after the cable is 
 laid and connected to the terminals.
 
 JOHN A. ROEBLING'S SONS co. 67 
 
 TELEPHONE CABLES. 
 
 Number pairs. 
 
 Outside diameters. 
 Inches. 
 
 Weights, 
 1 000 feet. 
 Pounds. 
 
 1 
 
 A 
 
 214 
 
 2 
 
 % 
 
 302 
 
 3 
 
 % 
 
 515 
 
 4 
 
 , 9 S 
 
 629 
 
 5 
 
 % 
 
 747 
 
 6 
 
 Si 
 
 877 
 
 7 
 
 H 
 
 912 
 
 10 
 
 H 
 
 1214 
 
 12 
 
 H 
 
 1375 
 
 15 
 
 i 
 
 1566 
 
 18 
 
 1A 
 
 1758 
 
 20 
 
 i 
 
 1940 
 
 25 
 
 i* 
 
 2332 
 
 30 
 
 i* 
 
 2748 
 
 35 
 
 13* 
 
 2985 
 
 40 
 
 1A 
 
 3176 
 
 45 
 
 1% 
 
 3365 
 
 50 
 
 1% 
 
 3678 
 
 55 
 
 i 
 
 3867 
 
 60 
 
 1% 
 
 4055 
 
 65 
 
 1H 
 
 4241 
 
 70 
 
 2 
 
 4430 
 
 80 
 
 2^ 
 
 4804 
 
 90 
 
 2J4 
 
 5180 
 
 100 
 
 2% 
 
 5505 

 
 JOHN A. ROEBLING'S SONS co. 
 
 TELEGRAPH CABLES. 
 
 Lead-encased for underground use. 
 
 THESE cables are made of either rubber, cotton or 
 paper insulation. The sizes and weights are ap- 
 proximately correct for rubber and cotton insulation. 
 Both sizes and weights are slightly reduced for paper 
 insulation. In all cases the cables are lead-encased. 
 
 Specifications for Telegraph Cables. 
 
 1. CONDUCTORS. 
 
 Each conductor shall be .064 inches in diameter, (14 B. & S. 
 G.,) and have a conductivity of 98 per cent, of that of pure 
 copper. 
 
 2. CORE. 
 
 The conductors shall be insulated to & with cotton, and 
 formed into a core arranged in reverse layers. This core shall 
 be dried and saturated with approved insulating compound. 
 
 3. SHEATH. 
 
 The core shall be enclosed in a pipe composed of lead and 
 tin. The amount of tin shall not be less than 2.9 per cent. 
 The pipe shall be formed around the core, and shall be free 
 from holes or other defects, and of uniform thickness and 
 composition. 
 
 4. INSULATION RESISTANCE. 
 
 The wire shall show an insulation of not less than 300 meg- 
 ohms per mile, at 60 F., when laid, spliced and connected to 
 terminals ready for use, each wire being measured against all 
 the rest and the sheath grounded. 
 
 5. CONDUCTOR RESISTANCE. 
 
 Each conductor shall have a resistance of not more than 28 
 International ohms, at 60 F., for each mile of cable, after the 
 cable is laid and connected up to the terminals.
 
 JOHN A. ROEBLING'S SONS co. 69 
 
 TELEGRAPH CABLES. 
 
 Number 
 conductors. 
 
 14 B. & S. G. 
 Insulated to & 
 
 16 B. & 8. G. 
 Insulated to ,&. 
 
 18 B. & 8. G. 
 Insulated to A- 
 
 Outside 
 diameters. 
 Inches. 
 
 jj 
 
 Outside 
 diameters. 
 Inches. 
 
 lj 
 
 ^ 
 
 Outside 
 diameters. 
 Inches. 
 
 !l 
 
 t~ 
 
 1 
 2 
 3 
 4 
 5 
 
 % 
 A 
 
 X 
 
 % 
 % 
 
 308 
 438 
 573 
 810 
 972 
 
 % 
 
 A 
 
 K 
 
 A 
 % 
 
 299 
 421 
 546 
 670 
 793 
 
 % 
 M 
 
 l' S 
 
 M 
 % 
 
 291 
 356 
 421 
 486 
 551 
 
 6 
 7 
 10 
 12 
 15 
 
 u 
 
 % 
 
 a 
 
 iA 
 1A 
 
 1132 
 1295 
 1512 
 1873 
 2263 
 
 ft 
 % 
 H 
 % 
 tt 
 
 946 
 
 965 
 1155 
 1327 
 1518 
 
 if 
 
 A 
 % 
 % 
 il 
 
 616 
 
 681 
 820 
 978 
 1148 
 
 18 
 20 
 25 
 30 
 35 
 
 IK 
 
 1A 
 1* 
 1A 
 1ft 
 
 2523 
 2756 
 3250 
 3515 
 3910 
 
 1A 
 1% 
 1A 
 1% 
 1* 
 
 1880 
 2076 
 2496 
 2768 
 8040 
 
 % 
 ii 
 i 
 1A 
 1A 
 
 1318 
 1477 
 1690 
 1903 
 2116 
 
 40 
 45 
 50 
 55 
 60 
 
 1% 
 lii 
 
 m 
 
 2 
 2A 
 
 4175 
 4441 
 4835 
 5100 
 5365 
 
 S 
 
 1% 
 1 
 1% 
 
 3312 
 3533 
 3755 
 3978 
 
 4200 
 
 Vi 
 i& 
 1A 
 1% 
 1A 
 
 2330 
 2471 
 2628 
 2866 
 3104 
 
 65 
 70 
 80 
 90 
 100 
 
 2% 
 2-ft 
 2A 
 2A 
 2A 
 
 5631 
 5897 
 6408 
 6916 
 
 7375 
 
 lit 
 
 1% 
 
 2 
 2A 
 2% 
 
 4422 
 4644 
 5087 
 5402 
 5720 
 
 1H 
 
 IK 
 1% 
 liJ 
 1% 
 
 3245 
 3402 
 3798 
 4027 
 4275 

 
 70 JOHN A. ROEBLING'S SONS co. 
 
 AERIAL CABLES. 
 
 THESE cables are made from double-coated rubber 
 wire, taped. After standing, the cable is double- 
 taped and covered with tarred jute, over which is placed 
 a braid of heavy cotton saturated with Weatherproof 
 compound. This outside covering protects the rubber 
 from the action of the air and from mechanical injury. 
 The separate wires are tested in water, and no wire is 
 used which will not fully meet a water test. The result 
 is a cable which will work under water as well as on a 
 pole line, if there is no danger of mechanical injury. 
 The ordinary size for telegraphic work is 14 B & S., in- 
 sulated to ^V A trace wire can be placed in each layer, 
 if desired. 
 
 The size galvanized strand to support these cables may 
 be found from the table page 39. Suppose the span is 
 130 feet and a 10-conductor 14 B. & S. G. Aerial cable is 
 used, then from these tables it is seen a J-inch ordinary 
 galvanized strand will support a cable weighing 423 
 pounds per 1 000 feet, with a 130-foot span. 
 
 Specifications for 14 B. & S. Aerial Cable. 
 
 1. CONDUCTORS. 
 
 Each conductor shall be .064 inches in diameter, (14 B. & S. G.,) 
 and have a conductivity of 98 per cent, of that of pure copper. 
 
 2. CORE. 
 
 The conductors shall be insulated to ,& with rubber and tape, and 
 formed into a core arranged in reverse layers. 
 
 3. PROTECTIVE COVERING. 
 
 The core shall be covered with two wraps of friction tape and one 
 wrap of tarred jute. Over this there shall be a braid saturated with 
 Weatherproof compound. 
 
 4. INSULATION RESISTANCE. 
 
 Each wire shall show an insulation resistance of not less than 300 
 megohms per mile, at 60 F., after being immersed in water 24 hours. 
 This test shall be made on the core after all the conductors are laid 
 up, but before the outside coverings are put on. 
 
 5. CONDUCTOR RESISTANCE. 
 
 Each conductor shall have a resistance of not more than 28 Inter- 
 national ohms, at 60 F., for each mile of cable.
 
 JOHN A. ROEBLING'S SONS co. 71 
 
 AERIAL CABLES. 
 
 Rubber Insulation. 
 
 
 14 B. & 8. G. 
 
 16 B. & S. G. 
 
 18 B. & S. G. 
 
 
 Insulated to & 
 
 Insulated to &. 
 
 Insulated to &. 
 
 
 
 E 
 
 | 
 
 
 | 
 
 1 
 
 1 
 
 *|j 
 
 S S.3 
 
 *S 
 
 
 j|g 
 
 o 6.3 
 
 g* 
 
 l 
 
 m 
 
 I"* 
 
 ill 
 
 I 2 
 
 |ll 
 
 |! 
 
 2 
 
 % 
 
 102 
 
 % 
 
 92 
 
 y* 
 
 82 
 
 3 
 
 % 
 
 149 
 
 A 
 
 126 
 
 H 
 
 104 
 
 4 
 
 A 
 
 183 
 
 H 
 
 155 
 
 A 
 
 127 
 
 5 
 
 H 
 
 226 
 
 % 
 
 193 
 
 H 
 
 151 
 
 6 
 
 % 
 
 260 
 
 ii 
 
 222 
 
 A 
 
 175 
 
 7 
 
 if 
 
 297 
 
 % 
 
 251 
 
 K 
 
 200 
 
 10 
 
 H 
 
 401 
 
 % 
 
 335 
 
 ii 
 
 256 
 
 12 
 
 i 
 
 465 
 
 if 
 
 393 
 
 H 
 
 296 
 
 15 
 
 i% 
 
 563 
 
 i 
 
 468 
 
 H 
 
 355 
 
 18 
 
 1A 
 
 651 
 
 1A 
 
 541 
 
 % 
 
 413 
 
 20 
 
 1^ 
 
 714 
 
 iy B 
 
 593 
 
 H 
 
 452 
 
 25 
 
 1% 
 
 863 
 
 !A 
 
 708 
 
 ii 
 
 541 
 
 30 
 
 IT'S 
 
 1008 
 
 1% 
 
 824 
 
 i 
 
 633 
 
 35 
 
 1% 
 
 1147 
 
 1A 
 
 938 
 
 1A 
 
 723 
 
 40 
 
 1A 
 
 1268 
 
 1% 
 
 1053 
 
 1^ 
 
 813 
 
 45 
 
 1% 
 
 1431 
 
 iJi 
 
 1182 
 
 1A 
 
 903 
 
 50 
 
 1% j 1577 
 
 1% 
 
 1311 
 
 
 994 

 
 72 
 
 JOHN A. ROEBLING'S SONS co. 
 
 SUBMARINE CABLES. 
 
 Number 
 conductors. 
 
 Outside 
 diameters. 
 
 Armor wires. 
 
 Total weights. 
 Pounds. 
 
 Number 
 of wires. 
 
 Num- 
 bers, 
 B. W. G. 
 
 1 000 feet. 
 
 Mile. 
 
 1 
 2 
 3 
 4 
 
 % 
 
 1 
 V/s 
 
 1A 
 
 12 
 15 
 14 
 16 
 
 8 
 8 
 6 
 6 
 
 1260 
 1722 
 2363 
 2794 
 
 6600 
 9092 
 12477 
 14752 
 
 5 
 6 
 
 7 
 10 
 
 IT"* 
 l 
 IX 
 
 1% 
 
 16 
 16 
 16 
 18 
 
 6 
 
 4 
 4 
 3 
 
 2968 
 3822 
 3972 
 5404 
 
 15671 
 20180 
 20972 
 28533 
 
 The core consists of 7 X 22 B. & S. tinned copper wires, 
 insulated with rubber to /? of an inch, laid up with 
 proper jute bedding. 
 
 We are prepared to furnish telegraph cables with 
 gutta percha insulation. This is the best insulation for 
 submarine work, and its reliability and durability more 
 than make up the difference in cost between it and any 
 other insulation. 
 
 We are prepared to furnish submarine cables of any 
 description for use in electric lighting and street railway 
 work. 
 
 No list of these cables can be made, owing to the vary- 
 ing conditions to be met.
 
 JOHN A. ROEBLING S SONS CO. 
 
 73 
 
 THE COLUMBIA BAIL-BOND. 
 
 THE COLUMBIA BOND consists of three parts, two 
 copper thimbles and the 
 connecting copper rod. On 
 each end of this copper rod is 
 a truncated cone- 
 head with a fillet 
 at the base. The 
 inside of the 
 thimble is tapered 
 to fit the head on 
 the bond, while the 
 outside is slightly tapered in the opposite way. 
 
 In applying the bond, the cone-shaped heads are 
 placed in the holes in the rail from one side and the 
 thimbles are slipped over them from the other. 
 
 A portable hand-press is then applied, and the wedge- 
 shaped head of the bond is forced into the thimble so 
 that it is not possible to see the line separating the 
 thimble and the head in a cross-section of the two. 
 
 The end of the head of the bond is expanded by a 
 center-punch, held in position in the press. 
 
 When installed, owing to the pressure exerted between 
 the head and the thimble, and also to the fact that they 
 are of the same kind of metal, the two become one, both 
 electrically and mechanically. 
 
 The contact of rail and bond is made by a wedge 
 expanding the thimble against the hole in the rail, and, 
 as the bond is wedged both ways, it cannot get loose. 
 
 For a 000 B. & S. G. or 000 B. & S. G. bond, the holes 
 in the rail should be |-inch, and for a 00 B. & S. G. or a 
 B. & S. G. bond, f -inch. 
 
 The total length of a bond is 3 inches more than the 
 distance from center to center of holes in rails. The 
 total length of a bond should be 8 inches more than that 
 of the splice plate.
 
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