This section is from the book "Scientific American Reference Book. A Manual for the Office, Household and Shop", by Albert A. Hopkins, A. Russell Bond. Also available from Amazon: Scientific American Reference Book.
The resistances are calculated for pure copper wire.
The number of feet to the pound is only approximate for insulated wire.
No. | Feet per Pound. | Resistance, Naked Copper. | ||||||
Cotton Covered. | Silk Covered. | Naked. | Ohms per 1,000 Feet. | Ohms per Mile. | Feet per Ohm. | Ohms per Pound. | ||
8 | .12849 | 20 | .6259 | 3.3 | 1600 | .0125 | ||
9 | .11443 | 25 | .7892 | 4.1 | 1272 | .0197 | ||
10 | .10189 | 32 | .8441 | 4.4 | 1185 | .0270 | ||
11 | .09074 | 40 | 1.254 | 6.4 | 798 | .0501 | ||
12 | .08081 | 42 | 46 | 50 | 1.580 | 8.3 | 633 | .079 |
13 | .07196 | 55 | 60 | 64 | 1.995 | 10.4 | 504 | .127 |
14 | .06408 | 68 | 75 | 80 | 2.504 | 13.2 | 400 | .200 |
15 | .05707 | 87 | 95 | 101 | 3.172 | 16.7 | 316 | .320 |
16 | .05082 | 110 | 120 | 128 | 4.001 | 23 | 230 | .512 |
17 | .04525 | 140 | 150 | 161 | 5.04 | 26 | 198 | .811 |
18 | .0403 | 175 | 190 | 203 | 6.36 | 33 | 157 | 1.29 |
19 | .03539 | 220 | 240 | 256 | 8.25 | 43 | 121 | 2.11 |
20 | .03196 | 280 | 305 | 324 | 10.12 | 53 | 99 | 3.27 |
21 | .02846 | 360 | 390 | 408 | 12.76 | 68 | 76.5 | 5.20 |
22. | .02535 | 450 | 490 | 514 | 16.25 | 85 | 61.8 | 8.35 |
23 | .02257 | 560 | 615 | 649 | 20.30 | 108 | 48.9 | 13.3 |
24 | .0201 | 715 | 775 | 818 | 25.60 | 135 | 39.0 | 20.9 |
25 | .0179 | 910 | 990 | 1,030 | 32.2 | 170 | 31.0 | 33.2 |
26 | .01594 | 1,165 | 1,265 | 1,300 | 40.7 | 214 | 24.6 | 52.9 |
27 | .01419 | 1,445 | 1,570 | 1,640 | 51.3 | 270 | 19.5 | 84.2 |
28 | .01264 | 1,810 | 1,970 | 2,070 | 64.8 | 343 | 15.4 | 134 |
29 | .01126 | 2,280 | 2,480 | 2,617 | 81.6 | 432 | 12.2 | 213 |
30 | .01002 | 2,805 | 3,050 | 3,287 | 103 | 538 | 9.8 | 338 |
31 | .00893 | 3,605 | 3,920 | 4,144 | 130 | 685 | 7.7 | 539 |
32 | .00795 | 4,535 | 4,930 | 5,227 | 164 | 865 | 6.1 | 856 |
33 | .00708 | 6,200 | 6,590 | 206 | 1033 | 4.9 | 1357 | |
34 | .0063 | 7,830 | 8,330 | 260 | 1389 | 3.8 | 2166 | |
35 | .00561 | 9,830 | 10,460 | 328 | 1820 | 2.9 | 3521 | |
36 | .005 | ......... | 12,420 | 13,210 | 414 | 2200 | 2.4 | 5469 |
 
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