Explanation of Tables. In the first column are given the sizes of wires by numbers. The B & S or American gauge is used. In the table below is given a comparison between the B & S and the Birmingham gauges.
The second column gives the diameters of wires. The diameter of No. 36 wire is 5 thousandths of an inch; the diameter of No. 24 wire is a little over 20 thousandths or 2 hundredths of an inch.
The third column contains what is called circular mils, a mil being a thousandth of an inch. The figures in this column are obtained by squaring those in the second; thus, for No. 36 wire, 5 × 5 = 25. This column is useful when working examples where the squares of the diameters are wanted. The rest of the table explains itself.
The table at the bottom gives a comparison between the fractional and decimal parts of an inch. Space can not be given here for a series of examples showing the many uses of this table. (See "Elementary Electrical Examples.")
COPPER WIRE TABLES. (Based on the B. A. Unit.)
| Gauge | DIAMETER. | Sectional AREA | Capacity. | OHMS | ||
| B.&S. No. | In 1000ths | In Circular Mils. | In Amperes. | Per 1,000 feet. | Per Mile. | Per Pound. |
| 0000 | .460 | 211600. | 312. | .04906 | .25903 | .000077 |
| 000 | .40964 | 167805. | 262. | .06186 | .32664 | .00012 |
| 00 | .3648 | 133079. | 220. | .07801 | .41187 | .00019 |
| 0 | .32486 | 105534. | 185. | .09831 | .51909 | .00031 |
| 1 | .2893 | 83694. | 156. | .12404 | .65490 | .00049 |
| 2 | .25763 | 66373. | 131. | .15640 | .8258 | .00078 |
| 3 | .22942 | 52634. | 110. | .19723 | 1.0414 | .00125 |
| 4 | .20431 | 41743. | 92.3 | .24869 | 1.313 | .00198 |
| 5 | .18194 | 33102. | 77.6 | .31361 | 1.655 | .00314 |
| 6 | .16202 | 26251. | 65.2 | .39546 | 2.088 | .00499 |
| 7 | .14428 | 20817. | 54.8 | .49871 | 2.633 | .00792 |
| 8 | .12849 | 16510. | 46.1 | .6529 | 3.3 | .0125 |
| 9 | .11443 | 13094. | 38.7 | .7892 | 4.1 | .0197 |
| 10 | .10189 | 10382. | 32.5 | .8441 | 4.4 | .0270 |
| 11 | .090742 | 8234. | 27.3 | 1.254 | 6.4 | .0501 |
| 12 | .080808 | 6530. | 23. | 1.580 | 8.3 | .079 |
| 13 | .071961 | 5178. | 19.3 | 1.995 | 10.4 | .127 |
| 14 | .064084 | 4107. | 16.2 | 2.504 | 13.2 | .200 |
| 15 | .057068 | 3257. | 13.6 | 3.172 | 16.7 | .320 |
| 16 | .05082 | 2583. | 11.5 | 4.001 | 23. | .512 |
| 17 | .045257 | 2048. | 9.6 | 5.04 | 26. | .811 |
| 18 | .040303 | 1624. | 8.1 | 6.36 | 33. | 1.29 |
| 19 | .03589 | 1288. | .... | 8.25 | 43. | 2.11 |
| 20 | .031961 | 1021. | .... | 10.12 | 53. | 3.27 |
| 21 | .028462 | 810. | .... | 12.76 | 68. | 5.20 |
| 22 | .025347 | 642. | .... | 16.25 | 85. | 8.35 |
| 23 | .022571 | 509. | .... | 20.30 | 108. | 13.3 |
| 24 | .0201 | 404. | .... | 25.60 | 135. | 20.9 |
| 25 | .0179 | 320. | .... | 32.2 | 170. | 33.2 |
| 26 | .01594 | 254. | .... | 40.7 | 214. | 52.9 |
| 27 | .014195 | 201. | .... | 51.3 | 270. | 84.2 |
| 28 | .012641 | 159.8 | .... | 64.8 | 343. | 134. |
| 29 | .011257 | 126.7 | .... | 81.6 | 482. | 213. |
| 30 | .010025 | 100.5 | .... | 103. | 538. | 338. |
| 31 | .008928 | 79.7 | .... | 130. | 685. | 539. |
| 32 | .00795 | 63. | .... | 164. | 865. | 856. |
| 33 | .00708 | 50.1 | .... | 206. | 1033. | 1357. |
| 34 | .006304 | 39.74 | .... | 260. | 1389. | 2166. |
| 35 | .005614 | 31.5 | .... | 328. | 1820. | 3521. |
| 36 | .005 | 25. | .... | 414. | 2200. | 5469. |
| 37 | .004453 | 19.8 | .... | 523. | 2765. | 8742. |
| 38 | .003965 | 15.72 | .... | 660. | 3486. | 13772. |
| 39 | .003531 | 12.47 | .... | 832. | 4395. | 21896. |
| 40 | .003144 | 9.88 | .... | 1049 | 5542. | 34823. |
| Gauge | FEET. | POUNDS. | ||
| B.&S. No. | Per Pound. | Per Ohm. | Per 1,000 feet. | Per Ohm. |
| 0000 | 1.56122 | 20497.7 | 640.51 | 12987. |
| 000 | 1.9687 | 16255.27 | 507.95 | 8333. |
| 00 | 2.4824 | 12891.37 | 402.83 | 5263. |
| 0 | 3.1303 | 10223.08 | 319.45 | 3225. |
| 1 | 3.94714 | 8107.49 | 253.34 | 2041. |
| 2 | 4.97722 | 6429.58 | 200.91 | 1282. |
| 3 | 6.2765 | 5098.61 | 159.32 | 800. |
| 4 | 7.9141 | 4043.6 | 126.35 | 505. |
| 5 | 9.97983 | 3206.61 | 100.20 | 318. |
| 6 | 12.5847 | 2542.89 | 79.462 | 200. |
| 7 | 15.8696 | 2015.51 | 63.013 | 126. |
| 8 | 20.0097 | 1599.3 | 49.976 | 80. |
| 9 | 25.229 | 1268.44 | 39.636 | 50. |
| 10 | 31.8212 | 1055.66 | 31.426 | 37. |
| 11 | 40.1202 | 797.649 | 24.924 | 20. |
| 12 | 50.5906 | 632.555 | 19.766 | 12.65 |
| 13 | 63.7948 | 501.63 | 15.674 | 7.87 |
| 14 | 80.4415 | 397.822 | 12.435 | 5.00 |
| 15 | 101.4365 | 315.482 | 9.859 | 3.12 |
| 16 | 127.12 | 250.184 | 7.819 | 1.95 |
| 17 | 161.29 | 198.409 | 6.199 | 1.23 |
| 18 | 203.374 | 157.35 | 4.916 | .775 |
| 19 | 256.468 | 124.777 | 3.899 | .473 |
| 20 | 323.399 | 98.9533 | 3.094 | .305 |
| 21 | 407.815 | 78.473 | 2.452 | .192 |
| 22 | 514.193 | 62.236 | 1.945 | .119 |
| 23 | 648.452 | 49.3504 | 1.542 | .075 |
| 24 | 817.688 | 39.1365 | 1.223 | .047 |
| 25 | 1031.038 | 31.0381 | .9699 | .030 |
| 26 | 1300.180 | 24.6131 | .7692 | .0187 |
| 27 | 1639.49 | 19.5191 | .6099 | .0118 |
| 28 | 2067.364 | 15.4793 | .4837 | .0074 |
| 29 | 2606.959 | 12.2854 | .3835 | .0047 |
| 30 | 3287.084 | 9.7355 | .3002 | .0029 |
| 31 | 4414.49 | 7.72143 | .2413 | .0018 |
| 32 | 5226.915 | 6.12243 | .1913 | .0011 |
| 33 | 6590.41 | 4.85575 | .1517 | .00076 |
| 34 | 8312.8 | 3.84966 | .1204 | .00046 |
| 35 | 10481.77 | 3.05305 | .0956 | .00028 |
| 36 | 13214.16 | 2.4217 | .0757 | .00018 |
| 37 | 16659.97 | 1.92086 | .06003 | .00011 |
| 38 | 21013.25 | 1.52292 | .04758 | .00007 |
| 39 | 26496.237 | 1.20777 | .03755 | .00004 |
| 40 | 33420.63 | 0.97984 | .02992 | .000029 |
| Comparative Table of the Fractional and Decimal Parts of an Inch. | |
|---|---|
| 1/64 | = .015625 |
| 1/32 | = .031250 |
| 3/64 | = .046875 |
| 1/16 | = .062500 |
| 5/64 | = .078125 |
| 3/32 | = .093750 |
| 7/64 | = .109375 |
| 1/8 | = .125000 |
| 9/64 | = .140625 |
| 5/32 | = .156250 |
| 11/64 | = .171875 |
| 3/16 | = .187500 |
| 13/64 | = .203125 |
| 7/32 | = .218750 |
| 15/64 | = .234375 |
| 1/4 | = .250000 |
| 17/64 | = .265625 |
| 9/32 | = .281250 |
| 19/64 | = .296875 |
| 5/16 | = .312500 |
| 21/64 | = .328125 |
| 11/32 | = .343750 |
| 23/64 | = .359375 |
| 3/8 | = .375000 |
| 25/64 | = .390625 |
| 13/32 | = .406250 |
| 27/64 | = .421875 |
| 7/16 | = .437500 |
| 29/64 | = .453125 |
| 15/32 | = .468750 |
| 31/64 | = .484375 |
| 1/2 | = .500000 |
Comparative Table of B. and S. and B. W. Gauges in Decimal Parts of an Inch.