# Brown & Sharpe wire gauge

Also called the American Wire Gauge (AWG). Used in the United States since at least the 1880s for wires in all metals except iron and steel. There are two defined sizes: number 0000 wire is 0.4600 inch in diameter and number 36 is 0.0050 inch. The diameters of intermediate numbers are found by subdividing the interval between those sizes into 39 geometrical steps, with a constant ratio between adjacent sizes of:

The diameter of each succeeding smaller size is the reciprocal, 0.890525 times the diameter of the previous, larger, size.

For electrical equivalents in ISO metric sizes, see the following tables:

ASTM Standard B 258-02, Standard specification for standard nominal diameters and cross-sectional areas of AWG sizes of solid round wires used as electrical conductors.

Properties of Bare Copper Wire
Gauge
(AWG)
Diameter Area Resistance in ohms, 20°C Weight
mils milli­meters circular mils square
millimeters
per
1000 feet
per
kilometer
1000 feet,
in lbs.
1 kilometer,
in kg
0000 460.0 11.68 211,600 107.2 .0490 .1608 640.5 953.2
000 409.6 10.40 167,806 85.03 .0618 .2028 507.9 755.9
00 364.8 9.266 133,077 67.43 .0779 .2557 402.8 599.5
0 324.9 8.252 105,535 53.48 .0983 .3224 319.5 475.4
1 289.3 7.348 83,692.7 42.41 .1239 .4066 253.3 377.0
2 257.6 6.544 66,371.3 33.63 .1563 .5127 200.9 299.0
3 229.4 5.827 52,634.3 26.67 .1970 .6465 159.3 237.1
4 204.3 5.189 41,741.3 21.15 .2485 .8152 126.4 188.0
5 181.9 4.621 33,102.4 16.77 .3133 1.028 100.2 149.1
6 162.0 4.115 26,251.4 13.30 .3951 1.296 79.46 118.3
7 144.3 3.665 20,818.3 10.55 .4982 1.634 63.02 93.78
8 128.5 3.264 16,509.7 8.366 .6282 2.061 49.97 74.37
9 114.4 2.906 13,092.8 6.634 .7921 2.599 39.63 58.98
10 101.9 2.588 10,383.0 5.261 .9989 3.277 31.43 46.77
11 90.74 2.305 8,234.11 4.172 1.260 4.132 24.92 37.09
12 80.81 2.053 6,529.95 3.309 1.588 5.211 19.77 29.42
13 71.96 1.828 5,178.48 2.624 2.003 6.571 15.68 23.33
14 64.08 1.628 4,106.72 2.081 2.525 8.285 12.43 18.50
15 57.07 1.450 3,256.78 1.650 3.184 10.45 9.858 14.67
16 50.82 1.291 2,582.74 1.309 4.016 13.17 7.818 11.63
17 45.26 1.150 2,048.21 1.038 5.064 16.61 6.200 9.226
18 40.30 1.024 1,624.30 .8231 6.385 20.95 4.917 7.317
19 35.89 .9116 1,288.13 .6527 8.051 26.42 3.899 5.803
20 31.96 .8118 1,021.53 .5176 10.15 33.31 3.092 4.602
21 28.46 .7230 810.114 .4105 12.80 42.00 2.452 3.649
22 25.35 .6438 642.450 .3255 16.14 52.96 1.945 2.894
23 22.57 .5733 509.486 .2582 20.36 66.79 1.542 2.295
24 20.10 .5106 404.041 .2047 25.67 84.21 1.223 1.820
25 17.90 .4547 320.419 .1624 32.37 106.2 .9699 1.443
26 15.94 .4049 254.104 .1288 40.81 133.9 .7692 1.145
27 14.20 .3606 201.513 .1021 51.47 168.9 .6100 .9077
28 12.64 .3211 159.807 .08098 64.90 212.9 .4837 .7199
29 11.26 .2589 126.733 .06422 81.84 268.5 .3836 .5709
30 10.03 .2546 100.504 .05093 103.2 338.6 .3042 .4527
31 8.928 .2268 79.7031 .04093 130.1 426.9 .2413 .3590
32 7.950 .2019 63.2075 .03203 164.1 538.3 .1913 .2847
33 7.080 .1798 50.1258 .02540 206.9 678.8 .1517 .2258
34 6.305 .1601 39.7516 .02014 260.9 856.0 .1203 .1791
35 5.615 .1426 31.5244 .01597 329.0 1079.4 .0954 .1420
36 5.000 .1270 25.0000 .01267 414.8 1361.0 .0757 .1126
37 4.453 .1131 19.8259 .01005 523.1 1716.2 .0600 .0893
38 3.965 .1007 15.7227 .00797 659.6 2164.1 .0476 .0708
39 3.531 .0897 12.4686 .00632 834.8 2728.9 .0377 .0562
40 3.145 .0799 9.88807 .00501 1049.0 3441.1 .0299 .0445

## sources

1

With the exception of No. 0000, which is 460 mils in diameter, and No. 36 which is 5 mils, the diameters of the sizes B. & S. G. are indeterminate. The ratio of the diameter of any one size to that of the next lower size in .890 525 718 5. Using this ratio and deriving the size of each number from the next greater finally gives us 5.000 000 02 mils as the diameter of a No. 36 instead of an even 5 mils. The ratio is, therefore, slightly too large.

Wire in Electrical Construction.
Trenton, NJ: John A. Roebling's Sons Company, 1916.
Page 51.

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