cars - American wire gauge

American wire gauge (AWG) is used in the United States and other countries as a standard method of denoting wire diameter, especially for non-ferrous, conducting wire. Increasing gauge numbers give decreasing wire diameters, which is similar to many other non-metric gauging systems. This seemingly-counterintuitive numbering is derived from the fact that the gauge number is related to the number of drawing operations that must be used to produce a given gauge of wire; very fine wire (for example, 30 gauge) requires far more passes through the drawing dies than 0 gauge wire.

AWG is also commonly used to specify body piercing jewelry sizes.

Gauge Chart.pdf Chart comparing all known wire gauges to each other

Formulas

1 inch = 25.4 mm

$D = 0.005 \left ( 92 ^ \frac{{36-AWG}}{39} \right )$

$\log(D) = \frac{36-AWG}{39}*\log(92)-\log(200)$

$AWG = 36 - \frac{39*\log(200D)}{\log(92)}$

where diameter D is in inches and log is a logarithm to any base.

Table of AWGs and approximate corresponding sizes

The following applies to solid wires. Stranded wires are calculated by calculating the equivalent cross-sectional area.

AWG	Diameter (mm)	Diameter (in)	Copper wire ohms/ 1000 ft	NEC ampacity with 60 °C insulation
0000000 (6/0)	14.732	0.5800
000000 (5/0)	13.119	0.5165
00000 (4/0)	11.684	0.4600
000 (3/0)	10.404	0.4096
00 (2/0)	9.266	0.3648
0 (1/0)	8.252	0.3249
1	7.348	0.2893		110
2	6.543	0.2576		95
3	5.827	0.2294		85
4	5.189	0.2043		70
5	4.621	0.1819
6	4.115	0.1620		55
7	3.665	0.1443
8	3.264	0.1285		40
9	2.906	0.1144
10	2.588	0.1019	1.0	30
11	2.304	0.0907
12	2.052	0.0808		20
13	1.829	0.0720
14	1.628	0.0641		15
15	1.450	0.0571
16	1.291	0.0508
17	1.150	0.0453
18	1.024	0.0403
19	0.9119	0.0359
20	0.8128	0.0320	10.0
21	0.7239	0.0285
22	0.6426	0.0253
23	0.5740	0.0226
24	0.5106	0.0201
25	0.4547	0.0179
26	0.4038	0.0159
27	0.3606	0.0142
28	0.3200	0.0126
29	0.2870	0.0113
30	0.2540	0.0100	100
31	0.2261	0.0089
32	0.2032	0.0080
33	0.1803	0.0071
34	0.1601	0.0063
35	0.1422	0.0056
36	0.1270	0.0050
37	0.1143	0.0045
38	0.1016	0.0040
39	0.0889	0.0035
40	0.0787	0.0031	1000

In the North American electrical industry, conductors larger than 4/0 AWG are generally identifed by the area in thousands of circular mils (mcm). (A circular mil is the area of a wire one mil in diameter.) One million circular mils (1000 mcm) is the area of a rod 1000 mils (one inch) in diameter.

Outside the U.S., wire is typically specified in terms of its area in mm².

A few cross-references between AWG and metric stranded wire:

24AWG: 7/0.2
20AWG: 16/0.2
18AWG: 24/0.2

Categories: Measurement