Understanding American Wire Gauge: A Comprehensive Guide
Introduction
The American Wire Gauge (AWG) is a standardized system for measuring the diameter of electrical wires. It was developed in the late 19th century by the American Institute of Electrical Engineers (AIEE), now known as the Institute of Electrical and Electronics Engineers (IEEE). The AWG system is used worldwide to specify the size of wires used in electrical and electronic applications.
What is AWG?
The AWG scale is a logarithmic scale, meaning that the diameter of each wire size is twice the diameter of the next smaller size. The larger the AWG number, the smaller the wire diameter. For example, a 10 AWG wire has a diameter of 2.588 mm, while a 12 AWG wire has a diameter of 2.053 mm.
AWG Table
The following table shows the relationship between AWG size, wire diameter, and cross-sectional area:
| AWG Size |
Diameter (mm) |
Cross-Sectional Area (mm²) |
| 0 |
8.252 |
53.48 |
| 1 |
7.348 |
42.41 |
| 2 |
6.544 |
33.63 |
| 3 |
5.827 |
26.67 |
| 4 |
5.189 |
21.15 |
| 5 |
4.572 |
16.78 |
| 6 |
4.115 |
13.31 |
| 7 |
3.658 |
10.55 |
| 8 |
3.264 |
8.366 |
| 9 |
2.913 |
6.635 |
| 10 |
2.588 |
5.263 |
| 11 |
2.286 |
4.153 |
| 12 |
2.053 |
3.310 |
| 13 |
1.829 |
2.625 |
| 14 |
1.628 |
2.082 |
| 15 |
1.454 |
1.651 |
| 16 |
1.291 |
1.309 |
| 17 |
1.151 |
1.040 |
| 18 |
1.024 |
0.823 |
| 19 |
0.912 |
0.653 |
| 20 |
0.813 |
0.518 |
| 21 |
0.721 |
0.405 |
| 22 |
0.641 |
0.325 |
| 23 |
0.573 |
0.258 |
| 24 |
0.511 |
0.205 |
| 25 |
0.455 |
0.162 |
| 26 |
0.405 |
0.129 |
| 27 |
0.363 |
0.102 |
| 28 |
0.326 |
0.083 |
| 29 |
0.292 |
0.066 |
| 30 |
0.262 |
0.053 |
| 31 |
0.234 |
0.042 |
| 32 |
0.208 |
0.033 |
| 33 |
0.183 |
0.026 |
| 34 |
0.163 |
0.020 |
| 35 |
0.146 |
0.017 |
| 36 |
0.131 |
0.013 |
| 37 |
0.117 |
0.011 |
| 38 |
0.104 |
0.008 |
| 39 |
0.091 |
0.006 |
| 40 |
0.081 |
0.005 |
Ampacity of AWG Wires
The ampacity of a wire is the maximum amount of current that it can safely carry without overheating. The ampacity of an AWG wire depends on several factors, including the wire material, insulation type, and ambient temperature. The following table shows the ampacity of AWG wires for different materials and ambient temperatures:
| AWG Size |
Copper Ampacity (A) |
Aluminum Ampacity (A) |
| 0 |
200 |
135 |
| 1 |
175 |
115 |
| 2 |
150 |
95 |
| 3 |
125 |
80 |
| 4 |
100 |
65 |
| 5 |
85 |
55 |
| 6 |
70 |
45 |
| 7 |
60 |
38 |
| 8 |
50 |
32 |
| 9 |
40 |
26 |
| 10 |
35 |
22 |
| 11 |
30 |
19 |
| 12 |
25 |
16 |
| 13 |
20 |
13 |
| 14 |
15 |
10 |
| 15 |
12 |
8 |
| 16 |
10 |
6 |
| 17 |
8 |
5 |
| 18 |
6 |
4 |
| 19 |
5 |
3 |
| 20 |
4 |
2.5 |
| 21 |
3 |
2 |
| 22 |
2.5 |
1.5 |
| 23 |
2 |
1.25 |
| 24 |
1.5 |
1 |
| 25 |
1 |
0.8 |
| 26 |
0.8 |
0.6 |
| 27 |
0.6 |
0.4 |
| 28 |
0.5 |
0.3 |
| 29 |
0.4 |
0.25 |
| 30 |
0.3 |
0.2 |
| 31 |
0.25 |
0.15 |
| 32 |
0.2 |
0.12 |
| 33 |
0.15 |
0.1 |
| 34 |
0.1 |
0.08 |
| 35 |
0.08 |
0.06 |
| 36 |
0.06 |
0.04 |
| 37 |
0.04 |
0.03 |
| 38 |
0.03 |
0.02 |
| 39 |
0.02 |
0.015 |
| 40 |
0.015 |
0.01 |
Voltage Drop in AWG Wires
When current flows through a wire, there is a voltage drop across the wire. The voltage drop is caused by the resistance of the wire. The longer the wire, the greater the resistance and the greater the voltage drop. The following table shows the voltage drop in AWG wires for different wire lengths and current levels:
| Wire Length (m) |
Current (A) |
Voltage Drop (V) |
| 10 |
1 |
0.001 |
| 10 |
10 |
0.01 |
| 10 |
100 |
0.1 |
| 100 |
1 |
0.01 |
| 100 |
10 |
0.1 |
| 100 |
100 |
1 |
| 1000 |
1 |
0.1 |
| 1000 |
10 |
1 |
| 1000 |
100 |
10 |
Why AWG Matters
AWG matters because it is a standardized system for specifying the size of electrical wires. This allows engineers and electricians to easily communicate with each other about the wire sizes that are needed for a particular application. AWG also helps to ensure that wires are properly sized for the amount of current that they will be carrying, which helps
