Wire gauge
Wire gauge is the measure of how large of a cross section a wire has. Knowing the gauge is important because it tells you how much current a wire can carry without being damaged - this quantity is called ampacity.
American Wire Gauge System
The American Wire Gauge system or AWG allows for standard wire sizes - determined by cross sectional area - to be identified and assigns them an AWG number. A lower gauge wire has a larger diameter and thus is able to carry higher currents. There are a total of 40 different gauge sizes with cross sectional areas ranging from 0.013 mm2 to 107.22 mm2 with their diameters changing incrementally between each gauge number.
Wire Gauge Values
AWG number | Cross sectional area (mm2) | Ohms/km (/km) | Ampacity (A) | Usage example |
---|---|---|---|---|
18 | 0.82 | 20.95 | 14 | Low voltage lighting |
16 | 1.31 | 13.18 | 18 | Extension cords |
14 | 2.08 | 8.28 | 25 | Lighting fixtures |
12 | 3.31 | 5.21 | 30 | Kitchen appliances |
10 | 5.26 | 3.28 | 40 | Electric dryers |
8 | 8.37 | 2.06 | 55 | Electric ovens |
6 | 13.30 | 1.30 | 75 | Large electric heaters |
4 | 21.15 | 0.81 | 85 | Large furnaces |
3 | 26.67 | 0.65 | 115 | Large commercial wiring |
2 | 33.63 | 0.51 | 130 | Car battery cable |
1 | 42.41 | 0.41 | 145 | Power distribution |
1/0 | 53.47 | 0.32 | 170 | Power distribution |
2/0 | 67.43 | 0.26 | 195 | Power distribution |
3/0 | 85.03 | 0.20 | 225 | Power distribution |
4/0 | 107.22 | 0.16 | 260 | Power distribution |
250 | 126.68 | 0.13 | 290 | Power distribution |
350 | 177.35 | 0.10 | 350 | Power distribution |
400 | 202.68 | 0.08 | 380 | Power distribution |
The figures above are taken from Table 310.15(B)(16) in the 2014 National Electrical Code (USA) and assume a temperature rating of 90°C.[2] Also, Table 3.1 on page 69 in Introduction to Electricity was used as a template and reference.[3]
For a more complete list, please see Dr. Rowlett's unit page.
References
- ↑ Wikimedia Commons. (October 3, 2015). Wire Gauge [Online]. Available: https://upload.wikimedia.org/wikipedia/commons/2/23/Wire_gauge_(PSF).png
- ↑ "2014 National Electrical Code" Table 310.15(B)(16)
- ↑ "Introduction to electricity" Pearson: Robert T. Paynter, B.J Toby Boydell