AWG Wire Gauge Chart
Complete American Wire Gauge (AWG) reference table with wire diameter, cross-sectional area, resistance, and ampacity ratings for both copper and aluminum conductors.
Understanding AWG Wire Gauge
The American Wire Gauge (AWG) system uses an inverse numbering system: smaller gauge numbers indicate larger wire diameters and higher current capacity. AWG 0000 (4/0) is the largest common wire gauge, while AWG 20 is suitable for low-current applications.
| AWG | Diameter | Cross-Section | Resistance (Ω/1000ft) | Ampacity - Copper | Ampacity - Aluminum | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| mm | inch | mm² | kcmil | Cu | Al | 60°C | 75°C | 90°C | 60°C | 75°C | 90°C | |
| 20 | 0.812 | 0.0320 | 0.52 | 1.02 | 10.150 | 16.700 | 11 | 11 | 15 | - | - | - |
| 18 | 1.024 | 0.0403 | 0.82 | 1.62 | 6.390 | 10.500 | 14 | 14 | 18 | - | - | - |
| 16 | 1.291 | 0.0508 | 1.31 | 2.58 | 4.020 | 6.600 | 18 | 18 | 24 | - | - | - |
| 14 | 1.628 | 0.0641 | 2.08 | 4.11 | 2.530 | 4.160 | 25 | 25 | 35 | 20 | 20 | 25 |
| 12 | 2.053 | 0.0808 | 3.31 | 6.53 | 1.590 | 2.610 | 30 | 35 | 40 | 25 | 25 | 30 |
| 10 | 2.588 | 0.1019 | 5.26 | 10.38 | 1.000 | 1.640 | 40 | 50 | 55 | 30 | 40 | 45 |
| 8 | 3.264 | 0.1285 | 8.37 | 16.51 | 0.628 | 1.030 | 60 | 70 | 80 | 45 | 55 | 65 |
| 6 | 4.115 | 0.1620 | 13.30 | 26.24 | 0.395 | 0.648 | 80 | 95 | 105 | 60 | 75 | 85 |
| 4 | 5.189 | 0.2043 | 21.15 | 41.74 | 0.249 | 0.408 | 105 | 125 | 140 | 80 | 100 | 110 |
| 3 | 5.827 | 0.2294 | 26.67 | 52.62 | 0.197 | 0.324 | 120 | 145 | 165 | 95 | 115 | 130 |
| 2 | 6.544 | 0.2576 | 33.62 | 66.37 | 0.156 | 0.256 | 140 | 170 | 190 | 110 | 135 | 150 |
| 1 | 7.348 | 0.2893 | 42.41 | 83.69 | 0.124 | 0.203 | 165 | 195 | 220 | 130 | 155 | 175 |
| 1/0 | 8.251 | 0.3249 | 53.49 | 105.60 | 0.098 | 0.161 | 195 | 230 | 260 | 150 | 180 | 205 |
| 2/0 | 9.266 | 0.3648 | 67.43 | 133.10 | 0.078 | 0.128 | 225 | 265 | 300 | 175 | 210 | 235 |
| 3/0 | 10.400 | 0.4096 | 85.01 | 167.80 | 0.062 | 0.101 | 260 | 310 | 350 | 200 | 240 | 275 |
| 4/0 | 11.680 | 0.4600 | 107.20 | 211.60 | 0.049 | 0.081 | 300 | 360 | 405 | 235 | 280 | 315 |
Wire Diameter
Wire diameter decreases as AWG gauge number increases. Each increase of 6 gauge numbers approximately doubles the wire diameter, while each decrease of 6 gauge numbers halves it.
Key Points:
- AWG 10 = 2.588mm diameter
- AWG 16 = 1.291mm (half of AWG 10)
- AWG 4 = 5.189mm (double of AWG 10)
Ampacity Ratings
Ampacity is the maximum current a conductor can carry continuously without exceeding its temperature rating. Values are based on NEC Table 310.16 for conductors in conduit or cable.
Temperature Ratings:
- 60°C - Standard thermoplastic insulation (TW)
- 75°C - Heat-resistant thermoplastic (THHN, THWN)
- 90°C - High heat-resistant (THHN, XHHW)
Wire Resistance
Resistance values are given in ohms per 1000 feet at 75°C (167°F). Lower resistance means less voltage drop and power loss over distance.
Material Comparison:
- Copper has approximately 61% of aluminum's resistance
- Aluminum requires larger gauge for same ampacity
- Copper is preferred for most residential applications
Choosing the Right Gauge
Select wire gauge based on circuit amperage, wire length, and acceptable voltage drop. Always follow NEC requirements and local electrical codes.
Selection Factors:
- Circuit current load and future expansion
- Wire run length and voltage drop (≤3% recommended)
- Installation method and ambient temperature
- Local electrical code requirements
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