Type your load below for the smallest qualifying size — or read the full table. Values assume ≤3 current-carrying conductors in raceway at 30 °C ambient.
| Size | Cu 60°C | Cu 75°C | Cu 90°C | Al 60°C | Al 75°C | Al 90°C |
|---|---|---|---|---|---|---|
| 14 AWG | 15 | 20 | 25 | — | — | — |
| 12 AWG | 20 | 25 | 30 | 15 | 20 | 25 |
| 10 AWG | 30 | 35 | 40 | 25 | 30 | 35 |
| 8 AWG | 40 | 50 | 55 | 35 | 40 | 45 |
| 6 AWG | 55 | 65 | 75 | 40 | 50 | 55 |
| 4 AWG | 70 | 85 | 95 | 55 | 65 | 75 |
| 3 AWG | 85 | 100 | 110 | 65 | 75 | 85 |
| 2 AWG | 95 | 115 | 130 | 75 | 90 | 100 |
| 1 AWG | 110 | 130 | 145 | 85 | 100 | 115 |
| 1/0 AWG | 125 | 150 | 170 | 100 | 120 | 135 |
| 2/0 AWG | 145 | 175 | 195 | 115 | 135 | 150 |
| 3/0 AWG | 165 | 200 | 225 | 130 | 155 | 175 |
| 4/0 AWG | 195 | 230 | 260 | 150 | 180 | 205 |
| 250 kcmil | 215 | 255 | 290 | 170 | 205 | 230 |
| 300 kcmil | 240 | 285 | 320 | 195 | 230 | 260 |
| 350 kcmil | 260 | 310 | 350 | 210 | 250 | 280 |
| 400 kcmil | 280 | 335 | 380 | 225 | 270 | 305 |
| 500 kcmil | 320 | 380 | 430 | 260 | 310 | 350 |
The everyday working column is 75 °C — what standard breaker and lug terminations are rated for (NEC 110.14(C)). The 90 °C column is mainly a derating start point. Small-conductor caps still apply: 15 A for 14 AWG, 20 A for 12 AWG, 30 A for 10 AWG copper (NEC 240.4(D)). For ambient or bundling corrections, use the ampacity calculator.