Table 310.21 Ampacities of Bare or Covered Conductors in Free Air, Based on 400°C (1040°F) Ambient, 800°C (1760°F) Total Conductor Temperature, 610 mm/sec (2 ft/sec) Wind Velocity
| Copper Conductors | |||
| Bare | Covered | ||
| AWG or kcmil | Amperes | AWG or kcmil | Amperes |
| 8 | 98 | 8 | 103 |
| 6 | 124 | 6 | 130 |
| 4 | 155 | 4 | 163 |
| 2 | 209 | 2 | 219 |
| 1/0 | 282 | 1/0 | 297 |
| 2/0 | 329 | 2/0 | 344 |
| 3/0 | 382 | 3/0 | 401 |
| 4/0 | 444 | 4/0 | 466 |
| 250 | 494 | 250 | 519 |
| 300 | 556 | 300 | 584 |
| 500 | 773 | 500 | 812 |
| 750 | 1000 | 750 | 1050 |
| 1000 | 1193 | 1000 | 1253 |