Maximum Ampacity (Current Capacity) for Wire & Cable
Determine the maximum amount of electrical current (amps) that can safely flow through different wire gauges.
This table provides you with the allowable ampacity (maximum current the cable can carry) that you can use with wires in conduit, raceway, cable or directly buried, assuming an ambient temperature of 86°F (30°C).
| Wire Size (AWG) | Copper Conductor Temp. Rating | Aluminum Conductor Temp. Rating | ||
| 75°C (167°F) | 90°C (194°F) | 75°C (167°F) | 90°C (194°F) | |
| 14* | 20A | 25A | ||
| 12* | 25A | 30A | 20A | 25A |
| 10* | 35A | 40A | 30A | 35A |
| 8 | 50A | 55A | 40A | 45A |
| 6 | 65A | 75A | 50A | 55A |
| 4 | 85A | 95A | 65A | 75A |
| 2 | 115A | 130A | 90A | 100A |
| 1 | 130A | 145A | 100A | 115A |
| 1/0 | 150A | 170A | 120A | 135A |
| 2/0 | 175A | 195A | 135A | 150A |
| 3/0 | 200A | 225A | 155A | 175A |
| 4/0 | 230A | 260A | 180A | 205A |
*National Electric Code specifies that the overcurrent protection device (e.g. a fuse or breaker) must not exceed 30A for 10 AWG wire, 20A for 12 AWG wire and 15A for 14 AWG wire.
Ambient Temperature Above 86°F (30°C)?
If your ambient temperature is higher than 86°F (30°C) then multiply the ampacity you found in the table above by the correction factor listed under the cable insulation temperature rating below:
| Temperature Range | 75°F Rated Insulation Correction Factor |
90°F Rated Insulation Correction Factor |
|
| 87-89°F | 31-35°C | .94 | .96 |
| 96-104°F | 36-40°C | 0.88 | 0.91 |
| 105-113°F | 41-45°C | 0.82 | 0.87 |
| 114-122°F | 46-50°C | 0.75 | 0.82 |
| 123-131°F | 51-55°C | 0.67 | 0.76 |
| 132-140°F | 56-60°C | 0.58 | 0.71 |