Friendly. Knowledgeable. Helpful.

“Hope to do more business with you in the future. altE rocks! Best customer service anywhere!” – Joe Stratham, NH

877-878-4060

Offices ARE NOT accepting walk-ins.

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

877-878-4060