4 AWG Wire Ampacity & Specifications
4 AWG copper wire carries 85A at 75°C (NEC Table 310.16), or 65A for aluminum; copper is typically protected by a 80A breaker.
Calculations are built on the 2023 National Electrical Code (NEC) and cross-checked against the published code tables. How we verify. Last updated June 2026.
4 AWG wire has an ampacity of 85A at 75°C for copper and 65A for aluminum (NEC Table 310.16). Its 60°C and 90°C copper ratings are 70A and 95A. Copper 4 AWG is commonly protected by a 80A breaker.
Copper 75°C
85A
Copper 90°C
95A
Aluminum 75°C
65A
Copper breaker (75°C)
80A
4 AWG Wire Specifications
| Ampacity — Copper (60 / 75 / 90°C) | 70 / 85 / 95 A |
| Ampacity — Aluminum (60 / 75 / 90°C) | 55 / 65 / 75 A |
| Cross-section | 41,740 circular mils |
| DC resistance — Copper | 0.308 Ω / 1000 ft |
| DC resistance — Aluminum | 0.508 Ω / 1000 ft |
| Typical voltage drop (240V) | 1.0% at 50 ft · 2.1% at 100 ft (at 80A) |
Common Uses for 4 AWG Wire
- 70–85A feeders and large appliance circuits
- Sub-panel feeders (70–85A)
Ampacities are from NEC Table 310.16. Copper 14, 12 and 10 AWG are limited to 15A, 20A and 30A overcurrent protection, aluminum 12 and 10 AWG to 15A and 25A (240.4(D)). Terminations rated 60°C or 75°C usually cap the usable ampacity below the 90°C value.
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