What Gauge Wire for a 60-Amp Circuit?
Use 6 AWG copper or 4 AWG aluminum for 60-amp circuits. 6 AWG THHN copper handles 65A at 75°C terminals — adequate for 60A.
6 AWG copper is the standard wire gauge for 60-amp circuits at the common 75°C termination rating. 6 AWG THHN delivers 65A at 75°C — 5A margin over the 60A breaker.
NEC reference
| Material | 90°C | 75°C | 60°C |
|---|---|---|---|
| 6 AWG copper | 75A | 65A | 55A |
| 4 AWG aluminum | 65A | 55A | 50A |
| 3 AWG aluminum | 85A | 75A | 65A |
Common 60-amp circuits
- 60A sub-panel feeder (detached garage, basement workshop, ADU)
- Tankless electric water heater (mid-size)
- Heat pump compressor (larger units)
- EV charger at 48A continuous (60A breaker per NEC 625.42 / 80% continuous rule)
- Large hot tub / spa (48A or 50A continuous, 60A breaker)
Sub-panel feeder typical configuration
A 60A sub-panel feed uses 4 conductors in a metal raceway:
- 2 × 6 AWG hot (240V)
- 1 × 6 AWG neutral (if 120V loads in sub-panel)
- 1 × 10 AWG EGC (per NEC 250.122)
Conduit fill in 1" EMT: 3 × 0.0507 + 1 × 0.0211 = 0.1732 in² = 20.0% fill ✓
Ampacity derating
With 4–6 CCCs: 75A × 0.80 = 60A — exactly meets 60A breaker, no margin.
With 7–9 CCCs: 75A × 0.70 = 52.5A — insufficient. Upsize to 4 AWG copper (85A × 0.70 = 59.5A — still marginal) or further.
Voltage drop at 60A continuous (EV charger scenario)
6 AWG copper: 0.398 Ω/1000 ft. At 48A continuous on 100 ft one-way (240V):
V drop = 200 × 48 × (0.398 / 1000) = 3.82V (1.6% of 240V)
Within 3%. For 60A circuits ≥ 130 ft, upsize to 4 AWG to keep drop under 3%.
Quick reference
- Wire: 6 AWG copper THHN/THWN-2 (or 3 AWG aluminum)
- Breaker: 60A 2-pole
- EGC: 10 AWG copper per NEC 250.122
- Conduit: 3/4" or 1" EMT for sub-panel feed