What Gauge Wire for a 60-Amp Circuit?

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

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