What Size Wire for a 60 Amp Breaker?
Short answer: for a 60 amp breaker, use 6 AWG copper THHN/THWN-2 in conduit when every termination is rated 75°C, or 4 AWG aluminum at 75°C. If you're limited to the 60°C column, the table points to 4 AWG copper. For long feeders, upsize for voltage drop.
60 amp wire size by wiring method
| Wiring method | Copper | Aluminum |
|---|---|---|
| THHN/THWN-2 in conduit, 75°C terminals | 6 AWG | 4 AWG |
| 60°C column (e.g., NM-B, UF, 60°C terminals) | 4 AWG | 3 AWG |
| SER cable, 75°C terminals | 6 AWG | 4 AWG |
Ground wire: 10 AWG copper or 8 AWG aluminum (Table 250.122 for 60 A).
60 A is the largest breaker where the 10 AWG copper equipment ground still applies. At 61–100 A the ground steps up to 8 AWG copper.
What about 6 AWG NM-B on a 60 amp breaker?
6 AWG NM-B is rated 55 A (60°C). NEC 240.4(B) allows rounding up to the next standard breaker size (60 A) when the conductor ampacity doesn't match a standard size, the circuit isn't a multi-outlet branch circuit for cord-and-plug loads, and the calculated load doesn't exceed 55 A. It's legal in the right situation, but many inspectors and electricians prefer 4 AWG NM-B or 6 AWG THHN at 75°C to avoid the argument.
60 amp wire size by distance (240 V)
| Conductor | 50 ft | 100 ft | 150 ft | 200 ft |
|---|---|---|---|---|
| Copper | 6 AWG (1.0%) | 6 AWG (2.0%) | 6 AWG (2.9%) | 4 AWG (2.5%) |
| Aluminum | 4 AWG (1.0%) | 4 AWG (2.0%) | 3 AWG (2.4%) | 2 AWG (2.6%) |
Smallest conductor that meets both the 75°C ampacity for a 60 A circuit and a 3% voltage drop at 48 A (80% of the rating), 240 V single-phase, one-way distance. Percent drop in brackets. If the circuit uses NM-B cable or 60°C terminations, start from the 60°C column instead.
At a 48 A load, 6 AWG copper reaches 3% drop at about 150 feet one way. 4 AWG copper stretches that to about 243 feet and 2 AWG aluminum to about 235 feet.
Worked example: 60 A feeder to a detached garage
A 60 A, 120/240 V feeder runs 110 feet underground in PVC to a garage subpanel. The load calculation puts the expected load at 48 A. All terminations are rated 75°C.
| Option | Ampacity at 75°C | Voltage drop at 48 A, 110 ft |
|---|---|---|
| 6 AWG copper THHN/THWN-2 | 65 A | 2 × 12.9 × 48 × 110 ÷ 26,240 = 5.19 V (2.2%) |
| 4 AWG aluminum XHHW-2 | 65 A | 2 × 21.2 × 48 × 110 ÷ 41,740 = 5.36 V (2.2%) |
Both work electrically. For the copper option, three 6 AWG THHN plus a 10 AWG ground total 0.1732 in², which fits ¾" PVC Schedule 40 (40% area 0.2032 in²). Aluminum XHHW-2 has its own areas in Chapter 9 Table 5, so size that raceway from those values rather than the THHN numbers. The equipment ground is 10 AWG copper or 8 AWG aluminum either way. The choice usually comes down to current copper vs. aluminum pricing and whether the subpanel lugs are rated AL/CU.
Common 60 amp circuits
- Subpanel in a garage, shop or ADU. Four-wire feeder (two hots, neutral, equipment ground). Neutral and ground are separated at the subpanel. A detached building also needs its own grounding electrode system (NEC 250.32). The full rule set is on the 100 amp subpanel page.
- Level 2 EV charger at 48 A. 48 A continuous × 1.25 = 60 A circuit. Most 48 A chargers are hardwired.
- Electric furnace or air-handler heat strips. A 10 kW strip heater draws 10,000 ÷ 240 = 41.7 A. As a continuous heating load it's sized at 125%, or 52.1 A, which lands on a 60 A circuit. Always use the nameplate MCA and MOCP, which already include that multiplier.
- Hot tubs and spas rated for 60 A, with GFCI protection at the disconnect.
Common mistakes inspectors flag
- 6 AWG NM-B on a 60 A breaker without a load calculation to show the load stays at or below 55 A.
- 6 AWG aluminum at 60 A. It's rated 50 A at 75°C. The aluminum answer is 4 AWG.
- Three-wire feeders to a detached building. New feeders need a separate equipment grounding conductor (250.32(B)(1)).
- Bonding screw left in the subpanel, which puts neutral current on the ground path.
- No grounding electrode at the detached building, or a missing building disconnect.
Frequently asked questions
Is 6 gauge wire enough for 60 amps?
6 AWG copper at 75°C is rated 65 A, so yes as THHN or other 75°C conductors with 75°C terminations. 6 AWG NM-B (55 A) needs the 240.4(B) next-size-up rule to go on a 60 A breaker. For a 50 A circuit, see 50 amp wire size.
What size aluminum wire for a 60 amp subpanel?
4 AWG aluminum at 75°C (65 A). 4-4-4-6 aluminum SER is common for this; the 6 AWG aluminum ground is larger than the 8 AWG minimum.
How far can I run 6 AWG copper on a 60 amp circuit?
At a 48 A load on 240 V, 6 AWG copper reaches 3% drop at about 150 feet one way. Check your own run in the voltage drop calculator.
What size wire for a 60 amp 220V circuit?
"220 V" and "240 V" describe the same North American residential supply. The size doesn't change: 6 AWG copper THHN with 75°C terminations, 4 AWG copper in NM-B or UF, or 4 AWG aluminum. Voltage only matters for the voltage drop percentage.
Can a 60 amp breaker feed a 100 amp subpanel?
Yes. The breaker protects the feeder, so a 100 A-rated panel fed from a 60 A breaker needs only 60 A conductors. It's a common way to leave room to upgrade the feeder later without replacing the panel. Mark the panel directory with the actual feeder rating.
What's the ampacity of 4 AWG copper?
70 A at 60°C, 85 A at 75°C and 95 A at 90°C per Table 310.16 (see the ampacity chart). That's why 4 AWG copper covers a 60 A circuit even in NM-B cable.
Last updated: October 6, 2026. Based on NEC 2023. Check results against the code edition and local amendments your jurisdiction enforces and with the AHJ; electrical work should be done by qualified people.