The quick answer
For a 60 amp circuit, use 6 AWG copper if you're running conduit (THHN/THWN), or 4 AWG copper if you're running NM-B "Romex". In aluminum, use 4 AWG. The equipment ground is 10 AWG copper either way.
Not sure of your wire type, or want one size that's always right? Run 4 AWG copper. It carries 60 amps in conduit and in Romex, so you can't get it wrong — which is exactly why a lot of electricians default to it at 60 amps.
Why 60 amps is the tricky one: 6 AWG is at its limit
Most breaker sizes have one obvious wire. 60 amps doesn't, because it lands right on the edge of what 6 AWG copper can do — and where it lands depends on the wire's temperature rating.
- 6 AWG copper as THHN/THWN in conduit (the 75°C column) = 65 amps → fine for a 60 amp breaker.
- 6 AWG copper as NM-B "Romex" (limited to the 60°C column, NEC 334.80) = only 55 amps → under 60, so it's not allowed.
This is the mistake that fails inspections. The 6-gauge Romex on the shelf is a 55-amp conductor — you cannot put it on a 60 amp breaker. Either pull 6 AWG THHN in conduit, or step the cable up to 4 AWG, which is 70 amps even at the 60°C Romex rating.
That's why "4 AWG copper" is the safe, universal answer: it clears 60 amps in every wiring method, so you never have to think about which column applies.
60 amp wire size chart
Every conductor in a 60 amp circuit, with the wire-type split made explicit:
| Conductor | Copper | Aluminum |
|---|---|---|
| Circuit wire — THHN in conduit (75°C) | 6 AWG | 4 AWG |
| Circuit wire — NM-B / Romex (60°C) | 4 AWG | 4 AWG * |
| Safe all-round choice | 4 AWG | 4 AWG |
| Equipment ground (NEC 250.122) | 10 AWG | 8 AWG |
* Aluminum works differently from copper here. There's no 60°C aluminum "Romex" for feeders — aluminum comes as SER or USE cable rated 75°C, where 4 AWG aluminum carries 65 amps. So aluminum doesn't have copper's Romex trap; 4 AWG is the aluminum answer either way. The equipment ground stays 10 AWG copper for a 60 amp circuit — the same ground size the code uses all the way from 30 up to 60 amps, and in cable it's already included.
What a 60 amp circuit usually powers
Sixty amps is a common "medium feeder" size. By far the most frequent use is a subpanel — feeding a detached garage, a shop, or a finished basement. After that come hot tubs and spas, EV chargers (a 48-amp charger runs on a 60 amp circuit), welders, smaller electric ranges, and some AC or electric-heat equipment. If yours is a subpanel, there's an extra wiring rule worth getting right — it's the next section.
If your 60 amp circuit feeds a hot tub or spa, NEC Article 680 requires GFCI protection — usually a 60 amp GFCI breaker — plus a disconnect within sight of the tub. It doesn't change the wire size, but budget for the GFCI breaker and confirm the disconnect with your inspector.
Wiring a 60 amp subpanel: the 4-wire feeder
A subpanel is not wired like a simple 240-volt appliance. It needs a 4-wire feeder: two hots, a neutral, and a separate equipment ground. So the cable is 6/3 or 4/3 with ground — never 6/2.
At a subpanel, the neutral bar must be isolated from the ground bar and the enclosure — they're only bonded together back at the main panel. Removing the bonding screw and adding a separate ground bar is required (NEC 250.32 / 408.40). Tying neutral and ground together at a subpanel is the single most common — and most dangerous — subpanel mistake.
Is a 60 amp subpanel enough?
For most detached garages and shops, yes. A 60 amp subpanel comfortably runs lighting, general outlets, and one big load — a welder, an air compressor, or an EV charger — with room to spare. Where 60 amps gets tight is when you want to run several big loads at once, or add electric heat: a 50-amp welder plus a 48-amp EV charger plus a space heater will out-pull a 60 amp feeder.
The honest way to decide is a quick load calculation rather than a guess. If you're adding electric heat, a second big machine, or planning ahead for an EV, stepping up to a 100 amp subpanel is often the smarter long-term call — the wire costs a little more now and saves a re-pull later. Run your actual loads through the calculator before you commit.
Copper vs aluminum for 60 amps
Aluminum is the budget option on 60 amp feeders — 4 AWG aluminum (65 amps at 75°C) in conduit, or a step larger in 60°C cable. Copper is 6 AWG in conduit or 4 AWG in Romex. Aluminum SER is common on garage-subpanel runs where the cost savings add up over distance.
If you go aluminum, treat the terminations properly: aluminum-rated lugs and breakers, antioxidant compound, and torque to spec. For an indoor subpanel run you'll often see aluminum sold as SER cable (for example a 4-4-4-6 aluminum SER for a 60 amp feeder — two hots, a neutral, and a ground), while an outdoor or buried run uses direct-burial USE conductors or THWN in conduit. For the full ampacity behind these numbers, see the AWG ampacity chart.
One more subpanel detail: the panel itself can be a main-lug type (no main breaker, protected by the 60 amp breaker back at the source) or a main-breaker type. Either works for a 60 amp feeder; a main-breaker subpanel just adds a convenient local shutoff, which many people like in a detached shop.
Long runs and voltage drop
Because 60 amp circuits so often feed a detached building, voltage drop matters. Keeping the drop under 3% (an Informational Note under 210.19(A) — advisory, not a hard limit) is the goal on a long run.
6 AWG copper → about 122 ft.
4 AWG copper → about 194 ft. On a long garage or shop feeder past these, step up a size — another reason 4 AWG is a popular default at 60 amps.
The Voltage Drop Calculator runs your exact length, load, and material in one step.
How 40, 50 and 60 amp wire compare
If you're deciding between breaker sizes, here's how the three common mid-range circuits line up. Notice the pattern: the jump from 50 to 60 amps is where copper crosses the line that forces the conduit-vs-Romex choice.
| Breaker | Copper | Aluminum |
|---|---|---|
| 40 amp | 8 AWG | 6 AWG |
| 50 amp | 6 AWG | 4 AWG |
| 60 amp | 6 AWG (conduit) / 4 AWG (Romex) | 4 AWG |
A 50 amp circuit is comfortable on 6 AWG copper in either Romex or conduit; at 60 amps that same 6 AWG only clears in conduit. If you're on the fence between 50 and 60, that wire-type wrinkle is worth factoring in.
Common 60 amp wiring mistakes
The signature one is putting 6 AWG Romex on a 60 amp breaker — it's a 55-amp conductor, so it's undersized and a real fire risk. Close behind is reading the 90°C column (75 amps) to justify going smaller; your terminals are 60 or 75°C, so that column doesn't apply. Then the subpanel errors: bonding neutral and ground together at the subpanel, or running 6/2 where a subpanel needs the neutral in 6/3. And on the long feeders 60 amps so often involves, forgetting voltage drop. As always, this is usually permit-and-inspection work, so confirm with your AHJ.
Frequently asked questions
Wire & CircuitWhat size wire do I need for a 60 amp breaker?
⚡ Wire Size calculator →
Wire & CircuitIs 6 gauge wire good for 60 amps?
Code & SafetyCan I use 6 AWG Romex for a 60 amp circuit?
Wire & CircuitWhat size wire for a 60 amp subpanel?
Wire & CircuitWhat size aluminum wire for 60 amps?
Code & SafetyWhat size ground wire for a 60 amp circuit?
Wire & CircuitWhat gauge wire for a 60 amp 240V circuit?
Wire & CircuitHow far can I run 6 AWG wire on a 60 amp circuit?
⚡ Voltage Drop calculator →
This guide is for general information based on the National Electrical Code. Local codes and your authority having jurisdiction (AHJ) may differ, and subpanel and feeder work is usually permit-and-inspection territory. Electrical work can be dangerous, so when in doubt, hire a licensed electrician.