Sixty amps is a common size for a small subpanel in a garage or a workshop, a hot tub, a tankless water heater, and a car charger that delivers forty-eight amps.
How to use this calculator
- Keep 60 amps for a feeder or circuit sized to its breaker.
- Choose NM-B cable for a run inside the walls of the house, or THHN wires for conduit, which is what most subpanel feeders and outdoor runs use.
- Enter the one-way distance. For a detached garage, measure to the subpanel, not to the far end of the building.
- Mark a car charger as continuous: its circuit is sized for 125 percent of the charging current.
Worked examples
A garage subpanel fed through the attic
Load current: 60 A · Circuit voltage: 240 V · One-way distance: 70 ft · Wire type: NM-B or UF-B cable (60 °C)
- Wire size
- 4 AWG copper
- Current the wire must carry
- 60.0 A
- Rated for
- 70 A
- Voltage drop
- 1.08%
- Longest run within 3%
- 195 ft
A hot tub on the patio
Load current: 60 A · Circuit voltage: 240 V · One-way distance: 45 ft · Wire type: THHN/THWN wires in conduit (75 °C)
- Wire size
- 6 AWG copper
- Current the wire must carry
- 60.0 A
- Rated for
- 65 A
- Voltage drop
- 1.10%
- Longest run within 3%
- 122 ft
A car charger at its highest setting
Load current: 48 A · Circuit voltage: 240 V · One-way distance: 55 ft · Wire type: THHN/THWN wires in conduit (75 °C) · Runs for 3 hours or more at a time: Yes, a continuous load
- Wire size
- 6 AWG copper
- Current the wire must carry
- 60.0 A
- Rated for
- 65 A
- Voltage drop
- 1.08%
- Longest run within 3%
- 153 ft
An aluminum feeder to a workshop
Load current: 60 A · Circuit voltage: 240 V · One-way distance: 180 ft · Conductor: Aluminum
- Wire size
- 2 AWG aluminum
- Current the wire must carry
- 60.0 A
- Rated for
- 90 A
- Voltage drop
- 2.87%
- Longest run within 3%
- 188 ft
Wire size for a 60 amp, 240 volt circuit by one-way distance
| One-way distance | Copper, THHN/THWN wires in conduit (75 °C) | Copper, NM-B or UF-B cable (60 °C) | Aluminum |
|---|---|---|---|
| 25 ft | 6 AWG | 4 AWG | 4 AWG |
| 50 ft | 6 AWG | 4 AWG | 4 AWG |
| 100 ft | 6 AWG | 4 AWG | 4 AWG |
| 150 ft | 4 AWG | 4 AWG | 2 AWG |
| 200 ft | 3 AWG | 3 AWG | 1 AWG |
Each cell: the smallest size that carries sixty amps within the usual branch-circuit drop, from the base ampacity table.
Cable or conduit: 4 AWG or 6 AWG
In the lowest temperature column, which NM-B cable must use, 6 AWG copper is rated 55 amps and 4 AWG 70 amps, so a 60 amp breaker on cable needs 4 AWG. Single THHN or THWN wires may use the next column, where 6 AWG carries 65 amps, when the breaker and the equipment terminals are rated for it; subpanels and car chargers generally are. Aluminum 4 AWG is rated 65 amps in the same column, and aluminum is the usual choice for a long feeder because the larger sizes cost far less than copper.
A subpanel feeder needs four wires
A subpanel takes two hots, a neutral and a separate ground, and in the subpanel the neutrals and grounds stay on separate bars. A detached building also needs its own grounding electrode. Voltage drop on a feeder is usually held tighter than on a branch circuit, about 2 percent, so the remaining 3 percent is left for the circuits beyond it: open More options and set the allowed drop to check a long feeder that way.
Hot tubs and car chargers
Hot tubs are fed through a GFCI disconnect within sight of the tub, and the manufacturer's manual names the breaker; many need sixty amps, some fifty. A car charger running at forty-eight amps is a continuous load: the wire must carry 125 percent of that, which is exactly sixty. Check the 50 amp wire guide if your charger runs at forty.
Common questions
Is 6 gauge wire good for 60 amps?
As single copper THHN or THWN wires with terminals rated for the higher column, yes: 6 AWG carries 65 amps. In NM-B cable it is rated 55 amps, so a 60 amp breaker on cable needs 4 AWG.
What size aluminum wire for a 60 amp subpanel?
4 AWG aluminum, rated 65 amps, for a short feeder. On a long run to a detached building, voltage drop often calls for 2 AWG; the table shows where.
What wire do I need for a 48 amp car charger?
A charger that delivers forty-eight amps is continuous, so its circuit is a 60 amp one: 6 AWG copper THHN in conduit, or 4 AWG copper NM-B cable, on a short run.
Does a 60 amp subpanel need a ground wire?
Yes. A subpanel is fed with two hots, a neutral and an equipment ground, and its neutral bar is kept separate from the ground bar.