Wire Size GuideNEC 2023 · 2026 · Updated Apr 2026

What wire size for a 25 amp circuit?

Q: What is the minimum wire size for a 25 amp circuit?

The minimum wire size is 10 AWG copper or 10 AWG aluminum per NEC 2023 Table 310.16 with 110.14(C) termination limits applied. For long runs, you may need to upsize to account for voltage drop. See the max distance table above.

Q: Can I use aluminum wire for a 25 amp circuit?

Yes. 10 AWG aluminum handles 25A. Aluminum requires anti-oxidant compound and AL-rated terminals (marked AL/CU on the device). It costs roughly 40-60% less than copper but requires a larger gauge for equivalent ampacity. See the 10 AWG copper vs aluminum comparison.

Q: How far can I run 10 AWG wire on a 25 amp circuit?

At 240V, 10 AWG copper can run approximately 116 feet before exceeding the 3% voltage drop recommendation. For longer distances, upsize to the next gauge. Use the voltage drop calculator for your exact scenario.

Q: What breaker size for a 25 amp circuit?

Use a 25A breaker. The breaker must match the circuit rating, not the wire ampacity. For continuous loads (like EV chargers), the breaker must be rated at 125% of the load per NEC 210.19(A)(1).

For a 25A circuit on a 25A breaker: Use 10 AWG copper (35A capacity) or 10 AWG aluminum (30A capacity). Common applications: dedicated appliance circuits where 20A is insufficient and 30A is oversized.

Copper10 AWG

Aluminum10 AWG

Breaker25A

Voltage240V

All valid wire sizes for a 25 amp circuit

A 25 amp circuit is less common than 20A or 30A but is used for specific appliances where 20A is too small and 30A is oversized. The minimum wire is 10 AWG copper. Common applications include ductless mini-split outdoor units and small tankless water heaters.

25A breakers are standard but not as common as 20A or 30A. Use 10 AWG copper per NEC Table 310.16 (35A at 75°C, well above 25A). Some mini-split manufacturers specify a 25A maximum overcurrent device.

Any gauge with ampacity equal to or greater than 25A per NEC 2023 Table 310.16, after 110.14(C) termination limits are applied. Smaller gauge number means thicker wire, higher cost, but lower voltage drop.

Gauge	Material	Capacity	Max distance (3% drop)	Conduit
10 AWG (minimum)	Copper	35A	116 ft	3/4" EMT
8 AWG	Copper	50A	185 ft	3/4" EMT
6 AWG	Copper	65A	294 ft	3/4" EMT
4 AWG	Copper	85A	468 ft	1" EMT
3 AWG	Copper	100A	588 ft	1" EMT
2 AWG	Copper	115A	750 ft	1" EMT
1 AWG	Copper	130A	937 ft	1-1/4" EMT
1/0 AWG	Copper	150A	1200 ft	1-1/4" EMT
2/0 AWG	Copper	175A	1500 ft	1-1/2" EMT
3/0 AWG	Copper	200A	1875 ft	2" EMT
4/0 AWG	Copper	230A	2307 ft	2" EMT
10 AWG (minimum)	Aluminum	30A	70 ft	1/2" EMT
8 AWG	Aluminum	40A	112 ft	3/4" EMT
6 AWG	Aluminum	50A	178 ft	3/4" EMT
4 AWG	Aluminum	65A	283 ft	3/4" EMT
3 AWG	Aluminum	75A	357 ft	1" EMT
2 AWG	Aluminum	90A	454 ft	1" EMT
1 AWG	Aluminum	100A	566 ft	1" EMT
1/0 AWG	Aluminum	120A	714 ft	1-1/4" EMT
2/0 AWG	Aluminum	135A	909 ft	1-1/4" EMT
3/0 AWG	Aluminum	155A	1153 ft	1-1/2" EMT
4/0 AWG	Aluminum	180A	1428 ft	2" EMT

Maximum wire run distance

One-way distance in feet before voltage drop exceeds 3%, per NEC Chapter 9 Table 8 resistance values. If your run is longer than these distances, upsize one gauge.

Gauge	Material	120V	208V	240V	480V
10 AWG	Copper	58 ft	100 ft	116 ft	232 ft
8 AWG	Copper	92 ft	160 ft	185 ft	370 ft
6 AWG	Copper	146 ft	254 ft	294 ft	588 ft
4 AWG	Copper	234 ft	405 ft	468 ft	937 ft
3 AWG	Copper	294 ft	508 ft	588 ft	1153 ft
2 AWG	Copper	370 ft	638 ft	750 ft	1500 ft
1 AWG	Copper	468 ft	810 ft	937 ft	1875 ft
1/0 AWG	Copper	588 ft	1034 ft	1200 ft	2307 ft
2/0 AWG	Copper	750 ft	1304 ft	1500 ft	3000 ft
3/0 AWG	Copper	937 ft	1666 ft	1875 ft	3750 ft
4/0 AWG	Copper	1200 ft	2000 ft	2307 ft	5000 ft
10 AWG	Aluminum	35 ft	61 ft	70 ft	141 ft
8 AWG	Aluminum	56 ft	97 ft	112 ft	225 ft
6 AWG	Aluminum	89 ft	154 ft	178 ft	357 ft
4 AWG	Aluminum	141 ft	245 ft	283 ft	566 ft
3 AWG	Aluminum	178 ft	309 ft	357 ft	714 ft
2 AWG	Aluminum	225 ft	389 ft	454 ft	909 ft
1 AWG	Aluminum	285 ft	491 ft	566 ft	1153 ft
1/0 AWG	Aluminum	357 ft	625 ft	714 ft	1428 ft
2/0 AWG	Aluminum	454 ft	789 ft	909 ft	1764 ft
3/0 AWG	Aluminum	566 ft	1000 ft	1153 ft	2307 ft
4/0 AWG	Aluminum	714 ft	1250 ft	1428 ft	3000 ft

Common 25A circuit projects

mini-split condenser
small tankless water heater
large window AC

Frequently asked questions

What is the minimum wire size for a 25 amp circuit?

The minimum wire size is 10 AWG copper or 10 AWG aluminum per NEC 2023 Table 310.16 with 110.14(C) termination limits applied. For long runs, you may need to upsize to account for voltage drop. See the max distance table above.

Can I use aluminum wire for a 25 amp circuit?

Yes. 10 AWG aluminum handles 25A. Aluminum requires anti-oxidant compound and AL-rated terminals (marked AL/CU on the device). It costs roughly 40-60% less than copper but requires a larger gauge for equivalent ampacity. See the 10 AWG copper vs aluminum comparison.

How far can I run 10 AWG wire on a 25 amp circuit?

At 240V, 10 AWG copper can run approximately 116 feet before exceeding the 3% voltage drop recommendation. For longer distances, upsize to the next gauge. Use the voltage drop calculator for your exact scenario.

What breaker size for a 25 amp circuit?

Use a 25A breaker. The breaker must match the circuit rating, not the wire ampacity. For continuous loads (like EV chargers), the breaker must be rated at 125% of the load per NEC 210.19(A)(1).

Do I need GFCI on a 25 amp circuit?

GFCI requirements depend on location, not amperage. NEC 2023 requires GFCI in kitchens, bathrooms, garages, outdoors, basements, laundry areas, and near sinks. Check the GFCI requirements by room for your specific installation.

Common products for 10 AWG Copper circuits

🧵Wire Roll10 AWG copper, 100ftCheck prices on Amazon (paid link) ⚡30A BreakerStandard pairing for 10 AWGCheck prices on Amazon (paid link) 🔌Dryer Cable10/3 NM-B for 30A dryersCheck prices on Amazon (paid link)

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NEC 2023 references verified April 2026