Wire Size GuideNEC 2023 · 2026 · Updated Apr 2026

What wire size for a 15 amp circuit?

Q: What is the minimum wire size for a 15 amp circuit?

The minimum wire size is 14 AWG copper or 12 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 15 amp circuit?

Yes. 12 AWG aluminum handles 15A. 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 14 AWG copper vs aluminum comparison.

Q: How far can I run 14 AWG wire on a 15 amp circuit?

At 120V, 14 AWG copper can run approximately 38 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 15 amp circuit?

Use a 15A 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 15A circuit on a 15A breaker: Use 14 AWG copper (20A capacity) or 12 AWG aluminum (20A capacity). Common applications: lighting and general-purpose outlets.

Copper14 AWG

Aluminum12 AWG

Breaker15A

Voltage120V

You\'re adding lighting to a room, wiring a new bedroom, or the breaker keeps tripping on a circuit that was fine until you plugged in one more thing. Most 15A searches come from homeowners figuring out why a circuit is overloaded or whether they can add an outlet to an existing run.

All valid wire sizes for a 15 amp circuit

A 15 amp circuit is the most common residential branch circuit, powering lighting fixtures, bedroom outlets, and general-purpose loads. NEC 240.4(D) limits 14 AWG copper to 15A maximum overcurrent protection.

Per NEC 240.4(D), 14 AWG copper must not be protected above 15A. The 90°C insulation rating only provides derating headroom, not increased breaker sizing.

Common mistake: Putting 14 AWG wire on a 20A breaker. NEC 240.4(D)(3) limits 14 AWG to 15A overcurrent protection, period. No exceptions, no derating tricks. The other common mistake: daisy-chaining too many outlets on one 15A circuit. There is no NEC limit on the number of outlets per circuit, but the practical limit is 8-10 general-purpose receptacles before the combined load risks nuisance trips.

Any gauge with ampacity equal to or greater than 15A 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
14 AWG (minimum)	Copper	20A	38 ft	1/2" EMT
12 AWG	Copper	25A	60 ft	1/2" EMT
10 AWG	Copper	35A	96 ft	3/4" EMT
8 AWG	Copper	50A	153 ft	3/4" EMT
6 AWG	Copper	65A	243 ft	3/4" EMT
4 AWG	Copper	85A	389 ft	1" EMT
3 AWG	Copper	100A	491 ft	1" EMT
2 AWG	Copper	115A	625 ft	1" EMT
1 AWG	Copper	130A	769 ft	1-1/4" EMT
1/0 AWG	Copper	150A	1000 ft	1-1/4" EMT
2/0 AWG	Copper	175A	1250 ft	1-1/2" EMT
3/0 AWG	Copper	200A	1578 ft	2" EMT
4/0 AWG	Copper	230A	2000 ft	2" EMT
12 AWG (minimum)	Aluminum	20A	36 ft	1/2" EMT
10 AWG	Aluminum	30A	58 ft	1/2" EMT
8 AWG	Aluminum	40A	93 ft	3/4" EMT
6 AWG	Aluminum	50A	148 ft	3/4" EMT
4 AWG	Aluminum	65A	236 ft	3/4" EMT
3 AWG	Aluminum	75A	297 ft	1" EMT
2 AWG	Aluminum	90A	375 ft	1" EMT
1 AWG	Aluminum	100A	476 ft	1" EMT
1/0 AWG	Aluminum	120A	600 ft	1-1/4" EMT
2/0 AWG	Aluminum	135A	750 ft	1-1/4" EMT
3/0 AWG	Aluminum	155A	937 ft	1-1/2" EMT
4/0 AWG	Aluminum	180A	1200 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
14 AWG	Copper	38 ft	66 ft	76 ft	153 ft
12 AWG	Copper	60 ft	104 ft	120 ft	241 ft
10 AWG	Copper	96 ft	167 ft	193 ft	384 ft
8 AWG	Copper	153 ft	267 ft	309 ft	612 ft
6 AWG	Copper	243 ft	422 ft	491 ft	967 ft
4 AWG	Copper	389 ft	681 ft	769 ft	1578 ft
3 AWG	Copper	491 ft	857 ft	967 ft	2000 ft
2 AWG	Copper	625 ft	1071 ft	1250 ft	2500 ft
1 AWG	Copper	769 ft	1363 ft	1578 ft	3000 ft
1/0 AWG	Copper	1000 ft	1666 ft	2000 ft	3750 ft
2/0 AWG	Copper	1250 ft	2142 ft	2500 ft	5000 ft
3/0 AWG	Copper	1578 ft	2727 ft	3000 ft	6000 ft
4/0 AWG	Copper	2000 ft	3333 ft	3750 ft	7500 ft
12 AWG	Aluminum	36 ft	63 ft	73 ft	147 ft
10 AWG	Aluminum	58 ft	102 ft	117 ft	234 ft
8 AWG	Aluminum	93 ft	162 ft	187 ft	375 ft
6 AWG	Aluminum	148 ft	256 ft	297 ft	588 ft
4 AWG	Aluminum	236 ft	410 ft	468 ft	937 ft
3 AWG	Aluminum	297 ft	517 ft	600 ft	1200 ft
2 AWG	Aluminum	375 ft	652 ft	750 ft	1500 ft
1 AWG	Aluminum	476 ft	833 ft	937 ft	1875 ft
1/0 AWG	Aluminum	600 ft	1034 ft	1200 ft	2307 ft
2/0 AWG	Aluminum	750 ft	1304 ft	1500 ft	3000 ft
3/0 AWG	Aluminum	937 ft	1666 ft	1875 ft	3750 ft
4/0 AWG	Aluminum	1200 ft	2142 ft	2500 ft	5000 ft

Common 15A circuit projects

bedroom outlets

Bedrooms typically get one or two 15A circuits for receptacles and lighting. AFCI protection is required on all bedroom circuits per 210.12(A), which has been in the code since 2002. Run 14/2 NM-B from the panel to the first outlet, then daisy-chain to additional outlets. Place receptacles so no point along the wall is more than 6 feet from an outlet per 210.52(A).

living room lighting

Living room lighting circuits use 14 AWG on a 15A breaker. With LED fixtures drawing 10-50 watts each, a single 15A circuit can handle an entire room of lighting plus several receptacles. AFCI protection is required per 210.12(A). Consider putting lights and receptacles on separate circuits so a tripped breaker does not leave you in the dark.

closet lights

Closet lighting has specific rules under NEC 410.16. Incandescent fixtures must be on the ceiling or wall above the door with the lens fully enclosed. LED fixtures can be closer to storage. The most common violation: a bare-bulb fixture inside a closet where clothes can contact it. A surface-mounted LED fixture on the ceiling is the simplest code-compliant option.

Frequently asked questions

What is the minimum wire size for a 15 amp circuit?

The minimum wire size is 14 AWG copper or 12 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 15 amp circuit?

Yes. 12 AWG aluminum handles 15A. 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 14 AWG copper vs aluminum comparison.

How far can I run 14 AWG wire on a 15 amp circuit?

At 120V, 14 AWG copper can run approximately 38 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 15 amp circuit?

Use a 15A 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 15 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 14 AWG Copper circuits

🧵Wire Roll14 AWG solid copper, 500ftCheck prices on Amazon (paid link) ⚡15A BreakerStandard pairing for 14 AWGCheck prices on Amazon (paid link) 🔧Wire Strippers14 AWG compatibleCheck prices on Amazon (paid link)

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NEC 2023 references verified April 2026