What breaker size for 14 AWG wire?

14 AWG copper at 75 °C terminations supports up to a 15 A overcurrent device, based on an estimated ampacity of 18 A. Aluminium of the same size supports less: about 14 A.

How many amps can 14 AWG handle?

Estimated 15 A at 60 °C, 18 A at 75 °C and 20 A at 90 °C for copper, at 30 °C ambient with no more than three current-carrying conductors.

How does a continuous load change the breaker size?

Continuous loads are sized at 125% of the load current before rounding up to the next standard device rating, so a breaker carries no more than 80% of its rating continuously.

Can the breaker be larger than the wire ampacity?

Only in specific permitted cases such as motor and transformer circuits, where the device protects against short circuit and ground fault while overload protection is provided separately. For ordinary branch circuits, the device must not exceed the conductor ampacity after derating.

14 AWG Breaker Size — Amps & Overcurrent Rating

14 AWG copper is estimated at 18 A at 75 °C, which supports a 15 A overcurrent device. Breaker pairing, continuous-load sizing and derating shown.

Quick answer

14 AWG copper pairs with a 15 A breaker at 75 °C terminations, from an estimated ampacity of 18 A. Aluminium of the same size is about 14 A. A continuous load on that circuit should not exceed 14 A, since continuous loads are sized at 125%.

Max breaker (Cu, 75 °C)

15A

Copper 60 / 75 / 90 °C

15 / 18 / 20A

Aluminium 75 °C

14A

Max continuous load

14A

Ampacity and breaker pairing

Estimated ampacity by material and insulation temperature rating, with the largest standard device each supports.

Material	60 °C	75 °C	90 °C	Max device @ 75 °C
Copper	15 A	18 A	20 A	15 A
Aluminium	12 A	14 A	16 A	—

Formula estimate

Derated ampacity and the device that still fits

Ambient temperature and conductor count reduce the usable ampacity before the breaker is chosen.

Conductors in raceway	30 °C ambient	40 °C ambient	50 °C ambient	60 °C ambient
3	20 A → 15 A	18 A → 15 A	16 A → 15 A	14 A → —
6	16 A → 15 A	15 A → 15 A	13 A → —	11 A → —
9	14 A → —	13 A → —	11 A → —	10 A → —
15	10 A → —	9 A → —	8 A → —	7 A → —
25	9 A → —	8 A → —	7 A → —	6 A → —

90 °C insulation, copper, capped in practice by the 75 °C termination rating.

Source & method: Continuous-load example: a 14 A continuous load needs 18 A of design current and a 20 A device. Size your own load.

Neighbouring sizes

Smaller16 AWG13 A copper at 75 °C Larger12 AWG24 A copper at 75 °C

Frequently asked

What breaker size for 14 AWG wire?: 14 AWG copper at 75 °C terminations supports up to a 15 A overcurrent device, based on an estimated ampacity of 18 A. Aluminium of the same size supports less: about 14 A.
How many amps can 14 AWG handle?: Estimated 15 A at 60 °C, 18 A at 75 °C and 20 A at 90 °C for copper, at 30 °C ambient with no more than three current-carrying conductors.
How does a continuous load change the breaker size?: Continuous loads are sized at 125% of the load current before rounding up to the next standard device rating, so a breaker carries no more than 80% of its rating continuously.
Can the breaker be larger than the wire ampacity?: Only in specific permitted cases such as motor and transformer circuits, where the device protects against short circuit and ground fault while overload protection is provided separately. For ordinary branch circuits, the device must not exceed the conductor ampacity after derating.