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What Size Wire for 15 Amp Circuit Breaker: Expert’s Advice

Written by Edwin Jones / Fact checked by Andrew Wright

what size wire for 15 amp circuit breaker

In every construction, circuit breakers are always on the list since their significance protects the establishment from unwanted electricity flow and fire incidents.

Circuit breakers have different types, features, and technical specifications to be the basis of our selection. The exact wire gauge also must be carefully considered.

So, What size wire for 15 amp circuit breaker? Is it right to use 12 gauge wire on a 15 amp breaker?

Actually, you can use 14-gauge wire as the ideal wire size for 15 amp circuit breaker or fuse. However, 12 gauge wire is considered a 15a wire gauge for some contractors. Let us continue learning.

Circuit Breakers and Gauge Wires


Circuit Breakers allow interrupting abnormal current that may damage the whole electrical system and cause fire incidents.

It is widely used all over the world with different variations. And each variation has distinct functions as to where it is needed to install.

Here are the common reasons why the circuit breaker trips:

  • The neutral wires fused with hot wires.
  • There is an occurrence of a ground fault.
  • High power consumption appliances.
  • There is a powerline rupture.
  • Overflowing current in the breaker.

On the other hand, Wire size plays an essential role in the performance of circuit breakers. The higher the wire size, the thinner the wire will be.

Here is the usage of different wire gauges:

  • Gauge 4 is for furnaces and large heaters.
  • Gauge 6 is for kitchen cooktops and ranges.
  • Gauge 10 is for water heaters, large AC units, and dryers.
  • Gauge 12 is for small AC units and residential outlets.
  • Gauge 14 is for circuits, devices, and lighting fixtures
  • Gauge 16 is for light-duty extension cords
  • Gauge 18 is for low-voltage lighting and cords

Therefore, choosing the exact wire size impacts the function of the circuit breaker for a steady flow of controlling electricity.

What Gauge Wire for 15 Amp Circuit? Is It 14 Gauge Wire or 12 Gauge Wire? What Is Their Difference?

Generally, there is not much difference between the two but the thickness of the wire.

By dimension, 14 gauge wire has a diameter of 1.628 mm while 12 gauge wire has 2.053 mm. Therefore, 12 gauge wire is thicker than 14 gauge wire, thus offering versatile uses.

It is relatively safe to choose the thicker wire for higher amperage of electricity without overheating since it allows delivery of power in long wire with less risk of voltage drop.

Besides, 12 and 14 gauges are considered suitable as a 15 amp wire gauge for a 15 amp circuit breaker.

How Far Can You Run 12 Gauge Wire on a 15 Amp Circuit?


15 amp breaker wire size of 12 gauge can run as far as 70 feet. It may serve a lot of outlets and lighting wirings.

12 gauge wire is the most commonly used wire size in all construction because of its flexibility and versatility.

However, the 15 amp wire size of gauge 12 is not fit when current overloading occurs. 14 Gauge is suited for current overloading under a 15 amp circuit.

Is It Suitable to Use 10 Gauge Wire on 15 Amp Breaker?

The answer is yes, it is suitable.

For a 240V 15 Amp wire size, 10 gauge wire is suitable. However, it is expensive. This gauge is thicker than the 12 gauge wire size, and it will be hard to wire up a 15 amp outlet.

The use of 10 gauge wire size occurs when the installed outlet is too far from the circuit breaker with a distance of more than 70 feet but less than 100 feet.


The value of choosing gauge wire in a particular breaker will give us assurance that all electrical installations will last and safely.

There are many sources of information about electrical circuit breakers and wire gauges.

But the most important thing is you know the answer to What size wire for 15 amp circuit breaker? It is allowed to use 12 Gauge wire size for almost every electrical activity and 14 Gauge wire for distinct electrical installations.

If you want to learn more about circuit breakers and the uses of wire gauges and want to add some information, don’t hesitate to share your thoughts.

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