15 Amp Circuit Breaker

Questions about 15 Amp Circuit Breakers

New and Updated about: 15 Amp Circuit Breakers

Chris in Wellington, Colorado asks:

Should a 15Amp circuit be 14AWG Wire?

My garage has a 15 amp circuit breaker. The circuit has both ceiling lights and receptacles. The lights are tapped into the first receptacle. All the wiring is 14 AWG. The breaker box is full (i.e., there is no room to add another circuit). I would like to upgrade the existing circuit to either 20 or 30 amps. If I run new 12 AWG or 10 AWG wire to the receptacles can I leave the 14 AWG for the lights or do I need to replace all the 14 AWG wire on the circuit?

Dave’s Answer:
The wire size for a 15 Amp circuit is 14AWG Copper. This wire size should be used throughout the circuit. When we find that there are more then one size of wire that has been installed within a circuit, then the circuit breaker must be sized to the smallest size of wire to prevent overheating of the wire which can lead to a potential fire hazard.
If you plan to upgrade the circuit to a larger size then all of the circuit wire should be upgraded as well.

Jack in Ohio asks:
Is 14-3 Romex better than 12-3 Romex for Wiring in a House?

Is 14-3 Romex just as safe or as good as 12-3 Romex? I’m planning on a four way switch for a ceiling fan in the kitchen and a separate switch for the fan blades. This is a two story house and already have newer 14-3 wire upstairs with 15 amp breaker, mostly for the lighting. The house is old, built around the turn of last century. I need to purchase a new 250’coil of wire and read somewhere “real men use 12-3 for the whole house”. Any advise you can give will help.

Dave’s Reply:
Electrical Circuit Planning

Actually, when I see that someone has wired a house (plugs and lights) with 12-2 or 12-3 I am surprised that they just wasted a lot of money and made the job much harder for themselves. Here’s why: Most of the outlets and switches in a home are 15 amp rated, therefore making up the wires to these devices takes much more time and effort. With few exceptions, it is not necessary to wire general purpose branch circuits in the common rooms with #12 wire and 20amp circuits. The overall expense is much more when using #12 wire compared to #14. The exceptions are in areas such as the kitchen, garage, and laundry room, etc., and for dedicated circuits for specific appliances and equipment.

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