What Gauge Wire For 20 Amp Circuit Breaker

Not a 25 amp breaker.

What gauge wire for 20 amp circuit breaker. Further down the line where i can not see there is some old 1960 s 14 gauge romex wire attached to it within the walls of the house. For example plugging a heater rated for 20 amps into a 15 amp circuit wired with 14 gauge wire poses a distinct danger. Nec says that a 12 g wire should be protected with a 20 amp breaker only. This old 14 gauge wire is attached to a plug i want to tap into with 14 gauge wire to add a ceiling fan in my bedroom.

Actually its not that easy to answer. Household receptacles are connected using 12 gauge wire. In real life you can do this and a 14 gauge wire can carry 20 amps safely but the problem is that it s not safe to do this in a house. Should the circuit breaker fail to operate correctly that heater will draw more current than the wires can safely handle and could heat the wires to the point of melting the insulation around the wires and igniting surrounding materials.

Can i use 10 gauge wire off of a 20 amp breaker for outlets. No you can t according to code. Consider not doing that and putting the red wire to good use as a multi wire branch circuit. In most home installations several 15 amp receptacles connect to a 20 amp circuit breaker.

What a wire is rated at and what it should be protected with is two different things. I gather you want to ignore the red wire. It depends upon the insulation and the number of wires carrying the same current in the bundle and also it requires specification of whether you are concerned about heat or signal voltage degradation. The wire has a rating that allows it to carry up to 20 amps.

I have a 20 amp breaker in my 1890 s home with 12 gauge wire attached to it. Building codes based on the national electrical code prohibit the use of 14 gauge wire anywhere on a 20 amp circuit. What makes me wonder about the 14 wire on the 20 amp circuit is if it s so bad why do all ceiling chandelers bathroom vent fans table floor lamps etc come with a stranded 18 guage cable. All wiring in such circuits must be 12 gauge or larger.

I mean everyone has lamps alarm clocks etc plugged into outlets that are on a 20 amp circuit with 12 wire running to them and it s obviously not a problem. This allows multiple devices to connect to a single 20 amp circuit as long as the total circuit load does not exceed 20 amps. Co alr are a sure bet because a 20a circuit requires 10 aluminum. You are entering a gray area of safety.