Can I Mix 12 And 14 Gauge Wire On A 15 Amp Circuit

Before changing the 15 amp breaker to a 20 amp breaker it is the responsibility of the electrician to make sure the entire circuit is run with a minimum wire size of 12 gauge.

Can i mix 12 and 14 gauge wire on a 15 amp circuit. No you can t according to code. Dangerous because an unsuspecting homeowner might eventually see the 12 gauge wire and replace the 15 amp breaker with a 20 amp breaker especially if he or she is getting nuisance trips on the circuit not realizing that further down the circuit the wiring is only 14 guage. 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. There is no problem using 12 awg wire on a circuit protected by a 15 ampere circuit breaker.

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. For example plugging a heater rated for 20 amps into a 15 amp circuit wired with 14 gauge wire poses a distinct danger. From that box however the circuit splits into two lines in order to power low voltage lighting controlled by two switches. For example at the end of a circuit i have a workbox.

If you mix a 12 and a 14 cable this is fine as long as you use a 15 amp circuit breaker to protect the entire circuit. Is it ok to use 12 2 wire on a 15 circuit tapping off a circuit outlet in use or running a new run back to the panel and putting in a 15 amp breaker will this wire work. Is there any reason anyone can think as to why this 12 wire is situated in a 15 amp circuit the rest of which is all 14 2. Is it ok to use 12 and 14 gauge wire in the same circuit.

If a 15 amp breaker is installed on a 12 gauge wire any electrician should think the wire is a long run and not that it was incorrectly installed on a 15 amp breaker. But just in case. It is perfectly acceptable to use a wire size that is larger than the breaker protecting the circuit will allow it is however not acceptable to use a wire size that is smaller than the breaker protecting the circuit this is where you would run the risk of a fire. Because it has even less chance of overheating 12 gauge wire is also acceptable on a 15 amp circuit.

The wire into this box is 12 gauge as is the entire circuit to that point. But i think that it is dangerous to do so. A 15 amp breaker on the other hand will trip before 14 gauge wire overheats. It s this gray area that most people don t know about not even experienced ele.