Lighting, Light Fixtures, Ceiling and Exhaust Fans - Need help adding a switch

I have a light fixture with a pull, i want to put a switch on it instead. The fixture has 14 awg wire, is it ok to run 12 awg wire(it is what i have laying around the house) just to put the switch on. I always was under the impression as long as you go up in size you were ok. Obviously the fixture runs to a 15 amp breaker.

Yes, this is legal.

The problems with mixing wire gauges arise when someone sees 12 awg wire and thinks "gee, I can put a 20 amp breaker on this instead!". Which is not likely to happen here.

But on second thought maybe I should add that it's legal in the US. That 'tandem breaker' thread of yours still has me scratching my head for various reasons... ;)

yeah, I am not sure what is going on there. It has not tripped for a few days now, so i am not worrying about it since the guys have assured me that it has to be a 15amp breaker.

so do you think i need to buy some 14awg wire and switch this fixture or can i stick w/ the 12awg

Like I said, if you're in the US you can use the 12 gauge that you have. That's the answer.

The reasons for going out and actually buying wire for this would include:
- If you're going to run into box fill limitations
- 14 gauge is easier to work with, and 12 gauge can be a real pain im my opinion when you have multiple switches in one box

It's up to you. I would just use the 12awg since you have it.

thank you very much, that is what i needed to know. i will continue on. sorry for my ignorance

It is perfect legal to use the #12 on 15 amp circuits but keep in your mind that if other wires are like #14 you are restricted to keep to 15 amp breakers.

just give you a head up with size issues.

Core did make good point with the amount of wire[s] in the box it can get overfilled if not carefull with it.

Merci, Marc

thanks for the post. I finished the wiring and it is working just right. I have read so much on mismatch wiring I started getting worried.

thanks for the clarity.

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The danger with using 12 gage (or larger) size wiring on a portion of a circuit that is wired with some 14 gage wire is that someone later on will on will find the 12 gage wire. This may lead them to think they can increase the load on the circuit when in fact they cannot, or should not.

If the 12 gage wire is at the panel, very few people (I suspect) would open every junction box to investigate the wiring. If the 12 gage wire is further down, someone might extend the circuit from the 12 gage wire without first checking the breaker. Then when they go to make the connection they discover a 15 amp circuit. They might not, at this point, run the circuit elsewhere.

If this were my house I would not have used the 12 gage wire on the circuit. If I found a situation where 12 gage wire was used on a 15 amp circuit I would either bring the entire circuit up to 12 gage wire or down to 14 gage wire, or at the very least I would make a note on my circuit breaker chart that the circuit contains both 12 and 14 gage wire. I recommend you do that.

Yeah that is probably a good idea. I love these forums. Thanks for the advice. I am learning everyday. It is a very short run of 12awg wire. I will label the box as having 12awg wire on it, better safe than sorry.

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