Multiple lights/ceiling fans on 14/2??

sleepy23 · 05-06-2007, 11:05 PM

well i did a search for 14/2 wiring and came up with a couple of different ideas. I am planning on transferring some fans from my upstairs down to the basement. On the circuit I will be using, there are or will be 10+ lights. Should I go ahead and wire the fans up with 12ga or is 14ga OK? Some ppl are telling me that 14ga is alright if you are just doing a few lights, others are saying to use 12ga to be safe. So with outlets and everything, I am col with how to wire those, just not sure about the draw of multiple lights on 14ga wire.
Thanks

HouseHelper · 05-07-2007, 09:50 AM

What is the wire gauge and breaker size of the existing circuit (assuming that is what you are attaching to)? If new, use 14ga and a 15A breaker.

jwhite · 05-07-2007, 08:59 PM

We need to know the amperage for what you are wanting to add to the downstairs circuit, and the amperage that is already on it, and as said what size wire and breaker are on that circuit now.

Next we need to do the math. P= E x I where P = watts, E = volts and I = amps

convert all the ratings you list into amps then post back with the totals.

darren · 05-07-2007, 09:02 PM

Hello

The number of lights on a circuit does not determine the size of wire. The size of wire is derermined by the breaker because the breaker is there to protect the wiring.

If you are using a 15A breaker you will be fine with #14, if you are useing a 20A breaker then you will have to use #12.

jwhite · 05-07-2007, 09:29 PM

Darren, I can see where you are confused, so let me try to help you understand better.

You are correct that 12 wire goes on a 20 amp breaker and 14 wire goes on a 15 amp breaker.

You misunderstand the aproach to sizing a circuit.

The first step is to calculate the load on the circuit.

Lets say we have 32 ea 60 watt bulbs. 60/120 = 0.5 and 32 x 0.5 = 16 amps.

Once we know the load we look next at wire size. A 16 amp load is above 15 so we would use a 12 wire. Last we size the breaker. 12 wire is good to 20 amps so that is easy.

We now can either use a 20 amp breaker and number 12 wire, or divide the circuit into two so as to not overload a 15 amp breaker.

I do not know the code in Canada, but I do know the NEC. So, before we argue the clause that in residential work, general purpose lighting outlets have no load, (meaning no load calculations need to be done on these circuits) lets move into a real installation where if we overload the circuit the breaker will neusance trip.

Sorry for the run on sentence, and I hope you understand this better now.

sleepy23 · 05-10-2007, 11:27 AM

wow, calculate loads on electrical circuits..havent done that since i was back in college ( and I hated electrical back then too). I ended up removing one of the lights already in the basement and replacing it with the two fans from upstairs. i wired them in with 14ga (like existing) and they work fine. no overloads, no problems.
Thanks