electrical question

[farmerpsv]

i get electricity at my new house next monday...yea!!! been so many set backs my head is spinning. anyway, i have my 3rd floor wired and need to install switches and outlets. i have 12g wire with 20A breakers, so i'm assuming i need to put 20A switches and outlets in. which, by the way, have you noticed that lowes and home despot have contractor boxes of 15A stuff coming out there ears for cheap, but all the 20A stuff is pricey? why is that? anyway, if some of you electrical wizes can check me on this i'd appreciate it.
thanks
paul

 

[BillyP]

I'm no electrician but are you going to plug in anything that will pull over 15 amps? I'd say you would be plenty safe with 15 amp switches and outlets.

 

[DaveNay]

I am not an electrical contractor nor inspector, but I believe it is against code to install lighting fixtures and switches on a 20A circuit.

Make sure you check with your local inspector to make sure. /forums/images/graemlins/grin.gif

 

[MossRoad]

I was always told that if you have a 20 amp breaker and you install a 15 amp outlet, you have the potential to burn up the outlet before the breaker can trip. I'd wait to hear from the professionals or check my local code. /forums/images/graemlins/crazy.gif

 

[Marlowe]

I'm no electrical contractor either, but what I do know;
If you have 12 gauge wiring it is certainly enough to carry 20 amps, or anything less than that. If you want to put 15 amp circuits in, you should change the breakers to 15 amps as well so the end circuits will be protected. Codes vary from one area to the next and you should obviously check yours first. I recently wired a house for my mom and we put in 12 gauge wiring throughout to keep it simple, but we were only required to put in 14 guage wiring for the 15 amp circuits. We simply put the lower amperage breakers on the lighting circuits. The code inspector was happy.

 

[BillyP]

Thanks for setting me straight guys /forums/images/graemlins/crazy.gif

 

[Bird]

Like Marlowe, when we built my brother's house, we used nothing but 12 gauge wiring, although some of the circuits had 15 amp breakers.

 

[MGB]

I would put the lighting circuit on a 15 amp breaker. You can use 15 amp receptacles on a 20 amp branch circuit. You can not use 20 amp receptacles on a 15 amp branch circuit. The reasoning for this is you could plug something that's rated for 20 amps (the male plug will have 1 horizontal prong) into the 20 amp receptacle and you'll keep tripping the breaker. The breaker doesn't always trip instantaneously therefore you're drawing more current then the wire can handle which creates heat on the wire. And you need to use AFCI breakers now for bedroom circuits. I'm not sure if the 2005 NEC requires them throughout the house. You should check with your local inspector.

 

[MossRoad]

I think you could plug two small space heaters into a 15 amp outlet and melt it well before the 20AMP breaker tripped. I've seen it happen. That's why I would never put a lower rated end on a circuit than what the breaker is rated for.

As for 12g wire on 15 amp circuits, I like it. It is much easier to wire a house with one size of wire and not worry about which circuit is 14 and which is 12. The 15AMP breakers on 12G wire will trip well before the wire melts.

As always, it is best to check you local codes. Our local electrical inspector was very helpful. I asked him what he would require before I did any repair/replacement work. He came out to inspect and pointed out a thing or two that I was not working on, but he would correct if it was his house. Nice guy. /forums/images/graemlins/laugh.gif

 

[BillyP]

Here's something I dug up.

The National Electrical Code, in article 210.21 (B) 1, 2, and 3, describes the requirements of single and multiple receptacles on a circuit. The use of multiple 15 amp receptacles on a 20 amp circuit is permitted in part 3. A duplex receptacle is considered as multiple receptacles and is therefore permissible to use as the single, or one of several, multiple type receptacles on the circuit.

Part of the UL listing for the 15 amp receptacles is that they are capable of feeding through the 20 amp circuit, the primary difference between 15 and 20 amp receptacles being the faceplate configuration.


Receptacles rated higher than the circuit rating may not be used, so 20 amp receptacles are not permitted on a 15 amp circuit.