Electricians

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chrisasst

Minister of Fire
Aug 13, 2008
1,289
cortland ny
ok, I have been searching internet for a while..I see all kinds of answers... So I will ask here...

I have 12/2 wire connected to 15 amp switches, lights and several 15 amp outlets. What size breaker should I use.

Last summer when I wired my living room / dining room, I used 15 amp breaker. ( double guessing myself now)

I am wiring my upstairs bedrooms and I am thinking I should use a 20 amp breaker.
 
My NEC is 1993, but this has not likely changed. Table 210-21. Circuit rating - 20 amperes, maximum cord and plug connected load to receptacles - 16 amperes.

Receptacle ratings can be 15 amperes if more than one receptacle on the circuit.
 
The 15 amp breaker on the 12/2 wire will not hurt a thing in fact it will make it safer. If you are using 15 amp devices the breaker should be 15 amps.
 
I am Not an electrician or anything resembling one. I don't see the need for a 20 amp circuit in a bedroom no matter what gauge wire is serving it.
What the heck will you be using in there. On second thought don't answer that maybe I don' wanna know.

:red:
 
I have no idea, just trying to match the wire with the correct breaker...

:coolmad:
 
chrisasst said:
I have no idea, just trying to match the wire with the correct breaker...

:coolmad:
If you have no idea, you really should not be doing breakers and wire selection. Get a book and learn.
 
gzecc said:
chrisasst said:
I have no idea, just trying to match the wire with the correct breaker...

:coolmad:
If you have no idea, you really should not be doing breakers and wire selection. Get a book and learn.

Umm, I was referring to
What the heck will you be using in there
 
I have seen quite a few lights and 15 amp swithes/outlets on 20 amp breakers. I do prefer to see 15 amp breakers on light circuits. The wiring in light fixtures is usually 14 gauge or less ( less being a higher number :eek:hh: ) and really shouldn't be on a 20 amp breaker (possible fire hazard during a direct short).
 
chrisasst said:
I have no idea, just trying to match the wire with the correct breaker...

:coolmad:
You need to match the breaker with the lowest amp device in the circuit, in this case that is 15 amp no matter how big the wire.
 
oldspark said:
chrisasst said:
I have no idea, just trying to match the wire with the correct breaker...

:coolmad:
You need to match the breaker with the lowest amp device in the circuit, in this case that is 15 amp no matter how big the wire.
There are exceptions to that in the NEC and some local variances. For plugs if there is more than one plug on a circuit they may be rated less than the circuits ampacity. In some locations in texas you can run a switch leg with one size smaller wire.

Generally a 15 amp switch would be fine to use on a 20 amp circuit, because the light will never be pulling the full ammount.
 
seige101 said:
Generally a 15 amp switch would be fine to use on a 20 amp circuit, because the light will never be pulling the full ammount.

15 amp switch means it can switch a 15 amp load.( although I wouldn't count on it lasting long if you had it switching a 15 amp load)
 
Hes got 15 amp outlets so so it should have 15 amp breaker.
 
oldspark said:
Hes got 15 amp outlets so so it should have 15 amp breaker.

All the houses around here are 20 amp circuits, 12 gauge wire and 15 amp circuits. The only time I see it different is dedicated outlets, and have even been told I couldn't have more than one 20 amp outlet on a 20 amp circuit. When I questioned it I was field-baptised to the term AHJ.
 
oldspark said:
Hes got 15 amp outlets so so it should have 15 amp breaker.
Sorry thats not true, better look at 210.21(B)(3). you can't have a single 15 amp receptacle on a 20 amp circuit but 1 15amp duplex receptacle is legal. In this case I assume he has multiple 15 amp duplex receptacles
 
Read his post, I am trying to stick to his question, he has several outlets. He needs a 15 amp breaker. I know what the code says for the most part but if it was my house and my circuit I put a 15 amp breaker on it.
 
oldspark said:
Read his post, I am trying to stick to his question, he has several outlets. He needs a 15 amp breaker. I know what the code says for the most part but if it was my house and my circuit I put a 15 amp breaker on it.

Wrong. Several outlets means he can use a 20A breaker if he wants to.
 
burnham said:
oldspark said:
Read his post, I am trying to stick to his question, he has several outlets. He needs a 15 amp breaker. I know what the code says for the most part but if it was my house and my circuit I put a 15 amp breaker on it.

Wrong. Several outlets means he can use a 20A breaker if he wants to.
I know that (I said I knew what most of the codes say, if I want a 20 amp breaker I use 20 amp outlets and if I want a 15 amp circuit I use 15 amp outlets, do not agree with the codes on some issues, some times that want you to over wire things and some times (as in this case) you can use a lower amp outlet on a bigger breaker. The 15 amp breaker is the safter way to go.
 
oldspark said:
] I know that (I said I knew what most of the codes say, if I want a 20 amp breaker I use 20 amp outlets and if I want a 15 amp circuit I use 15 amp outlets, do not agree with the codes on some issues, some times that want you to over wire things and some times (as in this case) you can use a lower amp outlet on a bigger breaker. The 15 amp breaker is the safter way to go.

I think he was looking for what the code says not someones opinion. Code says he can put a 20 amp breaker on his circuit and assuming he wired it correctly it will be perfectly safe.
 
The OP states the wire is 12/2 (all of it) than sure a 20 amp is fine. When i bought my house, I found many circuits with 14/2 romex and a 20 amp breaker. Also a few breakers double tapped. That was the first thing i fixed, inspector must of missed that one. I find myself more interested in arc fault breakers, i think NEC should require them. Having a 20 gauge fine copper strand lamp cord plugged into a 20 amp outlet and having the rocking chair short it out will sure get you a forth of july show and not draw enough to trip the breaker. By the way, happy 4th everyone!
 
Arc faults are required, any place a gfci isn't required and arc fault is, started in 08 code. I'm not sure anyone has proven that arc faults really work in the real world
 
Wallyworld said:
Arc faults are required, any place a gfci isn't required and arc fault is, started in 08 code. I'm not sure anyone has proven that arc faults really work in the real world

Sure they do, especially with the new safety plug outlets that you have to wiggle into the wall. Any kind of a draw like plugging the vacuum back after pulling it from the wall or even a computer xformer or cable box can trip it. The good news is you don't need a solid connection anymore, so don't worry about competent electricians.
 
Wallyworld said:
oldspark said:
] I know that (I said I knew what most of the codes say, if I want a 20 amp breaker I use 20 amp outlets and if I want a 15 amp circuit I use 15 amp outlets, do not agree with the codes on some issues, some times that want you to over wire things and some times (as in this case) you can use a lower amp outlet on a bigger breaker. The 15 amp breaker is the safter way to go.

I think he was looking for what the code says not someones opinion. Code says he can put a 20 amp breaker on his circuit and assuming he wired it correctly it will be perfectly safe.
Yep I know that now so code it is. Have a safe 4th.
 
chrisasst said:
ok, I have been searching internet for a while..I see all kinds of answers... So I will ask here...

I have 12/2 wire connected to 15 amp switches, lights and several 15 amp outlets. What size breaker should I use.

Last summer when I wired my living room / dining room, I used 15 amp breaker. ( double guessing myself now)

I am wiring my upstairs bedrooms and I am thinking I should use a 20 amp breaker.


For the situation you describe a 15 amp breaker would be code here, as this/these circuits are not dedicated for an appliance (fridge, stove, washer, dryer furnace, boiler, hot water tank etc, etc). In other woeds something that is rated for 20 amps.

Installing a 20 amp breaker just because the wire in the wall will handle it would leave you with an over supply situation at all switches & outlets, something to avoid, see also: house fire caused by electrical wiring in your local fire marshalls reports as another reason not to over supply any circuit/device in any home. NEVER.

Oldspark gave you good advise, use a 15 amp breaker in this situation, as over supplying any circuit is dangerous. Doing so will simply force whatever is connected to the circuit to cook as it will not draw enough to trip the breaker. You wouldn't plug your toaster into your range outlet just because you can, right? Same applies here.

Also arc fault breakers may be required in a bedroom by your local code (they are here) worth checking into while your at it. While your at it check with code officials as to the number of switches/outlets permitted on a circuit/breaker, from the way you have described previous wiring you may have too many switches/receptacles per circuit/breaker. Pretty sure from your description that you have exceeded maximum for code here, your code may differ however.

Hope this helps.
 
Also arc fault breakers may be required

Thank you, did not know this, from my research, apparently they are required on all new wiring.
 
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