Bathroom wiring /circuit breaker questions

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  #1  
Old 08-29-07, 10:05 AM
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Bathroom wiring /circuit breaker questions

Howdy. I'm in the middle of a bathroom renovation and want to be sure that I do the electric right.

Here's the plan.

I'm installing a vent light heater combo unit over the tub (It's approved for this location but needs to be gfci protected)

I'm putting an outlet near the sink as required by the code (also GFCI Protected)

I have two plug in light fixtures going into different areas of the bathroom but I need to have both work off one switch, so that means that there's a pair of receptacles going in - each with only one side switched.

Here's the issue:

My understanding of the code is that it will not allow an outlet on a circuit for installed equipment (heater/vent /light combo) so I am forced to use a gfci breaker for this circuit.

All of the other outlets will be on one circuit, but because of the complexity (in my mind) of the circuit with some parts of some outets being switched, I don't feel that I can bring the power into the room through a gfci outlet first to protect the remainder of the circuit that way so I need a gfci breaker for this too.

That being said I need two gfci breaker protected circuits. I have a 100 amp service but a new CH BR type load center installed. The load center is supplied by a 100 amp main breaker that the service feeds. I was hoping that I don't have to use up two spaces in the load center for the GFCI breakers, but I can't find a 1 pole duplex GFCI breaker? Do these exist?

And while we're at it, what's the difference between a duplex breaker and a twin breaker?

Thanks for your help!

HB
 
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Old 08-29-07, 10:15 AM
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You do not need two GFCI breakers. You do not even need one GFCI breaker.

One GFCI receptacle can be used as the first receptacle in the bathroom. Then you can feed the other two receptacles (including the switch) off the LOAD side of that GFCI.

For the vent/heater/light you can use a GFCI breaker if you want, or you can use a faceless GFCI. This is a GFCI with no receptacle spaces. You could even use an actual GFCI receptacle if you wanted to.

Consider making this a multi-wire circuit. If you go this route you could use a 240 volt GFCI breaker and be done with it. I recommend a 240 volt breaker whether you make it GFCI or plain. A multi-wire circuit will save you money by allowing you to use a run of 12-3 to the bathroom rather than two runs of 12-2.

In most cases the terms duplex breaker, twin breaker, mini breaker, and tandem breaker mean the same thing. That being two breakers in the space of one. These are quite different than a double pole breaker.
 
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Old 08-29-07, 10:21 AM
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So if I go with a multi- wire circuit I would use a 2 pole 240 volt 20 amp breaker and run 12-3 wire from there into the bathroom and then in the switchbox (or whatever box I came into first), I would split off that third wire and use it to power the second circuit?

Is this correct?

Thanks.
 
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Old 08-29-07, 11:19 AM
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You run the 12-3 into the bathroom and to a switch box. You then separate it into two circuits. One circuit used one hot, the neutral and ground, the other circuit uses the other hot, the neutral and ground. This separation must be made before you attach a GFCI receptacle or faceless GFCI.
 
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Old 08-29-07, 02:17 PM
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Thanks very much for your help!


HB
 
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Old 08-29-07, 02:44 PM
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GFCI breakers are expensive and are a pain as you have to venture to the panel when tripped. Also, I've never heard of using a 240volt breaker for 2 seperate branch circuits. (sorry Bob) I would just use 2 seperate 20amp breakers so that if one circuit trips the breaker it won't trip the other one with it. You have to make sure they're different phases if you want to save money by running a 12-3. Usually breakers 1+2 are A phase, 3+4 are B phase, 5+6 are A phase, 7+8 are B phase... The panel should have a drawing to verify this, otherwise you can check with a voltmeter (A-A = 120volts, B-B = 120 volts, A-B = 240 volts). Keep in mind that with duplex, or tandem breakers, although you have 2 mini breakers, they are both the same phase. The breakers don't have to be directly above or below each other, but you must make sure you have 2 seperate phases. Then bring your 12-3 to a doublegang box. The black can go to a GFCI outlet, and branch off from the load side to feed the outlets in the bathroom. The red would then go to a faceless GFCI and feed the light/fan/heater off the load side. The ground and neutral can be shared up to the line side of the GFCI's, but the neutrals should be seperate from the load side out. this is important because the GFCI's moniter the current between the hot and the neutral to make sure there's no ground fault. When 2 seperate phases share a neutral, they actually cancel each other out. For example if A phase is drawing 5amps and B phase is drawing 6amps the neutral will only be carrying 1amp. The GFCI's will see 5 or 6 amps on the hot, but only 1 amp on the neutral and will assume there's a ground fault.
 
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Old 08-29-07, 02:53 PM
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brewcityc,

I always recommend a 240 volt breaker when advocating for a multi-wire circuit in a residence. It is just too easy for homeowners to make a mistake and end up with both hot wires on the same leg of the incoming service. (Phase is actually an incorrect term here. but I knew what you meant.)

Further, there are cases with a multi-wire circuit where a common trip breaker is required, so using one anyway means you don't have to decide if your situation is one of them.

Finally, a 240 volt breaker makes it obvious that the two circuits are related.

Yes, if wired properly two regular breakers are allowed, but using a 240 volt breaker is easier, safer and eliminates the possibility of a mistake (in most cases).
 
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Old 08-29-07, 03:08 PM
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Originally Posted by racraft View Post
brewcityc,
(Phase is actually an incorrect term here. but I knew what you meant.)
I have always wondered how a residential 240 volt circuit operates when each leg is 120V to ground. My impression was that the red and black each represent a separate phase with an angle of 180 degrees, so the difference is always 240V. If this is not the case, how is 240V derived? TIA for any responses.
 
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Old 08-29-07, 03:31 PM
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The power company generates single phase power for your house. (Three phase power is commonly used for businesses and is different.)

They center tap the transformer and use the center tap as the neutral. This means that the power you get is single phase, but that each hot leg is 180 degrees out of phase with the other one.
 
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