Bathroom Electrical Circuit Drawing

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  #1  
Old 06-02-13, 06:08 PM
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Bathroom Electrical Circuit Drawing

Hi everyone,

I am re-wiring a half bath and the full bathroom which is directly on top. The half bath will have a GFCI socket, a light & fan. The full bath above will have 2 GFCI sockets, a light & fan, and a vanity light. I ran 12/3 from the panel to the half bath with the idea of using the 1 hot (red) for the half bath and the other hot (black) for the full bath upstairs. Based on advice on previous threads if multiple blow dryers etc are plugged in.

I based the wiring of the GFCI off the following diagram from the book.



Here is a a drawing of the circuit I created.



How does it look guys?

PS Is it correct to assume that all light housing boxes are metal? I ask because in the black and decker book I see that the green wire (the ground) is always screwed into a box. That makes sense for the light housing boxes but if you are using plastic boxes for the switches you wouldn't screw it in.

Thoughts comments? As you can see from the above drawing, I will be using the black hot for upstairs bath and the red hot for the downstairs. The neutral will be shared path back to the panel.
 
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  #2  
Old 06-02-13, 06:17 PM
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Looks ok
At your first receptacle, instead of putting both neutral wires on the device....make a splice with those two neutrals and leave a tail out to the device.

You're showing the lower bathroom wiring in two wire w/ground cable with a red and white wire......good for demo purposes but the actual colors will be white and black.
 
  #3  
Old 06-02-13, 10:04 PM
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There's no need, and no benefit, in providing GFCI protection to either lighting or fans. Based on your text (not on your drawing) it appears that the GFCI protection for the receptacle in each bathroom will be the receptacle itself.

I would terminate the wires in the 2-conductor cable that continues to lighting and fans next to the panel feed wires, on the LINE terminals. In the second floor bath, the wires in the cable going to the second (standard) receptacle should be terminated to the LOAD terminals on the GFCI in that bath. Again, the wires feeding other loads should be connected to the LINE terminals.
 
  #4  
Old 06-03-13, 12:09 AM
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Exclamation Updated Diagram

I have slightly modified the drawing after some feedback.

PJmax, yes I used the red instead of black for illustration purpose. The 12/2 I have is black and white.

Nashkat1, that makes sense that there is no benefit in providing gfci protection to the lights and fan. I guess that makes sense only of you are outside as the black top drawing illustrates. I updated the drawing and removed GFCI protection to the lights and switch.

thoughts?

Name:  Electrical CircuitAI File 2.jpg
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PS here is a link to the bigger image. Hard to see since forum shrinks original.

http://img716.imageshack.us/img716/9...cuitaifile.jpg
 
  #5  
Old 06-03-13, 05:55 AM
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Something I read (possibly Wiring Simplified) suggested running 12(14)/3 from the last switch to the last feature so that you still have a neutral wire in case you upgrade that final fixture/switch to something that requires a neutral in the future.
 
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Old 06-03-13, 06:06 AM
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Under 2011 NEC all switches must have a neutral even if not needed. There are minor exceptions but only if the neutral remains easily added at a later date such as conduit.
 
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Old 06-03-13, 06:38 AM
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Something I read (possibly Wiring Simplified) suggested running 12(14)/3 from the last switch to the last fixture
As Ray mentioned, you only need a neutral at the switch location (which the drawing above has). Usually this is only relevant for a switch-loop, not in this case.

I think the most recent drawing looks good. One clarification though, the 12/3 will connect to a 20A double-pole breaker or two 20A single-pole breakers with a handle tie. If it's actually a fuse box, two 20A fuses.

And you probably figured out the answer to your grounding question. Metal boxes need a separate ground wire screwed (using a green screw) to them. Plastic boxes don't need any grounding.
 
  #8  
Old 06-03-13, 06:48 AM
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Red face

Zorfdt,

Yes the 12/3 will connect to a 20A double-pole breaker. Assuming here that 1 hot (black) goes to one switch and the other hot (red) goes to other switch correct?

As far as metal boxes, am I correct in assuming all light fixtures go in some fort of metal box? Thinking that would be the case because of heat.

There will be a neutral inside the box (its pigtailed in diagram).

Guys, am I correct in also assuming that in the book drawing (the one with black background), if the GFCI gets tripped, the light switch and light bulb get there power cut off?
 
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Old 06-03-13, 09:58 AM
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the 12/3 will connect to a 20A double-pole breaker.
The better practice for protecting the two hot legs of a MWBC, at least IMO, is to use two single-pole breakers with their handles joined with a handle tie; this allows each circuit to trip without having to trip the other while still insuring that both will be turned off if work needs to be done.

1 hot (black) goes to one switch and the other hot (red) goes to other switch correct?
I hot goes to each bathroom and, in each bathroom, goes first to the GFCI receptacle in that bathroom, as you said earlier and show in your drawing.

As far as metal boxes, am I correct in assuming all light fixtures go in some fort of metal box? Thinking that would be the case because of heat.
No. I prefer to always use metal boxes, but that's because they will be bonded to ground. Plastic boxes are rated for the heat that will be present.

am I correct in also assuming that in the book drawing (the one with black background), if the GFCI gets tripped, the light switch and light bulb get there power cut off?
Yep.

there is no benefit in providing gfci protection to the lights and fan. I guess that makes sense only of you are outside as the black top drawing illustrates.
GFCI protection isn't required nor necessarily beneficial for exterior lighting either. GFCI protection is required where a person might inadvertently contact ungrounded power while, themselves, providing a path to ground. Thus receptacles in kitchen, bathrooms, garages, outside, etc.
 
  #10  
Old 06-03-13, 01:09 PM
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Guys after reading up on a multi-wire branch circuit (mwbc) here is a drawing I made of what the connection will look like at the panel.



Could anyone clarify the part about the handles being joined? With the above drawing, each hot is on its own bus. I have some fuses that have 2 handles tied to each other but they are on the same side of the bus.
 
  #11  
Old 06-03-13, 01:38 PM
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Could anyone clarify the part about the handles being joined? With the above drawing, each hot is on its own bus. I have some fuses that have 2 handles tied to each other but they are on the same side of the bus.
No, they aren't. If they are directly across from each other they are on the same bus, and leg. That will blow, literally.

The two breakers must be installed in two adjacent slots on the same side of the panel. Then each will be on a different leg and bus.

The two hot buses in your panel serve alternating rows of breakers, not the opposite sides. Pull the cover and look.
 

Last edited by Nashkat1; 06-03-13 at 04:00 PM.
  #12  
Old 06-03-13, 03:44 PM
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Thanks for pointing that out Nashkat1. I just updated the drawing.

Ok so based on everything that has been discussed. I need to get a "20 Amp Two-Pole Circuit Breaker" like this:



The Multiwire Branch Circuit drawing connection at the fuse panel should look like this:



Final circuit design should look like this:


Thoughts? Do we have a winner?
 
  #13  
Old 06-03-13, 04:06 PM
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based on everything that has been discussed. I need to get a "20 Amp Two-Pole Circuit Breaker"
No.
Originally Posted by Nashkat1
The better practice for protecting the two hot legs of a MWBC, at least IMO, is to use two single-pole breakers with their handles joined with a handle tie; this allows each circuit to trip without having to trip the other while still insuring that both will be turned off if work needs to be done.
The Multiwire Branch Circuit connection drawing at the [main distribution] panel should look like this:
Yes.

Do we have a winner?
Close, but no cigar. Yet.
 
  #14  
Old 06-03-13, 05:31 PM
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Question Handle Tie

Nashkat1,

So you would recommend two single-pole breakers 20 AMP breakers and a handle tie. Is this the handle tie you are referring to?

Name:  Handle tie - GE-Breakers-GENTHT104-2720.jpg
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If one side of the circuit gets tripped wouldn't tying the 2 together trip the other breaker too? That is of course if the above image is correct.
 
  #15  
Old 06-03-13, 07:38 PM
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So you would recommend two single-pole breakers 20 AMP breakers and a handle tie.
Yes.

Is this the handle tie you are referring to?
Possibly. Is that a handle tie made by the company that manufactures the breakers you'll be installing?

If one side of the circuit gets tripped wouldn't tying the 2 together trip the other breaker too?
No, and that is the point of using two single-pole breakers with their handles joined with a handle tie. Simultaneous trip in a 2-pole breaker is insured by a connection that doesn't rely on the handles.
 
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