One Romex

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  #1  
Old 11-27-14, 10:55 PM
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One Romex

There is a duplex receptacle under the sink. The top receptacle is hot and is used for the dishwasher. The bottom receptacle is switched and is used for the garbage disposer. There is one 12/3 with ground going to the receptacle. In the breaker box the black goes to a 20 amp breaker for the dishwasher. The red goes to an adjacent 20 amp breaker for the disposer. The white goes to neutral. The bare goes to ground. Is it OK for these two adjacent breakers to share a neutral?
 
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Old 11-27-14, 11:12 PM
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As long as you can measure 208 or 240V between the red and black you're legal.
 
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Old 11-28-14, 04:49 AM
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Are the handles tied together? They must both trip at the same time. It is called a MWBC, or multi wire branch circuit.
 
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Old 11-28-14, 09:04 AM
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They are not tied together. I will go get a handle tie and fix it.

If I convert the breakers to duel afci/gfci breakers, do I just have the neutral go to the first breaker and then jump between the neutral connections of the two breakers?
 
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Old 11-28-14, 12:16 PM
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With GFCI and a MWBC you need a two pole breaker. There are none currently made that also do AFCI the way you need for the 2014 NEC.

What brand panel do you have?

One option is to put AFCI breakers in and then change to two GFCI receptacles. Other option is to add a sub-panel for the extra breakers.
 
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Old 11-28-14, 01:39 PM
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Square D Homeline. Does the 2014 code require the garbage disposer circuit to be AFCI protected? If I use two Dual Function AFCI/GFCI breakers and tie them together with a handle tie and split the neutral and have it go to each breaker will it work and will it meet code?
 
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Old 11-28-14, 01:43 PM
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I am trying to see if I can get AFCI protection without having to run another line. The current line is 12/3 with ground which has two hots but only one neutral.
 
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Old 11-28-14, 01:59 PM
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You can not tie two GFCI or AFCI/GFCI dual function breakers together.
Per Square-D - http://download.schneider-electric.c...e=HRB86114.pdf
"This arc-fault and ground-fault detection device is
not designed or intended for use on circuits in
which the neutral conductor is shared with other
circuits. The circuit breaker will nuisance trip in
“shared neutral” circuits."
2014 NEC says all 120v 15 and 20 amp kitchen circuits need AFCI protection.

One last option - check amperage ratings of dishwasher and GD. If low enough combine them on one 20 amp circuit and don't use the red wire in the existing 12/3 cable.
 

Last edited by Astuff; 11-28-14 at 02:32 PM.
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Old 11-28-14, 02:47 PM
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Are you under 2014 code where you live? Do you absolutely need to adhere, to it? Just curious.
 
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Old 11-28-14, 04:57 PM
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You have a multi-wire circuit. If this is an existing installation it would be grandfathered in. Handle ties were required about 2002, GFCI protection in 2014, and AFCI may not be required at all depending on a few things.

BTW - There are AFCI/GFCI combo single pole breakers available now.
 
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Old 11-28-14, 06:32 PM
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BTW - There are AFCI/GFCI combo single pole breakers available now.
As far as I know, only Square D has them in both Homeline and QO versions. They have a purple test button.

Are the handles tied together? They must both trip at the same time. It is called a MWBC, or multi wire branch circuit.
Common trip is not required on a multiwire branch circuit, but common disconnect is. When using a handle tie, normally one single pole breaker will trip telling the electrician on which circuit he must look for the problem. This is the big advantage in using handle ties. 2-pole breakers can also be used on a multiwire branch circuit and would provide a common trip making troubleshooting a little bit more involved.
 
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Old 11-29-14, 08:53 AM
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I have installed a handle tie to tie the two existing breakers together. I plan on adding a couple of circuits in the future. If I am required to bring things up to 2014 code when I do the job, I will combine the dishwasher and garbage disposer onto one circuit. If by then there is a breaker solution where I can have two circuits, then I will probably do that.

I am in Colorado. Colorado has adopted the 2014 code. When I add the two circuits I will first contact the inspector to be sure that all the old stuff is grandfathered.

Thanks a lot for the help.
 
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Old 11-29-14, 09:38 AM
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I will combine the dishwasher and garbage disposer onto one circuit
Your original question was if the neutral can be shared, answer is yes. It was done all the time, especially on DW and Disposer Circuits. I would just leave it alone. One good thing is that you learned to turn off both breakers when working on either circuit.

Right now you have Disposal and Dishwasher on two circuits, that's not a bad thing. Codes change, but that doesn't mean you have to go through the house and start rewiring everything.

If safety is paramount to you, than yes, go for it. But don't feel this must be done.
 
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Old 11-30-14, 06:53 PM
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Thanks for all the help, advise, and encouragement.
 
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