[harry_ho]

Hey, folks.

I am in the planning stages of gutting and rebuilding my kitchen and want to get everything compliant with the current codes. I'm wondering, can the two small-appliance circuits be a multiwire branch? Will the GFCI receptacles function properly (or at all) with the shared neutral?

Sorry if this has come up before. I've searched here and the NEC (2008 in Georgia), but haven't been able to find a definite answer.

 

[Code05]

Yes, if you pigtail the neutral at the first outlet and keep line and load connections correct.

 

[gregzoll]

harry_ho, can you possibly upload a preliminary plan on what loads you are looking at, and floorplan with placement of possible outlet locations, along with current floorplan of the before as it is now? Also, have you made sure that your current panel has enough slots available if you need to add circuits, to bring the Kitchen & dining areas up to current codes.

Keep in mind, that the sabc can be one on the counters, and one for baseboard that serves both kitchen & dining. For example, in my Kitchen, I have one sabc for the right side of the counter next to the sink, a sabc for the left side of the sink to serve a countertop microwave & portable dishwasher. A sabc to serve the other side of the Kitchen for the outlet, for the counter to the left of the stove, the outlet to serve the stove for 120vac (gas), and the outlet for the couter to the right of the stove. Then of course, the sabc to serve the disposal, and the sabc to serve the baseboards for both the Kitchen & dining areas.

 

[harry_ho]

Yes, if you pigtail the neutral at the first outlet and keep line and load connections correct.

So, supposing I terminate one ungrounded conductor (let's say the black one) on the first GFCI's line terminal, should I then continue with 12-3 romex to the second circuit's GFCI line side, terminate the other hot wire (the red one) there, and cap the black wire inside the first box? Or would it be better to jump to the second circuit with some 12-2 and splice its black wire with the red inside the first box?

 

[gregzoll]

harry_ho, I would say that in my opinion, that it depends on how your local looks at it. Really need a floor plan to show what you are trying to do.

 

[harry_ho]

harry_ho, can you possibly upload a preliminary plan on what loads you are looking at, and floorplan with placement of possible outlet locations, along with current floorplan of the before as it is now? Also, have you made sure that your current panel has enough slots available if you need to add circuits, to bring the Kitchen & dining areas up to current codes.

Currently, the kitchen is about 12' by 12', but I'm going to rip everything out down to bare studs. Probably, it'll end up being around 12' by 8' in a horseshoe configuration. There are no cabinets along one of the 12' walls now, so I think the kitchen can be condensed and shrunken quite a bit. I'm having some local cabinet guys come in next week to help me decide on the layout and make some drawings. If it ends up being anything at all like what's in my head, there will be about seven countertop receptacles and no base receptacles. I had planned on single-appliance circuits for the dishwasher, disposal, fridge, and microwave/vent hood combo. And the range, of course. The dining room (attached to kitchen, not seperate) will most likely only be large enough to accomodate a six-foot long table, so I'm thinking it will need only a receptacle on each wall to satisfy the spacing rule.

And yes, I have about twenty spaces available in my panel. I replaced the original (crammed) panel before even moving into this place.

I can upload the layout when I get it from the cabinet makers, if you'd like. I'm sure I'll need some more advice on this.

Thanks a ton, guys.

 

[harry_ho]

harry_ho, I would say that in my opinion, that it depends on how your local looks at it. Really need a floor plan to show what you are trying to do.

The residential inspectors in my county are complete morons. They do those all-in-one framing, plumbing, electrical, roofing inspections. No specialized inspectors here. That's why I wanted to ask around on here. The AHJ's a joke.

 

[gregzoll]

The residential inspectors in my county are complete morons. They do those all-in-one framing, plumbing, electrical, roofing inspections. No specialized inspectors here. That's why I wanted to ask around on here. The AHJ's a joke.

So are mine. That is why when I was dating my wife back when she bought this place, she sought what my opinion was. The first thing that I did after she closed on it, was start to rip the four main circuits into sub circuits to bring it more into today's codes.

Our local says that as long as you do not cause problems with your neighbors on the shared transformer, they really do not care.

 

[harry_ho]

Okay, I made a quick and dirty sketch of the new kitchen layout with appliances and receptacles marked. Of course, nothing is to scale, distances are approximate, etc.

 

[Code05]

I would not call that area on the left a dining area. If it was, I would have to invoke 210.12 and require AFCI for the 2 wall receptacles. I do not want to do that. Just put a table there after I am gone.:whistling2:

You could do this a variety of ways.

One option.

1 14 amp MWBC for disposer and dishwasher.
1 20 amp MWBC for range hood and fridge(the two wall rec. with the fridge)
1 20 amp MWBC for counter rec.
add more as you want.

MWBC must be on either a 2 pole breaker or 2 single breakers with a handle tie.

 

[SD515]

1 14 amp MWBC for disposer and dishwasher.

You mean 15A ?

Am I going to have to stock up on 14A breakers again?? :laughing:

 

[harry_ho]

I would not call that area on the left a dining area. If it was, I would have to invoke 210.12 and require AFCI for the 2 wall receptacles. I do not want to do that. Just put a table there after I am gone.:whistling2:

If I remember correctly, Georgia has an amendment to NEC 2008 that eliminates most of the AFCI requirements. I only see arc-fault breakers feeding bedrooms here in new construction.

 

[AllanJ]

GFCI receptacles work fine on a multiwire branch circuit so long as each outlet box has its own GFCI receptacle and nothing is connected to the load terminals of any of the GFCI receptacles.

Correction: You can hang a new two wire continuation off of the load terminals of any of the GFCI receptacles where the portion of the circuit hung off is not part of a MWBC.

Example: MWBC (3 wires) to first outlet box. GFCI receptacle line terminals connected to red and white. White pigtailed to non-MWBC 2 wire continuation, MWBC black connected to continuing non-MWBC black.

At second outlet box connect up GFCI line terminals to incoming 2 wire cable, connect up GFCI load terminals to continuing 2 wire cable with neutrals separate also.

Third and further outlet boxes can use ordinary receptacles protected by GFCI in box #2.

Optional: Tee off a 2 wire (non-MWBC) cable from load terminals of GFCI #1 and continue to other ordinary receptacles as desired.

t is not useful to continue a 3 wire cable fromt he load terminals of a GFCI because you can no longer make use of both the red and black wires. The GFCI load side protected neutral (say, accompanying the black wire)_ must be different from the line side neutral (say accompanying the red wire).

However the 3 wire cable carrying all raw (non-GFCI protected) power can continue as an MWBC past any of the outlet boxes.

 

[AllanJ]

So, supposing I terminate one ungrounded conductor (let's say the black one) on the first GFCI's line terminal, should I then continue with 12-3 romex to the second circuit's GFCI line side, terminate the other hot wire (the red one) there, and cap the black wire inside the first box? Or would it be better to jump to the second circuit with some 12-2 and splice its black wire with the red inside the first box?

Your choice.

If you permanently terminate one ungrounded conducter on the first GFCI and permanently terminate the other hot wire at the second circuit's GFCI line side then you should jump to the second circuit with some 12-2.

Whereas if you want to do a little futureproofing, you can continue both red and black (connect together blacks with pigtail to line side of GFCI #1 and direct connect the reds) using 12-3 wire to outlet box #2 and cap off the black there. This lets you continue the MWBC later (both halves unprotected; any needed GFCI protection provided by additional GFCI units downstream).

 

[harry_ho]

Hmmm...I think I understand most of that. Maybe a drawing is in order...

Those two lower receptacles...will they both be protected when wired this way, or would they each have to be GFCI receptacles, too?

 

[frenchelectrican]

Hmmm...I think I understand most of that. Maybe a drawing is in order...

Those two lower receptacles...will they both be protected when wired this way, or would they each have to be GFCI receptacles, too?

This is the most common way I deal with the MWBC avce GFCI recptales.

Just remember to pigtail non GFCI side netural so you know you can not disconnect it by mistake.

And also make sure if you going to use use single gang box get the deep wells type { 22 CI } so they will have more room to hold it otherwise the other option I do this often is use the 1900 box { 4X4X1 1/2 inch box } with single gang mudring { 5/8 inch ring if you going to use half inch drywall if other thickness just measure it and add 1/8 inch to it ( that will take care of screws they are pesky if not watch out ) and that will take care of it }


Merci,
Marc

 

[AllanJ]

The two lower receptacles as shown are protected and should be ordinary receptacles.

For box fill purposes GFCI receptacle units count the same two points each as ordinary duplex receptacles. But because GFCI receptacles are bigger, the box can be difficult to work in even if the point count is legal. So you should use a somewhat larger box than the point count suggests.

 

[pw5599]

In the CEC they take into account the additional depth of a GFCI outlet and you have to adjust the boxfill according the depth of a particular outlet. The thicker the GFCI outlet, the less wires and caps allowed.