Odd Multiwire Circuit

George Stolz

Moderator
Staff member
Consider the attached picture.

Assuming the circuit breaker handles are tied together, could you legally use a pair of 12-2 NM cables to go to different points in a kitchen, and then combine them back together to come into, say, an island with a single 12-3 NM cable?
 

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ActionDave

Moderator
Staff member
So you want to combine a MWBC with a ring circuit. Cool.
I wonder what happens to the neutral current divided up portion of the circuit? Do you get some of that EMF that is being discussed in the 12-2 Travelers thread?
 

jeremysterling

Senior Member
So you want to combine a MWBC with a ring circuit. Cool.
I wonder what happens to the neutral current divided up portion of the circuit? Do you get some of that EMF that is being discussed in the 12-2 Travelers thread?
Right on! Can we put a GFCI in there, too!:happyno:
 

John120/240

Senior Member
George, what is the intended application or is this just theoritcal ? At # 4 you would have

240V. Handles are tied together so thats kosher. So as to the ring circuit issues..........IDK
 

jeremysterling

Senior Member
A GFCI receptacle will work just fine.
By that, I hope you mean the recept will trip and not provide any power.

If you have a GFCI wired line/load at outlet "1" and a load on circuit "A" at outlet "4", a portion of the neutral current will run on the circuit "B" neutral homerun. That portion should be enough to trip the GFCI.
 
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al hildenbrand

Senior Member
By that, I hope you mean the recept will trip and not provide any power.

If you have a GFCI wired line/load at outlet "1" and a load on circuit "A" at outlet "4", a portion of the neutral current will run on the circuit "B" neutral homerun. That portion should be enough to trip the GFCI.
Its much simpler than that. Just don't try to use the load side terminals of any GFCI receptacle that has line connections at #1, #2, #3, or #4.
 

jeremysterling

Senior Member
Its much simpler than that. Just don't try to use the load side terminals of any GFCI receptacle that has line connections at #1, #2, #3, or #4.
Agreed.

However, I was contributing to the line of furthering the complicated nature of the OP circuit. What could be simpler than a SABC? Finding a circuit with parallel #12 neutrals, non-grouped MWBC, ActionDave's problematic EMF(!), and GFCI's crammed into every outlet.

Of course, we could plan ahead and put a 1900 box at outlet #3 to make room for your joints.
 
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