Multiwire circuits- splitting neutrals

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Keraunos

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I cannot seem to locate a NEC reference that covers "T"-ing a neutral of a multiwire circuit, in order to run each circuit in opposite directions. Is this a violation?
 
Keraunos said:
I cannot seem to locate a NEC reference that covers "T"-ing a neutral of a multiwire circuit, in order to run each circuit in opposite directions. Is this a violation?
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Isn't the whole point of a multi-wire branch circuit to share the neutral between multiple circuits? I don't see how this would be a code violation.
 
Keraunos said:
I cannot seem to locate a NEC reference that covers "T"-ing a neutral of a multiwire circuit, in order to run each circuit in opposite directions. Is this a violation?
Click to expand...



Welcome to the forum,,,you will not find a reference against that because it would in itself defeat the purpose of a MWBC.
 
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do you mean bringing a MWBC (lets say 3 wire Red, Black, Neutral) to a junction box, then taking two 2 wire circuits from there (for example Red/Neutral headed east and Black/Neutral headed west)?
 
A MWBC is created by connecting two (or three) wires to two (or three) breaker positions, and running those wires, along with one neutral wire, out of the panel. But at some point, each of the ungrounded (phase) wires will land on a receptacle, or a light fixture, or some other outlet or piece of equipment. When it does, it will have a neutral wire with it. So you are going to have to split the neutral run somewhere along the line.
 
FWIW, the NEC is a 'permissive' set of rules. It more or less states what you cannot or must do. If a particular design is not addressed, then 'permission' to do so is assumed.
 
Keraunos said:
I cannot seem to locate a NEC reference that covers "T"-ing a neutral of a multiwire circuit, in order to run each circuit in opposite directions. Is this a violation?
Click to expand...
The only recent change in '08 on MWBC's is to have handle ties on the breakers serving it - so that people who are not qualified to work on them don't hurt themselves or damage the loads attached to them by working them live. :roll: Another change is the grouping of conductors so that persons who lack a clue in figuring out which wire is which don't confuse the wires of one MWBC with those of another. Something most people who would ever come back to the same install would do anyway... Out of courtesy to themselves...
 
Welcome to the forum.:)

Also remember that the continuity of the neutral of a multiwire branch circuit shall not depend on device connections such as lampholders, receptacles etc...

Check out 300.13(B)

Chris
 
That is correct - taking a single circuit (1 hot, 1 neutral) from a multiwire circuit (2 hots , 1 neutral) physically in one direction, and the other circuit in the other direction "T", then the homerun being the 2 hots and 1 neutral. Electrically...I'm fine with it, and I realize it would work. But this is an existing condition that I'm trying to verify is in compliance.
 
Uh -huh...

I think it is time for a broad and sweeping analogy:

If the MWBC were a constitutional amendment - it may be second only to the 'right to incandescent light...' I know these fundamental electrical rights are being trampled - but..... :roll: Yeah - it's compliant...
 
Keraunos said:
That is correct - taking a single circuit (1 hot, 1 neutral) from a multiwire circuit (2 hots , 1 neutral) physically in one direction, and the other circuit in the other direction "T", then the homerun being the 2 hots and 1 neutral. Electrically...I'm fine with it, and I realize it would work. But this is an existing condition that I'm trying to verify is in compliance.
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It is fine.
 
Keraunos said:
That is correct - taking a single circuit (1 hot, 1 neutral) from a multiwire circuit (2 hots , 1 neutral) physically in one direction, and the other circuit in the other direction "T", then the homerun being the 2 hots and 1 neutral. Electrically...I'm fine with it, and I realize it would work. But this is an existing condition that I'm trying to verify is in compliance.
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How else would you do it? At some point most MWBC's seperate into two wire circuits.

Roger
 
Just let me give a forewarning that if this is a residential circuit and AFCI is required then you would need an Combo DP arc fault breaker. Not a good idea to begin with.
 
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