Multiwire Branch Circuit Code (sharing Neutral)

CNC

All i have is my NEC handbook, and im looking for the exact article to find where it states i can use for example a 12/3, and branch off with a 12/2 from one box to supply another circuit, like in a kitchen, i use a 12/3 from the panel, and use one for the plug circuit, and one for the dishwasher (just an example). NOW i dont need to use a 2 pole breaker, unless its terminated on the same yoke, like a duplex outlet, correct. I just need the article number, and cant find it in this little handbook, and dont have my code book on me. thanks guys

mickeyco

210.4 Multiwire Branch Circuits.
(A) General. Branch circuits recognized by this article
shall be permitted as multiwire circuits. A multiwire circuit
shall be permitted to be considered as multiple circuits. All
conductors of a multiwire branch circuit shall originate
from the same panelboard or similar distribution equip-
ment.
FPN: A 3-phase, 4-wire, wye-connected power system
used to supply power to nonlinear loads may necessitate
that the power system design allow for the possibility of
high harmonic currents on the neutral conductor.
(B) Disconnecting Means. Each multiwire branch circuit
shall be provided with a means that will simultaneously
disconnect all ungrounded conductors at the point where
the branch circuit originates.
(C) Line-to-Neutral Loads. Multiwire branch circuits
shall supply only line-to-neutral loads.
Exception No. 1: A multiwire branch circuit that supplies
only one utilization equipment.
Exception No. 2: Where all ungrounded conductors of the
multiwire branch circuit are opened simultaneously by the
branch-circuit overcurrent device.
FPN: See 300.13(B) for continuity of grounded conductor
on multiwire circuits.
(D) Grouping. The ungrounded and grounded conductors
of each multiwire branch circuit shall be grouped by wire
ties or similar means in at least one location within the
panelboard or other point of origination.
Exception: The requirement for grouping shall not apply if
the circuit enters from a cable or raceway unique to the
circuit that makes the grouping obvious.

__________________
Some people climb mountains. I take out the trash. But we both do it for the same reason.

CNC

so thats saying, no matter what, i need to use a 2 pole breaker on any multi wire branch circuit?

mickeyco

I should note that what I posted is from the 2008 NEC, if you're on 2005 I believe what you said was correct. I'm not really an electrician* but I play one here on the board when the electricians are away. I'm not sure if you have to have a 2 pole breaker or can just tie two singles together (not even sure if you can "legally do that) but they do have to simultaneously disconnect, so why not use a 2 pole.




*although I do have the license

__________________
Some people climb mountains. I take out the trash. But we both do it for the same reason.

Speedy Petey

CNC, if you are under NEC 2005 or earlier then you are correct in your first post.
The 2008 NEC added the requirement for all MWBCs to originate from a two (or three) pole breaker.

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mickeyco

Can you tie two single pole breakers together?


.

__________________
Some people climb mountains. I take out the trash. But we both do it for the same reason.

Dan_Watson

I believe you can.

OCRS

For split plugs, the breakers have to be tie-barred.

Speedy Petey

I actually prefer to say:

Where a multiwire branch circuit supplies more than one device or equipment on the same yoke, a means shall be provided to disconnect simultaneously all ungrounded conductors supplying those devices or equipment at the point where the branch circuit originates.

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Speedy Petey

Yes, with a proper handle tie. NOT a nail or screw or a piece of #10 solid.

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mickeyco

I've seen that a few times.

__________________
Some people climb mountains. I take out the trash. But we both do it for the same reason.

OCRS

Much more eloquent than I sir

CNC

Thanks guys, i was right with my dispute with a fellow electrician, i didn't have my code book, with the article number, but he kept insisting it didnt matter, they always had to be tied together. O well, i need to start to get familiar with the 2008 changes!