Multi wire branch circuit clarification

[Dustin Foelber]

I am confused on the new code addressing multi wire branch circuits. The only reference I can find is 210.7 about devices in the same yoke. I am being told by my inspector all branch circuits feeding outlets with the same return path conductor need to be on a multi pole breaker. Can anyone please clarify.

 

[pete m.]

210.4(B)

Pete

 

[Dustin Foelber]

Thanks Pete. Working to much. Dont know how i missed that. 240.15 B (1) Permits single pole as long as identified. Does one supercede?

 

[Twoskinsoneman]

Basically you can use single poles with handle ties as long as there are no line to line loads on the MWBC.

edit to add: I know 240.15(B)(1) says with or without handle ties, but it doesn't make any sense because it also says except where limited by
210.4(B). So you can't have a MWBC with single poles without handle ties. BTW the "without handle ties" part has been removed from the 2011 NEC.

 

[Dustin Foelber]

Can you use single poles not grouped yet identified? Such as circuit 12, 19, 27 with the a common return path conductor and permenantly labeled

 

[augie47]

Can you use single poles not grouped yet identified? Such as circuit 12, 19, 27 with the a common return path conductor and permenantly labeled

I believe that is one of the things they were trying to prevent. If you had that layout how would you satisfy the "(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."

 

[Dustin Foelber]

True. Thanks Augie. Pretty much clears it up for me.

 

[Volta]

I believe that is one of the things they were trying to prevent. If you had that layout how would you satisfy the "(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."

Shunt trip!

I mean, if you had extra money you didn't want anymore . . .

 

[dana1028]

Basically you can use single poles with handle ties as long as there are no line to line loads on the MWBC.

edit to add: I know 240.15(B)(1) says with or without handle ties, but it doesn't make any sense because it also says except where limited by
210.4(B). So you can't have a MWBC with single poles without handle ties. BTW the "without handle ties" part has been removed from the 2011 NEC.

As you said, 2011 changes the language because it did not 'correlate' with 201.4 - looks like it was Bryan Holland who submitted the change.

10-29 Log #190 NEC-P10 Final Action: Accept in Principle
(240.15(B)(1))
_______________________________________________________________
Submitter: Bryan P. Holland, City of North Port
Recommendation: Revise as follows:
(1) Multiwire Branch Circuit. Except where limited by 210.4(B) Individual
single-pole circuit breakers with or without handle ties with a means to
simultaneously disconnect all ungrounded conductors per 210.4(B), shall be
permitted as the protection for each...
Substantiation: Section 210.4(B) negates the proposed deleted text of this
proposal. This revision better correlates the two sections and helps to clarify
the intent of 240.15(B)(1).
Panel Meeting Action: Accept in Principle
Panel Statement: See panel action on Proposal 10-30 which meets the intent
of the submitter to provide correlation.
Number Eligible to Vote: 12
Ballot Results: Affirmative: 12
_______________________________________________________________