sharing neutral

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mimo

Member
Where a shared neutral is used for combining lighting and other branch circuits, should we use a handle tie between 1-pole breakers to disconnect all ungrounded conductors simultaneously where the wires originate in one junction box?!
thank you
 

billsnuff

Senior Member
It sounds like the shared neutral in your case isn't a line to line load but a MWBC, which puts you at 240.15B1, which means you would be limited by 210.4B, IMHO. But then, I have been wrong before..........:D
 

pete m.

Senior Member
Location
Ohio
(2) Grounded Single-Phase and 3-Wire dc Circuits. In grounded systems, individual single-pole circuit breakers with identified handle ties shall be permitted as the protection for each ungrounded conductor for line-to-line connected loads for single-phase circuits or 3-wire, direct-current circuits.


I do not see where this section allows what you are saying???:confused:

Pete
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Where a shared neutral is used for combining lighting and other branch circuits, should we use a handle tie between 1-pole breakers to disconnect all ungrounded conductors simultaneously where the wires originate in one junction box?!
thank you

Yes you must use either handle ties or a DP/3P breaker.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
(2) Grounded Single-Phase and 3-Wire dc Circuits. In grounded systems, individual single-pole circuit breakers with identified handle ties shall be permitted as the protection for each ungrounded conductor for line-to-line connected loads for single-phase circuits or 3-wire, direct-current circuits.


I do not see where this section allows what you are saying???:confused:

Pete

Read 240.15(B)(1)
 

jumper

Senior Member
I believe the OP meant 210.15(B)(1) in his #3 post and I see where it could be confusing. When they rewrote 210.4(B) the section does not make complete sense. The "or without" is obsolete in 210.15(B)(1).

They changed it in the 2011 for clarity.

(1) Multiwire Branch Circuit. Individual single-pole circuit
breakers, with identified handle ties, shall be permitted
as the protection for each ungrounded conductor of multiwire
branch circuits that serve only single-phase line-to neutral
loads.
 
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