cerberus79 17 posts 05-06-2017 9:09pm
Also you would not connect to a double pole breaker, that is for 240 vac here in the US . They would connect to single pole breakers as they are 120 vac.
Multiwire branch circuitshttp://ecmweb.com/code-basics/branch-circuits-part-1A multiwire branch circuit basically consists of two or more ungrounded conductors that share a neutral. All conductors of a multiwire branch circuit must originate from the same panelboard [210.4(A)].
For personnel safety, each multiwire branch circuit must have a means to simultaneously disconnect all ungrounded conductors at its origin [210.4(B)]. If that origin is two or more breakers, you can provide this disconnect by using single-pole circuit breakers with handle ties identified for the purpose [240.15(B)(1)].
"single-pole circuit breakers with handle ties identified for the purpose"
The tie used must be a Listed tie for the intended purpose.
Or, just use a 2 pole breaker......
Or, in the case of a 3ph. 4wire multiwire branch circuit a 3 pole breaker.
Just going from memory I believe this was added to the 2008 NEC. After State and local AHJs adopted the new language, at least in my state, the 120V as well as 277V multiwire branch circuit became a thing of the past. I don’t know of anyone that installs them today, or for the last 8 years.
Best regards,
Jim

