Ran across Murray 200amp service panel with neutral bar that was added “floating”

ptonsparky said:
I see you found your answer already but a single #12 could easily serve as the neutral for multiple MWBCs. Most of the load would balance out. Legal at one time.
Click to expand...
Looks like 200.4 (prohibiting common neutrals except where allowed elsewhere) first appeared in the 2011 NEC.

215.4(A) stills says "Up to three sets of 3-wire feeders or two sets of 4-wire or 5-wire feeders shall be permitted to utilize a common neutral." I guess since this is for feeders, the common neutral conductor could be sized for the calculated from all of the associated feeder.

For branch circuits, prior to the 2011 NEC, I think that Articles 200 and 210 were silent on the matter. But branch circuits don't have an allowance for reducing the size of the grounded conductor. So if you shared say a single neutral between (2) 20A MWBCs, it could not be a #12, it would need to be sized for 40A.

Cheers, Wayne
 
You must log in or register to reply here.
Top