# Parallel feeder neutral



## RMSpry (Jan 6, 2008)

Does this help? (from 2008 NEC)

"215.4 Feeders with Common Neutral Conductor.
(A) Feeders with Common Neutral. 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.
(B) In Metal Raceway or Enclosure. Where installed in a metal raceway or other metal enclosure, all conductors of all feeders using a common neutral conductor shall be enclosed within the same raceway or other enclosure as required in 300.20."


----------



## raider1 (Jan 22, 2007)

215.4 is almost identical in the 2005 NEC as it is in the 2008.

Chris


----------



## JohnJ0906 (Jan 22, 2007)

JohnJ0906 said:


> Also, is there a minimum neutral size? The only places I could find a minimum size was dealing with a service, not a feeder.


To be honest, I thought that there would be a requirement that the neutral would have to be sized (at a minimum) to 250.122, due to the fact that it would need to carry fault current in the case of a line-to-neutral fault. If there is such a requirement, I can't seem to find it.


----------



## goose134 (Nov 12, 2007)

I don't have a copy of the NEC handy, but from the Chicago code I have this: 310.4 (3) The paralleled conductors in each phase, neutral, or grounded circuit conductor shall: Be the same size in circular mil area.
I can't imagine that it would be that different in NEC. Hope it helps.


----------



## JohnJ0906 (Jan 22, 2007)

goose134 said:


> I don't have a copy of the NEC handy, but from the Chicago code I have this: 310.4 (3) The paralleled conductors in each phase, neutral, or grounded circuit conductor shall: Be the same size in circular mil area.
> I can't imagine that it would be that different in NEC. Hope it helps.


Key word, "each".

Still doesn't require the neutral to be a) paralleled at all even if the phase conductors are, or b) the same size as the phase conductors.

Thank you all for your replies.


----------



## billsnuff (Dec 29, 2007)

http://www.electrical-installation...._files/EIG-G-sizing-protection-conductors.pdf

not nec, but try page 42.


----------



## gilbequick (Oct 6, 2007)

Don't you size the neutral according to the ocpd? That being said it's up to you if you want to parallel up or just run a bigger cable (given you meet the minimum size for paralleling).

I can't find anything saying you "must" parallel the neutral if you parallel the ungrounded conductors.


----------



## raider1 (Jan 22, 2007)

A feeder neutral load is determined by 220.61.

A feeder neutral conductor only needs to be sized to carry the load determined by 220.61.

Chris


----------

