splicing neutrals in multiple circuits?

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Praedatus1

Praedatus1

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I'm pretty sure it's wrong, but where does the NEC specify about not splicing different circuit neutrals in a box? Say I have 2 circuits in a box, say, 2 12-2's. Can I simply put the neutrals together like the grounds? Thanks guys.
 
Re: splicing neutrals in multiple circuits?

best reference that comes to mind would be 310.4 , not paralleling conductors smaller than 1/0.
 
Re: splicing neutrals in multiple circuits?

The section to cite would be 310.4, since you'd have two neutrals paralleling back to the panel from the box in question.

When the two conductors aren't exactly the same in length, the current doesn't flow evenly back on both conductors, which can cause one of them to overheat and either die sooner, or worse.

Not to mention they're smaller than 1/0. :D

Not to mention EMF. :D

Best bet: even on the same circuit (say two threeways in same circuit, box to box) if something has an intended neutral path, force it to use it.
 
Re: splicing neutrals in multiple circuits?

morning mr.stolz.. didn't mean to step on your toes.
 
Re: splicing neutrals in multiple circuits?

Originally posted by Praedatus1:
I'm pretty sure it's wrong, but where does the NEC specify about not splicing different circuit neutrals in a box? Say I have 2 circuits in a box, say, 2 12-2's. Can I simply put the neutrals together like the grounds? Thanks guys.
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you can certainly do this as long as you do not end up with a parallel circuit.

you could not for instance run the (2) 12-2s from the panelboard to a jbox and jumper them in the jbox. you could run 12-2 from the field devcies to a jbox and from the jbox back to the pb run a single larger neutral that would cover both circuits.

[ January 09, 2006, 09:05 AM: Message edited by: petersonra ]
 
Re: splicing neutrals in multiple circuits?

I was taught keep neutrals seperate for one reason not EMF but safety.If the neutral connection is lost there are 2 circuits that will look for a return path and without one available they will find eachother.So 240 v at that point.I have encountered this probably a dozen times in the past 10 years and tv`s electronics pay hell when this occurs. ;)
 
Re: splicing neutrals in multiple circuits?

Another reason: if someone deenergizes a circuit for any reason, they should be able to expect that the entire circuit is dead, especially if they're troubleshooting.

This is similar to the reason that multiwire circuits can't have device terminals connecting the neutral ins and outs together.
 
Re: splicing neutrals in multiple circuits?

Originally posted by Praedatus1:
I'm pretty sure it's wrong, but where does the NEC specify about not splicing different circuit neutrals in a box? Say I have 2 circuits in a box, say, 2 12-2's. Can I simply put the neutrals together like the grounds? Thanks guys.
Click to expand...
Just out of curiousity, why would you?
 
Re: splicing neutrals in multiple circuits?

hey, i've been at work all day. Appreciate your comments, though. I came across it in a commercial building, a machine shop, actually. The original installers ran a pipe 40 feet from a pb, set a box, and split in 2 directions with 2 separate circuits for lighting. There was also another circuit for recepticles in the box, so I had 3 hots, 2 neutrals for home runs. They shared the neutral for the lighting, but wadded up all the neutrals under 1 wire nut. I took them apart and re-worked it. Just curious, though, on which code covered it. I knew about the paralelled runs smaller than 1/0. Didnt know if there was something I missed in class. I guess not. :) Thanks again.
 
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