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Posted By: rwilsond Neutrals Combined in Outlet Box Question - 02/25/10 09:18 PM
Here's an oddity I came across. An electrician was called to a house, because of lights flickering. He came to believe there was an open in the neutral of a 2-wire branch circuit. But he was unable to locate and correct the open. So, he jumpered the neutral to the neutral of another 2-wire branch circuit, in an existing outlet box.

Which sections of the NEC did he violate?

300.3(B)? 310.4?
I'd agree with you 300.3(B).
Posted By: Rewire Re: Neutrals Combined in Outlet Box Question - 02/26/10 03:19 PM
210.4 (B)
210.4(B) is for ungrounded conductors not grounded conductors.
Posted By: Rewire Re: Neutrals Combined in Outlet Box Question - 02/27/10 01:33 AM
Originally Posted by Yoopersup
210.4(B) is for ungrounded conductors not grounded conductors.
The OP said he was dealing with 2 MWBC so these 4 wires now comprise the MWBC so all 4 breakers would need to disconnect at the same time its a subtle violation.
Posted By: wa2ise Re: Neutrals Combined in Outlet Box Question - 02/27/10 02:33 AM
I don't know the code, especially chapter and verse, but I think you'd have 4 bad results: a) depending on the phasing of the other circuit, if it happens to be the same phase you could get an overloaded neutral, b) Violation of that code rule saying "no paralleled wires (except for a few well restricted exceptions)", and c)the other circuit's breaker needs to be ganged with the first circuit's breaker. And you'd have current passing thru the hot wire of one cable (raceway) and returning thru a separate cable (raceway) neutral wire (because of an open on the first raceway's neutral) which I'm sure is a 4th violation and if not, still undesirable. You'd have a large loop of 60Hz magnetic activity happening, and in severe enough cases you could get magnetic inductive heating of connector and box hardware.
Posted By: Rewire Re: Neutrals Combined in Outlet Box Question - 02/27/10 04:31 AM
300.3 B(4) allows seperate cables as long as you comply with 300.20 B
Rewire:

Originally Posted by Rewire
Originally Posted by Yoopersup
210.4(B) is for ungrounded conductors not grounded conductors.
The OP said he was dealing with 2 MWBC so these 4 wires now comprise the MWBC so all 4 breakers would need to disconnect at the same time its a subtle violation.


I think you should go back to the OP again! Two (2) wire branch circuits IMHO are a hot & a neutral. Therefore he now has two hots (of unknown phase) and one neutral.

Yes, a 2 pole CB (single handle) would be required, and yes, the neutral could be overloaded depending on the phasing, but that is unknown as of now.

It's a dangerous practice to do what the OP found.
Posted By: Rewire Re: Neutrals Combined in Outlet Box Question - 03/01/10 02:02 AM
Originally Posted by HotLine1
Rewire:

Originally Posted by Rewire
Originally Posted by Yoopersup
210.4(B) is for ungrounded conductors not grounded conductors.
The OP said he was dealing with 2 MWBC so these 4 wires now comprise the MWBC so all 4 breakers would need to disconnect at the same time its a subtle violation.


I think you should go back to the OP again! Two (2) wire branch circuits IMHO are a hot & a neutral. Therefore he now has two hots (of unknown phase) and one neutral.

Yes, a 2 pole CB (single handle) would be required, and yes, the neutral could be overloaded depending on the phasing, but that is unknown as of now.

It's a dangerous practice to do what the OP found.
The OP needs clarity, a branch circuit by definition has 2 conductors so stating it was a 2 wire branch circuit was a bit misleading I made the assumption he was speaking of a MWBC either way a handle tie breaker would be required a simple voltage check at the box would tell you if you were on the same phase.
Back to basics:
Hot Neutral in Romex or in Conduit. Or Two hots & neutral
in Romex or conduit,or three phase wye 3 hots & neutal . All fine if using single, two pole , breakers as per code.
Now if you run to seperate romexs say to a J box each with there own neutrals I'd say you can't use either neutral for either circuit. One thats in each romex must be used with that romex. Otherwise you could pick up neutrals wherever.
I've seen j boxes where Electricans have just tied all the neutrals in the j box underneat one wirenut saying well they all come from the same panel.
Yoopersup
Yoop:
I didn't want to get into this, but grabbing or combining neutrals can result in a shock hazzard to an unsuspecting person. Yes there are NEC Articles as quoted within this thread which I agree with. Also, '08 requires the MVBC's to be 'bundled' in the panel for neutral ID. Just a bad situation.

Posted By: wa2ise Re: Neutrals Combined in Outlet Box Question - 03/03/10 02:31 AM
This thing sounds like the sort of thing done to "get 'er done", to not spend lots of billable hours that a homeowner isn't gonna want to pay for, and to not look like the electrician was gouging the homeowner, but still look like he fixed the problem. "What, ten hours at $X an hour to find and fix a loose screw on an outlet?!". And if a subsequent problem arises from this bad fix, the electrician could claim that "I didn't do it" and someone else was messing around before or after he was there. This is a shoddy way to do business, I'd agree.
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