Multi-parallelled grounded conductors

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wbalsam1

Senior Member
Location
Upper Jay, NY
An electrician friend of mine described a recent discovery of a wiring condition that exists on a job where he was called to troubleshoot something else.

The original electrician wired fluorescent lighting branch circuits out of a 3-phase load center in this manner: a red with it's own neutral, a blue with it's own neutral and a black with it's own neutral. These conductors were in conduit and routed up into a dropped ceiling void and then went to a junction box where all the neutrals were twisted together under a big blue wirenut and connected to AC cables going to the different lighting fixtures. (in other words, the fixture neutrals and BC neutrals are all grouped together under one huge wirenut).

The whole clothing store's lighting was done this way and has been working for twenty years without a problem.

Must be a heck of a load spark present when you untwist a big blue, heh? :-?:D
 
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physis

Senior Member
The whole clothing store's lighting was done this way and has been working for twenty years without a problem.

I wouldn't expect a problem with it, at least not aside from what might happen to it the same as anything else. And the extra hastle of working with it being wired that way.
 

physis

Senior Member
apparently the guy that installed it never heard of 310.4

I had first thought there might be a violation there but 310.4 says .......conductors of 1/0AWG and larger, comprising each phase, polarity, neutral, or grounded circuit conductor, ................

Does this apply if it's only grounded conductors?

Another thing I was noticing is that 310.4 "permits" parallelling 1/0 and larger, but doesn't prohibit anything. Isn't the NEC a pemissive code? Meaning that anything that isn't specifically prohibited is allowed.

I'm actually just being curious about this, nothing more.
 

don_resqcapt19

Moderator
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Location
Illinois
Occupation
retired electrician
Another thing I was noticing is that 310.4 "permits" parallelling 1/0 and larger, but doesn't prohibit anything. Isn't the NEC a pemissive code? Meaning that anything that isn't specifically prohibited is allowed.

I'm actually just being curious about this, nothing more.
I fully agree with you, but CMP 6 does not.
6-8 Log #2235 NEC-P06
Final Action: Reject

(310.4)

____________________________________________________________

Submitter:


Donald A. Ganiere, Ottawa, IL​

Recommendation:


Revise as follows:​

310.4 Conductors in Parallel. Aluminum, coper-clad aluminum, or copper​
conductors of size 1/0 AWG and larger size #1 AWG and smaller , comprising

each phase, polarity, neutral, or grounded circuit conductor, shall be permitted
to not be connected in parallel (electrically joined at both ends).
Substantiation:


There is no code rule that prevents the installation of
conductors smaller than 1/0 AWG in parallel in the current code. The existing​
rule just specifically permits the use of conductors 1/0 and larger in parallel,

but does not prohibit smaller conductors from being paralleled.
Panel Meeting Action: Reject
Panel Statement: The present language meets the requirements of Section
3.1.3 of the NEC Style Manual. Article 310.4 permits conductors 1/0 or larger
to be installed in parallel. The general rule is that conductors sized smaller than
1/0 are not permitted to be run in parallel.
Number Eligible to Vote: 11
Ballot Results: Affirmative: 11​

____________________________________________________________

I took another shot at this again for 2011...it will probably have the same result.
Note: red text in the proposal is text to be deleted, and blue text is new.
 
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physis

Senior Member
Appearantly we do agree here Don. :smile:

Edit: How bout "shall not be permitted" though?
 
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don_resqcapt19

Moderator
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Location
Illinois
Occupation
retired electrician
I find 310.4 quite clearly defines wires smaller than 1/0 with the exception No. 1. This gives the parameters for 1/0 and smaller being allowed in parallel under the given conditions.
Dennis,
How do the words "shall be permitted" act to prohibit the paralleling of conductors smaller than 1/0 from being paralleled? Under the current code there is nothing that says you can't parallel smaller conductors. It is an incorrect use of the words "shall be permitted". The style manual says these words are to be used like an exception to permit an alternate method of installation. There is no main rule for these words to act as an exception.
 

Dennis Alwon

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Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Dennis,
How do the words "shall be permitted" act to prohibit the paralleling of conductors smaller than 1/0 from being paralleled? Under the current code there is nothing that says you can't parallel smaller conductors. It is an incorrect use of the words "shall be permitted". The style manual says these words are to be used like an exception to permit an alternate method of installation. There is no main rule for these words to act as an exception.

Don the exception says you may parallel smaller than 1/0 under certain conditions. IMO, this eliminates anything smaller than 1/0 unless it fits the parameters of the exception. You can play with the words all you want but to me it is quite clear.
 

iwire

Moderator
Staff member
Location
Massachusetts
Don the exception says you may parallel smaller than 1/0 under certain conditions. IMO, this eliminates anything smaller than 1/0 unless it fits the parameters of the exception. You can play with the words all you want but to me it is quite clear.


I agree with Don, the NEC is a permissive document and there are no words that prevent paralleling smaller conductors.

That is not 'playing with the words'
 

Twoskinsoneman

Senior Member
Location
West Virginia, USA NEC: 2020
Occupation
Facility Senior Electrician
IMO the intent of the code is clear (under 1/0 no paralleling).....but the code says what it says and I agree with the group that claims the code does not come right out and say no paralleling under 1/0...

There are a couple of other places the code makes this mistake but I'm having a hard time remembering it...

Maybe something about running free conductors without conduit...
To be honest can't recall. Will try to find some examples...
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Don the exception says you may parallel smaller than 1/0 under certain conditions. IMO, this eliminates anything smaller than 1/0 unless it fits the parameters of the exception. You can play with the words all you want but to me it is quite clear.
An exception to a rule that does not exist does not create a rule. Yes, we are all well aware of the intent of 310.4, but the code wording does not match the intent. There is no way that any reasonable reading of the words "shall be permitted" can be read as prohibiting something else. There are a number of other cases where the code tries to do the same thing. The most notable would the "common neutral" rules in 215.4(A) and 225.7(B). The code panels are on record as saying the specific permission to use a common neutral in these two cases acts to prohibit the use of a common neutral in all other cases, however again the code wording does not support the panels intent.
 

physis

Senior Member
IMO the intent of the code is clear (under 1/0 no paralleling)

I agree with that as well.

I really see no reason they did not accept Don's proposal

Bob, are you playing both sides of the feild here?

If I did that you know you'd light me up for it. :grin:

Edit: I probably shouldn't have said that cause I had done something very similar just recently.
 
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iwire

Moderator
Staff member
Location
Massachusetts
Bob, are you playing both sides of the feild here?

I do not think I am.

1) I think the intent is clear, don't parallel conductors smaller then 1/0 unless we meet the conditions.

2) I don't think the words really say that when taken with the knowledge that the NEC is a permissive standard.

If I did that you know you'd light me up for it. :grin:

:D

No, not me, I would never do that. :D
 

physis

Senior Member
Dennis,
How do the words "shall be permitted" act to prohibit the paralleling of conductors smaller than 1/0 from being paralleled? Under the current code there is nothing that says you can't parallel smaller conductors.

I think that's the whole thing right there.

I guess CMP 6 figures that it's position is simply imposed because most contractors aren't very interested in arguing with AHJ's.

Charlie E. says that a proposal can't be declined without good reason. It's pretty clear that this isn't true. Don's proposal is clearly valid, (although I'd use slightly different language than he did).

It seems that CMP 6 is perfectly comtortable with the existing language that simply doesn't say what they insist it does.

Wouldn't this be called incompetance anywhere else? Especially given that this has been brought to their attention, formally, a number of times.
 
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