Tv electricians

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Re: Tv electricians

Originally posted by georgestolz:
No, the exception seems to indicate that cables being supported on bridle rings are not bundled, but still subject to derating. ;)
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I think your misunderstanding me.

The CMP must have considered MC run through bridle rings as bundled or there would be no need for the exception. :p

[ May 29, 2005, 12:32 PM: Message edited by: iwire ]
 
Re: Tv electricians

Hello forum,

I am new here , hope to contribute and be contributed too.

As to how many wires per hole Mike Holt answered
that.You can see the calculation at:

http://ecmweb.com/nec/code_qa_092304/index.html

I printed that for my inspectors.

The answer is 9 current carring conductors.
What is a current carrring conductor?The line conductor,the neutral is the grounded conductor.
So you can have 9 120v wires per hole.
Careful,the neutral in a nonlinear load is counted as a current carring conductor as per
310.15(b)(2)(a).
 
Re: Tv electricians

I had an inspector that was shot down by an insurance company for allowing "too many wires per
hole" because of the heat dissapation.Not on one of my jobs,but he called to tell me.

I agree with most,why derate an NM wire through
an 1 1/2 inch thick hole?

Some times the powes that be demand that;

IT IS NOT OURS TO WONDER WHY ONLY BUT TO DO OR DIE!!!!
 
Re: Tv electricians

From Bob

"That is the argument here. :) "

I like to say discussion :) ) is that good enough? Or do we separate them a certain measurement?

I am still out on this subject. Sort of like a jury, prove me wrong :D
 
Re: Tv electricians

Originally posted by pierre:
From Bob

"That is the argument here. :) "

I like to say discussion :)

While the jury may be out in NY :D

As a matter of fact that exception 5 that I mentioned does not exist here in MA, it was amended to something totally different.

They are strict here on the bundling issue but at the same time they ease up on the amount of derating. (We use a different table than the NEC)
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Re: Tv electricians

Bob
Are you saying that Mass. has a state amended code requirement that states how many cable/conductors can be passed through a hole in the framing member before ampacity adjustment has to be applied?
If so, what is it...just curious.
 
Re: Tv electricians

IF we weren't permitted multiple holes in one bored hole, I'd be screwed. The IRC boring and notching rules state that bored holes have to be 2" apart, edge to edge. Can you imagine what the home runs in a basement would look like if I had one cable per hole, and holes 2 inches apart? I'd have holes bored over an 80" spread near the panel. My preference always has been (and will remain) to drill one large hole and run the majority of the home runs through that large hole.
 
Re: Tv electricians

Originally posted by pierre:
Bob
Are you saying that Mass. has a state amended code requirement that states how many cable/conductors can be passed through a hole in the framing member before ampacity adjustment has to be applied?
If so, what is it...just curious.
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No, what I am saying that inspectors here use the rules in the NEC with their interpretation that a group of cables run through a series of holes are indeed bundled and subject to derating.

That derating ends up with 9 CCCs allowed which in cable would be three 3 wire or four 2 wire cables.
 
Re: Tv electricians

Bob
This line of questioning is purely for me to get a better grip on this topic. You have a good sense of what "really" happens in the field as far as what works and doen't work, so don't take this as I am grilling you - even though I may work you over a bit :)

As posted before would you accept as good practice, more than three cables(more than 9 ccc) through a hole in the framing member if the installer were to separate the cables as they passed from one member to the next?
 
Re: Tv electricians

I would.

Edit: Oops, I thought I was Bob. :D

[ May 29, 2005, 07:40 PM: Message edited by: physis ]
 
Re: Tv electricians

If I didn't shave my beard would be turning white. And I could stand to loose a few.
 
Re: Tv electricians

Just a tidbit: 300.4(A)(1)indirectly limits hole size in top and bottom plates to 1", as long as they're centered and plumb (unless protector plates are used, of course).
 
Re: Tv electricians

Originally posted by pierre:
so don't take this as I am grilling you - even though I may work you over a bit :)
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STOP PICKING ON ME! :(

Typically it will be when I have to many cables supported by J-hooks or bridle rings above a ceiling where they are in 'free air'. They are even more adamant about the cables run in walls with thermal insulation.
 
Re: Tv electricians

Just so I understand.

Are your inspectors siting electrical codes or are they just adament about stuff? :confused:
 
Re: Tv electricians

Originally posted by physis:
Just so I understand.

Are your inspectors siting electrical codes :)

The interpretation here by the inspectors is if I run 15 NM cables through the same hole in row of say wall studs or hung on J-hooks for distance longer than 24" the cables are 'bundled' and subject to the NEC derating rules.

Other areas of the country certainly may feel otherwise. :p
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