Conduit fill with Romex

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tallgirl

tallgirl

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Glendale, WI
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Controls Systems firmware engineer
How does one calculate how many pieces of whatever size Romex one can put into whatever size piece of conduit?

Had my answer to the question "What do you think about this building?" not been "It needs a bulldozer", this might have been useful for me to know last week. They didn't like my answer, and I'm back home now, so I no longer gotta-gotta know the answer.
 
For flat style NM cables you would measure the width of the cable and calculate as if it were a round conductor.
 
cowboyjwc said:
I agree with infinity, but I always ask the question, why are you using romex if you have conduit?
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Because the conduit only extends below the building (pier and beam -- this is New Orleans), it doesn't continue on forever after.
 
I actually thought of that after I had typed my response, but was to lazy to edit it.

I'm not to sure that I would worry a lot about fill if you are only running it for a short distance and I assume that at least one end is open. You shouldn't have to much of a heat problem.
 
Tom,
John, I think she is in a situation where 334.15 (B) would come into play.
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I hope that is what Julie it talking about because if the conduit is running out of a panel there is a violation of 312.5(C).
Don
 
If that conduit is only an isolated section, and not complete from point to point, it is "sleeving for protection" (note 2 to the fill tables), and the fill need not be calculated. Sleeving for protection need not even be an NEC raceway. If there's more than one cable in that pipe, however, you will have derating concerns if the sleeve is greater than 24".
 
Man i see alot of this. why do people think that the derrating factors do not apply to their situation. why? because its in romex the rules dont apply?
 
raider1 said:
I disagree, it's up to the electrician to know the rules and wire to the code.

Chris
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The purpose of an inspector is to find the things the electrician did not know.If we all were perfect he would not have a job.I exspect the inspector to be a code exspert and spot violations.The chances of a master seeing every house his men wired is slim to none.
 
Jim W in Tampa said:
The purpose of an inspector is to find the things the electrician did not know.If we all were perfect he would not have a job.I exspect the inspector to be a code exspert and spot violations.The chances of a master seeing every house his men wired is slim to none.
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Jim, I pride myself in knowing the code(s) as well as the Inspector.

That doesn't mean he doesn't need to inspect my work, it doesn't mean he will find any deficiencies, it doesn't mean he won't find any deficiencies, and it doesn't mean he won't have a job if I monopolize all the work in the area.

Roger
 
The purpose of an inspector is to find the things the electrician did not know.
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Again I disagree, the purpose of an inspector is to inspect the wiring to make sure that it meets the code. It is the responsibility of the electrician to install electrical systems according to the code.

For example if I am going to install MC cable it is my responsibility to understand the requirements for that particular wiring method, not just install it and have the inspector tell me what i can and can't do.

Chris
 
raider1 said:
I disagree, it's up to the electrician to know the rules and wire to the code.

Chris
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This is very true. The inspector's job is to make sure contractors don't bend too many rules. If there was no oversight I think the mateing call of the dollar could be to strong for some people ( maybe even me ).
 
don_resqcapt19 said:
Tom,

I hope that is what Julie it talking about because if the conduit is running out of a panel there is a violation of 312.5(C).
Don
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'Splain?

This is a common wiring method -- a piece of conduit, something on the order of 1" or so RMC typically -- is run from the bottom of the panel to the sill and into an LB. Another piece of conduit is connected to the back of the LB a foot or so. Romex is run inside that and stapled to the floor joists shortly after exiting the conduit.

The only difference, from what I can tell, between what I just described and the exception that's permitted is the direction is "down" instead of "up" (and they tend to ignore (d) ....)
 
tallgirl said:
The only difference, from what I can tell, between what I just described and the exception that's permitted is the direction is "down" instead of "up" (and they tend to ignore (d) ....)
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Therein lies your violation. To make your proposed installation compliant, there would need to be a box on the end of that pipe where the romexes enter the pipe to the panel.
 
mdshunk said:
Therein lies your violation. To make your proposed installation compliant, there would need to be a box on the end of that pipe where the romexes enter the pipe to the panel.
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How does that agree with (c) of the exception? It doesn't say "box", it says "fitting" and describes the fitting as providing protection against abrasion.

There might be something I'm missing in my description because this is the most common way wires are run out of a panel and under a pier and beam house, just after through the back of the panel and into the wall.
 
tallgirl said:
How does that agree with (c) of the exception? .
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Nothing in that exception applies to you, since you're not entering the top of the enclosure. Plain and simple. To enter the bottom with a cables in a raceway, you need a transition fitting (some call it a combination coupling) or a box. No way around it.
 
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