US NEC question.

Hi eveyone,
I know it makes no sense to run nm-b in conduit for long runs, both cost and possible heat, but where in the code does it tell you not to?
thanks,
tom @ www.URLBee.com
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It doesn't say you can't. In fact the 2005 code clears that language up
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On 18 Jan 2005 02:08:07 GMT, snipped-for-privacy@aol.com (Greg) wrote:

Didn't get the new 2005 book yets, since I heard rumors there were typos, so two things please: What does it say to clear this up? Also, if I do buy a book and more "page changes" are made, anywone know where I can go to print up these changes to insert them into my book?
Thanks,
tom
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snipped-for-privacy@intertainia.com wrote:

What it does say, IIRC, is that if you DO run it in conduit, you're supposed to de-rate it.
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The errata is here http://www.electrical-contractor.net/NFPA/2005NEC/70-2005_NEC-Errata.pdf
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On 18 Jan 2005 07:00:18 GMT, snipped-for-privacy@aol.com (Greg) wrote:

Thank you. Not looking a gift horse in the mouth, but is there a place to get the 'changed pages' so you can print them up in insert them in you book, or do you need to get a new book eveytime the typos are caught?
I've been eyeing the loose-leaf book, and I was wondering if there was an added benifit to geting it, like keeping up to date all the time.
thanks,
tom
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BTW the change is in 334.15(B) and says you can install NM in conduit to provide physical protection. There is no requirement for derating.
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On 18 Jan 2005 07:07:34 GMT, snipped-for-privacy@aol.com (Greg) wrote:

I know the 2002 even tells you to run NM throught conduit between dwelling floors, but I've been told over and over never run it though for conduit work.
Example, if you run nm throught an unfiinished basement, when you get to the wall, you need some protection for the cable. So, I was planning on using emt(looks nicer than rnc to me), well I was told the portion that goes into the emt needs to be unsheathed, per code. But no one can tell me where it actually says so. ART 334 says you it can be run in conduit. Note 9 of Chapter 9, even gives how to figure conduit fill with this oval shapped cable(like NM).
So is this working practice from the past, or an actual code enforcement?
Thank you, everyone.
later,
tom @ www.BookmarkAdmin.com
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That was never true. Actually using a cable this way is violating the listing. A cable is an assembly and designed to be used with the sheath on. I am also not sure where the derating rumor came from. Derating is based on the number of current carrying conductors grouped together ... period. 4 or more current carrying conductors are derated the same if they are in a cable, a 1/2" pipe or a 4" pipe. With a 90c conductor it is pretty hard to come up with a case where derating will affect NM-b anyway.
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