ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Top Posters(30 Days)
dsk 13
Admin 8
doc 3
Recent Posts
Bathroom electrical
by doc. 08/19/17 06:53 AM
electircal ageing test on IPC
by SIAME. 08/15/17 02:43 AM
electrical aging test on IPC
by gfretwell. 08/15/17 12:27 AM
"Line level" audio on Cat 5?
by gfretwell. 08/08/17 10:39 PM
Fire alarm phone lines and color coding
by gfretwell. 08/08/17 10:26 PM
New in the Gallery:
Gallery Test
Popular Topics(Views)
240,033 Are you busy
175,645 Re: Forum
167,877 Need opinion
Who's Online Now
0 registered members (), 79 guests, and 12 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate This Thread
#209231 - 03/17/13 03:24 PM romex  
watersparkfalls  Offline
Member
Joined: Mar 2005
Posts: 216
Washington...Not DC
Romex now has to be derated going though holes in wood structures? We are using the 2011 NEC here and I don't see any exceptions in the Washington Administrative Code(which supersedes NEC).

I didn't remember that when taking my continuing education class, but have recently gone to work for another contractor who has contracts for mixed use buildings that are stick built. We are using romex in the dwelling units so I thought I would read up(years since I used romex) and 334.80 directs you back to the conduit fill table.

Am I crazy or misinterpreting?
Thanks,
H20


2017 / 2014 NEC & Related Books and Study Guides

#209232 - 03/17/13 03:49 PM Re: romex [Re: watersparkfalls]  
gfretwell  Offline


Member
Joined: Jul 2004
Posts: 9,103
Estero,Fl,usa
NFPA is crazy, you are reading it right.
They are really telling us we need to drill more holes. In reality you still have the practical limit of 9 current carrying conductors (using the 90c column) through one hole so it is not that restrictive.

I am still not sure why I don't have to derate until a nipple is 2 feet long, even if it is packed in foam but I have to derate in a 1.5" penetration with some foam in it.


Greg Fretwell

#209238 - 03/17/13 10:23 PM Re: romex [Re: watersparkfalls]  
Tesla  Offline
Member
Joined: Jun 2004
Posts: 1,273
Sacramento, CA
The nipple 'exception' is there to cover the ubiquitous 'Romex risers' all over America -- coming vertically up out of a panel. Whatever heat buildup induced by such a short run is cancelled by the 'naked' (sheathless) conductors within the panel.

Due to practice, and economics, such long nipples are not seen elsewhere in Romex installations.

========

NEMA standards limit Romex to 3 conductors plus a bare/ papered grounding/bonding conductor.

The NEC is just doing its part to make sure that no-one attempts to bore (hole saw?) oversized penetrations within wall studs. Yes, more, smaller, penetrations result in a stronger stud/ joist.

Anyone stuffing Romex beyond three cables per... is naughty.


Tesla


Member Spotlight
Tom
Tom
Shinnston, WV USA
Posts: 1,044
Joined: January 2001
Show All Member Profiles 
Featured:

2017 Master Electrician Exam Preparation Combos
2017 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Shout Box
Powered by UBB.threads™ PHP Forum Software 7.6.0
Page Time: 0.010s Queries: 15 (0.002s) Memory: 0.7530 MB (Peak: 0.8768 MB) Zlib enabled. Server Time: 2017-08-21 15:56:48 UTC