ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Shout Box
Recent Posts
VDE 0100 to introduce AFCIs
by sparky. 01/20/18 05:09 PM
MRI LED lights dimmer control replacement - wow!
by Potseal. 01/19/18 08:52 PM
Video: Inventor of the GFCI self-testing shocks
by Bill Addiss. 01/17/18 11:11 PM
FPE in Germany
by HotLine1. 01/17/18 07:07 PM
Fujifilm Recalls Power Adapter Wall Plugs
by Admin. 01/16/18 07:04 PM
New in the Gallery:
Housebilding DIY wiring
SE cable question
Who's Online Now
1 registered members (sparky), 7 guests, and 12 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
NM in conduit #90572
11/30/04 11:58 AM
11/30/04 11:58 AM
E
energy7  Offline OP
Member
Joined: Jun 2002
Posts: 58
Oxnard, CA, USA
A comment in the "horse barn" thread has stirred this question.
Can you run NM in conduit for any significant distance. My understanding of 336-6 (and now 334-15) is that conduit protection is used in short runs for specific hazards.
Because NM is a cable assembly and not just conductors, running it in conduit is "mixing wiring methods", and you're subject to overheating.

2017 / 2014 NEC & Related Books and Study Guides
Re: NM in conduit #90573
11/30/04 12:10 PM
11/30/04 12:10 PM
R
Roger  Offline
Member
Joined: May 2002
Posts: 1,716
N.C.
This has been cleared up in the 2005 NEC.

It is specifically allowed in the .22 sections of the conduit articles if the particular cable article doesn't prohibit it.

Roger

Re: NM in conduit #90574
11/30/04 12:39 PM
11/30/04 12:39 PM
G
gfretwell  Offline

Member
Joined: Jul 2004
Posts: 9,166
Estero,Fl,usa
I don't see how heating is considered an issue at all, code wise. You derate the same in 1/2" conduit as you do in 4" for the same conductor fill. A piece of Romex in "free air" EMT will certainly run cooler than it would buried in insulation in an attic.


Greg Fretwell
Re: NM in conduit #90575
11/30/04 12:50 PM
11/30/04 12:50 PM
G
gfretwell  Offline

Member
Joined: Jul 2004
Posts: 9,166
Estero,Fl,usa
the .22 additions only point out rules that always existed. Basically you use the widest dimension of an oval cable as the diameter when computing fill. That is because when you get a twist in it the widest dimension becomes the diameter.


Greg Fretwell
Re: NM in conduit #90576
11/30/04 11:07 PM
11/30/04 11:07 PM
J
John Steinke  Offline
Member
Joined: Apr 2001
Posts: 518
Reno,Nv., USA
Romex is listed as a 60 degree assembly.
The THHN wire inside romex is listed as a 90 degree wire.

By putting romex in pipe, you are throwing away 30 degrees of de-rating, before you do anything else.

Also, the inside of conduit can sometimes be considered a wet location; romex is not allowed in wet locations.


Featured:

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

 

Member Spotlight
BEAMEUP
BEAMEUP
WA
Posts: 27
Joined: December 2004
Show All Member Profiles 
Top Posters(30 Days)
Admin 20
Potseal 15
sparky 15
Popular Topics(Views)
243,571 Are you busy
180,368 Re: Forum
170,845 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.6.1
(Release build 20180101)
Page Time: 0.018s Queries: 14 (0.004s) Memory: 0.9666 MB (Peak: 1.1066 MB) Zlib enabled. Server Time: 2018-01-20 22:33:02 UTC