ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Shout Box
Recent Posts
High current GFI vs regular GFCI
by gfretwell. 11/16/18 01:45 AM
This anti-theist is priceless!!!
by djk. 11/14/18 07:19 AM
Single phase and what you call it.
by dsk. 11/12/18 11:10 AM
220/230/240V 60Hz Systems
by Albert. 11/07/18 12:48 AM
New in the Gallery:
What is this for?
Plug terminals
Who's Online Now
0 registered members (), 27 guests, and 25 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Brittle THHN insulation on NM-B conductors #185812
03/29/09 04:44 PM
03/29/09 04:44 PM
N
newsgraphics  Offline OP
Member
Joined: Nov 2005
Posts: 11
California
Last night I was installing a ceiling fan in our relatively new house (built in 2005). It was pre-wired for ceiling fans, so this should have been an easy installation. However, after twisting the wire nut onto two of the conductors, I noticed that the insulation on the THHN jacket had literally split and exposed the bare copper wire!

Admittedly, I did crank those wire nuts on tightly, but I have never had a problem with insulation splitting like this before. I ended up having to cut it back about two inches. Has anyone else had this occur before?

2017 / 2014 NEC & Related Books and Study Guides
Re: Brittle THHN insulation on NM-B conductors [Re: newsgraphics] #185813
03/29/09 05:17 PM
03/29/09 05:17 PM
G
gfretwell  Offline

Member
Joined: Jul 2004
Posts: 9,302
Estero,Fl,usa
I have seen a lot of the teflon jacket splitting off but the thermoplastic insulation always seems OK.


Greg Fretwell
Re: Brittle THHN insulation on NM-B conductors [Re: gfretwell] #185814
03/29/09 05:19 PM
03/29/09 05:19 PM
N
newsgraphics  Offline OP
Member
Joined: Nov 2005
Posts: 11
California
Must have been Chinese made wire or something!

Re: Brittle THHN insulation on NM-B conductors [Re: newsgraphics] #185817
03/29/09 09:14 PM
03/29/09 09:14 PM
K
KJay  Offline
Member
Joined: Nov 2007
Posts: 763
MA, USA
Just wondering, did you remove the NM outer jacket with a utility razor knife or maybe use those Klein NM cable stripping pliers?
I've often seen the type of problem you described when these tools are used.

Re: Brittle THHN insulation on NM-B conductors [Re: KJay] #185820
03/30/09 02:15 AM
03/30/09 02:15 AM
N
newsgraphics  Offline OP
Member
Joined: Nov 2005
Posts: 11
California
Hard to say what kind of tool was used by the original installers, this is a tract home, but your suspicions sound quite plausible.


Featured:

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

 

Member Spotlight
Grover
Grover
Sebago, ME, USA
Posts: 109
Joined: January 2005
Show All Member Profiles 
Top Posters(30 Days)
Admin 8
Popular Topics(Views)
251,506 Are you busy
188,682 Re: Forum
178,386 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.6.1
(Release build 20180101)
Page Time: 0.021s Queries: 15 (0.004s) Memory: 0.9684 MB (Peak: 1.1081 MB) Zlib enabled. Server Time: 2018-11-16 13:54:29 UTC