ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat
Recent Posts
Anybody comment on materials pricing?
by gfretwell - 06/10/21 01:33 PM
2 pole GFI feeding 1 and 2 pole loads
by gfretwell - 06/04/21 02:27 AM
Lock-down Thread
by HotLine1 - 06/01/21 08:15 AM
Updated Forum Software
by Admin - 05/31/21 12:09 AM
Square D "All-In-One" Panelboard
by HotLine1 - 05/29/21 12:13 PM
New in the Gallery:
2020 - 2021 Winter Project
2020 - 2021 Winter Project
by Bill Addiss, April 29
Garden 2021
Garden 2021
by Bill Addiss, April 26
Who's Online Now
0 members (), 36 guests, and 18 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Page 1 of 2 1 2
#93735 06/08/05 07:15 PM
Joined: Jun 2004
Posts: 613
S
Member
Is romex (NM) allowed to be used in the walls and ceilings of a horse barn in areas specified by 547.1 where it will be concealed by a finish surface such as wood on the walls and plastered ceilings?

shortcircuit

2017 / 2014 NEC & Related Books and Study Guides
Joined: Mar 2005
Posts: 212
G
Member
The way I read it, I think you're OK.

Joined: Jun 2004
Posts: 613
S
Member
Can anyone explain what the last sentance of 334.10(3) means or maybe have a link to such list as described?

"Cables shall be concealed within walls, floors, or ceilings that provide a thermal barrier of material that has at least a 15-minute finish rating as identified in listings of fire-rated assemblies."

My concern is if romex (NM) is concealed behind finish walls of wood on the interior of a horse barn, is the wood wall finish acceptable as a 15-minute fire-rated assembly?

shortcircuit

Joined: Dec 2003
Posts: 751
E
Member
As I recall, 1/2 inch wallboard has a 15 minute rating.
Let me check the UL book for others.


Earl
Joined: Dec 2003
Posts: 751
E
Member
Nope, no wood. All the listed assemblies are gypsum wallboard, plaster, cement block, masonry or 24 gauge metal panels.


Earl
Joined: Dec 2003
Posts: 751
E
Member
Oh yeah, and concrete.


Earl
Joined: Dec 2003
Posts: 751
E
Member
Now you got me going.

My rule of thumb is just not sufficient. the finish ratings go all over the chart, depending on the manufacturer and the product. Examples: American Gypsum Co. 5/8 inch Gypsum board Types AGX-1,2&3 have 23 minute finish ratings. AGX-5 has a 26 minute finish rating. US Gypsum Co. 1/2 inch Gypsum Wallboard (GWB) Types AR, FRX-G, SCX, SHX or WRX all have a 29 minute finish rating.
There are hundreds more. But, the lowest rating I could find for 1/2 inch GWB was 20 minutes. The rating for some 3/8 inch GWB was 8 minutes, so watch out!
The assembly also required paper tape over the joints, and usually a minimum of 2 coats of joint finishing compound.

Sounds like, to make your installation code compliant, you need to add 1/2 GWB over the walls of the barn where you have run the romex.


Earl
Joined: Dec 2003
Posts: 751
E
Member
You can research them yourself at: http://www.ul.com/fire/building.html
Click on the picture of the front cover of the building materials directory.


Earl
Joined: Dec 2003
Posts: 751
E
Member
http://database.ul.com/cgi-bin/XYV/...d=1074327030&cfgid=1073741824&ve rsion=versionless&parent_id=1073984818&sequence=1


Earl
Joined: Jun 2004
Posts: 613
S
Member
Thanx earlydean, but I couldn't navigate through to where I could find specific listings on sheetrock and wood?

shortcircuit

Page 1 of 2 1 2

Link Copied to Clipboard
Featured:

Tools for Electricians
Tools for Electricians
 

* * * * * * *

2020 Master Electrician Exam Preparation Combos
2020 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
Lostazhell
Lostazhell
Bakersfield, CA (Originally Orange Co.)
Posts: 1,437
Joined: February 2004
Top Posters(30 Days)
Admin 11
Trumpy 10
Popular Topics(Views)
280,292 Are you busy
213,387 Re: Forum
200,328 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.7.5