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)
239,989 Are you busy
175,584 Re: Forum
167,836 Need opinion
Who's Online Now
0 registered members (), 61 guests, and 7 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate This Thread
#198996 - 02/10/11 12:52 AM conduit to suspended ceiling  
triple  Offline
Member
Joined: Apr 2002
Posts: 184
Wisconsin
Does emt piped directly to a box in a suspended ceiling tile violate the NEC? The tile will no longer be removable or replacable.


2017 / 2014 NEC & Related Books and Study Guides

#199001 - 02/10/11 03:28 AM Re: conduit to suspended ceiling [Re: triple]  
gfretwell  Offline


Member
Joined: Jul 2004
Posts: 9,103
Estero,Fl,usa
How did you support the EMT within 3' of the box?
How is the box secured?
Answer those and it is probably legal.

I would start at 314.23(D) and work backward from there.

If the box was independently supported from the structure of the building it would make the decision easier. Then the ceiling is just "there" and not part of the equation.




Greg Fretwell

#199022 - 02/10/11 04:12 PM Re: conduit to suspended ceiling [Re: triple]  
Tesla  Offline
Member
Joined: Jun 2004
Posts: 1,273
Sacramento, CA
Sounds VERY flaky.

It'd get shot down here.

If it's directly on the tile then it's unsupported by California standards.


Tesla

#199024 - 02/10/11 04:46 PM Re: conduit to suspended ceiling [Re: triple]  
renosteinke  Offline
Cat Servant
Member
Joined: Jan 2005
Posts: 5,316
Blue Collar Country
It's not a bad question ...

Caddy and B-Line both make brackets that are designed to clip onto the grid and support a box anywhere in the tile. The 'customary' wiring method is for the last part of the conduit run to transition to flex or MC; then you can still move things if needed.

Yet, these days we're not supposed to 'support' anything from the grid. Light fixtures need their own support wires. Would this bracket also need to have wire supports too? Or, is the support of the conduit enough?

What if the ceiling tile has been replaced by a wood panel, and the box attached to it?

I fear we have pretty much made the suspended ceiling obsolete.


#199035 - 02/11/11 01:24 AM Re: conduit to suspended ceiling [Re: renosteinke]  
PAteenlectrician  Offline
Member
Joined: Jan 2011
Posts: 64
Cressona, Pa, U.S.A. (Schuylki...
What if the ceiling shifts? shocked


#199038 - 02/11/11 02:36 AM Re: conduit to suspended ceiling [Re: triple]  
gfretwell  Offline


Member
Joined: Jul 2004
Posts: 9,103
Estero,Fl,usa
Reno, 314.23(D)(1) does make it sound like those caddy clips are legal if the box is smaller than 100 cu/in

Quote
(D) Suspended Ceilings. An enclosure mounted to structural or supporting elements of a suspended ceiling shall be not more than 1650 cm3 (100 in.3) in size and shall be securely fastened in place in accordance with either (D)(1) or (D)(2).
(1) Framing Members. An enclosure shall be fastened to the framing members by mechanical means such as bolts, screws, or rivets, or by the use of clips or other securing means identified for use with the type of ceiling framing member(s) and enclosure(s) employed. The framing members shall be adequately supported and securely fastened to each other and to the building structure.


I still imagine most AHJs will want to see a supplemental support wire or two. You could do the EMT thing if it was supported by the building structure within 18" of the box.
I have seen smokes and alarm beacons or beepers in a 1900 box, hanging in the grid but they were on an MC whip.


Greg Fretwell


Member Spotlight
akmaster
akmaster
alaska
Posts: 70
Joined: June 2012
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: 0.012s Queries: 15 (0.003s) Memory: 0.7782 MB (Peak: 0.9279 MB) Zlib enabled. Server Time: 2017-08-20 17:33:57 UTC