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410.16 (C) vs. "independent support" #170504
11/04/07 07:05 PM
11/04/07 07:05 PM
R
Redsy  Offline OP
Member
Joined: Mar 2001
Posts: 2,056
Bucks County PA
Where do we get a requirement to independently support lay-in luminaires? Local rules?

Sometimes I see it, sometimes I don't.

Thanks,

John

2017 / 2014 NEC & Related Books and Study Guides
Re: 410.16 (C) vs. "independent support" [Re: Redsy] #170508
11/04/07 07:47 PM
11/04/07 07:47 PM
HotLine1  Offline

Member
Joined: Apr 2002
Posts: 6,986
Brick, NJ USA
Redsy:
A 'plain english' explanation....

NEC requires fixtures to be 'attached' to the grid, by mechanical means; screws, clips, rivets, etc. in most cases. This is the 'basic' NEC requirement...this is what an Electrical Inspector can enforce, but....

Ind. support is required in seismic areas.

Ind. support MAY be required by plans/specs.

Ind. support IS required in certain 'Fire Rated' ceiling assemblies (I have never seen one)

And; a 'COMMON SENSE' rule would be IF the fixture deflects the grid....install support!.

Who the enforcement falls upon...Electric Insp for NEC and Plans/Specs.; Building or Fire for seismic; Fire/Building for 'fire rated' assembly. (My understanding of the NJ UCC)

The 'common sense' rule.....enforcement??



John
Re: 410.16 (C) vs. "independent support" [Re: Redsy] #170512
11/04/07 09:13 PM
11/04/07 09:13 PM
R
Redsy  Offline OP
Member
Joined: Mar 2001
Posts: 2,056
Bucks County PA
Thanks John!

I'm bidding a "Family Dollar" store in Camden.
The specs are "cookie cutter" for each store. They require 8' fixtures, surface mounted on a drop ceiling. (I know I mentioned troffers in my original post, but I believe the question still pertains.)
I'm looking at Caddy "4G" series fixture mounts and wonder if additional support would be required.

http://www.erico.com/products/CADDYcfcTwistOnFixSprt.asp

Last edited by Redsy; 11/04/07 09:15 PM.
Re: 410.16 (C) vs. "independent support" [Re: Redsy] #170526
11/05/07 08:32 AM
11/05/07 08:32 AM
HotLine1  Offline

Member
Joined: Apr 2002
Posts: 6,986
Brick, NJ USA
John:
IMHO, the 'common sense' aproach should be used. Back in time..8' channels were heavy, made of real metal, and had heavier mag ballasts, so...additional support was required.

What do the plans/spec indicate; if anything. Also, I (IMHO) would check out the grid. Some 'new' grid is pretty flimsy, and how much support is on the grid itself?

I have negotiated 'extra' ceiling wire from the ceiling contractor; it was a worthwile $$$ spent.

Check out Caddy 'IDS' items Independent Support Clips.



John
Re: 410.16 (C) vs. "independent support" [Re: HotLine1] #170528
11/05/07 09:49 AM
11/05/07 09:49 AM
electure  Offline

Member
Joined: Dec 2000
Posts: 4,271
Fullerton, CA USA
HotLine,

We'll have to make you an official "California Guy". crazy

Out here in Seismic Area 4, we use the Caddy IDS hangers that you recommend for just such an application.

http://www.erico.com/products/CADDYcfcIndSprtClps.asp

They're of extra value when the layout of the fixtures, lighting track, etc. don't fall right on a main runner of the grid. The cross tees are comparatively weak and the IDS support clips can provide the support for the fixtures no matter what the layout.

Usually the GC will have the ceiling contractor shoot the additional support wires and seismic splay wires. If not, a case of beer or 2 to the ceiling guy seems to do the trick

smile

Re: 410.16 (C) vs. "independent support" [Re: HotLine1] #170529
11/05/07 09:50 AM
11/05/07 09:50 AM
G
ghost307  Offline
Member
Joined: May 2005
Posts: 945
Chicago Illinois USA
I like the 'extra' ceiling wire idea.

I worked at an industrial plant outside Chicago and one of the processes was carried out in a room that had 2x4 troffers and a suspended ceiling. The process was apparently corrosive to the ceiling wires, because 1 day the whole grid let loose and dropped tiles on everybody.

The troffers stayed hanging by their small safety chains. If not for that little bit of extra protection, I'm sure that someone would have gotten a fixture dropped on their head that day.


Ghost307
Re: 410.16 (C) vs. "independent support" [Re: ghost307] #170539
11/05/07 02:06 PM
11/05/07 02:06 PM
HotLine1  Offline

Member
Joined: Apr 2002
Posts: 6,986
Brick, NJ USA
Electure:
Thank you for the honor of being a Calif. guy. I spent a little shy of three weeks from SF to San Diego quite a few years ago, and really would like to get back! This time SF north to ???




John

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