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#172419 - 12/19/07 05:28 AM Support for Luminaires/Light fixtures etc.
George Little Offline
Member

Registered: 01/18/04
Posts: 1492
Loc: Michigan USA
The age old question is, Do I need to provide independent support for 2X4 lay-ins in suspended ceilings. My answer has been "No" and qualified by saying that the ceiling needs to be adequately supported and the fixture needs to be secured to the ceiling grid. My code reference is 410.16(C). We have some inspectors who maintain that this type of fixture needs to be supported by the building structure. The grey area is the support of the suspended ceiling used to support the fixture (I think). I usually look for at least 2 support wires at the fixture and they should be on the main "T's" not the cross "T's". Works for me.
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George Little

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#172433 - 12/19/07 07:54 AM Re: Support for Luminaires/Light fixtures etc. [Re: George Little]
renosteinke Offline
Cat Servant
Member

Registered: 01/22/05
Posts: 5299
Loc: Blue Collar Country
Comes down to the basic principle of 'cite your source.'

NEC's not the only code out there. Support of fixtures is also addressed by other codes and standards.

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#172442 - 12/19/07 09:11 AM Re: Support for Luminaires/Light fixtures etc. [Re: renosteinke]
sparkyinak Offline
Member

Registered: 07/08/07
Posts: 1286
Loc: Alaska
I concur with renosteinke. For example, IBC requires a suspended ceilings in siesmic areas be designed to support the ceiling, lights, ducting, sprinklers, and anything attached. Does this mean that the ceiling can support the lights? Not yet. There is still the project specs, state, and local ordinances, before it gets to the NEC. One you get to the NEC you still need to ensure the clips or rivits are listed. If you are going to screw, bolt or rivit to the grid, you want to verify that grid is designed for that. When using the fasteners, you know darn well the the t-grid will get flatten from the riviter or tek-screws from the cordless. That will effect the structual integrity of the t-grid. Each project I was on, the fixtures were supported seperately from the T-grid. Then again I live in an active siesmic zone. Local fire code may require supporting the fixtures too.

If the ceiling is existing, the same rules applies, except the ceiling may not be able to support the lights. I did a retro project where the first light I popped out, the ceiling darn near come down. the ceiling was supported by speaker wire. The wire in the are snapped and tention on the fixture was keeping everything together.
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#172449 - 12/19/07 09:51 AM Re: Support for Luminaires/Light fixtures etc. [Re: sparkyinak]
Yoopersup Offline
Member

Registered: 03/04/03
Posts: 826
Loc: Michigan
George
300.11 a(1) Fire rated ceilings says independent support,as far as other ceilings. I agree with checking with listing and labeling of the ceiling and required support wires it calls for. Yoopersup

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#172459 - 12/19/07 05:09 PM Re: Support for Luminaires/Light fixtures etc. [Re: Yoopersup]
leland Offline
Member

Registered: 08/20/07
Posts: 856
Loc: Lowell area, Ma. USA
MA. Code.
Any fixture with a ballast needs additional support.

410.16 (C)-- Add second paragraph.
"In addition to,or in lieu of,the machanical means,electrical fixtures containing ballasts,other than simple flourescent reactance ballasts,shall be supported directly to the building structure by wire,chain or threaded rod of sufficiantstrength to carrythe fixture.Flourescent fixtures shall be supported at each end of a diagonal axis of the fixture. (luminaire, replaced with fixture by me)."

My understanding, is for fire fighter safety, knock the ceiling down and don't worry about the 30# fixture.

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#172520 - 12/20/07 01:26 PM Re: Support for Luminaires/Light fixtures etc. [Re: Yoopersup]
George Little Offline
Member

Registered: 01/18/04
Posts: 1492
Loc: Michigan USA
 Originally Posted By: Yoopersup
George
300.11 a(1) Fire rated ceilings says independent support,as far as other ceilings. I agree with checking with listing and labeling of the ceiling and required support wires it calls for. Yoopersup

Ernie– One of the reasons I became an inspector twenty years ago is because I was tired of Inspectors telling me- "This is what I want" My mentor used to tell me "Tell them to show you in the book" and that's the best advice I've received so far. You can secure the wiring methods and the fixtures to the suspended ceiling and the ceiling support wires PERIOD. I don't care if it is a rated ceiling or not. That is what it says in 300.11. The trick is designing the ceiling and support system to accommodate this extra load. Read the exceptions. Read the Design Professionals documents. Read the prints. You guys are getting me mad and I'm taking names, Oh ya, Happy Holidays to those who celebrate them what ever they may be \:\)
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George Little

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#172525 - 12/20/07 02:25 PM Re: Support for Luminaires/Light fixtures etc. [Re: George Little]
Yoopersup Offline
Member

Registered: 03/04/03
Posts: 826
Loc: Michigan
George
How does the contractor prove to you he has the Additional support other then required by the ceiling supplier??According to the 2005 NFPA handbook (All Luminaries are NOT allowed to be supported OR secured to the support wires OR T bars of a fire rated ceiling assembly Unless the assembly has been tested and listed for that use.page 266 NFPA 2005 Code handbook.
PS (Merry Christmas)

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#172530 - 12/20/07 03:59 PM Re: Support for Luminaires/Light fixtures etc. [Re: Yoopersup]
George Little Offline
Member

Registered: 01/18/04
Posts: 1492
Loc: Michigan USA
 Originally Posted By: Yoopersup
George
How does the contractor prove to you he has the Additional support other then required by the ceiling supplier??According to the 2005 NFPA handbook (All Luminaries are NOT allowed to be supported OR secured to the support wires OR T bars of a fire rated ceiling assembly Unless the assembly has been tested and listed for that use.page 266 NFPA 2005 Code handbook.
PS (Merry Christmas)

I read it Ernie and when you read all the commentary it is clearly doable albeit not easy. It would be a special installation and the Inspector, Contractor, UL and Engineer would need to work together and that is pretty unlikely to happen. So the operative word is "unless" according to the NEC and also according to the Handbook. See ya later. Merry Christmas Ernie.
_________________________
George Little

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#172549 - 12/20/07 09:16 PM Re: Support for Luminaires/Light fixtures etc. [Re: George Little]
sparkyinak Offline
Member

Registered: 07/08/07
Posts: 1286
Loc: Alaska
George any Yooper, I'm just carious where abouts in MI are you at? I'm guessing that Yooper is from the U.P. I was born and raised about an inch below the right pinky.
_________________________
"Live Awesome!" - Kevin Carosa

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#172594 - 12/21/07 05:41 PM Re: Support for Luminaires/Light fixtures etc. [Re: sparkyinak]
HotLine1 Offline

Member

Registered: 04/03/02
Posts: 6785
Loc: Brick, NJ USA
George:
FWIW, Caddy made/makes a clip that is intended to identify ceiling wire used for support of cabling.

I don't have a Caddy book handy, but:
Painted bright yellow, 3 to 4" long, one end has a hole for the wire to go thru, other end clips onto the 'T' bar. Support wire cannot flap in the breeze, so this Caddy secures the lower end. With the bright yellow paint, as long as the AHJ isn't color-blind, it's a no-brainer.
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John

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