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.

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.

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.

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

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.

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

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 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.

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.

I had often wondered over the past 30 years why this requirement for 2X4 fixture support varied evrywhere I went, then a firefighter explained he didn't like things falling on his head when trying to do his job. Since then, regardless of local requirements, I have attached wires to opposite corners and used the grid clips.

See Art 410.16 (C). Local code variations will apply. Like you said, it is different everywhere you go. So use the local requirement even though this article allows the fixture to be supported by the ceiling members. I don't support fixtures like you do, unless I have to. I make sure the ceiling grid is supported at the fixture on opposing sides. Thus the term "lay in" fixture.

This is a tbar ceiling done the California (read seismic) way.

The blue highlighted wires are the ceiling grid support wires.

The yellow highlighted wires are the independent supports to the fixture. The fixture is screwed to the grid main runner on the corners opposite those of the wires.

The duct and register are both supported by the sheet metal strap, and it is in turn supported, by an independent wire, to the structure. It is secured to the grid's main runner with screws

The tin stud seismic brace you see is screwed with multiple screws to the grid's main runner, and to the structure above. It must be perpendicular to the grid. (I think this occurs every 12 feet so that no spot on the ceiling is more than 8 feet from one).
The wires highlighted in red are seismic bracing. They are splayed in all 4 directions at angles, keeping the tin stud in compression (and securing the ceiling), and are also connected to the structure.


You can thank your lucky stars that you don't have to go through this.

--You can thank your lucky stars that you don't have to go through this. --

"You aint just whistling dixey"

Nice pic, Thanx.

You folks certainly have a world of worry and concern out there.
Is this a suspended ceiling? or sheetrock?

Either way nicely demonstrated and supported.

"Seismic" Is becomming very popular here aswell.


PS: Hope all is well with my western counterparts, See it's a tough go out that way lately.

Good luck to all.