Means of support

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bke5

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I was failed for a ceiling concealment for not having my lay-ins tied up in opposite corners. I can not find anything in NEC or IBC other than they must be screwed bolted or riveted to the grid.
 
Sometimes the local towns,cities require that they be tied up.Once awhile back, a roof top unit was blown off the roof and the suction from that pulled the lay-in fixtures up out of the grid and crashing down.Ever since, it was a requirement to tie up to the structure.

As far as nec, only listed screws rivits bolts are required where the ceiling is properly supported according to manufacturing spec.

How is your wiring system supported? That needs to be supported by your own independant support from structure to grid.You can't use the builders grid wire for you wiring supports.
Rick
 
The building inspector should be the one to check the installation directions of the ceiling.Depending on the lights weight,they may need more support wires. Neal
 
I thought there was something in the code that said the luminaires had to be supported independently from the ceiling. Some towns make us use a tie wire for lay-in and recess lights. We take a piece of ceiling wire and either run a screw to a wood joist of tie it around a bar joist. My understanding of this is that it keeps the lights from falling on fire fighters when they spray at a ceiling.

I have also had to bend over the "hurricane clips" on a lay in troffer across the grid in North Texas. What ever floats their boat is cool with me as long as I get the green tag.
 
RUWired said:
Sometimes the local towns,cities require that they be tied up.Once awhile back, a roof top unit was blown off the roof and the suction from that pulled the lay-in fixtures up out of the grid and crashing down.Ever since, it was a requirement to tie up to the structure.
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A roof top unit got blown off the roof, so they make stricter requirements for attaching light fixtures:confused:

Steve
 
Have had inspectors differ on this here.Some want grid wires some just screws some both.Fire department and ahj are the ones to ask for where your at.A lot depends on how high off floor and how big is ceiling.12 x12 room at 8 feet with 2 fixtures might get off easy.Really not an nec issue.
 
From the NEC

From the NEC

I would go with: (bold added)
410.16(C) Suspended Ceilings. Framing members of suspended ceiling systems used to support luminaires (fixtures) shall be securely fastened to each other and shall be securely attached to the building structure at appropriate intervals. Luminaires (fixtures) shall be securely fastened to the ceiling framing member by mechanical means such as bolts, screws, or rivets. Listed clips identified for use with the type of ceiling framing member(s) and luminaire(s) [fixture( s)] shall also be permitted.
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The bold above covers the fixture support and the concept of additonal wires as being at appropriate intervals.

The way it is looked at around here, the initial ceiling support wires are there for the ceiling alone. Ask the ceiling guy! Every time I have asked the ceiling contractor to supply the Manufacturers load data, the response has been to add extra wires for the fixtures. Therefore, if anything extra is installed, the weight must be supported by additional wires to the structure.

Heck, look at the way the NEC treats conduit and boxes:
300.11(A)(2) Non?Fire-Rated Assemblies. Wiring located within the cavity of a non?fire-rated floor?ceiling or roof?ceiling assembly shall not be secured to, or supported by, the ceiling assembly, including the ceiling support wires. An independent means of secure support shall be provided.
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websparky said:
The bold above covers the fixture support and the concept of additonal wires as being at appropriate intervals.
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Actually, it covers support of ceiling members that in turn support fixtures. It does not say that the fixtures themselves require independent support. (No, you haven't claimed otherwise.) What are "appropriate intervals"?

Every ceiling grid we've installed had support wires at 4' intervals, and we have never needed to add more wires for fixture weight to pass electrical and building inspections. (We're also licensed for res. & comm. improvement)
 
Dave, Larry is right, let's bold the whole sentence and take note that only the Framing members are being addressed.

(C) Suspended Ceilings; Framing members of suspended ceiling systems used to support luminaires (fixtures) shall be securely fastened to each other and shall be securely attached to the building structure at appropriate intervals. Luminaires (fixtures) shall be securely fastened to the ceiling framing member by mechanical means such as bolts, screws, or rivets. Listed clips identified for use with the type of ceiling framing member(s) and luminaire(s) [fixture(s)] shall also be permitted.
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Attaching the fixtures to the structure comes under other codes or standards, not the NEC.

When attaching support wires to the fixtures for seismic requirements we leave slack, so these wires are not relieving the grid from supporting the weight of the fixtures even in this scenario.

Roger
 
My building official gave me a page from the UBC that showed a picture of how the grid lights were to be installed. It shows a support wire on opposite corners.
 
jshaw said:
My building official gave me a page from the UBC that showed a picture of how the grid lights were to be installed. It shows a support wire on opposite corners.
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Corners of the grid surrounding the fixture, or corners of the fixture housing itself?
 
bke5 said:
I can not find anything in NEC or IBC other than they must be screwed bolted or riveted to the grid.
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bke5,
In the 2003 IBC, look at Section 1621. That section references ASCE 7, which you probably don't have. Section 9.6.2.6.2 of ASCE 7 references design standards published by CISCA (Ceilings and Interior Systems Construction Association). I am not familiar with CISCA standards for lesser seismic design categories, but for seismic design categories D, E, and F, the CISCA standard for seismic zones 3 and 4 is referenced. This document requires light fixtures to be positively attached to the grid and to be independently supported from the structure above.

If your seismic design category is less than D, a different CISCA standard or none at all may apply.
 
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