Light Fixture - Seismic Clamps Only

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cbishop7

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We have a project that does not allow powder actuated tools, which we would use to shoot up our grid wires to support our light fixtures.

We came across these seismic fixture clamps that attach the fixture straight to the ceiling grid and states it is compliant with NEC 410.16(C) and eliminates the need for extra drop wires or chains.

Can this be used in lieu of shooting up the two grid wires (one on each corner) that is normally used? Or would we still need to use the grid wires as well.

http://www.cooperbline.com/pdf/cata...n/BLF09-PDF-WebPI/AT-SeismicFixtureClamps.pdf
 
I have always been told that the grid was not rated to hold the weight of the light fixture. this is why you can screw the fixture in place but would still need drop wires to hold the weight.
 
That's NOT what the literature say. The literature says the clips provide solid attachment, but says nothing about seismic requirements.

Formerly, the NEC only addressed independent fixture support in FIRE RATED suspended ceilings. This required the sparky to know if the entire suspended ceiling / ceiling / floor assembly was a fire rated design, of which the suspended ceiling was a necessary component. Not something you can easily determine in the field.

Now the NEC requires the additional support wires no matter what role the grid plays in the fire rating of the ceiling.

NEC requirements are completely apart from seismic requirements. I confess to never having seen a 'seismic code' - if anyone has a link, please share! - but the independent support of the fixtures has been a constant in areas that do have seismic standards.

If you dig deeper into that same catalog, you'll find all manner of clever, UL-listed clips for attaching conduit and boxex to the grid. I'm more than a little confused, as you're not allowed to use the grid to support your pipe, and I'm not so sure anymore about the brackets that suspend a box over the tile.
 
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I guess the real question I am getting to, is if this construction is in a building where there is no seismic requirements, do we still need the grid wires to support the fixture, or would these seismic clamps be enough?

Also, this would be in a non-rated ceiling.

Thanks.
 
cbishop7 said:
We have a project that does not allow powder actuated tools, which we would use to shoot up our grid wires to support our light fixtures.

We came across these seismic fixture clamps that attach the fixture straight to the ceiling grid and states it is compliant with NEC 410.16(C) and eliminates the need for extra drop wires or chains.

Can this be used in lieu of shooting up the two grid wires (one on each corner) that is normally used? Or would we still need to use the grid wires as well.

http://www.cooperbline.com/pdf/cata...n/BLF09-PDF-WebPI/AT-SeismicFixtureClamps.pdf
Click to expand...

410.16(C) applies to fixtures in clothes closets (2011 NEC). I believe the relevant section is 410.36(B), means of support - suspended ceilings. The fixture clamps you're referring to will satisfy this requirement. They will NOT "eliminate the need for extra drop wires or chains" because those methods are not required by the NEC nor do they satisfy 410.36(B). Thats a building code issue.
 
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