I'm having trouble finding references. When I'm done typing this I'm going to go
https://www.electrical-contractor.net/the_store/NEC_Code2002.htm?RCKeepShoping=Keep+Shopping

and get myself the 99'-2002 handbook on CD rom.

I've been told no electric on the grid, only power directly associated with grid mounted fixtures can be supported by the grid, power can be supported as long as it has dedicated pencil rods gong to it etc., etc.

Is there an NEC reference or is this a building code issue. I'm sure it is also a local issue.

300.11

Roger

Quick. Thanks Roger. Now I'd like to see you with a pistol.

Okay, so under what circumstance would these:
http://www.erico.com/products/CADDYcfcElecCompSprts.asp

be used? Are these only for the exception?

For you inspectors, under what conditions do you allow wiring fastened to the grid? Do you require ceiling manufacture's instructions allowing such?

Ceiling grids come in three basic weights. If you find the heavy duty weight, it may be sufficient to attach the conduit to the grid. Light duty grid, never. Yes, it is required by the building code to obtain the permission of the engineer who designed the ceiling grid to attach the wiring to the grid. We lowly electricians never know the weight of the tiles, nor the capacity of the supporting wires, nor the weight of the grid.
Seems kinda odd, because the weight of the fixtures is often much greater than the weight of the wires, and there is no limit on the number or weight of fixtures in the NEC, other than the manufacturers installation instructions.

Here in Phoenix, AZ we run our own grid wires that are painted red to allow the inspector to differentiate our wires from the grid guy's wires. Then we use these, http://www.erico.com/products/CADDYcfcConduitHangers.asp

When using conduit you need to use the #9 wires, which are thicker than the the normal #12 wires. #12 wires are sufficient for running mc cable.

You will need to use these with the #9 wires so you don't bend the grid and it helps to differentiate from the grid guy's wires. http://www.erico.com/products/CADDYcfcIndElectDrp.asp

Prooving once again that great minds think alike.....
With luck, tomorrow there will be a pic in the Photo forum, with exactly this same question!

Looking forward to it. I searched the archives and was suprised to see little discussion on the topic over the last 5 years. Then, within hours of each other......

I may have oversimplified the rules but when I looked at wiring methods supported above a "T"bar, I just satisfied myself that the load was being carried by a support method other than what the "T"bar guy installed to hold up his stuff. If there appeared to be a different kind of wire than the ceiling support and that was carrying the electrical it was OK with me.
There is a lot of "judgement call" here.
I was really just happy to see it was't laying on the ceiling tile but I did try to enforce the intent of the code.
Before they tightened up this article there was really a lot of abuse in suspended ceilings, like MC daisy chained between the layins, with no support at all.

Here's something I always wondered:

How do the cieling guys attach the wire to the building supports without having to reach up there?

Is there some pole that they use, standing on the floor and twisting the wire in place?

Any help...


Dnk......

It's been a while since I saw T bar go up but as I recall they go up and hang all the wires first, then come down to ceiling level, set the laser and hang the Tbar from the dangling wire.
I have seen places with more space above the T bar than below it.

A tool is sold that goes on 3/4" EMT that allows you to reach up to the bar joists through the grid and twist on the tie wires.

That aside it is just as easy to make one.

We also have a long drill extension (about 12') that allows you to reach up and install drill tipped eye bolts on jobs that you can not wrap around a truss.

These work well in corrugated metal buildings with the perlins that support the roof deck.

Ideally you want to get them in before the grid as Greg said.

Thanks guys, the reason for the question is:

What do you do if the cieling is exsisting, and you want to add some wire for new lay-in lights?

I am thinking it would be easy to get one of these tools, and add some wires to attach to the lights, for support.

Any pics of these "tools" or ideas where to get one?


Dnk.........

We use this pole with tech screw eye bolts that the #12 wire goes thru. http://www.sammysuperscrew.com/sampole.htm
First you screw the screw into the metal roof deck and then pull down about 10" and twist the wire and then pull the wire out of the pole.

I used one of those pole tools for the first time a couple of months ago. It worked great, quick and easy to use.