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.
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.
#54815 - 08/08/0506:44 PMRe: wiring system supported from grid
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.
#54819 - 08/10/0501:24 PMRe: wiring system supported from grid