Suspended ceiling box.

[electrofelon]

Does a box for a receptacle or a switch, mounted in a t-bar ceiling need independent support from the grid? I couldn't find any requirement in 314, but it just seems odd that I can't batwing an MC to a grid wire but I can support a box by the grid. Doesn't seem to make any sense.

 

[electrofelon]

Bump!

 

[mopowr steve]

You can batwing a MC to a grid wire that YOU install for it, not the wires dedicated to support of the grid I think by rights, although I’ve never been dinged for doing so to the ceiling grid tie wires.
My interpretation from an inspector here is that if the grid is supported by #12 grid tie wire and if it is within 6” of a fixture, additional tie wires are not required to fixture but fixture must be screwed to grid in 4 places near corners into the main runners.
As for your receptacle which I am assuming your using a Caddy grid bar for, there is a hole in the mounting tab that attaches the box to it for a tie wire. Maybe that’s what you should use?

 

[LarryFine]

. . . fixture must be screwed to grid in 4 places near corners into the main runners.

Every troffer I've seen for many years has a fold-out grid hook on each corner.

 

[electrofelon]

You can batwing a MC to a grid wire that YOU install for it, not the wires dedicated to support of the grid I think by rights, although I’ve never been dinged for doing so to the ceiling grid tie wires.
My interpretation from an inspector here is that if the grid is supported by #12 grid tie wire and if it is within 6” of a fixture, additional tie wires are not required to fixture but fixture must be screwed to grid in 4 places near corners into the main runners.
As for your receptacle which I am assuming your using a Caddy grid bar for, there is a hole in the mounting tab that attaches the box to it for a tie wire. Maybe that’s what you should use?

But is the support wire for the box required? I didn't see it in the book. Unless it's in the instructions for the caddy bar?

 

[Fred B]

I think it's in building code not NEC. Been told reasoning is Fire department doesn't want fixtures dropping out of grid when they must get grid open to fight a fire, might presume the same apply to any fixture.