Installation of cable tray above solid ceiling

One of the first concerns is using plenum rated cable if the space above the ceiling has environmental air supply or return. Beyond that item you must insure local codes will allow the method you desire, as well. To my recollection the NEC would allow tray above a permanent ceiling just as it would conduit.

Fudgemiester makes sense to me.{p] Can't see where you are.

There may well be a point when in the installation an inspection is required.

I mean how are you going to install this, if it is inaccessible?

Not sure what you mean by sub-circuit cables. I guess you mean power runs off a sub panel fed from the main panel.

I imagine that the more important thing regardless of inspection or whatever is the separation distance between wires as laid.

I read of one case where an electrician failed an inspection for too much neatness since he tie wrapped everything close together which would enhance induction heating due to field resistance.

(There is something wrong with my language here?)

Dear All,

Thanks for all your valuable thoughts. This is a new installation, that's why we can do the cable tray now before putting up solid ceiling. But after completion of building cable tray will not be accessible for inspection or maintenance. I later found in NEC 396.2 (I)

"Adequate Access. Sufficient space shall be provided adequate access for installing and maintaining the cables."

So, I suppose it will violate NEC if we install cable tray above solid ceiling since there wont be any access for cable tray in future for any inspection or maintenance purpose.

NEC Article 392 says: 392.6(H) Exposed and Accessible as permitted by 392.6(G) where made in accordance with 300.21 (spread of fire). So cable tray must be accessible, but can extend through a wall or floor if it does not create a problem with the fire rating. 392.6 (I) Adequate Access says there must be sufficient space around the tray to permit installation and maintenance of cables The question then becomes is the tray easily accessible above the hard ceiling?

You need an access hatch and clear working room above the ceiling. If you are in per contract and plans this will be a change order for you.