Plenum Ceilings Junction box and conduit fittings

[Fordean]

Just curious
Plenum ceiling usually use the MC type cable and emt. 4 11/16 box where needed.

The Plenum rated boxes. Don't have a ground screw hole to keep plenum seal. How do they ground box, With no tailing. Grounded Locking ring with screw?

Also, EMT fittings. Are there a specific type. For plenum. Like Set screw should or should not be used. And only Compression type?

MC cabling not a issue. But if you use a MC connector above ceiling. Is that ok? Just looking to avoid inspection issues. Seems things are really getting stricter.

 

[augie47]

The primary requirement is simply metallic wiring methods.
Beyond that there are no restrictions.
Most, if not all, 4" and 4-11/16 have a threaded spot for a ground screw.
Under today's energy codes a plenum ceiling would be rare I'm told.

 

[Fordean]

The primary requirement is simply metallic wiring methods.
Beyond that there are no restrictions.
Most, if not all, 4" and 4-11/16 have a threaded spot for a ground screw.
Under today's energy codes a plenum ceiling would be rare I'm told.

Appreciate the response. But I know about the screw. I worry a inspector that may have a strict standard. Attached is a spec of a Plenum type of box. They have no screws. Don't know how long this has been around. But I never used one, Even in past installs.

 

[infinity]

I cannot think of a location where those would be required except maybe in Chicago.

 

[Fordean]

I cannot think of a location where those would be required except maybe in Chicago.

I never used them. Just all metal wiring/conduit But i do use Plenum rated Cat 6. I see many not use Plenum low volts but would hate to have to change.

 

[don_resqcapt19]

As far as I know, the only place that requires a plenum rated box is Chicago. They also require the use of flexible metal tubing in plenum ceilings...another thing that is pretty much only used in Chicago.