Plenum Ceiling

[paul]

We have a situation at the job I'm on, where we need to run ground wires in a plenum ceiling to telephone Master Ground Bars throughout the floor. Normally we run these wires in PVC, but it's not allowed in the plenum ceiling. The insulation, THHN, is also not rated for plenum. The specs do not allow us to run it in any metal raceway, nor have it ran as a bare conductor. Does anyone have any thoughts on how to do this?

 

[ron]

Re: Plenum Ceiling

I don't see a down side of installing it bare (maybe you can offer to add tags for identification) or in metallic raceway (bonded at the ends).
You will need to ask the person who wrote the specs disallowing bare conductors and metallic raceway.

 

[jerryb]

Re: Plenum Ceiling

Another possibility would be an American Insulated Wire Corp. type CK-5482-H cable. The description would be "Type RHH/RHW, low-smoke, low-flame spread insulation, gray presaturated cotton braid exterior, Class D stranded copper conductor. Cable to conform to UL 1277, IEEE 383-1974 and UL standard 44."

This cable is used in a wireless phone company (who will remain names - recenlty murged with another phone company) for their DC wiring of switching equipment. The cables are run in parallel bundles from the battery racks, to 4000 amp bus bars and to the switching equipment.

Hope this helps.

 

[paul]

Re: Plenum Ceiling

jerry,

I know exactly which cable you're talking about. I'll pass this by the engineer to see what his thoughts are on it.

Ron,

Bare and metal raceway are not an option, as the phone company will not allow it. No exceptions.

Thanks guys.

 

[eprice]

Re: Plenum Ceiling

paul,

Another option you could explore with AHJ approval: You could consider runing in PVC conduit and then wrapping the conduit with a listed wrap made for the purpose, so that it is no longer "exposed" in the plenum.