Plenum Rated dielectric coupling for conduit penetrating a partition?

[RASanders]

We have a project with return (environmental air) above accessible ceilings, so it is a "plenum."

One of the key client requirements for entry into an isolated/secure area of the project requires dielectric separation/isolation of any metallic conduit at the penetration through that floor-to-ceiling partition, which is also a fire-rated wall.

Does anyone know of such a junction box, threaded coupling, or other approved/listed method or device for penetrating a sealed partition wall above the ceiling in an air plenum...
...but which allows for ONLY the ground/bonding conductor to pass through (it is monitored), but prevents any continuous metal contact between the EMT on either side with dielectric (NO metal-to-metal) isolation?

We found a phenolic coupling for threaded conduit, but it does not specifically indicate UL/FM listing for plenum use...

 

[Sierrasparky]

Interesting requirement.
How do you expect the conduit to be grounded at all sections?

 

[cloudibew]

tricky, my first thought is to utilize pvc or carflex for your penetrations changing over from emt to pvc/ carflex back to emt, sleeve and fire caulk it. Bonding bushing on the other end just to be safe. i would certainly call the inspection authority down for a consult and explain in detail or show him a mock up.

This keeps box and mounting hardware requirements down and the number of taps on the circuitry as potential points of failure. Also keeps perpendicular penetrations easy. Oh and cheap even if schd80 is used compared to fancy boxes.

Second thought could also just chip the floor up and do any of that via UG.

3rd thought pcv boxes on both sides of the pennetration and bonding bushing.

Maybe?