Couplings/Unions in Class 1 Div 2 Areas

[rcwilson]

Contractor installed a security system in a gas compressor room running wiring in rigid conduit. Room is classified as Class 1 Div 2. These circuits are low voltage (power over ethernet) but not intrinsically safe. Conduit is appropriately sealed at Class 1 Div 2 to non-hazardous boundary. Equipment is all Class 1 Div 2 rated.

Some conduit runs are assembled with the C-H "HDG" 3-piece, concrete tight couplings that connect conduit without turning, like a union. These couplings are not listed in the catalogs as Class 1 Div 2. Some electricians on site are saying all the HDG couplings need to be replaced with explosion proof unions.

Contractor is quoting 501.10 B (4) "Boxes and fittings shall not be required to be explosion proof..." Per definitions, a coupling is a fitting.

Are these couplings suitable for this application? (I tried to find UL file E-19189 for the HDG coupling but haven't located it yet.)

 

[don_resqcapt19]

In general, there is no need to use explosionproof conduit fittings and unions in Class I, Division 2 applications. The execption would be fittings and unions that are installed between an enclosure that requires a seal and the seal.
I am not sure why there is even a listing for boxes and fittings for use in Division 2 areas, as nothing special is required. I expect the listing is just for marketing purposes to sell more expensive boxes and fitting.

 

[rcwilson]

Thank you, that is what we thought. We figured if a standard LB fitting is ok, why not a UL listed coupling?

I appreciate the confirmation. We did verify there is nothing but solid conduit between the seals and enclosures or the boundary.