I have existing UG, concrete encased, conduits that stub up 4" above grade, below a power distribution bldg. The bldg is approx. 24 inches above the grade. The bldg is in a non-classified area and the conduits go into a Class I, Div 2 area. There are conduits that terminate with a female coupling that is even with the top of(or 1" above)the duct bank and a conduit screwed into this, then terminates into an approved "sealing" hub at the floor of the bldg.

Does this meet the code requirement?

Some of the conduits extend past the top of the concrete(no couplings), then aa approved seal is installed, then conduit to a hub at the bldg floor. Those adhere to the code requirement.

The UG conduits travel approx. 25ft before they enter the "boundry" of the CL1,Div2 area. Where the conduits stub up inside(25ft-100ft)the Cl1,Div2 area, they have seals. Your comments are appreciated and welcomed.

I will recommend from my experience both ends of explosion proof conduit to be earthed.

Mike,

The text that talks about the revision for this paragraph in the NEC says in part: "the required boundary seal isn’t required to be explosionproof, but it must be identified for the purpose." What sealing device(s) that are non-explosionproof are available that are "identified for the purpose"? Thanks...

Dan

I usually just read the information, and not watch the video. But I was so taken aback by the thought of a "Non-explosionproof seal" that I watched the video. I appreciated the background from suppliers and others.

I do recall a comment in the report on proposals (?) related to seals and referring to "what will they use? wet paper towels? 2 or 3? "

I'll bet some application with large sizes and multiple conduits will surface in the future.

Lynn Adams

The biggest thing I dislike about hazardous locations guidelines is the generalities. "The required boundary seal isn't required to be explosionproof but it must be identified for the purpose."

Life would be much easier if there was a listing number for the seal in this case, and similarly better specifics for other cases.

We know it's for blocking vapors, but what determines how well it must do this besides a listing or a test at inspection? If it gets cold, will we have a "Space Shuttle Challenger O-ring" condition? Will it crack under sunlight? Will the fumes eat it? Will age wither it and when?

If you are installing a minimart, the fuel pumps and fittings are all designed and pre-approved - just assemble in accordance with the instructions and you're done.

On esoteric installations, many aspects leave you on your own to determine whether the part is right, and with manufacturers ascared of lawyers, good luck getting an answer to that effect in writing...

This is just my pet gripe on hazloc.

I wish the code would address the difference between requirements for a site with gasoline and a site with only diesel. Most inspectors require us to treat them the same.