Interesting. It never occurred to me that an electrical box not being used as an electrical box would still have to meet this requirement.
I have seen some installations where they do this kind of thing to enclose sampling stations and such to keep it out of the weather.
I have even seen GP electrical boxes used for storage in div 1 areas. Are you suggesting that is not a permitted use?
Would this apply as well to sound enclosures around equipment in Div 1 areas? Those are boxes.
I guess the word "approved" would be key.
How the box is used does make a difference, of course. In Class I, Division 1, what must be considered is whether the box can collect ignitable vapors
and if there is a potential
electrical ignition source inside.
Philosophically, Division 1 considers both common and uncommon or abnormal sources of
electrical ignition because, in the fire triangle, oxygen is always present and fuel can be potentially under common conditions. In Division 2, since fuel is not commonly present, only common or routine sources of ignition are considered.
I still don’t have a secure handle on the process and operations involved, but using cords (even “extra hard usage” type SOOW) in this installation does not appear to meet any of the applications permitted in 501.140(A). The raceway/enclosure wiring method also appears to provide a substantial gas transmission system and flame path to the "outside world."
This is why I wanted to know if the installation and / or electrical area classification is consistent with any of the standards listed in 500.4(B). As I said, the list is neither exhaustive nor exclusive and I’d certainly consider another reputable document, but I’d sure like to know what it was and what it said.
