Wow, that looks like an agonizing quandary, for likely corrosives and flammable vapors are anticipated. I’m not up on the latest in enclosure innovations from Appleton or Crouse-Hinds, but it looks like “combination” NEMA type 6 or 6P and 7 enclosures [99NEC Table 430-91] would be needed.
There is another wrench-in-the-gears here. In typical situations for this type of equipment, it would seem to be insanity not to use some sort of anti-seize compound on ALL threaded surfaces. Is there anything listed for such an application that will preserve explosion-proof integrity?
[This message has been edited by Bjarney (edited 11-16-2003).]