I worked in a slaughter house then a large candy plant that both had nightly hose down with pressure washers. Found water in most enclosures. We used best in class Allen Bradley Stainless Steel boxes ( guessing NEMA 4 ) that had heavy duty screws with a thick soft rubber O ring and the cover on these start stop stations had a heavy full size gasket. We tried to only enter thru the bottom of boxes but would find a halve inch or more of water in them. Finally drilled two 1/8" holes at a angle towards wall in bottom of boxes to drain water.