@ FlightPath OBN....Sorry, I didn't explain my thoughts very clearly....the box-flange is currently about an inch wide.....double it and add the thicknesss of the lid.....fold it back on itself, thus forming a slot...do that on 3 sides and the lid will slide into the slot....bolts (same relative position as the plastic-fronted "Demo" box)would only have tension if a pressure-event tried to force the lid upward....remember it's restrained by a 1" wide cpntinuous flange folded over 3 sides....If the top belly's it will try to pull out from the slot....the flange, being 2 thicknesses with a fold, is unlikely to bow outward anyway....but any bowing tendency would give shear on the bolts....lighter and stronger and cheaper to produce ehan what appears to be a cast /welded flange on the box as pictured....also the lid has nothing stiffening the edge-that's why the bolts have to be so close and so plentiful- to stop the tin-lid blowing between them.
As for maintenance- it's a sealed unit- uncouple the cables, uncouple the vent-pipe, heave out the "dead" box and shove in another....same as before, just a "bit" heavier and a drain to disconnect/reconnect.
@ Seth. Thanks for the correction
Fascinating reading.
@Syseng. I agree with you , re Condensation....any present across the "live" bits would electrolyse and would "self-heal" anyway....bit of an old wives' tale, like the film-scenario of an electric-fire being chucked in a bath/swimming-pool and electrocuting the occupant(s).....fuse usually blows first!....pos-neg-earth about 5mm apart water, same resistance per linear distance, so victim more than 10 Cm away, is virtually insulated.
@ Mark in CA....Atomic Power Plants are normally occupied by professional engineers, who usually know what they're doing (unlike commercial Pax.)
When they foul up, you getCHERNOBYL ....Nuff said?