Mike, I think if you look closely, it's not double-lugged. The center wire has its own hole, right in the middle and underneath the other two. The middle setscrew is to the right of the others.
I'm not sure, but I think I see the enclosure bond at the bottom left. Either that, or the EGC is just lying loose! The conduits are probably RNC, so no bonding nuts.
I'll guess that the larger wires are the load, that they've been beefed up to reduce voltage drop on a long run, and that they go to two separate load centers. (Am I close?)
Alan, suppose those lugs had been bolted to a separate plate of plywood, then screwed as an assembly to the backboard. There'd be a full thickness of plywood between live parts and the enclosure. Would you have accepted it then?
