I've seen a much smaller version of this: A UPS distribution board with all the phases and neutrals separated out. The UPS was very heavily loaded; most of the circuits were less than 50A, but near capacity.
The four nipples between the wire-way and the panel were so hot you couldn't keep your hand on them for more than about a second. I'd wager something like 130-140 degrees F.
I'd be interested to see how hot this installation actually does get....
-John
