Adam:
In the larger panel, there is a line drawn between the Main Breaker (I assume) and the rest of the breakers. There also appear to be a couple of mounting screws along that line. Does this indicate that there is a plate beneath that separates the Main section from everything else? I've seen such panels before (mostly here at ECN), but I think they were primarily of Canadian origin since I have not seen anything like this in the U.S (with the possible exception of some old Wadsworth equipment from long ago).

Also, is there a particular reason for mounting the panels horizontally?

Mike (mamills)