Of course the answer may differ between manufacturers, but what is the difference between top and bottom feed? I typically use Siemens for my 250-1000 amp panelboards and a line in the part numbers indicates top or bottom feed. Is there a difference? The cabinet mounting studs are symmetrical, so I dont see how it could be a wire bending space thing. There isnt any lettering or lebeling that would be upside down, other than what is on the breakers. I have thought about this when putting the panelboard into the cabinet and can never see anything that would be different or matter if I just installed it the other way.....?