I have a question. You have an 800 amp 480 volt 3 phase service. The first piece of equipment in the service is a fusible disconnect that feeds a CT cabinet, then goes to a large 2 piece MDP cabinet. Now if someone taps the busbar inside of the MDP and goes to a separate fusible 400 amp disconnect which then feeds a beaker panel which is connected to a large PV system. That feeder is a tap. Right? It is in pipe and troughs and all that is in the service room. However can you run that unfused tap wire inside of the same trough as all the other wires that all have proper OC protection on them? You are trying to run, fused and non fused wires in the same trough. Now can you cite sec. 230.7 of the 2011 NEC? The 400 amp wire is a feeder, but is it a tap or a service conductor? It feeds a PV system and other than the original 800 amp fuses, there is no other protection on that 400 amp wire. Plus it runs through a trough with all the other conductors. I know it would be safer if it was in a different conduit run away from the other conductors.
That is one of my main concerns, however I would need a code section to cite. Since the "tap" is after the main fusible disconnect, it is not technically a service conductor. It would be a feeder wire. Yet, there would only be an 800 amp OCP protecting that feeder and it is running through a trough with all the proper OCP wires.