So I have a big vertical riser box filled with 500 Kcmil feeders w/ #4/0 EGC's, say 20 sets. I choose to splice all of the feeders at a midpoint in the run. Are you saying that I need to splice together all 20 #4/0 EGC's? I say that the only requirement is that the box is grounded to one of them and that the rest can simply be spliced straight through.
Yes, I believe that you would have to splice them together. Here is what 250.148 says:
"Where circuit conductors are spliced within a box, or terminated on equipment within or supported by a box, any equipment grounding conductor(s) associated with those circuit conductors shall be spliced or joined within the box or to the box with devices suitable for the use in accordance with 250.148(A) through (E).
250.148(C) goes on to state:
"Metal boxes. A connection shall be made between the one or more equipment grounding conductors and a metal box by means of a grounding screw that shall be used for no other purpose or a listed grounding device."
So the best way to comply with 250.148 in your example is to use a listed grounding terminal kit with multiple lugs bolted to the metal box and used to splice all the equipment grounding conductors.
I have done this in the past, albeit not to the extent that your example is showing.
Chris
Question I have a 2 gang box in the bathroom of a house it has a lighting circuit and a gfci circuit in it. The AHJ wants the 2 devices in there own box because he says the 2 different grounds can not be in the same box. And a different inspector for the same city says they are ok in the same box as long as ALL the ground wires are termanated together undere the same wirenut.
