My question is, I have a 2000 amp mdp with 12 3" emt and 5 1 1/4 emt coming out of the top of it. I have ground bushing on all of the connectors in the mdp. On the other end of the 3" emt they go in to 6 36" x36" jbox. My project manager wants to see grounding bushing on the pipes coming in and leaving the jboxes. Same with the 1 1/4 they go in to 4 24x24 boxes. No splices in any of the boxes, voltage is 480. It seems like a lot more grounding then necessary. I understand on the service side but none of the hole are concentric or eccentric. Code references would help me out, thanks.
If there are no service conductors or GECs in any of the conduits, then you only need a grounding bushing per code in the following scnearios:
1. The enclosure is non-metallic
2. The conduit doesn't terminate onto an enclosure on either side, and therefore needs a grounding connection
3. There are concentric or eccentric knockouts on a metal enclosure remaining, and voltage is >250V to ground
It is OK to have a "better to have and not need than need and not have" mentality about using them, because it will improve the bonding performance above the minimum required by code, and there is no adverse effect to overkill on making sure all non-current-carrying metal is bonded to the equipment grounding system. Job specs may require them, above and beyond the NEC.