I'm trying to get a better grasp on when grounding bushings are required.
I've read 250.92 and 250.97.
You have to bond any metallic service entrance raceways. 250.92
250 volts or more: You only have to bond raceways after the service if they terminate into concentrics or eccentrics that are not listed for bonding. 250.97.
How about flex carrying 480 3-phase stubbing up from a PVC FA to a transformer? This would be after the service. The way I'm interpreting it is that it wouldn't require a grounding bushing.
Say a grounding bushing is required on the service side, rigid conduit, no concentrics. Can you use one of these: