Grounding Bushings

[Jsaarc]

Are grounding bushings required on the 3" EMT feeder conduit .
The EMT leaves the power source switch board overhead and arrives at the sub panel with underground 3" rigid stub ups.
I feel pretty sure the rigid stub ups need grounding bushings, but I am not sure about the 3" EMT connectors connectors.

 

[augie47]

What voltage are we discussing ? Are there any concentric/eccentric knockouts ?
(Take a look at 250.97)

 

[Jsaarc]

What voltage are we discussing ? Are there any concentric/eccentric knockouts ?
(Take a look at 250.97)

There are concentric knockouts at the power source switch board.
This is a 277/480 volt, 3 phase 4 wire, 2500 amp feeder. Ten 3" conduits in parallel.
Each conduit has 4 # 350 MCM Al and a 600mcm Al equipment ground.

 

[Dennis Alwon]

Gus got it.. 250.97