Ground Bushings Requirements

[harborrick]

We add 60 amp to 4000 amp sub feeders in alot of switchgear. 600v and 208v My question is that most other feeders I see do not have gr bushings.Concetric KO or not. I do know when concentric we use gr bushing. Do I need gr bushing if I punch the holes? Do I need on both sides? All conduit will be EMT.
Thanks for your help in advance.

 

[infinity]

If there are no concentric or eccentric KO's then a bonding bushing is not required for either voltage system you mentioned. For above 250 volts to ground a bonding bushing would be required if there are concentric or eccentric KO's.

 

[augie47]

If they are feeders, as long as there are no concentric or eccentric knockouts, no grounding bushing is required

 

[harborrick]

If there are no concentric or eccentric KO's then a bonding bushing is not required for either voltage system you mentioned. For above 250 volts to ground a bonding bushing would be required if there are concentric or eccentric KO's.

Thanks. Ok if which is mostly what we do. Is 277v to ground ,then we should us a ground bushing on both ends. Also we always run a gr wire.
Thanks