3 phase 4 wire 208v

[harborrick]

I replace a 600 amp three phase 4 wire 208 V sub panel with the main breaker. It is being fed from a 600 amp three phase 4 wire panel board

There was no ground wire running through the conduit and not sure it is rigid all the way through but I assume it is

All the conduit have ground bushings which link together and go to the neutral buss. I would assume to not bond the ground to the neutral buss. The ground bushing wire should just go to ground buss.

Can you direct me to the codebook in this matter please thank you in advance

 

[ActionDave]

I replace a 600 amp three phase 4 wire 208 V sub panel with the main breaker. It is being fed from a 600 amp three phase 4 wire panel board

There was no ground wire running through the conduit and not sure it is rigid all the way through but I assume it is

250.118 tells us that metallic conduit is an NEC accepted equipment grounding conductor.

All the conduit have ground bushings which link together and go to the neutral buss. I would assume to not bond the ground to the neutral buss. The ground bushing wire should just go to ground buss.

If it is at the service then 250.80 tells us that is the way it is supposed to be.

 

[kwired]

If the source end is the service disconnecting means there is supposed to be a bonding jumper in there from the grounded conductor to the enclosure, making the neutral same potential as the grounding bus - most of us see no problem landing EGC's and bonding jumpers on the neutral at the service equipment.

Such jumpers at the sub panel end would need to land on the cabinet or EGC bus and not the neutral bus though.

Such jumpers are not prohibited but also are not required unless there is something that interrupts continuity involved.