Bonding a neutral on a sub panel fed from xfrmr fed from a higher voltage sub panel

[johnheathman]

I've got a 208/120 volt sub panel fed from a xfrmr fed from a 277/480 volt sub panel that's fed from a service disconnect on a rack of service disconnects on the other side of the parking lot which all share a single #6 from a ground rod to a ground bar that serves the only ground for 4 200 amp service disconnects 1-480 3phase, 3-240 single phase. Since it's on a rack away from the bldg there's no uffer or bldg steel grounds present. Each disconnect has separate neutral and ground going to sub panel in bldg. Also there is a 208/120 volt 3 phase panel inside fed from the 480 volt 3 phase sub panel. Where does the neutral of the 208 volt panel get grounded from?

 

[infinity]

So let's see if I have this straight, you have a 480 volt feeder to the building from a remote service disconnect which feeds a 480-208Y/120 volt transformer which feeds a 208Y/120 volt panel?

 

[jaggedben]

The neutral on the 208V system should be grounded to a grounding electrode system at the building. The grounding electrode conductor connection should be at the transformer or at the first disconnect on the secondary side of the transformer. You haven't mentioned the location of that disconnect (separate disconnect or main breaker in the panel?).

Sounds like the service location needs at least another rod to be compliant with current code. Sounds like the building needs grounding electrodes too; you didn't mention any electrodes there. The 480V subpanels you mention being at the building should have their groundbars connected to an electrode system atthe building.

It sounds like you said there are multiple 200A 480/277 feeders going from the service to the building? That's actually a violation.