bus duct fed from transformer

[ElectricPersonality]

Curious how to size the supply side bonding jumper for a bus duct that connects the transformer secondary to a 480V switchboard. For this application, the transformer is owned by the customer, so they are not service conductors. If the bus duct has an internal ground bus, is this usually sufficient capacity for the supply side bonding jumper requirements? If not, not sure how to determine the size of the supply side bonding jumper (if use a GROUND CABLE) by using table 250.122 since the table assumes you are running cable phase wires?

 

[Dsg319]

I do not have an answer to your question wether or not that’s the correct way to do it. But the supply slide bonding jumper is sized from table
250.102(c)(1)

 

[augie47]

Good question to pose to the manufacturer.
I have noted that some feeder buss manufacturer give the area of the grounding buss. You might compare that to the 250.102(C) required conductor area.