Dave,
Quote
Yes. The "XO" terminal at the xfmr needs to be bonded to the enclosure of the xfmr, ...

The 480 volt secondary of this system is not required by the code to be a grounded system. You can leave XO floating. If you choose to have a grounded 480 volt system, then you must tie XO to a grounding electrode system.
Don

Don(resqcapt19)