nameplate states primary 208V secondary 480V/266V . Nameplate shows Delta- H1 H2 H3 and Wye - X1 X2 X3 ,XO
Allright-ee then, you have a Delta x Wye Transformer, with that X0 Terminal being the "Common" lead.
Bond that Termination (X0) to the following:
* Grounding Electrode System,
* Equipment Grounding Conductor(s) for the SDS side,
* Transformer Enclosure.
Land the Branch Circuit's Equipment Grounding Conductor
(EGC coming in to the Transformer, with the Branch Circuit that feeds it)
to a separate lug, terminated to the Transformer's Enclosure.
The X0 Termination will be the Termination Point for the SDS' system grounded conductor (AKA - "Neutral").
If there is no need to include the common grounded conductor with the SDS' Secondary Feeders, then you could contemplate not installing it out of the Transformer.
This would apply if the designed loads were only L-L / L-L-L.
If it is cost efficient, go ahead and install that Grounded Conductor between the Transformer and the first Panelboard.
Let us know if you have more Qs.
Scott
