K-13 rated transformer grounding electrode conductor

[fredw]

If you have a K-13 rated transformer that serves a 120/208V panelboard with a 200% rated neutral, does the grounding electrode conductor need to be increased 200%?

[ron]

Although an equipment grounding conductor is increased based on volt drop, it nor a GEC gets increased due to potential hamonic content.

[dereckbc]

No. A K rated transformer establishes a rating method to indicate thier ability for nonsinusodial load currents without exceeding thier tempature rise limits. The GEC and EGC's do not carry any load currents