beanland
Senior Member
- Location
- Vancouver, WA
I am working with modifications to an existing installation. A 120V 40A breaker feeds a single-phase 120-to-600V 5kVA step-up transformer. The 600V circuit runs 1300 feet underground (#4XHHW) to a matching transformer where the 600V is returned to 120V for utilization. NEC 250-20 requires grounding one leg of the new 120V feed from the second transformer but I find no requirement to ground one leg of the 600V separately derived source. Is this required, optional, prohibited?
