I have a 277/480 volt panel and need to install a stepdown transformer to 120/208. I am a little confused on the wiring between the 277/480 panel and the transformer, concerning the grounded conductor do I need to install this between the 2 or just ABC and a equipment ground then the way the xfrmer is tapped it will create the neutral. The building is metal but doesn't qualify as a grounding electrode so I would bond this and wire from ground rod at transformer. There is no water lines or Ufer. The wiring from load side of xfmer would be ABC,neutral and system bonding jumper.
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