I am curious - different local requirements
I am curious - different local requirements
When an EC installs a Customer Owned Pad Mounted XFMR, and typically uses multiple PVG underground conduits to get the secondary power (three phase four wire) into the building structure:
How many conductors are in each conduit?
A. (4) Three ungrounded phase conductors and one grounded conductor
or
B. (5) Three ungrounded phase conductors, one grounded conductor, and one grounding conductor.
If you contemplate the above, for situation A. then one would need to draw a "schematic" indicating what the path (including the source and the OCPD), of a major ground fault within the building would be.
If you only 4 conductors in the pvc, and bond only in the transformer, how would a ground fault in the premisies cause the OCPD to open?
If you have 5 conductors in the pvc, I know you would only bond in the transformer, otherwise the grounding conductor would carry return current between the switchboard and the transformer. (not desired).
Is this a NATIONAL code, or is delegated down to the local AHJ?