We have some Transformer primaries rated 8320V Wye and some are 8320V Delta. Will this cause any problems on the secondary 480/277 side as far as a floating neutral?

Issue:
Transformer Primaries

Product Line:
MV Transformers

Environment:
Applies to Medium Voltage Transformers by SquareD/Schneider Electric

Cause:
Delta vs. Wye Transformer windings

Resolution:

Standard procedure for connections to a Wye primary Transformer are to hard wire the neutral/ground terminal on the Transformer to the ground bus in the switchgear. The ground bus in the switchgear should also be hard wired to the neutral/ground terminal of the upstream service Transformer. Cable connecting all of the ground connections eliminates the return circuit to the service Transformer neutral through earth which would introduce an impedance into the circuit.

Released for:Schneider Electric USA