I have been asked to hire an electrician to feed a 75kVA 208/480-400 transformer to supply either 480-277 or 400-230. Is there a code violation with using a Manual Transfer Switch to take two tap settings off the transformer secondary, 480 & 400, and feeding loads via a dedicated 480V MCB and a 400V MCB? And have Administrative Controls in place to prevent 480V loads from being connected when the taps (transfer switch) is in the 400V position and vice versa. Am I bound to use a Tap Switch instead? Nothing is done immediately. We either setup for 480V or 400V prior to energizing. The location is in Washington State. Both the 480V & 400V loads are only powered by the transformer. Thanks in advance for your input.
