I have a client who is requesting that thier medium voltage (2300V) well pump motors be started in what I would call a Hi-Lo-Hi type arrangement. Distribution power is at 13.2KV, power is stepped-down to 480V for motor control, and then is stepped-up again for the 2300V motor. I have proposed putting short circuit and overload protection between the step-up transformer and the motor (at 2300V), but the client insists that it is not necessary and that the short circuit and overload protection can be done at the 480V level. I feel confident that disconnection of all ungrounded conductors at the 2300V level is what is required by 2008 NEC 430.225, but I don't have a good explanation of why the client can't or shouldn't do it their way. Am I right on this? And if so, can someone give me a good explanation on why the short circuit and overload protection shouldn't be at the 480V level?
Thanks in advance for the help.
Thanks in advance for the help.
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