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Monday, April 24, 2017
Question:
Per NEC 430.122, what is the reason for the requirement to size the wire to the input current rating of a drive? For an analogy you don’t have to size the wire for a NEMA Size 1 full voltage starter for the current rating of the starter.
Thanks, Kevin Therne
A
Answer:
Hey Kevin thanks for your question. Power conversion equipment (adjustable speed drive) has losses so the drive input current can be more than the motor current. A typical controller (starter) is not a load, it just makes and breaks the motor current so does not increase the current.