Card 20 / 30: You are about to perform absence-of-voltage testing on a 480 V panelboard. There has been no arc-flash study done and there are no labels. You can determine from the transformer nameplate of the transformer feeding the panelboard that the short-circuit current will be less than 50,000 amperes, and the breaker feeding this panel is an MCCB with an instantaneous trip unit and a clearing time of less than two cycles. What is the flash protection boundary?
A) 42"
B) 48"
C) 60"
D) There’s no way to tell

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