In order to definitively determine whether or not fuse "1", shown in the illustration is blown using an on-line testing technique, across what points would you connect the voltmeter leads? EL-0062

Correct Answer: Option C — the bottom of fuse "1" and the top of either fuse "2 or 3"

Connecting across the bottom of fuse 1 and the top of fuse 2 or 3 places the meter across the open fuse terminals while energized, measuring full line potential due to the open circuit condition. This validates an online blown fuse per IEEE 45 testing practices.