Which of the following precautions should be taken when measuring high voltages with a voltmeter?

Answer: B. Ensure that the voltmeter and its leads are rated for use at the voltages being measured

When measuring high voltages, make sure the voltmeter and its leads are rated for the voltages being measured. Under-rated meters or leads can break down and expose you to deadly voltage. A good voltmeter has high impedance, not low, so that choice is wrong.

Tip: Check the meter and lead voltage ratings first.