A crane will operate where the boom or load could approach an overhead power line carrying less than 50 kV. What MINIMUM clearance is generally required between the equipment and the energized line?

Explanation

Correct: for lines up to 50 kV, the general minimum clearance for cranes and their loads is 10 feet, increasing for higher voltages. Three feet is far too close for crane work and applies, if anything, to certain low-voltage qualified electrical tasks, not crane operation. Twenty feet is the default when the line voltage is unknown, but for a known sub-50 kV line 10 feet is the stated minimum. Operator care alone is never an acceptable substitute for the clearance.