Under what condition is it acceptable to operate a crane under an energized powerline?

Under what condition is it acceptable to operate a crane under an energized powerline?

• A. It is always acceptable if the line appears insulated.
• B. The boom cannot enter the prohibited zone while raised to its highest angle and fully extended.
• C. It is acceptable during maintenance only.
• D. It is acceptable if the operator can see the line at all times.

Answer: (B)

The key idea is keeping the crane completely out of the power line’s danger area. The prohibited zone around an energized line is the space where the crane’s boom or load could contact or arc to the line if moved. The only acceptable condition is when the crane’s maximum reach—its highest angle and full extension—cannot bring the boom into that zone. In other words, plan the lift so the line stays outside the crane’s worst-case reach, and if necessary adjust the setup or de-energize the line before proceeding.

Insulation of the line does not make it safe to operate closer, because electrical faults or arcing can still occur. Seeing the line or performing maintenance does not guarantee safety on its own; proper clearance and, if possible, keeping the line de-energized or shielded are required.