Electrical Clearances: Minimum Distances from Power Lines

Electricity can jump. A crane, its boom, its load line and its load must all stay outside a minimum distance from an energized power line. The distance depends on the line's voltage, and on whether the crane is operating or traveling with no load. Always presume a power line is energized unless the line's owner confirms it has been de-energized and visibly grounded at the work site.

Table A: minimum clearance distances for equipment operations

Use this table while the equipment is operating near power lines.

Table T: minimum clearance distances while traveling with no load

Use this table while the equipment is traveling with no load and the boom lowered. The distances are shorter than Table A because the boom is down and nothing is on the hook.

The prohibited zone

The prohibited zone around power lines: the space within the minimum clearance distance, in every direction.

Think of the clearance as an invisible box around the lines. No part of the crane, the load line, or the load (including the rigging) may enter it. Voltages are given in kilovolts (kV) of nominal alternating current, so read the voltage from the line owner rather than guessing.

Remember

• Power lines are presumed energized until the line owner says otherwise.
• When the boom can reach a power line, a dedicated spotter whose only job is to watch the clearance must stay in constant contact with the operator.
• Read the voltage first, then pick the distance from the list that matches what the crane is doing.