Power Line, Clearance, and Environmental Hazards
Table A clearances
OSHA 1926.1407–1926.1411 treat power lines as energized unless the utility deenergizes and visibly grounds them. Table A minimum clearance for equipment and load is: up to 50 kV, 10 ft; over 50 to 200 kV, 15 ft; over 200 to 350 kV, 20 ft; over 350 to 500 kV, 25 ft; over 500 to 750 kV, 35 ft; over 750 to 1,000 kV, 45 ft. For unknown voltage, treat the line as higher and get the utility involved. A spotter does not authorize working inside the table distance; it is a control, not a waiver.
Environmental limits
Wind, ice, rain, lightning, heat, and visibility all affect capacity and control. Sail area on a panel or bundle can make a light load unmanageable. Stop when wind exceeds the manufacturer's limit or when the load cannot be controlled with tag lines. Account for boom deflection and load swing, which reduce clearance even when the unloaded boom measures clear.
Worked example
A 138 kV line is 14 ft from the boom tip at maximum radius. Table A requires 15 ft for over 50 to 200 kV. The lift is prohibited. Options: deenergize and ground the line, relocate the crane, or reduce radius so the tip stays at 15 ft or more with margin for swing and deflection.
Traps
Using 10 ft for every line; believing rubber tires insulate the crane; letting a spotter justify closer approach; assuming a line is dead because it looks inactive; and ignoring induced voltage or the line's sway are frequent errors.