31 Jul Dangers of Powerline Contact

Dangers of Power Line Contact

Overhead power lines present a serious electrocution hazard on construction sites. Cranes, boom trucks, concrete pumps, drilling rigs, aerial lifts, backhoes, ladders, and other equipment can contact energized lines directly or come close enough for electrical arcing to occur.

Never assume an overhead line is harmless because it is common, appears insulated, or is located near homes or businesses. Treat all overhead power lines as energized unless the utility owner confirms they have been de-energized and visibly grounded.

Know the Hazard

Electrical contact does not have to occur directly with a worker. When equipment contacts an energized line, electrical current can travel through:

• Booms, masts, and other equipment components.
• Load lines, rigging, and suspended loads.
• Tag lines and other conductive materials.
• The equipment frame and outriggers.
• Workers touching the equipment or load.
• The ground surrounding energized equipment.

Ground workers are particularly vulnerable because they may provide a path between energized equipment and the earth.

High-Risk Equipment and Activities

Pay particular attention when operating or working around:

• Cranes and boom trucks.
• Concrete pumps.
• Drilling and boring equipment.
• Aerial lifts and buckets.
• Backhoes, excavators, and similar equipment.
• Dump trucks with raised beds.
• Scaffolds and long conductive materials.
• Metal ladders.
• Pipes, rebar, and other materials capable of reaching overhead lines.

Power-line hazards must be evaluated before equipment is set up, operated, moved, raised, lowered, assembled, or disassembled.

Maintain Required Clearance

Before work begins, identify the location and voltage of overhead power lines and establish the required clearance.

For cranes and derricks covered by OSHA’s construction crane standard, when operating near energized lines, the minimum clearance generally includes:

These distances apply to crane operations under 29 CFR 1926.1408. Other equipment and activities may be subject to different OSHA requirements.

When possible, the safest approach is to have the utility owner/operator de-energize and visibly ground the lines before work begins.

Safe Work Practices

Before operating equipment near overhead lines:

• Survey the work area and identify overhead electrical hazards.
• Determine the line voltage and required minimum clearance.
• Plan equipment travel routes, setup locations, and material-handling activities accordingly.
• Establish barricades or warning lines where appropriate.
• Use a dedicated spotter when required to maintain clearance.
• Keep workers who are not essential to the operation away from equipment operating near power lines.
• Never rely solely on proximity alarms, insulating links, or similar devices as substitutes for required clearance.
• Lower equipment completely before traveling whenever practicable.
• Use nonconductive tag lines when tag lines are required near electrical hazards.
• Never erect, lower, or relocate a conductive ladder where it could contact an energized electrical conductor.

If Equipment Contacts a Power Line

If equipment contacts an energized power line, do not approach or touch the equipment.

The operator should normally:

1. Remain inside the cab.
2. Warn everyone nearby to stay away.
3. Attempt to move the equipment away from the line only if this can be done safely.
4. Contact emergency services and the utility owner/operator.
5. Remain in the cab until the utility confirms the line has been de-energized.

Anyone on the ground must stay away from the equipment, load, rigging, and surrounding area because the ground itself may be energized.

If fire or another immediate danger makes it necessary for the operator to leave the equipment, the operator should jump clear without simultaneously touching the equipment and ground, keep both feet together, and move away using small shuffling steps or hops. Do not take normal strides because hazardous voltage differences may exist across the ground.

Remember

Overhead power lines can kill without warning. Never assume a line is insulated or de-energized. Identify electrical hazards before work begins, maintain the required clearance, and keep equipment, materials, and workers away from energized conductors.