Safety measures for working around overhead power lines are covered in OSHA’s regulation 1910.333(c)(3). If work is to be performed near overhead lines, the line must be deenergized and grounded, or other protective measures must be implemented before work is started. If protective measures are provided, such as guarding, isolating, or insulating, these precautions must prevent employees from contacting such lines directly with any part of the body, or indirectly through conductive materials, tools, or equipment.
The regulation also addresses the operation of mechanical equipment, such as cranes, near overhead power lines. This provision requires that equipment be operated so that a clearance of 10 feet from any energized overhead line is maintained.
Exceptions for cranes are made when an insulating barrier has been erected to prevent contact with the line. The barrier must be rated for the voltage of the line being guarded and must not be a part of or attachment to the vehicle or its raised structure.
When the work falls under OSHA’s Construction Standards, regulation 1926.550(a)(15) provides two options where operations are closer than 10 feet from the power line. One option is to deenergize and visibly ground the line. The other option is to use insulating barriers to prevent physical contact with the line.
In circumstances where it is difficult for a crane operation to maintain the required distance by visual means, an observer must be positioned so as to be able to visually monitor the clearance between the equipment and the power lines. The designated observer cannot be assigned other duties that interfere with the ability to give a timely danger warning to the crane.
It is also notable the OSHA safety requirements differ for qualified vs. unqualified persons who are mechanical equipment operators. These specific requirements permit only qualified persons to operate mechanical equipment closer than the 10 foot provisions.
Electrical contact with uninsulated vehicular equipment or suspended loads, such as occurs in pole setting or other similar operations, cannot simply be avoided. Therefore, additional safety requirements are necessary when operating mechanical equipment near exposed electrical lines where there is a possibility of dangerous voltages being impressed or induced on mechanical equipment.
Some supplemental protective measures include the use of overhead line insulation, equipment insulation, equipment grounding/bonding, and the use of electrical protective equipment.
Specific safety measures for aerial lifts include:
- Maintain and operate elevating work platforms according to the manufacturer’s instructions.
- Never override hydraulic, mechanical, or electrical safety devices.
- Never move the equipment with workers in an elevated platform unless this is permitted by the manufacturer.
- Do not allow workers to position themselves between overhead hazards, such as joists and beams, and the rails of the basket. Movement of the lift could crush the worker(s).
- Maintain a minimum clearance of at least 10 feet, or 3 meters, away from the nearest energized overhead lines.
- Always treat power lines, wires and other conductors as energized, even if they are down or appear to be insulated.
- Use a body harness or restraining belt with a lanyard attached to the boom or basket to prevent the worker(s) from being ejected or pulled from the basket.
- Set the brakes and use wheel chocks when on an incline.
- Use outriggers, if provided.
- Do not exceed the load limits of the equipment. Allow for the combined weight of the worker, tools and materials.
For more safety information for your construction site, contact our offices at Diversified Safety Services.
