Environmental, Health and Safety Services

Overhead Power Lines

  • Unqualified persons working on the ground, or on an elevated platform such as a scaffold or aerial lift, are not allowed to bring any conductive object, or any insulated object that does not have the proper insulating rating (including vehicles and mechanical equipment), closer to unguarded, energized overhead lines than the distances allowed below:

Voltage to Ground

Minimum Approach Distance

50 kV or less

10 feet

Over 50 kV

10 feet + 4 inches for every 10 kV over 50 kV

    • The clearance requirement for scaffolds, vehicles and mechanical equipment may be reduced if:
      • The vehicle is in transit with its structure lowered.  The clearance may be reduced to 4 feet when near energized lines operating at less than 50 kV, or 4 feet plus 4 inches for every 10 kV over 50 kV.
      • Insulating barriers (not a part of the vehicle attachment or its raised overhead linestructure) are installed to prevent contact with the lines and the barriers are rated for the voltage of the line being guarded. The clearance may be reduced to the distance allowed by the design of the insulating barrier.
      • The equipment is an aerial lift insulated for the voltage involved and the work is performed by a qualified person. The clearance between the uninsulated portion of the lift and the power line may be reduced to the distance specified for qualified persons.
    • Persons working on the ground are not allowed to contact the vehicle or mechanical equipment or any of its attachments unless:
      • The person uses protective equipment rated for the voltage, or
      • The equipment is located so that no uninsulated part of its structure can provide a conductive path to persons on the ground.  Equipment shall not approach closer to the line than 10 feet for voltages less than 50 kV, or 10 feet plus 4 inches for every 10 kV over 50 kV.
    • When any vehicle or mechanical equipment is intentionally grounded, persons may not stand near the point of grounding when there is any possibility of contact with overhead energized lines.  Additional precautions (e.g. such as the use of barricades or insulation) must be taken as necessary to protect persons from hazardous ground potentials that can develop within a few feet or more outward from the grounding point.
  • Qualified employees working in the vicinity of overhead lines, whether in an elevated position or on the ground, are not allowed to approach or take any conductive object without an approved insulating handle closer to exposed energized parts than allowed in the "Approach Boundaries to Engergized Parts" table, unless:
    • The person is insulated from the energized part by using appropriate voltage-rated gloves, with voltage-rated sleeves if necessary, or
    • The energized part is insulated from all other conductive objects at a different potential and from the person, or
    • The person is insulated from all conductive objects at a potential different from the energized part.