Write a risk assessment for crane operations near power lines

A safe crane operation near overhead power lines begins with a documented risk assessment and work-zone evaluation. Treat all lines as energized unless the utility owner confirms they are de-energized and visibly grounded. Before work starts, identify all overhead lines, determine voltage, define the crane work zone, and evaluate whether any part of the crane, load line, load, rigging, or lifting accessories could breach the required clearance at maximum working radius. If that is possible, the preferred control is to have the utility de-energize and visibly ground the line; if not, the employer must establish and document encroachment-prevention measures before lifting begins. [4] [11] [6]

Key hazards to address in the risk assessment:

• Direct electrical contact between boom, hoist line, load, rigging, or accessories and the line
• Arc-over/flashover, because electricity can jump through air even without direct contact
• Ground gradient/step potential around energized equipment after contact
• Secondary hazards such as fire, dropped load, structural damage, and worker panic or unsafe rescue attempts

[1] [8] [2] Minimum approach distance must be based on line voltage. For cranes, rigging, and personnel lifting, the commonly applied Table A / Table 4 distances are: up to 50 kV = 10 ft; over 50 to 200 kV = 15 ft; over 200 to 350/345 kV = 20 ft; over 350/345 to 500 kV = 25 ft; over 500 to 750 kV = 35 ft; over 750 to 1,000 kV = 45 ft. If voltage is unknown, do not guess—obtain it from the utility. As a practical site control, many employers also establish a larger safe working clearance by adding the crane's maximum reach and load extension to the regulatory minimum so the crane is physically positioned far enough away that contact is not possible during normal operations. [7] [3] [3]

Exclusion zones should be established in layers. First, define the crane work zone either by marked boundaries or as a 360-degree area around the crane to its maximum working radius. Second, establish a no-entry boundary at the applicable minimum approach distance or, where using the 20-foot option, at 20 feet from lines up to 350 kV and 50 feet for lines above 350 kV. Third, barricade the crane operating area to keep unauthorized personnel out, and do not store materials under overhead lines. No part of the crane, load line, or load should pass below an energized power line unless the utility has confirmed de-energization and visible grounding, except where a specific regulatory exception applies. [11] [11] [13] [16]

A compliant lifting plan / pre-lift plan for work near power lines should include:

• Site address/location and date of planning meeting
• Names, roles, and signatures of operator, lift director/supervisor, riggers, signal person/spotter, and other affected workers
• Drawing or sketch showing crane setup, swing radius, work zone, line locations, voltages, minimum approach distances, exclusion zones, and travel path
• Utility coordination details, including whether lines are energized, de-energized, grounded, relocated, or insulated by the utility
• Selected control method: de-energize and ground, 20-foot clearance, or Table A/Table 4 minimum approach distance
• Equipment configuration, maximum boom/jib length, maximum working radius, load weight, rigging/accessories, and confirmation that no component can breach the boundary
• Required controls such as elevated warning lines, barricades, nonconductive tag lines, range limit/range control devices, proximity alarms, insulating link/device where used, and posting of electrocution warnings
• Communication method between operator and dedicated spotter/signal person, stop-work authority, and emergency response steps for electrical contact

[11] [10] [14] Competent operator responsibilities include being trained and authorized, understanding the applicable minimum approach distance, verifying the lift plan and work-zone controls before operating, obeying warning lines and range limits, stopping work if line location/voltage is uncertain or conditions change, and never relying solely on proximity devices or insulating links as the primary protection. The operator must maintain control of boom movement, travel slowly near lines, and remain in the cab if contact occurs unless there is an immediate life-threatening reason to evacuate. [1] [8] [5] [8] [8]

Dedicated spotter responsibilities are critical whenever required by the plan or regulation. The spotter must have no conflicting duties, be positioned to effectively judge clearance, maintain continuous communication with the operator, use a visual aid that clearly identifies the minimum clearance distance, and give timely stop/hold instructions so the crane never breaches the boundary. If the operator cannot see the warning line, a dedicated spotter is required in addition to other encroachment controls. [13] [5] [9]

Recommended safe work procedure:

1. Perform a pre-job site survey and identify all overhead lines before mobilizing the crane.
2. Contact the utility early to verify voltage and determine whether lines can be de-energized, visibly grounded, relocated, or insulated by the utility.
3. Select crane location and lift path to avoid operating under or toward lines whenever possible; reposition the crane or change the method if needed.
4. Define and mark the work zone and exclusion boundaries with warning lines, barricades, signs, painted lines, or range-limiting devices.
5. Hold and document a planning/pre-lift meeting with all affected personnel; review hazards, roles, communication signals, stop-work authority, and emergency actions.
6. Use nonconductive tag lines if tag lines are necessary; keep riggers and ground workers clear of suspended loads and away from the load line above any insulating link/device.
7. Implement at least one additional encroachment-prevention measure such as a dedicated spotter, proximity alarm, range-control warning device, range-limit device, or insulating link/device, as required by the selected compliance option.
8. Post electrocution hazard warnings on the crane, restrict access to essential personnel only, and continuously monitor for changing conditions such as wind, boom deflection, load swing, terrain, or line sag.
9. Stop work immediately if the crane approaches the limit, if communication is lost, if the spotter loses position or visibility, or if site conditions change.

[14] [15] [4] [11] [6] Emergency response for electrical contact must be preplanned and drilled. If the crane contacts a power line, the operator should, if possible, move the boom away from the line. Everyone on the ground must stay away from the crane, load line, and load, and no one should touch the equipment. The operator should remain in the cab unless there is imminent danger such as fire. If evacuation is unavoidable, the operator must jump completely clear without touching the equipment and ground at the same time, land with feet together, and move away using small shuffling steps to reduce step-potential exposure. Secure the area, call emergency services and the utility, and do not allow re-entry until the utility confirms the line is grounded or safe. [3] [1] [8] [3] [3]

For compliance, align the procedure with OSHA crane power-line rules, applicable ANSI/ASME crane standards, and site-specific safety requirements. At minimum, the employer should ensure: a documented hazard assessment; utility coordination; voltage determination; use of Table A/Table 4 minimum approach distances; documented planning meetings kept on site; trained operators, crew, and dedicated spotters; warning lines/barricades and required additional controls; posted electrocution warnings; and stop-work authority when controls are inadequate. Site rules may be more stringent than OSHA/WAC and should be followed if they impose larger exclusion zones, permit requirements, or additional lift-plan approvals. [4] [11] [8] [12] [12]