Hazard Identification and Power Line Safety Flashcards

A crane is operating near a 138 kV transmission line. The employer has NOT obtained a utility company determination of the electrical hazard, and no qualified electrical worker is on site. Under OSHA 1926.1408, what is the minimum required clearance the crane and its load must maintain from the energized line?

Answer: 20 feet

Under OSHA 1926.1408 Table A, when no utility determination has been made and no qualified electrical worker has determined a safe clearance, the default minimum clearance is 20 feet for lines up to 350 kV. This default applies regardless of voltage until a proper determination is completed. The 10-foot rule only applies when voltage is confirmed to be 50 kV or less.

During a pick, a tag line handler reports that the load swung and the wire rope made brief, momentary contact with an energized distribution line before the operator broke contact by lowering. No visible damage to the rope is observed. What is the CORRECT next step before the crane may continue operations?

Answer: The crane must be inspected by a qualified person before resuming operations, and the wire rope must be removed from service until inspected for damage

Any electrical contact event requires the crane to be taken out of service and inspected by a qualified person before resuming operations per OSHA 1926.1411. Wire rope that has contacted an energized source must be removed from service until evaluated — internal conductor damage can exist without visible external signs. Simply waiting or logging the incident does not satisfy the regulatory requirement.

A utility company has de-energized and visibly grounded a 69 kV line for crane work below it. Under OSHA 1926.1408, what clearance requirement now applies to the crane working under that line?

Answer: No minimum electrical clearance is required — the line is treated as a non-electrical hazard only

When a utility has de-energized AND visibly grounded the line, OSHA 1926.1408(a) exempts it from electrical clearance requirements. The line is treated as a physical obstruction only, not an electrical hazard. Written confirmation is not required by the standard — visible grounding by the utility is sufficient. All other options misstate the requirement by retaining an electrical clearance that no longer applies.

An operator is positioning a crane for a pick when the spotter reports that the boom tip will be within the Table A clearance envelope of an overhead line, but the load radius will keep the hook and load well outside the envelope. The lift plan does not address power line proximity. What must happen before the lift proceeds?

Answer: Operations must stop and the employer must satisfy all OSHA 1926.1407 planning and precautionary requirements before any part of the crane enters the Table A zone

OSHA 1926.1407 prohibits ANY part of the crane or its load from entering the Table A clearance zone without completing the full power line safety planning process — including contacting the utility, establishing safe limits, and implementing all required precautions. The restriction applies to the crane itself, not just the load. A spotter alone does not authorize entry into the zone without the prior planning steps being completed.

A crane operator is working on a site where the measured voltage of an overhead line is confirmed at 345 kV by a utility representative on site. Using OSHA 1926.1408 Table A, what is the minimum required clearance?

Answer: 25 feet

OSHA 1926.1408 Table A specifies clearance requirements by voltage range. For voltages over 350 kV, 25 feet applies, but 345 kV falls within the 'over 300 kV to 350 kV' range, which also requires 25 feet. Many test-takers confuse the 20-foot default (no determination made) with the voltage-specific values. At 345 kV, the table-specified minimum is 25 feet — the same as the next tier, because the 300–350 kV bracket carries that requirement.

An assembly crew is erecting a lattice boom crane near overhead lines. The boom sections are being manually connected at ground level, but during assembly a section will be lifted by a assist crane whose load line will pass within 12 feet of a 25 kV distribution line. The assist crane operator states this is permissible because 12 feet exceeds the 10-foot minimum for lines under 50 kV. Is this correct, and why?

Answer: No — the 10-foot minimum is a floor, not a target; the employer must also evaluate whether additional clearance is required based on site conditions, and the lift plan must specifically address the power line hazard before the assembly lift begins

The 10-foot clearance in Table A is a regulatory minimum, not an automatic safe distance — OSHA 1926.1407 still requires the employer to survey the worksite, assess electrical hazards, and implement all applicable precautions before working near lines. The lift plan must address the power line proximity. Additionally, at 12 feet, the margin above the 10-foot minimum is only 2 feet, which may be insufficient given dynamic factors like boom deflection, sway, or wind — the employer's competent person must evaluate these. A spotter alone does not replace the planning requirement.