Working Beside 13.8 kV With a Laborer on the Tagline
A 45-ton telescopic-boom all-terrain crane with 60 ft of main boom is working beside a three-phase, open-wire distribution line on wooden poles. The utility's e-mail says the line "should be 13.8 kV." The contractor's plan calls for 12 ft of clearance between the boom and load and the conductors at the closest point of the swing, with a laborer in a hard hat holding a nylon tagline on a 5,200 lb, 40 ft steel beam. The beam must be slewed through an arc that brings the boom tip close to the line. The tagline handler is standing between the crane and the line. Wind is 12 mph and the ground is damp. The crane has an operable boom-tip limit device but no proximity alarm. The job superintendent says the crew does this all the time and has never had a problem.
1. What minimum clearance applies, and is the 12 ft plan acceptable?
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Minimum approach distance: for distribution lines of 50 kV or less, the equipment-operator clearance in the OSHA table (1926.1408, Table A) is 10 ft. So 12 ft is nominally inside the rule by 2 ft - and that is exactly why the plan should be rejected as written.
- The table distance applies to every part of the crane, the load, and the rigging, at every instant of the swing - not to the boom tip at the planned position. It must survive boom deflection under load, swing overshoot, wind sway, and the load rotating.
- The voltage is unverified. "Should be 13.8 kV" is not a determination. If the utility cannot confirm in writing, plan to the higher voltage class and re-read the table.
- A 40 ft steel beam on a tagline swings; 2 ft of margin disappears quickly, and the tagline handler standing between the crane and the line is in the worst possible position.
Conclusion: 12 ft is not acceptable on this plan. Either increase the distance substantially or apply different controls (below), and get the voltage confirmed in writing first.
2. What controls should be applied, in order of preference?
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Hierarchy, best first:
- Eliminate the exposure. Have the utility de-energize and visibly ground the line for the duration of the pick, with the utility's confirmation in hand. This is the only control that removes the hazard.
- Re-site or re-plan out of the exposure. Move the crane, change the approach, shorten the boom, or re-sequence so the swing arc never comes inside the table distance. Ask whether the beam can be set from the other side.
- Engineering controls from the utility. Cover-up/line hose or a temporary barrier installed by the utility.
- Only if the above are infeasible, work under the energized-line provisions (1926.1410): the utility is involved, a dedicated spotter is assigned whose sole job is to watch the clearance, who has a full-time view, direct communication with the operator, and authority to stop the operation, and who is in contact with the utility. This is not the laborer holding a tagline.
Also required: a pre-lift meeting with the operator, signalperson, and tagline handlers; a posted warning line or marker at the safe approach distance; taglines that are dry and non-conductive, handled by someone standing outside the fall zone and never between the crane and the line; and a stop-work trigger for wind or loss of communication. The superintendent's "we always do it this way" is not a hazard assessment.
3. The boom tip contacts the conductor while the tagline handler is holding the beam. Describe the immediate actions and the reporting obligations.
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Immediate actions:
- Operator: stay in the cab. The cab is the safest place - it is generally the best-protected part of the machine. Warn everyone away, and only if there is fire or another immediate threat to life should he leave. If he must leave, he jumps clear, lands with feet together, and shuffles or hops away without touching the crane and the ground at the same time.
- Tagline handler: release the tagline immediately and move away with feet together, shuffling, without touching the crane, the load, or anyone in contact with them. Do not run.
- Everyone else: stay back - a wide perimeter, not just a few feet - and keep others, including the public, out. Do not touch the crane, the load, or an injured person who may still be in contact with the energized equipment.
- Call 911 and the utility immediately. Nobody approaches until the utility confirms the line is de-energized and grounded.
- Once cleared, if the operator can safely break contact by moving the machine, that may be done; otherwise the machine stays put until the line is dead.
After the incident:
- Treat the crane as damaged: no return to service until inspected per 1926.1412 (post-incident inspection) and cleared by a qualified person.
- Preserve the scene, take photos, record witness statements, and secure the machine.
- Reporting: OSHA must be notified of a fatality within 8 hours and of an in-patient hospitalization, amputation, or loss of an eye within 24 hours (29 CFR 1904.39). Notify the utility, the general contractor, and the insurer, and complete the company incident report. Follow up with a root-cause review of the lift plan, the spotter assignment, and the voltage verification - all three failed before the contact happened.