Tower Crane Working Near a 33 kV Overhead Line
A project manager is responsible for a 7-storey hotel in Lekki, Lagos. The site has a tower crane with a 45 m jib. A 33 kV overhead line runs 12 m from the crane mast and crosses the site access road. The lift plan states that the crane will not slew over the line, but the line is not switched out and no goalposts or warning flags are installed. The safety officer has issued a stop-work notice after a near-miss in which the crane's trolley came within an estimated 3 m of the line. The project director wants to resume concrete placement because a 180 m³ pour is scheduled for tomorrow and the concrete supplier will charge for cancellation. The crane operator says he has done this before and can work with a banksman. Wind gusts are forecast at 25 km/h. The client is threatening liquidated damages.
1. What immediate decision should the project manager make and why?
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The project manager should uphold the stop-work notice for all crane operations near the line until the hazard is controlled. A near-miss with a 3 m approach to a 33 kV line is a serious warning: electricity can arc across a gap, and the operator's experience is not a control. The project manager has the authority and duty to stop unsafe work even under schedule pressure. He should isolate the crane, barricade the area, inform the client and site management, and record the decision. He should not direct the operator to proceed with a banksman alone, because administrative controls do not prevent contact or arcing. The 180 m³ pour should be rescheduled or placed using a safer method, such as a concrete pump positioned outside the exclusion zone, after a risk assessment.
2. Develop the safe work method and controls that must be in place before lifting resumes.
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The hierarchy of control should start with elimination: ask the utility to de-energise and isolate the 33 kV line for the lift period, with written confirmation and lock-off. If that is impossible, reroute the line or relocate the crane. Engineering controls include physical barriers, goalposts, warning flags, insulated guards where appropriate, and limiting slewing with mechanical stops. Administrative controls include a revised lift plan, a competent banksman, exclusion zones, a permit-to-work, toolbox talks and wind monitoring. The revised plan should state the minimum approach distance required by the utility and the crane manufacturer, and stop work if wind exceeds the crane's limit. Emergency contacts and rescue arrangements should be briefed. Only after these controls are verified should the safety officer lift the stop.
3. How should the project manager handle the schedule and commercial pressure?
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The project manager should put the safety decision in writing to the project director and client, explaining the near-miss and the controls required. He should explore alternatives: reschedule the pour, use a pump or mobile crane positioned away from the line, or cast in sections. Any delay should be documented as a safety-related instruction, and the contract administrator should assess an extension of time or cost claim under the contract. The project manager must not accept a verbal instruction to resume unsafe work; if pressed, he should escalate to his professional head and, if necessary, COREN. Safety and professional obligations override liquidated damages. The client should be told that an accident would cause greater delay and liability.