Power shut off as tower crane strikes powerlines

A tower crane hit powerlines in Queensland during an incident in November 2018.

According to a Workplace Health and Safety Queensland incident alert, lifting equipment attached to a tower crane servicing a construction project contacted live overhead powerlines next to the site.

This caused the power supply within the local area to automatically shut off. There were no injuries and it appears the crane unintentionally rotated over the powerlines under its own power. Investigations are continuing.

The incident alert said that before setting up a crane or other operating plant near overhead powerlines, the PCBU should conduct an inspection to check if any of the powerlines may pose a risk. The PCBU must ensure that no-one and no equipment comes within an unsafe distance of an overhead or underground electric line.

If it is not reasonably practicable to ensure a safe distance, Workplace Health and Safety Queensland said that the PCBU must ensure a risk assessment is conducted for the proposed work and control measures are consistent with the risk assessment and any requirements of the electrical entity responsible for the powerline.

According to the incident alert, the PCBU should consider:

• identifying the minimum clearance distance from the closest part of the crane or other operating plant to the power line;
• the work environment and the nature of the load to be moved such as dimensions and inadvertent movement during operation;
• if the load is being carried above the electric lines, the potential consequences of it falling onto the live powerlines eg, moving a swimming pool from the street over live powerlines into the yard of a home;
• wind strength and direction and weather conditions;
• the possibility of sway and sag of the overhead powerlines (sway of overhead powerlines is usually caused by wind, while sag may vary as temperatures vary);
• functional behaviour of the crane, load or equipment that could result in inadvertent contact with electric lines;
• the possibility of the crane or other equipment becoming live through voltage induced by adjacent electric lines, especially high-voltage lines;
• how the load is secured and whether any part of the load may inadvertently move during the operation and enter the exclusion zone.

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