Overhead electrical risks

Incident

On Friday 22 March 2019, WorkSafe ACT was called to a multi-level residential construction site in Curtin. A worker on site had received an electric shock when the metal top hat roofing purlin he was installing came into contact with nearby overhead electric power lines.

Thankfully upon the top hat contacting the power lines, the Residual Current Device (RCD) fused to overload and trip, with the worker receiving a minor electric shock. The worker was transported to a medical facility where the relevant medical assessment cleared him of any serious concerns. Had the top hat contacted the power lines in another sequence the result may well have been catastrophic.

An investigation into the incident has identified that a number of factors that contributed to the incident. These included:

• due to the additional dwellings being constructed, the building envelope has come within approximately 3.5metres of the existing overhead power lines
• suitable controls had not been implemented to ensure visual indicators were in place denoting the presence of overhead power lines
• the length of the metal top hat was in excess of 3.5m and when being positioned for installation had exceeded the safe approach distance of 3m
• before works had commenced a specific visual risk assessment had not clearly identified hazards in the immediate work area
• the worker advised a major factor leading to the incident has been complacency on his behalf given he has been working predominately on residential sites in green field areas where underground utility services where installed.

Risks

Currently a significant number of residential construction is being undertaken in the older suburbs across Canberra with multi-level construction featuring predominantly. Potentially workers will impede within safe approach distances of 3 metres of overhead power lines. When these works involve both plant and workers, a significant risk of a potential catastrophic event exists, with additional risk of the public being impacted.

Mitigating the risks

Before commencing works the person conducting a business or undertaking (PCBU) must identify existing hazards on site and implement appropriate safety in design principles and control measures to ensure the safety of workers on the site. Consideration be given how the relevant tasks can be performed safely without encroaching the safe approach distance and relevant controls to mitigate the risk.

If you are a PCBU you should ensure an appropriate safe system of work is in place:

• the presence of overhead power lines has been clearly identified and suitable visual indicators are present;
• all contractors are inducted and advised of the presence of the overhead power lines;
• construction is planned, to ensure workers are not put at unnecessary risk if performing tasks in the vicinity of the overhead power lines;
• before any works commence that do not require a Safe Work Method Statement (SWMS), commence a suitable Risk Assessment;
• a site specific SWMS is developed and followed for all relevant high risk construction activities that encroach on the safe approach distance to overhead power lines;
• the use of appropriately trained personal to act as spotters when works may encroach on the safe approach distance;
• if scaffold is erected in the vicinity of the overhead power lines suitable containment be incorporated to minimise the risk of workers inadvertently having items protrude into the safe approach distance; and
• under the provisions of section 166 of the Work Health and Safety Regulation 2011 - Overhead and underground electric lines- a PCBU at a workplace must ensure so far as reasonably practicable, that no person plant or thing at the workplace comes within an unsafe distance of an overhead or underground power line.

For further information contact WorkSafe ACT on 13 22 81 or email WorkSafe@act.gov.au.

This Alert contains information emerging during an investigation by WorkSafe ACT into the mentioned incident at the date of this report. The information contained in this report does not necessarily reflect the final outcome of WorkSafe’s views or proposed actions with respect to this incident. WorkSafe ACT does not warrant the information in this report is complete or up-to date and does not accept any liability to any person for the information in this report, or its use.