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QLD: safety alert issued for overhead powerline incidents

The following article is a news item provided for the benefit of the Workplace Health and Safety profession. Its content does not necessarily reflect the views of the Australian Institute of Health & Safety.
Date: 
Monday, 13 December, 2021 - 12:00
Category: 
Policy & legislation
Location: 
Queensland

Workplace Health and Safety Queensland recently issued a safety alert following an incident in which a man suffered electric shock and severe burns while installing gutter guarding on the roof of an industrial shed.

For reasons yet to be established, the worker came into contact with a nearby 11kV single wire earth return (SWER) while he was on the roof.

In another incident, a worker suffered serious burns and other minor injuries when a mobile concrete placing boom contacted an 11kV overhead powerline at a residential construction site.

Initial enquiries indicate the mobile concrete placing boom was operating at the time of the incident.

While investigations into both incidents are continuing, the alert noted working near powerlines can be fatal.

Touching them or straying into the exclusion zone around them can result in a serious electric shock, and simply being close to the line conductors may allow a ‘flashover’ or arc to take place. The risk of flashover increases as the line voltage increases.

Hazards from overhead powerlines may arise from:

  • a person or something the person is holding, or is in contact with, coming closer than the relevant exclusion zone distance to an overhead powerline
  • operating plant coming closer than the relevant exclusion zone distance to an overhead powerline
  • damage to overhead powerlines or related equipment
  • building structures near overhead powerlines.

Before carrying out work near overhead powerlines, the alert said a worksite inspection should be conducted to identify potential hazards including the presence of energised overhead powerlines or associated electrical equipment that may pose a risk.

The most effective way to eliminate any risk of electric shock is by turning off the power. The PCBU, principal contractor or the operating plant owner should discuss options for de-energising or re-routing the electricity supply with the relevant electricity entity. De-energising or re-routing powerlines should be arranged with the electricity entity as quickly as possible as this can take some time to arrange. This includes complying with any electrical entity requirements under relevant electrical safety legislation.

If eliminating the risk is not reasonably practicable, you must consider using substitution, isolation or engineering controls, or a combination of these control measures, to minimise the risk. This may include:

  • Substituting or replacing a hazard or hazardous work practice with a safer one. This may include performing the work another way, for example using non-conductive tools designed to reduce the possibility of direct contact with the overhead powerline.
  • Separating the hazard or hazardous work practice from people by erecting a physical barrier consisting of non-conductive material to prevent any part of plant or equipment or to prevent a person, anything held by a person, or anything attached to a person, from entering an unsafe distance.
  • Engineering controls are physical control measures to minimise risk, for example:
    • limiting movement of plant with mechanical stops
    • fitting plant with programmable zone limiting devices
    • mechanically limiting slew speed of a crane to slow
    • using electrically insulated plant and equipment.

The alert said to only consider administrative controls when other higher-order control measures are not reasonably practicable. For example:

  • Develop a safe system of work before you start:
    • Identify overhead and underground powerlines using maps and/or talking to the property owner and electrical entity. The Look up and Live map is an interactive geospatial map developed to display the Energex and Ergon Energy electricity networks, including sourced third-party information. The Look up and live app provides site-specific information and can link you to the relevant entity when extra help is needed.
    • Conduct a site-specific risk assessment. Think about:
      • the type of plant and equipment/tools used
      • site and weather conditions – be aware that powerlines sag or sway in hot or windy weather
      • type of work being done
      • set-up and pack-up procedures.
    • Follow the safety advice given by your electrical entity.
    • Carefully plan tasks to be done near powerlines and work away from them whenever possible, not underneath them.
    • Manage and supervise the work to ensure safe work practices and procedures are followed.
    • Ensure safe work method statements (SWMS) are developed where required.
    • Have appropriately trained and qualified people who are authorised to carry out the work.
  • Keep your workers and contractors informed about electrical safety:
    • induct and train your workers and contractors in safe work procedures, emergency procedures and exclusion zones
    • show your workers the safe distance from a powerline by marking it on the ground
    • ensure operators know the height and reach of machinery or hand-held items to be used
    • operators should use a safety observer when carrying out work near powerlines.
  • Make hazards more visible by:
    • using warning signs to indicate the location of overhead powerlines and defined work areas
    • arranging for the electricity entity to identify exposed energised low voltage conductors (up to and including 1000 volts) and fitting them with approved visual indicators like sheeting or sleeves e.g. tiger tails. A competent person should inspect visual indicators each day before starting plant operations
    • if visual indicators have moved or been damaged the electricity entity should be contacted so they are replaced or located in the correct position.

The alert said control measures should be reviewed regularly to make sure they work as planned.