Release of Beldon electrical accident report

Western Australia’s electrical safety regulator has concluded its investigation into the electrical accident that seriously injured a 12-year-old girl at a property in Beldon in March 2018.

In a report released today, Building and Energy (formerly EnergySafety) outlined the findings of its investigation into the cause of the accident. The investigation included on-site inspections and testing at the house and at nearby properties. It also included independent expert assessments of the earthing at the property and equipment involved in the accident.

The report found:

  • the accident resulted from the failure of a neutral conductor that formed part of the aerial service cable which supplies electricity to the property;
  • the ‘open circuit neutral’ fault occurred inside the mains connection box (MCB) attached to the roof of the property;
  • the failure of the neutral conductor caused metallic parts connected to the electrical earthing system, including the garden tap, at the property to become electrically live, up to 230 volts; and
  • the neutral conductor of the aerial service cable failed after it was subjected to prolonged heating.

Due to the damaged condition of the MCB, the investigation could not determine the cause of the heating and whether it started on the aerial service side or the consumer side of the MCB.

The MCB is a connection point between the aerial service cable (owned by the network operator, Western Power) and the consumer mains cable (belonging to the home owner, the Department of Communities).

“When an open circuit neutral fault like this occurs, the electrical earthing system within a property will become live and dangerous, along with any metallic water pipes connected to the earthing system,” Director of Energy Safety, Saj Abdoolakhan said.

“This means if someone makes contact with the live metallic water pipes or taps, electricity will flow through their body to earth.

“The severity of the electric shock and injuries depends on the magnitude of electric current and the duration of exposure.

“Unfortunately, the reason for the failure of the Western Power aerial service neutral conductor could not be determined as the evidence was destroyed by the heating.

“While our investigation has answered many questions, it is disappointing – above all, for the young girl and her family – that we cannot be more conclusive due to the damaged condition of the components.”

To help prevent other similar incidents, Mr Abdoolakhan is urging consumers to act immediately on signs of a faulty neutral connection before it fails and becomes an open circuit.

“Early detection will stop these rare events from occurring by enabling repairs before a neutral fault becomes a neutral failure,” he said.

“A faulty neutral will cause a voltage rise on the electrical earthing system, which can present as electric shocks from taps, pipes or appliances at home. These are warning signs that something could be wrong with the electrical wiring or appliances.

“Please take note of any tingle or shock and report them to your network operator immediately and avoid touching any metallic appliances, water taps or gas fittings until the network operator can determine the cause of the fault.”

Building and Energy’s Electrical Accident Report is available online at: https://www.commerce.wa.gov.au/publications/beldon-electrical-accident-report

Additional resources are available at Building and Energy’s website:

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Media contact: Sarah Roberts – 0466 409 828 or CPmedia@dmirs.wa.gov.au

Please note the diagrams below. Additional images are available by request.

diagram_1_-_electricity_flow_-_normal.jpg
diagram_1_-_electricity_flow_-_normal.jpg, by sgrove

 

 

 

 

 

 

 

 

 

 

 

diagram_2_-_electricity_flow_-_open_circuit_neutral_due_to_fault_in_mcb.jpg
diagram_2_-_electricity_flow_-_open_circuit_neutral_due_to_fault_in_mcb.jpg, by sgrove

 

Building and Energy
Media release
27 Sep 2019

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