Note: The Department of Mines, Industry Regulation and Safety’s investigation is ongoing. The information contained in this significant incident report is based on materials received, knowledge and understanding at the time of writing.
Summary of incident
In February 2018, an electrician went to install a new power supply in a wall-mounted, low voltage (415 V) switchboard to provide three-phase power for an electric motor. He removed the scutcheon panel from the front of the switchboard (which was still live) and, as he tried to remove an existing circuit breaker with a screwdriver, there was an arc flash.
The electrician received thermal burns to his face, upper body and hands. His assistant also received burn injuries and both workers were temporarily blinded. Both the electrician and his assistant required hospital treatment for their injuries.
Direct causes
There was a short circuit while working on the live switchboard.
Contributory causes
Electrical work was undertaken while the switchboard was live. An inadequate risk assessment was conducted before carrying out the live electrical work. There were inadequate fault protection devices upstream of the switchboard. Inadequate personal protective equipment (PPE) was worn.
Actions required
When working on or near energised electrical equipment, the following actions are recommended to reduce the potential for electric shock and arc flash incidents:
– Before working on or near electrical installations, determine whether there is a requirement to work on the installation while energised.
– If a situation meets the conditions to work on or near energised electrical equipment or circuits, duty holders are to:
-undertake a written risk assessment, performed by a competent person develop a written safe work method statement
-confirm suitable safety equipment and PPE are selected and used.
These actions reflect the requirements of the latest codes of practice (below) and the obligations under regulation 55 of the Electricity (Licensing) Regulations 1991 (ELR), which will come into effect on 14 May 2018.
Note: A risk assessment should include considering existing fault protection upstream of the electrical installation to be worked on. If required to de-energise the electrical installation, develop an appropriate procedure for de-energising the electrical equipment or circuits to be worked on.
Further information
Standards Australia, www.standards.org.au
AS/NZS 3000 Electrical installations (Australian/New Zealand Wiring Rules)
Department of Mines, Industry Regulation and Safety
EnergySafety, www.commerce.wa.gov.au/publications
Persons working on or near energised electrical installations – code of practice
Safe low voltage work practices by electricians – code of practice
Mining safety publications, www.dmp.wa.gov.au/Safety/Safety-335.aspx
Mines Safety Bulletin No. 138 Electrical arc flash hazards in mining
