The Electrical Safety Office is investigating another arc flash incident which resulted in a worker sustaining burns while working on an energised electrical distribution board.
A short circuit created an arc flash while the worker was attempting to change out a circuit breaker in the distribution board. This incident is a good reminder that working with switchboards carries an increased risk of injury due to a greater presence of high fault current. As a precaution, you should isolate the power to the entire switchboard, even if this means rescheduling the work to another time.
Work on energised electrical equipment is only permitted in the four specific circumstances set out in section 18 (1) of the Electrical Safety Regulation 2013. Breaches of this requirement may result in referrals to the Electrical Licensing Committee for disciplinary action. The risks associated with performing work near exposed live parts can be equivalent to those associated with live work. Typical risks include:
- electric shock, including from ‘step-and-touch’ potentials
- causing burns
- toxic gases.
If there is a safety risk associated with working near energised electrical parts, conduct a written risk assessment to determine the risk level and to decide on the appropriate control measures. To determine the risks of arc flashes, the assessment must consider the level of possible fault current present.
Choose controls that most effectively eliminate or minimise the risk of working near energised electrical parts. This may involve a single control measure or a combination of two or more different controls including:
- electrically isolating nearby electrical equipment or installations before starting work and ensuring they can't be reconnected while the work is being carried out
- using insulated or non-conductive physical barriers to prevent inadvertent contact with energised parts
- ensuring workers have appropriate knowledge and skills to perform the work safely
- ensuring testing procedures are in place to prove parts are de-energised before work commences
- ensuring people not required for the work are excluded from the area, using screens, barriers and signage
- ensuring workers have the tools, test equipment and PPE suitable for the rated level of fault current.
Consideration should also be given to using a safety observer.
More information is available at Electrical arc flash. General safety guidance on managing electrical risks can be obtained from the Managing electrical risks in the workplace code of practice 2021 (PDF, 1.25 MB) .