Cut branch contacts HV conductor

Vegetation Management Work           

Background

Vegetation management workers were pruning a tree on behalf of an electricity distribution business in a hazardous bushfire risk area as part of a cyclical electric line clearance program. 

The work was being performed from an elevated work platform (EWP). The worker was pruning branches located beside the electricity conductors, that were growing above the height of the conductors. A cut branch then fell onto the high voltage (HV) conductors.

The cut branch was estimated to be two metres long. The HV conductor was pulled down by the weight of the cut branch causing it to contact a low voltage (LV) conductor below. This resulted in a HV injection into the LV conductor causing a disruption to electricity supply to nearby properties.

The incident created an unsafe electrical situation that had the potential to cause fire, property damage, serious personal injury or in the worst circumstance an electrocution. Fortunately, no one was injured. 

The incident was reported to the distribution business and to Energy Safe Victoria (Energy Safe).

Investigation Findings

Energy Safe conducted an investigation of this incident and found:

• the work crew members stated a gust of wind blew the cut branch onto the line
• the cutting method used did not allow for appropriate control of the branch
• the EWP operator failed to ensure the vegetation Safe Approach Distance (SAD) was maintained when pruning the tree
• the work crew failed to implement control measures to ensure the work could be completed safely.

Energy Safe’s view is that the combination of these failures resulted in a breach of Electricity Safety legislation; heavy penalties may be applied to such breaches.

Key Lessons

• Ensure all site hazards are identified and actions to control the hazards are implemented
• Continually monitor site and environmental conditions and adjust work sequences and practices to adapt to changing conditions
• If necessary, cease work when hazards change or can’t be managed and wait until it is safe to continue
• Always maintain all SADs when undertaking works in the vicinity of live electrical apparatus
• Regularly reassess each worksite for hazards when completing work on trees near electric lines.

Important information

• Completing work on trees near electric lines in windy conditions creates additional risks that must be considered.
• Failing to identify hazards at the work site will place workers and the public at risk of serious personal injury or in the worst circumstance, electrocution
• Ensure each individual work site is assessed for hazards and controls are implemented to manage risks; this should be an ongoing process throughout the work task to adapt to changing conditions
• Worksites that are near electric lines are dangerous. Vegetation management workers have been seriously injured and electrocuted when they have made contact with both uninsulated low voltage and high voltage electric lines. 

Enforcement outcomes

Having completed its investigation of this incident it is Energy Safe’s view the EWP operator failed to ensure the branch being pruned maintained the required SAD from the electric line. This is in breach of the Electricity Safety (General) Regulations 2019. A warning letter was issued to the EWP Operator for the identified breaches. 

Additionally, the investigation identified the importance of the role of a safety observer in maintaining appropriate safety standards when electric line clearance work is being performed.

Energy Safe may choose to prosecute or take other enforcement action where it considers a breach of the Electricity Safety Act 1998 or Electricity Safety Regulations has occurred.