OSH alert - Excavator struck overhead powerlines (May 2016)

Key learnings from a High Potential incident.

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HPI OSH Alert #480

Date of incident: 28 May 2016

Safety Flash issued: 08 June 2016

What happened?

Overhead powerlinesJust before the end of the work day an operator of a 30 tonne excavator was instructed to park the machine at the front of the site.

Without using a spotter the operator parked the machine next to the excavator attachments as this was the most convenient location. The excavator attachments had been placed underneath a powerline. The barricading previously set up to prevent access to the powerlines was moved during the day and not replaced.

While trying to manoeuvre the excavator into place, the vehicle made contact with the 440 volt overhead powerline causing it to arc, break and fall to the ground. The operator then exited the cab instead of remaining in the vehicle until help arrived.

Why did this happen?

  • Barricading preventing access to the powerline corridor was moved earlier in the day and was not replaced.
  • The overhead powerlines were not considered in the contractor’s risk assessment as the original plan was to exclude access to the powerline corridor.
  • There was no Management of Change (MoC) process used or a review of the contractor’s risk assessment when changes to site layout and laydown area occurred.
  • The team that attended the Construction Risk Assessment Workshop and start-up meeting were not the same team that undertook the demolition works.
  • The subcontractors were a newly established company and there was no intense supervision by the main contractor.

What will the business area involved in the incident do to stop this from happening again?


  • Implement a Take 5 risk assessment tool to assess and manage changing circumstances. Provide instruction to site workers through a toolbox meeting.
  • Liaise with the supplier of mobile plant and attachments; communicate the issues arising from ongoing problems with the couplings and attachments sourced from Perth and determine a resolution.


  • Discuss the use of the Management of Change process (MoC) when the environment/job changes
  • Reinforce that when tasks change there is a requirement to update the risk assessment.
  • Reinforce the need for a spotter when excavators or cranes are working around powerlines
  • Update the Phone Daily Review Meeting checklist to prompt questioning of organisation, work system, documentation or engineering change.
  • Reinforce the need for main contractors to formally nominate subcontractors in accordance with item six on the Start-up Agenda Minutes, which states:
  • Approvals required where subcontractors were not nominated in the Bid.
  • Approvals required for subcontractors not on the approved list of Principal’s subcontractors (Refer to list in Contract).
  • Regional North West Projects team to carry out a toolbox topic at their next safety meeting which covers the requirements for attendees at Start-Up meetings. This is to refer to the contract management system.

What will our organisation do to stop this from happening again?

  • Update the minor works procedure (Cat D) to include contract management processes.
  • Include the contract management process in the regional project leader induction package and share the learning with the regional Operational Engineering Forum.


What key learnings can you discuss with your team to stop this from happening again?

1. Safe Job Planning steps must be followed for all tasks completed onsite.

  • Do you complete a new risk assessment before starting each new job/task during the day?
  • Do contractors working under your supervision have a MoC process to ensure changes to site conditions during the day are reviewed for OSH risks.
  • Do you undertake a group risk assessment prior to commencing work onsite when there are multiple work groups or people?

2. Risk workshops and Start-Up Meetings need to be undertaken with ALL of the key personnel including site supervisors, Contractor Project Manager and Leading Hands.

  • Do you complete a risk workshop or start-up meeting prior to work commencing involving a contractor?
  • Do you know who is required to attend a Start-Up meeting or Risk Workshop?
  • Have you discussed with your contractor the site laydown area locations and traffic movement plans?

3. After striking overhead powerlines with mobile plant, operators should not exit the machine until advised to by the supply authority.

Are you aware of the safety requirements for operating machinery if you make contact with electrified services?

Have you reviewed contractor/operator Verification of Competencies (VoCs) for operating plant and machinery?

Further information

If you would like further information about anything included in this HPI OSH Alert, please contact Charis Neumann, Senior OSH Analyst Incidents on 6330 6629.