Perth, WA, Australia — Western Power has admitted it was to blame for the Hills bushfire that destroyed two homes last week, accepting that a tree growing into power lines caused the fire.
The blaze that started last Thursday razed homes in Brindle Rd and Hollett Dve in Parkerville, damaged 13 other dwellings in Hills suburbs and destroyed 17 cars and other property.
Helicopters, 170 firefighters and 50 firetrucks and other appliances worked to fight the fire, which was contained early on Friday morning.
Power industry regulator EnergySafety said today that the fire was caused by contact between a tree branch and a 22,000 volt overhead power line.
An investigation found the contact had led to burning vegetation falling to the ground and igniting dry grass near the power line, EnergySafety said.
But it said that while Western Power had been responsible for pruning the tree, it had not broken any laws as the relevant guidelines were not reflected in current legislation.
Western Power said it accepted EnergySafety’s findings and was working with property owners who had suffered loss or damage.
The utility said it had planned to prune the tree but a safety issue with a contractor had delayed its pruning program.
It was a regrettable outcome of important actions that needed to be taken to ensure contractor safety that there was a delay to the program of work, Western Power general manager of asset management Mark de Laeter said.
He said Western Power had doubled the number of crews working on pruning vegetation.
A Western Power insurance assessor had completed initial assessments and met all available property owners.
Director of Energy Safety Albert Koenig said EnergySafety had worked with Western Power, the Fire and Emergency Services Authority and the police to investigate the incident.
Investigations found the contact took place approximately mid-span between poles, Mr Koenig said.
“Regrowth from previously cut trees located directly below the power line had grown into the power line and had made direct contact with the outer phase conductor.
This was evident from the burns to the tree branch and burn marks on the conductors.
The ensuing high resistance fault to ground resulted in the tree branch burning and hot embers falling and igniting the dry grass.
This contact between the tree branch and high voltage power line would not have occurred if the tree had been adequately pruned to ensure that branches did not encroach within an acceptable safety distance of the power line.
The pruning did not occur despite Western Power being responsible for controlling trees of this type and location, in accordance with the Guidelines for the management of vegetation near power lines issued by EnergySafety in 2006. Western Power had agreed to work to those Guidelines.
Mr Koenig said the current legislation did not as yet reflect the obligations set out in the Guidelines, so Western Power was not considered to have breached any laws.
However, as a follow up to this incident, EnergySafety will be taking up with Western Power its failure to carry out the necessary tree pruning and will require Western Power to review and improve its vegetation control practices.
Western Power said residents could contact 13 13 51 to report concerns they had about vegetation growing too close to powerlines.