Cape Naturaliste fire started by Western Power power line
Issue Date: - Friday, 6 March 2009
A bush fire near Cape Naturaliste Lighthouse on February 7, 2009 which burned 108 hectares of bushland was started by a pole-top fire on a Western Power high voltage power line.
This is the main conclusion of a report into the fire cause released today by the Director of Energy Safety, Ken Bowron.
“The bush fire originated at pole number 108 on the single-phase 12,700 volt overhead spur line off Feeder (BSN 510.0) near Cape Naturaliste Lighthouse, Dunsborough,” Mr Bowron said.
“The pole-top caught fire because of leakage current from the high voltage active conductor to the underslung earth return conductor.
“Dust or salt spray on the insulators, combined with light rain and high humidity, caused enough leakage current to generate sufficient heat at the point of contact between the wood and metal surface of the insulator support bracket to ignite the wood.
“Hot embers from the ensuing fire ignited vegetation under the power line.”
The investigation found no other credible ignition source, for example lightning, clashing conductors, vehicle movements, fuse operation or arson.
It also found remnants of previous pole top fires on this power line.
Mr Bowron said the most recent pole-top fire, along with evidence of previous ones, brought into question the effectiveness of Western Power’s inspection and maintenance processes for the power line in question.
“Further investigations are required to identify the risks of future pole-top fires in the area and the scope of the preventative work required to minimise this risk,” Mr Bowron said.
Media contact: Nicola Easton (08) 94225208