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What causes pole top fires or insulator sparking?

Pole top fires can happen when there is a run of very hot, dry and windy days followed by a sudden misty, cold front.

Humidity and light rain can combine with dust built up on insulators, resulting in tracks of dirt that can allow electricity to spark, in some cases eventually resulting in metal fixtures heating to a point that causes a fire.

We undertake an extensive preventative maintenance program on our network of more than 800,000 poles which includes siliconing insulators, high-pressure cleaning to remove built up dust, and managing trees and vegetation near wires. Siliconing insulators prevents the dust and pollution building up, and we give priority to high bushfire risk areas. We do this as an alternative to washing.

With our network spanning a vast distance and incorporating hundreds of thousands of poles, it is not practicable to wash poles and wires more regularly.

Pole top fires are not unique to WA and due to environmental conditions can cause issues for electricity networks.

We are often asked why we don’t underground more powerlines to prevent these occurrences. We work with the State Government, local councils and land developers to convert overhead power to underground where it makes economic sense to, as undergrounding power can be much more expensive than building and maintaining overhead infrastructure. Find out more about the differences between installing overhead vs underground power supplies in our network.