A secret Powercor maintenance report predicts the electricity giant will have to lift the replacement rate of wooden poles eight-fold in an attempt to keep Victorians safe from bushfires.
The prediction comes as 171,415 third-rate mountain grey gum and messmate wooden poles have reached their critical end of life stage.
Compensation action by 189 fire victims led to a Supreme Court trial against Powercor and inspection service Electrix, which was settled mid-last week - but not before the secret report's existence was revealed.
The discovery of the October 28, 2019, reliability-centred maintenance report that outlined Powercor's inspection regime failures was the tipping point of the trial.
Key was the revelation that 384 poles had failed in the past 10 years even though only 210 were reported to the state's independent regulator, Energy Safe Victoria.
Read more: Secret report reveals power giant's failings
The report, which Australian Community Media has obtained, revealed 75 per cent of those 384 poles had not been identified during inspections as being of concern.
The report also revealed data "indicated the inspection process was not adequately detecting or managing a condition-based problem, a small but important portion of the time".
Those points raise queries about just how poles are checked.
Energy Safe Victoria earlier this year found there were no systemic issues in Powercor infrastructure system and that it was fit for purpose.
Questions are now being asked about how that could be true when Energy Safe Victoria was not aware of the holes in the inspection regime or the 384 failed wooden poles.
Energy Safe Victoria was identified in the 2009 Black Saturday Royal Commission as a weak regulator and this could spell the end for it in its current form.
Questions have been put to Energy Safe Victoria about how it could make its findings based on limited knowledge. Those same questions have been put Victorian Energy Minister Lily D'Ambrosio.
Mid-last month on a catastrophic fire risk day, 41 Powercor lines failed, blacking out almost 100,000 customers in Bendigo, Ballarat and Geelong.
The tsunami of pole replacements in the next 15 years was identified after a rotten and termite-riddled mountain grey gum pole at The Sisters in south-west Victoria collapsed at 8.50pm on St Patrick's Day last year, sparking a devastating fire.
It was one of four fires caused by electrical infrastructure in the area that night.
Community pressure has forced massive changes within Powercor, with Australian Community Media highlighting the issues since last year's fires.
Good wood standards for poles have been lifted and Powercor has planned more frequent inspections in an effort to quell community concerns.
Those changes came after the pole at The Sisters known as 'pole No. 4' was checked less than four months before the St Patrick's Day fires, in a process estimated during the compensation court hearing to have taken just 90 seconds.
The wind on St Patrick's Day peaked at 104km/h while the Australian standard for wooden power poles is to withstand 180km/h winds.
Over the past decade Powercor has on average replaced about 1000 poles a year, a fraction of one per cent of its 567,000 pole system.
Powercor has pledged to replace 2200 poles by the end of this year.
A Powercor spokeswoman said the company was confident in its network safety.
"We have a robust pole inspection and replacement program," she said when contacted about the report's findings.
"When operating an above ground network like ours, assets such as poles can fail for a range of reasons, including from car accidents, lightning strikes, weather and environmental conditions. Reports like this one provide the detailed information we need to responsibly invest and maintain our assets and deliver power safely and reliably.
"We have provided this report to Energy Safe Victoria. Information from the report will also be included in our 2021-2026 pricing submission to the Australian Energy Regulator to support our plan to increase the number of poles replaced on our network.
"The report also validates the improvements we made to our pole inspection process in March.
"These changes involved updating our pole inspection process to increase the frequency of inspections and the number of poles being replaced.
"The report reconfirms that our unassisted failure rates are below the national average.
"Customers can get more information about our pole inspections at https://www.powercor.com.au/safety/safety-around-our-networks/pole-inspections/."