The Rapid Earth Fault Current Limiter system was to cost $151 million to implement after the Black Saturday Royal Commission but the costs have blown out and the there are now serious and probing questions being asked about the costs and effectiveness of the system.

State Energy Minister Lily D'Ambrasio persistently claims the system, which will cost each south-west household more than $400, will prevent 70 per cent of fires.

But, experts are saying that on catastrophic days of bushfire - such as St Patrick's Day, Black Saturday and Ash Wednesday fires - REFCL may have only stopped one or two fires.

A Powercor spokeswoman said said REFCL was having an impact on the reliability of power supply which led to the Apollo Bay decision.

"We have assessed the current fire danger risks in the region and have chosen to temporarily disable the bushfire safety device," she said.

"As we head into summer, we always work closely with emergency service agencies to assess the fire danger risks in our regions and this will allow us to determine when we switch the REFCL back on.

"We will continue exploring different solutions to ensure we can continue to maintain reliability for the community while operating the bushfire safety device.

"The majority of faults in the Apollo Bay area during the past few months have been caused by vegetation contacting our power lines during high winds in heavily forested areas," she said.

The decision comes after recognised Australian expert on resonant earthing, Dr Bill Carman, questioned Victoria's adoption of REFCL.

He said the bushfire Royal Commission was entrusted with the task of investigating the cause of the disaster and producing guidelines to ensure the horror of Black Saturday would never be repeated.

Dr Carman said the REFCL solution was a broad blanket approach that did not come close to that aim.

He suggested that public statements about the effectiveness of REFCL had overstated its benefits and added at some point it must be questioned whether or not the original assumption about REFCL was correct?

The expert also questioned should the utilities have been forced by government regulation into installing one particular technology?

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Dr Carman said REFCL could simply not do what had been hoped and continuing operational issues meant an ongoing band-aid approach to implementation was being forced on electricity distributors.

He advocated a community inclusive approach:

"We only need one fire to start to cause another Black Saturday. There are factors such as lightning and arson outside our control, but we can control the fuel load and the power network.

"We cannot afford to let the power network cause a bushfire under extreme bushfire risk conditions. The consequences are too drastic for communities, properties and lives.

"Turning off the power has to be an option during those times and the community needs to be aware and prepared for that."

Dr Carman said the South Australian approach was progressive, level headed and effective.

"A lot of aspects of what they do make good sense," he said.

"They have worked closely with the CSIRO to understand how to manage each part of their network under high fire danger threat conditions and keep in close communication with the other emergency services groups and the affected communities".

"REFCL will not solve the issues caused by extreme fire risk days," he said.

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