For commercial reasons Powercor operated a system which included an unacceptable risk, the Supreme Court of Victoria has heard.
The argument was part of the opening address of Tim Tobin SC, appearing for the plaintiffs in Black Saturday bushfire class action Thomas v Powercor Australia Limited.
Defence counsel David Curtain QC, for Powercor, denied the plaintiffs' allegations and said Powercor's maintenance system was based on expert advice and not cost-driven.
Powercor assets started a fire on February 7, 2009, which burnt 2346 hectares and 13 houses on the outskirts of Horsham. The trial began on Monday at Horsham Law Courts and is expected to last six weeks before Justice Jack Forrest.
Mr Tobin told court Horsham field staff knew of faults found at three-year inspections and complained about Powercor reducing inspection frequency, but the company 'would not be moved' from a new five-year inspection system it introduced in the 1990s.
He said Powercor didn't make the change because it was safer, but it claimed with new technology, inspections every five years would be just as safe as three-year inspections.
Mr Tobin said reactive maintenance was less expensive than proactive maintenance and Powercor could still maintain targets if faults occurred.
He said Powercor reduced staff numbers after it became a private electricity distributor in 1994 and eventually subcontracted out power pole inspections.
Mr Tobin said for the past 13 years such inspections did not involve inspectors ascending power poles and coach screw insecurities were only detected when already known about.
The fire started at power pole 15 on the Remlaw Spur single-wire earth return ? SWER ? line, when a conductor fell from the pole after two remaining coach screws became loose due to wind-induced vibration, enabling the pole cap to detach. Some time before Black Saturday the first of the three coach screws that held the pole cap in place on top of pole 15 had come out.
Mr Tobin alleged Powercor breached its statutory and common law duties, and caused a nuisance for which the plaintiffs could claim damages.
"What might be acceptable to Powercor is not acceptable at these times when there's such devastation," he said.
Mr Curtain told court the transmission of electricity carried inherent dangers, including the risk of fire, which could not be reduced to zero.
He said Powercor's five-year inspection cycle was the industry norm and SWER lines were an effective, economic and reliable method of power line configuration in rural areas.