High-voltage switch danger for mine sites

Mine sites are reminded of the EnergySafety Order regarding high-voltage switches
Date: Thursday, 19 February 2015

Switch at the centre of the Morley Galleria explosion that killed two people can be found on some mine sites 

The type of high-voltage (HV) switches at the centre of the Morley Galleria explosion that killed two people can be found on some mine sites in Western Australia.

Department of Mines and Petroleum State Mining Engineer Andrew Chaplyn said mine sites are required to review high-voltage switchgear on site.

“If they have any Long and Crawford oil-insulated combined-fuse switches installed, they must ensure there are warning signs on all switches about the need for complete isolation from supply before performing any repair, fault finding, maintenance or fuse replacement,” Mr Chaplyn said.

“This isolation must remain effective until all work is completed and all lids and covers are replaced.”

Mr Chaplyn said mine sites also need to advise an Electrical Inspector from the department if any of these switches are installed onsite and any programs to replace them.

“These switches could have been in service for up to 40 years and are either approaching or past their safe service life,” he said.

Last week EnergySafety imposed new safety precautions for high-voltage oil-insulated combined-fuse switches produced by Long and Crawford.

The EnergySafety Inspector’s Order requires the switch to be completely disconnected from the electricity supply before any person may open the switch’s lid.

“The inherent danger of these switches was tragically highlighted by the accident at the Morley Galleria, which claimed the lives of two young men and severely injured two others,” Mr Chaplyn said.

“This is why we are reminding industry about the EnergySafety Order regarding the dangers of working with these switches.”

EnergySafety Director Ken Bowron said the type of switch involved allows the three fuses to be changed while the in-coming electricity supply at the base of the tank remains energised.

“It is unsafe to perform work on any item of electrical equipment while it remains energised, especially high-voltage equipment,” he said.

“We are looking into all aspects of these switches as part of the investigation process following the Morley Galleria accident and the Order we have issued is made in light of evidence we have to date.”

The department has issued notices to registered mine managers in Western Australia and more information and guidance is available from the department’s Resources Safety Division.

The department will also provide notice of any future findings or orders from the EnergySafety investigation that have implications for the resources industry.