SEVERAL incidents have occurred where fuses have failed, resulting in arc blast damage to electrical enclosures in a motor control centre, according to NSW Department Of Primary Industries director, Mine Safety Operations Branch Rob Regan.
The latest incident involved a fuse-type 500NH3G-690 OEZ fuse.
Regan said arc blast was a known source of serious injury or death.
Fuses are used in electrical circuits to disconnect faulty circuits (short circuits) to prevent injury to people and equipment damage. They are designed to contain the arc energy within the fuse when used within their rating. They are widely used in the mining and other industries.
On 27 June 2006 an electrical fuse link supplier used the Australian Product Recalls system to recall fuses – some part numbers included NHG3-630 to NH63-315; see www.recalls.gov.au.
Since that date a second electrical fuse link supplier has been required to recall fuse links identified as ‘Bussman OEZ Czech catalogue 630NH3G-690’ fuse links. The failure mode of the catalogue 630NH3G-690 fuse links was “under certain overload conditions the integrity of the fuse ceramic body and metal end caps can rupture …”.
“All mines should review all fuses they have in service and all spare fuses at the site,” Regan said.
“If the above fuses are in use, the mine must contact the fuse supplier for advice, assess the risks and take immediate action to control the risks.
“Where these fuses are in use, it may be necessary to prevent access to the associated switchgear locations while ever the switchgear is energised, until suitable replacement fuses are installed.”
Known suppliers of the above fuses are: Alstom Industrial Products Limited (fax 1300 550 187); and Cooper Electrical Australia Pty Limited (fax 02 9725 5318).
Other suppliers may supply this type of fuse under an alternative name.
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