A tamper-proof spindle has been designed and developed to reduce safety risks to underground mining personnel.
The tamper-proof spindle prevents the restrained plug from being removed without first isolating the circuit.
The previous plug design consisted of a standard lock that went through the end of the socket housing once the plug was inserted. However it became evident that this design was not tamper proof, when a customer encountered a problem when the restrained plug was removed from the socket.
Proof Mining Solutions, together with a large end-user, engineered a solution to this problem by developing a tamper-proof spindle for its restrained plugs and sockets.
The design for the spindle is similar to that used on wheel nuts, with the female section fitted in the spindle and the male sprocket on the loose handle, ensuring that the plug can be removed only once the circuit has been isolated.
Each handle has its own unique serial number to ensure that the handle supply is strictly controlled, allowing the end-user to log and issue the handles to authorised personnel only.
Powermite restrained plugs and sockets are available in 300 A to 425 A 1.1 kV, 200 A 1.1 kV and 120 A 1.1 kV and are flameproof, certified to South African National Standards (SANS) IEC60079-0-1 and SANS 1489. The products are suited for power supply to underground as well as surface-to-underground machines and feature copper grub-screw or crimp-type connectors, individually screened insulators and complete phase segregation.
The restrained plugs and socket range is also available in anti-theft material, which is lighter in weight and consists of a mix of zinc, copper and aluminium, which holds no resale value, thereby reducing the risk of theft.