In order to carry out the maintenance of the circuit breaker the work involves the removal of 3 blast valves, 1 per phase, in order to refurbish the contacts and seals.
The CB has to be stripped of various components and a valve cover to expose the blast valve. The blast valve is then extracted by using 2 jacking bolts which lift the blast valve away from its housing). When you reach the limit of the jacking bolts the valve is manually handled to remove the valve to a barrow to be transported away to a workshop for repair. Once complete the process is reversed and the blast valve replaced in the blast valve housing and the cover replaced.
The key objective is to safe guard the current workforce, This will be delivered in an effort to reduce the manual handling requirements for MDE Substation staff to complete maintenance activities in a manner which will not place unnecessary stresses on their bodies and thus reduce occupational health issues.