|
Precautions before starting maintenance:
Switch off incoming power supply before removing top plates and side covers. Lock out incoming power supply.
Measure voltages on busbars to ensure that busbars are de-energised.
Switch off the control supply.
Isolate remote control voltage sources.
Ensure that only qualified personnel are instructed and permitted to use the defeat mechanism to gain access to an energized compartment.
Do not attempt to withdraw the unit or disconnect any terminations when the defeat mechanism has been used to open a compartment door.
Current transformer primaries must not be energized when secondary are open circuited.
Short all CT secondaries.
In case of shutdown on only one feeder, padlock the power switch in OFF position.
For safety of personnel working on busbars, provide temporary earthing using a metallic chain/strip near the workplace. Remove this earthing only after the job is completed.
After maintenance, if MCC is going to be de-energised for a longer period, switch on the panel space heaters to prevent moisture condensation on the cables/insulators.
|
