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Safe working on Electrical Equipment - Coggle Diagram
Safe working on Electrical Equipment
Procedure for shutdown
Step 1:
study the circuit and identify the circuit – breakers or control switches to be opened.
Step 2:
Open and lock the circuit-breaker or switch in the ‘off’ position and keep the key in your Personal custody.
Step 3: Hang or tie a ‘men-at-work’ notice board on the circuit breaker or switch handle.
Step 4: For test the supply , after making sure that the testing device itself is ok.
Step 5: Earth the equipment.
Testing device for Electricity
Test Lamps
Low Voltage
Voltmeter (or) Two lamps connected in series
Medium Voltage
Spark Tester (or) Electrostatic Voltmeter
High voltage below 11KV
Metrac live- line indicator
33KV to 275KV
Special Shutdown Precautions in substations and Power House
In addition to switching off the circuit-breaker, the corresponding isolating switch should also be opened.
The authorized official in charge must be thoroughly familiar with the circuit layout and interconnections.
For instance, it is not enough to switch off the H.T circuit breaker for isolating a
transformer.
The transformer terminals may continue to be alive through the L.T side. Similarly ring mains or bus-couplers may feed currents into equipment, even though the direct link has been cut off.
In substation and power houses, an ‘authorized person’ should available at any time, who will be in overall control of the switching operations, and no operation should be carried out without his personal knowledge.
Authorized Person
Definition
An authorized person is one who is specifically empowered by the administration to carry out a specified task or duty
Types
Unskilled Labourer
Skilled Electric fitter
High tension Linesman
Substation Operator
Electric Fore man, Electric Charge man