Personal Protective Equipment (PPE)

• Electrically insulating safety helmet
• Insulating rubber gloves (must meet IEC standards)
• Insulating boots
• Insulation mat
• Face shield, safety glasses, or arc protective hood

• Use a pneumatic glove tester to check for damage

High Voltage Operation Procedure

1. Obtain electrical permit to work
2. Follow the DIE principle: Disconnect, Isolate, Earth
3. Perform earthing down, circuit earthing, and bus bar earthing

• Connect earth to all three conductors at the circuit breaker
• Use a key system to prevent circuit breaker activation until earth is removed
• For bus bar work, isolate from all electrical sources and use portable leads for earthing

1. Issue before starting work
2. Include work description and isolation details
3. Declare earthing down and safety measures
4. Authorize work commencement
5. Cancel permit after job completion

Safety Measures

• Place danger signs at the front door
• Display single line diagram
• Cover entire switchboard length with rubber mat
• Provide fire extinguisher (Class C)
• Display first aid chart
• Ensure electrical installation license is visible
• Maintain a key box and logbook

1. Wear correct PPE
2. Isolate work area from power supply
3. Implement lockout and tagout procedures
4. Verify absence of voltage using appropriate detectors
5. Apply short circuit and earth systems
6. Mark work area and warn others
7. Issue permit to work
8. For external high voltage work, obtain certification from supply controller

Transformer Isolation

1. Obtain necessary approvals
2. Open circuit breaker in high voltage system (HVS)
3. Set HVS circuit breaker to isolated position
4. Use earth switch in HVS to ground cable
5. Retrieve key from ground switch panel
6. Place warning signs on HVS front
7. Use HVS key to access transformer room
8. Verify transformer is not energized
9. Apply mobile grounding device to each transformer phase

Additional Safety Measures

• Regular training for personnel on HV equipment maintenance
• Use of approved safety clothing and equipment
• Regular testing of safety equipment
• Strict access control to HV switchboards and equipment
• Implementation of permit-to-work scheme and isolation procedures
• Use of live-line tests and earthing-down before work commencement
• Installation of HV circuit breakers (air, gas, or vacuum types)
• Use of neutral earthing resistors to minimize earth fault current
• Utilization of high-quality insulating materials like Micalastic
• Design of HV equipment for 20-year insulation life
• Installation of special relays for overall HV circuit protection