High Voltage Operation, Maintenance Safety Procedure

Personal Protective Equipment (PPE)

Essential PPE for High Voltage Work:

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

Glove Testing:

• Use a pneumatic glove tester to check for damage

High Voltage Operation Procedure

Pre-Work Steps:

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

Earthing Process:

• 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

Permit to Work:

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

Workspace Setup:

• 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

Work Procedure:

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