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:
- Obtain electrical permit to work
- Follow the DIE principle: Disconnect, Isolate, Earth
- 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:
- Issue before starting work
- Include work description and isolation details
- Declare earthing down and safety measures
- Authorize work commencement
- 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:
- Wear correct PPE
- Isolate work area from power supply
- Implement lockout and tagout procedures
- Verify absence of voltage using appropriate detectors
- Apply short circuit and earth systems
- Mark work area and warn others
- Issue permit to work
- For external high voltage work, obtain certification from supply controller
Transformer Isolation
- Obtain necessary approvals
- Open circuit breaker in high voltage system (HVS)
- Set HVS circuit breaker to isolated position
- Use earth switch in HVS to ground cable
- Retrieve key from ground switch panel
- Place warning signs on HVS front
- Use HVS key to access transformer room
- Verify transformer is not energized
- Apply mobile grounding device to each transformer phase