LV Panel Changeover SOP

1. Purpose

To safely transfer the load between two power sources (e.g., utility and DG/UPS) while maintaining continuity and protecting equipment and personnel.

2. Scope

Applicable to LV switchboards, distribution panels, and sub-panels in industrial, commercial, or institutional facilities.

3. Responsibilities

  • Operators: Follow SOP, ensure safety, and maintain logs.
  • Maintenance Team: Inspect and service changeover switches and panels.
  • Supervisors: Authorize changeovers and monitor compliance.

4. Safety Precautions

  1. Only trained and authorized personnel may operate LV panels.
  2. Wear PPE: insulated gloves, helmet, and safety shoes.
  3. Confirm both sources are stable before changeover.
  4. Never operate panel with wet hands or in wet areas.
  5. Ensure proper earthing of panels and equipment.
  6. Keep clear of busbars and live connections during operation.

5. Pre-Operation Checks

  • Visual Inspection:

  1. Check panel for damage, overheating, or loose connections.
  2. Ensure indicator lights and meters are working.

  • Source Verification:

  1. Confirm utility supply voltage and frequency are within limits.
  2. Verify generator or alternate source is available and running (if applicable).

  • Load Assessment:

  1. Check total load and ensure it is within the panel capacity.

  • Isolation Readiness:

  1. Identify breaker positions for safe transfer.
  2. Ensure changeover switch is functioning properly.

6. Changeover Procedure

6.1 Manual Changeover

  1. Inform relevant personnel of upcoming transfer.
  2. Turn OFF the load breakers connected to the panel.
  3. Switch main source breaker OFF (e.g., utility).
  4. Operate the manual changeover switch to select the alternate source (e.g., generator).
  5. Close the main breaker for the alternate source.
  6. Turn load breakers ON sequentially.
  7. Verify correct voltage, current, and phase sequence at the panel.
  8. Record time, source, readings, and operator name in the logbook.

6.2 Automatic Changeover (ATS – Automatic Transfer Switch)

  1. Ensure ATS is functional and configured correctly.
  2. Check both sources for voltage and frequency limits.
  3. ATS will automatically detect utility failure and start generator if needed.
  4. Verify load is transferred smoothly and no breaker trips.
  5. Record changeover events and source readings in the logbook.

7. Monitoring During Operation

Continuously monitor:

  1. Panel voltage, current, and frequency
  2. Load distribution and balance
  3. Indicator lights and alarms

Ensure load remains within rated capacity.

8. Fault Handling

1).. No supply from alternate source:

  1. Check breaker positions and source availability.
  2. Inform control room and maintenance team.

2).. Panel breaker trips during changeover:

  1. Identify overloaded circuits.
  2. Reduce load or isolate faulty circuits before re-energizing.

3).. Phase reversal or incorrect voltage:

  1. Immediately disconnect load.
  2. Correct source or phase connection before re-energizing.

9. Shutdown / Reverting to Main Supply

  1. Turn OFF load breakers.
  2. Switch main source breaker ON (utility).
  3. Operate changeover switch back to main source.
  4. Close load breakers sequentially.
  5. Record readings and time in logbook.

10. Maintenance

  • Monthly: Inspect panel, breakers, and changeover switch for signs of wear or overheating.
  • Quarterly: Test ATS (if installed) and verify correct operation.
  • Annually: Full preventive maintenance, including cleaning, tightening connections, and testing protection relays.

11. Documentation

  • Logbook: Date, time, source, operator, readings, and observations.
  • Fault report: Description and corrective actions.
  • Maintenance record: Details of inspection, testing, and repairs.

12. Best Practices

  • Never bypass interlocks or protective devices.
  • Avoid frequent changeovers under full load.
  • Ensure communication with control room during every changeover.
  • Test alternate power source periodically under load conditions.


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