1. Safety First 

• De-energize equipment and apply LOTO (Lockout/Tagout)
• Verify absence of voltage (use properly rated tester)
• Wear proper PPE per NFPA 70E
• Discharge stored energy (springs, capacitors) 

  2. Visual Inspection

  Check for:
  • Dust, dirt, moisture buildup
  • Signs of overheating (discoloration, burnt smell)
  • Loose hardware or misalignment
  • Corrosion on busbars and terminals
  • Insulation damage or cracks. 

    3. Cleaning

    • Use dry air (low pressure) or vacuum (non-conductive)
    • Wipe insulation with lint-free cloth
    • Avoid moisture unless using approved cleaning agents

    ⚠️ Do NOT use compressed air aggressively—it can push debris deeper. 

    4. Mechanical Inspection

    Inspect:

    • Racking mechanism (smooth operation)
    • Spring charging motor (for VCBs)
    • Interlocks (mechanical & electrical)
    • Contact wear (especially VCB or ACB)
    • Lubricate moving parts (use manufacturer-approved grease)

      5. Electrical Testinging:

      Common Tests:

      • Insulation Resistance (Megger)
      • Contact Resistance (Micro-ohm test)
      • Primary Injection Test (verifies CTs & breaker performance)
      • Secondary Injection Test (relay functionality)
      • Timing test (breaker open/close speed) 

        6. Connections & Busbars

        • Torque-check all bolted connections
        • Inspect busbars for:
          • Hot spots
          • Insulation condition
        • Use thermal imaging if available

          7. Protection & Control System

          • Verify relay settings
          • Test trip functions
          • Check control wiring
          • Inspect terminal blocks for tightness

            8. Auxiliary Systems

            • Check control power supply (AC/DC)
            • Inspect batteries (if applicable)
            • Verify indicator lights, meters, and alarms

              9. Documentation

              • Record all test values
              • Compare with previous results (trend analysis)
              • Note any abnormalities or corrective actions

                10. Maintenance Frequency (Typical)

                Equipment Type	Frequency
                Medium Voltage Switchgear	1–3 years
                Low Voltage Switchgear	1 year
                Critical Systems	6–12 months