Surges, or transients, are brief overvoltage spikes or disturbances of a power waveform that can damage, degrade, or destroy electronic equipment within any home, commercial building, or industrial and manufacturing facilities. Transients can reach amplitudes of tens of thousands of volts. Most equipment is designed to handle minor variations in their standard operating voltage. However, surges can be very damaging to nearly all equipment.

A typical building experiences multiple power surges every day.

The average cost of downtime caused by a power surge is $130,000 per event.

Symptoms of Power Surges

  • Circuit board failure
  • Lighting failure
  • Motor failure
  • Phantom equipment restart

Causes of Power Surges

  • Internal Sources
    60 – 80% of power surges originate within facilities. These are typically caused by large loads switching off and on

    • Switching of electrical loads from
      • Contactor, relay & breaker operations
      • Switching of capacitor banks and loads (e.g. power factor correction)
      • Discharge of inductive devices (motors, transformers, etc.)
      • Fault or arc initiation
      • Arcing faults (ground)
      • Fault clearing or interruption
      • Power system recovery (from outage)
      • DC Battery storage systems
    • Magnetic & inductive coupling from
      • Elevators
      • HVAC (with variable frequency drives)
      • Fluorescent light ballasts
      • Copy machines
      • Computers
  • External Sources
    • Lightning
    • Grid & capacitor bank switching
    • Damage to power lines or transformers


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