EL
BG
DE
ES
FR
ITGlossary · Power quality
Voltage Spike
A momentary, very high voltage rise lasting microseconds, e.g. from lightning or load switching, that can damage equipment.
Technical level:Intermediate
Voltage spikes last from a few microseconds to a few milliseconds, but the voltage can reach many times its normal level, even thousands of volts. They are caused by lightning on the grid or near the building, by switching operations of the distribution company and by large inductive loads such as motors, lifts and compressors switching on or off.
A strong spike can destroy a power supply instantly. Smaller but repeated spikes gradually wear out electronics and cause unexplained faults or freezes. Most UPS units and stabilizers include surge protection, but its capacity is limited.
In areas with frequent lightning, combine the UPS with a surge protective device in the electrical panel and protect network and telephone lines as well.
Related terms
- Surge ProtectorA device that limits brief voltage spikes from lightning or grid switching by diverting the excess energy to earth.
- OvervoltageA voltage above normal that lasts from seconds to hours and can stress or damage connected equipment.
- ATS (Automatic Transfer Switch)A device that automatically moves the load from the grid to a generator during an outage and back again when grid power returns.
- Automatic Voltage Regulator (AVR)A device that automatically maintains a constant voltage level to protect electrical equipment from fluctuations.
- Input Voltage WindowThe range of mains voltage within which a UPS keeps powering the load from the grid without switching to battery.
- RFI — Radio Frequency InterferenceA subset of EMI: high-frequency noise from electronic equipment that can disturb radio, Wi-Fi and other devices.