Causes and relevance of transients and surges

• Lightning strikes — Large scale impact, high current and voltage, but least common occurrence.

• Power switching — Increasing occurrences:

• Utility and customer load switching – Motors, large loads, faults, capacitor banks, fuse and circuit breaker operation*, etc.

• Source switching — Smart grid, gensets, photovoltaic power systems and wind power generation, etc.

* During overcurrent events, both circuit breakers and fuses can produce arc voltages 2-3 times the system voltage in accordance with the UL standards.

Damage caused by transients and surges

• Disruptive – A voltage transient enters an electronic component and it interprets the transient as a valid logic command, resulting in system lock-up, malfunction, faulty output or corrupted files.

• Dissipative – Associated with short duration repetitive low energy level surges, resulting in equipment failure over time including electronic components, ballasts, motors and controllers, service entrance equipment, panelboards and switchgear.

• Destructive – Associated with high level energy surges, resulting in immediate equipment failure including electronic components, ballasts, motors and controllers, service entrance equipment, panelboards and switchgear.

Eaton has a comprehensive array of surge protective devices and suppressors to meet your needs ranging from residential to industrial applications. They help reduce costly downtime and protect sensitive electronic equipment against the damaging effects of transients caused by lightning, utility switching, internal load switching and more.

Bussmann series UL and data signal surge protective device application guide no. 3193 (eaton.com)