Surge protection
The need for surge protection
Today’s world is full of electronic products and electrical devices that are susceptible to damage from overvoltage surges. Surges caused by static discharge, capacitive and inductive loads or lightning can quickly destroy sophisticated electronic equipment and components used in industrial and commercial applications. These surges cripple operations – particularly the data and communication systems that virtually every enterprise relies upon today, including panels with their reliance on control circuits. Also, the CEC requires a listed SPD to be installed on various equipment types including elevators on emergency systems, critical operations data systems, industrial machinery with safety interlock circuits, wind electric systems, fire pump controllers, emergency panelboards and switchboards and critical operations power systems.
Case studies and references for industrial and commercial applications
G.W. Allen and D. Segall with IBM – Two year study at over 200 locations in 25 cities – 88.5% of AC power problems are transient voltage related.
2011 Erimar Systems Integration — A lightning strike entered the metals fabricating facility and destroyed $20,000 worth of control panels, electrical infrastructure and Cisco infrastructure. Loss of data system also cost 11 days of production.
IEEE Emerald Book and NFPA 780 both recommend using surge protection as a part of a building’s lightning protection system. Suppressors at the service entrance only reduce, but not completely eliminate, the high-energy transient. A second surge protective device must be applied upstream of critical equipment. All SPDs should comply with UL 1449 4th Edition or later.
1999-2001 Electric Power Research Institute (EPRI) Study – Concluded downtime from power sags, surges and transients cost US industry:
$50 Billion+ in 1999
$100 Billion+ in 2000
$200 Billion+ in 2001
Continues to escalate as more electronic equipment is used
Plant Services Magazine – 35% of lost production hours can be attributed to transient voltage problems.
Florida Light and Power 1999 Study — Sources of Facility Surge and Overvoltage Events:
~60% Internally Generated
~40% Externally Generated
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)
