Power or voltage surges are brief bursts of energy caused by sudden change in the electrical conditions of a circuit; they are virtually inevitable. Wherever electrical or electronic equipment is used, power surges can and do occur. While often lasting only a millisecond, power surges can raise the voltage in electronic circuits from a few hundred to as much as several thousand volts. They are one of the most sever, common and immediate dangers to modern, sensitive electronic equipment. Business Week estimates that power surges cost $26 billion a year in lost time, equipment repair and replacement costs.
What Causes Power Surges?
• It’s estimated that 60 percent to 80 percent of power surges are caused by events or problems arising within the facility housing the electrical and electronic equipment. The balance is generated by external events that affect the internal electrical system through power cords, telephone lines, and cable, satellite and antenna lines. Events causing surges include:
• Local Power System/Utility Problems – Poor power quality is one of the major causes of downtime. The most common source for externally generated surges is the local electric company. Problems and point of failure include faulty wiring by a utility, equipment breakdowns, downed power lines, grid shifting (reallocating stored energy to match demand), and capacitor switching (a routine, daily event.)
• Large users of the same power line at other facilities can also create power surges. Heavy electrical equipment that frequently turns on and off, such as high-powered motors, elevators, or heating/air conditioning equipment, creates sudden, brief demands for power that can upset the steady voltage flow in the electrical system and result in power surges may also be caused when two power lines come into contact with each other as a result of vehicle crashing into power poles, falling tree limbs, ice storms and even animals.
• Lighting – Power surges caused by direct lightning strikes are rare events, accounting for only two percent of power surge damage. Lighting is however a very common occurrence, striking the surface of the Earth about 100times every second. When lighting directly strikes exposed cables feeding electric equipment, the extremely large, overwhelming power surges it produces are devastating. Importantly, lighting does not need to actually directly hit an object on the ground to induce a power surge. Lighting can create strong electromagnetic fields, which can induce a power surge that affects power, telecommunications and radio frequency transmission lines; these in turn affect electric equipment inside a facility. Due to the low voltages normally used in data transmission cables and the sensitivity of the connected electronics, communications cables are extremely susceptible to induced voltage surges.
• Events Arising Within a Facility – Switching high-powered electrical devices like elevators, air conditioners, refrigerators, pump, compressors and motors on and off are common causes of internally generated surges. The ignition and interruption of electrical arcs used in welding devices can also cause surges, as can the tripping of fuses and circuit breakers. Typically, but not always, these surges are rather small and degrade electrical equipment, rather than destroy it.
What Type of Businesses and Equipment are at Risk
Every business relies on modern electronic equipment to some degree –and such equipment can be easily damaged or weakened by surges. Businesses face significant threats if their products and services rely on sustaining continuing operations supported by electronic or telecommunications equipment, or if malfunctions of sensitive electronic equipment change the nature of critical products and/or services. Businesses with electronic systems in hazardous locations, such as potentially explosive atmospheres, obviously are exposed to catastrophic risks. Businesses located in areas with poor local power supplies or where weather conditions making lightning strikes more likely also face increased risk of damage from power surges.
Examples of businesses and equipment at risk include:
• Manufacturing operations where there is significant use of motors and other high voltage equipment.
• Businesses that depend on computers, and use office equipment such as printers, faxes and photocopiers.
• Businesses that use security or alarm systems, telemetry or monitoring networks, bar code scanners, or thermostats.
• Healthcare facilities with equipment monitoring and assisting life support systems.
• Information and order processing operations with heavy reliance on communications.