Where do transients originate?
Approximately 20% of all transients originate outside the facility from such sources as lightning, utility grid switching, switching large capacitor banks on the utility lines, electrical accidents or heavy motors or loads from nearby industry. The remaining 80% are generated inside the facility and come from unsuspected sources such as microwave ovens, laser printers and copiers, air conditioner motors, hair dryers, refrigerators, and even electrical devices or lights turning on and off.
