Short term decreases in voltage levels. They are the most common power problem. These are typically caused by the start-up power demands of electrical devices such as compressors, motors, elevators, etc. Electric companies cope with extreme power demands by systematically lowering voltage levels in certain areas for hours or days at a time. The end result can be data loss or corruption.
Sags also reduce the efficiency and life span of electrical equipment.
A total loss of utility power. Blackouts are caused by excessive demands in the power grid by lightning storms, ice on power lines, car accidents, backhoes, earthquakes, power rationing, etc. A spike is also known as an impulse. It is an instantaneous, dramatic increase in voltage. Similar to the force of a tidal wave, a spike can enter electronic equipment and damage or completely destroy components.