所有的电器在使用时最忌电网电压过高过低，不论工业设备还是家用电器都有一个额定电压，电压范围通常规定为170V-240V（可以在电器设备的铭牌或说明书上看到）。如果超出这个电压就超出了电器的绝缘强度和耐压值，电器会因此发热、击穿而烧坏甚至起火。目前由于零线被盗、设备老化、技术故障、人为故障、自然灾害、停电再来电等原因引起的电压不稳、电压过高过低导致大片区大量电器被烧坏、烧毁的情况不断发生，人们损失惨重，索赔无门，劳民伤财的事接踵而至，应加设益民超压、过压、欠压保护器（又名电器保护器），以防止电气火灾，保护生命财产安全。

All electrical appliances in use should avoid too high or too low grid voltage. Both industrial equipment and household appliances have a rated voltage. The voltage range is usually set at 170V-240V (which can be seen on the nameplate or instructions of electrical equipment). If this voltage is exceeded, it will exceed the insulation strength and withstand voltage value of the electrical appliances, and the electrical appliances will be heated, broken down and burned or even ignited. At present, due to zero-wire theft, equipment aging, technical failures, man-made failures, natural disasters, blackouts and power re-generation, voltage instability, too high or too low lead to a large number of electrical appliances being burned and destroyed in a large area, people suffer heavy losses, there is no way to claim compensation, and the casualties of people and property come one after another, so it should be done. Set up over-voltage, over-voltage and under-voltage protectors (also known as electrical protectors) to prevent electrical fires and protect life and property.