MF20ZGQ self duplex overvoltage protector is also called full automatic reset overvoltage undervoltage protector, which is suitable for single phase AC voltage 230V, frequency 50Hz, rated working current 60A and below current or load. As a single-phase line overvoltage caused by a neutral line fault to protect the single phase power equipment, the protector can quickly and reliably cut off the circuit when the voltage is higher than the protector's overvoltage action voltage value or the undervoltage action voltage value of the protector, so as to achieve the safety of the electrical protection. When the city is restored to normal power, the electric power is restored to normal. The protector can automatically connect the power supply and restore the power supply automatically. All functions are automatically implemented without personnel operation. It is mainly used for the protection of distribution lines in residential residential boxes or the protection of single-phase electrical equipment.