When choosing an overvoltage and undervoltage protector, you need to consider the following key factors:
Structural type: There are two types of overvoltage and undervoltage protectors: integral type and assembled type. Household distribution boxes generally use integral type because they are more convenient to install and wire.
Pole selection: Select the number of poles according to the power supply type. Household distribution boxes generally use single-phase power supply, and use two poles (1P+N); for large household distribution boxes with three-phase power supply, four poles (3P+N) must be used.
Overcurrent protection type: The overvoltage and undervoltage protector in the household distribution box generally does not need to have overcurrent protection function.
Installation method: Generally, the panel installation method is selected, which is consistent with the installation method of the small circuit breaker in the household distribution box.
Voltage protection type: The overvoltage and undervoltage protector in the household distribution box should use a self-recovery protector with overvoltage and undervoltage protection functions.
Rated parameter selection: Including rated voltage, rated current and rated frequency. When the household distribution box is a single-phase power supply, the rated voltage is 230V; when the rated current of the incoming circuit breaker is 50A, the rated current of the over-voltage and under-voltage protector can be 50A or 63A; the rated frequency is 50Hz.