The FAR6B-U self-resetting over-voltage and under-voltage protector uses a miniature circuit breaker with short-circuit and overload protection as the main switch, and is equipped with an ultra-small intelligent electrical operator with a microprocessor. It can detect the power supply voltage, realize the over-voltage or under-voltage tripping protection, and automatically recloses after the voltage is restored, ensuring the safe operation of the load equipment under normal voltage. It is mainly suitable for occasions where the grid voltage is unstable or for the protection of equipment that is relatively sensitive to voltage fluctuations. It meets the requirements of the Code for Design of Residential Buildings JGJ242-2011 for self-resetting over-voltage and under-voltage protectors. This series of products features a small size, high breaking capacity, reliable operation, stable performance, and a good human-machine interface. The communication function can be added to achieve "remote signaling", "remote measurement", "remote control", and "remote adjustment" (bidirectional communication between the master station and the slave station).