The C3s series intelligent air circuit breakers (hereinafter referred to as the circuit breakers) are suitable for power distribution networks with an alternating current frequency of 50Hz, a rated operating voltage of AC400V or AC690V, and a rated current of 6300A or less. They are used to distribute electrical energy and protect circuits and power supply equipment from damages caused by faults such as overload, undervoltage, short - circuit, and single - phase grounding. Meanwhile, they can also be used as disconnectors.