The rated insulation voltage of the CYM6E electronic liquid crystal molded case circuit breaker is 1000V, suitable for use in distribution networks with an AC frequency of 50Hz, a rated voltage of 400V and below, and a rated current up to 800A. Under normal conditions, the circuit breaker can be used for infrequent switching of lines and infrequent starting of motors. It protects the lines against overload and short circuits, and provides protection against overvoltage, undervoltage, and phase loss in the lines.