C45N series circuit breaker is used in lighting distribution system or motor distribution system for protecting overload and short-circuit in the system. The product is novel in structure, light in weight, reliable and excellent in performance. Its case and body adopt high fire-registrant and shockproof plastic. The product, with long life, is mainly used in AC 50Hz/60Hz, single-pole 240V or two, three, four-pole 415V circuit for overload and short-circuit protection as well as for infrequent on and off switch electric equipment and lighting circuit in normal case.