The NF-CW series plastic outer covering type circuit breaker (hereafter refers to as circuit breaker), is this company uses the international advanced design, one of the technique of manufacture development, development new circuit breakers. Its fixed isolation voltage is 690V, is suitable in exchanges 50Hz, fixed working voltage 400V and below, does the fixed operating current to the 800A electric circuit is infrequent transforms rubber electric motor infrequent starting. The circuit breaker has the overload, the short circuit and owes the voltage protection installment, can protect the line and the power equipment is damaged.