The breaker is suitable to be applied in the power distribution system for illumination (corresponding to model C) and motor (corresponding to model D). The circuit breaker is characterized by elegant appearance, small volume, light weight, excellent and reliable performance, high breaking capacity, instantaneous tripping, guide rail installation, case and components are made of high fire-retardant and shockproof plastic, as well as long service life properties. It mainly functions as overload and short-circuit protection in the line of single-pole of 230V and 2-, 3-, or 4-pole of 400V, when current is up to 63A. Also, it is used for infrequent making and breaking electrical apparatus and lighting circuit under normal conditions.