The enclosure and parts are made of fireresistance and shock withstanding material. It is suitable for circuit of AC 50/60Hz, rated working voltage 240/415V and rated current 6~63A. It is mainly applied to office buildings, dwelling houses and similar building, used to protect illumination, distribution lines and equipment against overload and short-circuit, and it also can be used for infrequent conversion of circuit under normal conditions. The product is in accordance with IEC 60898-1.