This series vacuum breakers are suitable for the control and protection of the electricity supply and distribution systems whose rated voltage is no more than 12KV, AC three phase and 50Hz in the power sector and industrial enterprises. It is especially suitable for the place where the operation is frequently done. The vacuum arc-chute installed in the breaker has the advantages of fast recovery of medium intensity, high insulation property, low speed of arc energy and electro-corrosion, no explosion, no pollution, low noise, good adaptability, etc. The pure air insulating distance of the upper space of the series product is exceeded the national standard. It has been ranked into the list of new mechanical and electric products on national level examined by the National Economy and Trade Committee. The series breaker without operating device can match the series switchgear of type XGN-10(Z), GG-1A, and users may equip it with the electromagnetism and the spring operating devices themselves.