Zw8-12 (FG) type outdoor high voltage vacuum circuit breaker, three-phase AC 50Hz outdoor high voltage switchgear. It is composed of operating circuit, conductive circuit, insulation system, sealing parts and shell. The overall structure is three-phase total box type. Used in 10kV rural power network and urban power system, as load current, overload current, short circuit current and other similar places. Executive standard: GB1984-2003 "high voltage AC circuit breaker"; GB/T11022-1999 "High voltage switchgear and control equipment standard common technical requirements"; 1IEC62271-100 HIGH voltage AC circuit Breaker 1.It is equipped with CT23 type spring energy-stored operating mechanism. Energy-stored, opening and closing can be achieved by motor or by manual. 2. ZW8-12 (FG) consists of ZW8-12 breaker and isolator, called combined breaker, can be used as sectionalizer. 3.The structure of breaker is of three-phase assembled in a tank, three-phase vacuum arc-extinguishing chamber enclosed in metal tank, insulation material between phases and phase to each made of SMC. 4. Reliable performances, and high insulating strength.1. Ambient air temperature: -5~+40 and the average temperature should not exceed +35 in 24h. 2. Altitude above sea level for operation site should not exceed 2000M. 3. Relative humidity should not exceed 50% at max temperature +40. Higher relative humidity is allowed at lower temperature. Ex. 90% at +20. But in view of the temperature change, it is possible that moderate dews will produce casually. 4. Installation gradient not exceed 5°. 5. Install in the places without fierce vibration and shock and the sites insufficient to erode the electrical components. 6. Any specific requirement, consult with manufactory.