VK172-12P Indoor high voltage vacuum circuit breaker adopts spring operating mechanism, which can store energy by AC and DC power supply or by hand. It has the advantages of small volume, strong breaking capacity, high insulation strength, no pollution, no explosion danger and so on. The product can provide control and protection for distribution facilities no matter under normal conditions or fault conditions (Especially under short circuit conditions). Under rated parameters, the products can operate frequently and cut off short-circuit current for many times. The circuit breaker can be used not only for fixed installation unit, but also with special propulsion mechanism to form handcart unit. The secondary protection function is powerful, and the closing and opening coil anti burning, three times forced opening and anti tripping functions are compatible with comprehensive protection.