Abstract: A vacuum circuit breaker comprises a base, a support frame and an insulating frame. The insulating frame has a plurality of housing portions juxtaposed and separated from one another. These housing portions are made of plastics as a unit. The insulating frame is supported by the support frame which is detachably mounted on the base. The vacuum circuit breaker has a plurality of vacuum valves each having a fixed and a movable electrode, and plural sets of main circuit conductors. Each vacuum valve and each set of the main circuit conductors are provided in each housing portion. The vacuum circuit breaker has a operating mechanism moving the movable electrode of the vacuum valve, and the operating mechanism is supported by the support frame.

Abstract: In this vacuum interrupter device, one or more upper terminals and lower terminals connected to a vacuum interrupter built in the device are attached to an insulating barrier which is provided with a plurality of chambers opening outward and capable of being closed by removable covers. In each of said chambers is placed one of non-linear resistors as many as said upper or lower terminals, one end of each of said resistors being connected to one of the upper or lower terminals corresponding thereto which is connected to the electric load, thereto and another end of each of said resistors being grounded through a switch.