A vacuum monitored disconnect switch includes vacuum interrupter with a high-voltage electric contactor inside a vacuum bottle, which can fail causing the vacuum switch to electrically short potentially causing extensive damage to the switch and other components. A vacuum monitor in fluid communication with the vacuum bottle includes a capacitance manometer for detecting a vacuum failure of the vacuum bottle. The capacitance manometer and associated components are powered by a current transformer (CT) that harvests power from the power line controlled by the vacuum disconnect switch. A porcelain tube in fluid communication with the interrupter vacuum bottle provides high voltage isolation between the vacuum interrupter bottle and the capacitance manometer to protect the manometer and associated electronics.

A vacuum circuit breaker includes a grounded tank in which an insulating gas is sealed, a vacuum valve, a movable-side electrode, a fixed-side electrode, a bellows fixed to the movable-side electrode allowed to pass therethrough, to expand and contract in the vacuum valve, a pressure valve regulating gas pressure between a first area enclosed by the bellows and a movable-side frame and a second area enclosed by the grounded tank outside the first area, a pressure release valve releasing the insulating gas from the first area to the outside of the grounded tank, and an anomaly determination unit determining leak of the insulating gas from the grounded tank, based on a gas pressure in the second area measured by a pressure sensor.

A vacuum circuit breaker includes a grounded tank in which an insulating gas is sealed, a vacuum valve, a movable-side electrode, a fixed-side electrode, a bellows fixed to the movable-side electrode allowed to pass therethrough, to expand and contract in the vacuum valve, a pressure valve regulating gas pressure between a first area enclosed by the bellows and a movable-side frame and a second area enclosed by the grounded tank outside the first area, a pressure release valve releasing the insulating gas from the first area to the outside of the grounded tank, and an anomaly determination unit determining leak of the insulating gas from the grounded tank, based on a gas pressure in the second area measured by a pressure sensor.