Abstract: A switchgear according to the present invention includes: an air intake mechanism attachment body arranged on an air intake portion provided on a housing; an air intake opening provided in the air intake mechanism attachment body; a check valve type shutter which is arranged on the inner side of the air intake opening on the housing, performs an air intake from the outside of the housing, and blocks the air intake opening in the occurrence of an internal short circuit fault; and a ground fault partition body which is arranged between said check valve type shutter and a conductive portion in said housing and in which the length of at least one side is longer than said check valve type shutter.

Abstract: An insulation degradation monitoring device by which a degradation state of an insulator can be constantly monitored by a simple configuration, and a degradation degree can be decided. An insulation degradation monitoring device for an insulator, by which a high-voltage charging portion of an electric instrument is insulated from and supported to a grounding metal component, includes a penetration-type electric current sensor which is inserted to a connecting portion of the insulator and the grounding metal component, and detects a leakage electric current which is passed from the high-voltage charging portion through the insulator and is flowed to the grounding metal component; and a decision means which is connected to an output side of the electric current sensor, and decides a degradation degree of the insulator in accordance with a value of the leakage electric current.

Abstract: An insulation degradation monitoring device by which a degradation state of an insulator can be constantly monitored by a simple configuration, and a degradation degree can be decided. An insulation degradation monitoring device for an insulator, by which a high-voltage charging portion of an electric instrument is insulated from and supported to a grounding metal component, includes a penetration-type electric current sensor which is inserted to a connecting portion of the insulator and the grounding metal component, and detects a leakage electric current which is passed from the high-voltage charging portion through the insulator and is flowed to the grounding metal component; and a decision means which is connected to an output side of the electric current sensor, and decides a degradation degree of the insulator in accordance with a value of the leakage electric current.