A gas circuit breaker including: a cylindrical tank; a stator fixed inside the tank; and a mover disposed so as to face the stator. The mover is movable between a closing position and a cutoff position, the mover is in contact with the stator when located in the closing position, and the mover is out of contact with the stator when located in the cutoff position. The stator includes: a stator-side main contact fixed inside the tank; a stator-side resistance contact having a ring shape surrounding the stator-side main contact; and a spring and a dashpot supporting the stator-side resistance contact from a direction opposite to a direction in which the stator-side resistance contact faces the mover. The mover includes: a mover-side main contact disposed so as to face the stator-side main contact; and a mover-side resistance contact disposed in such a way as to face the stator-side resistance contact.

Disclosed herein is a circuit breaker having a closing resistor, which is capable of preventing impact caused when the circuit breaker is opened and closed from being transferred to peripheral structures. The circuit breaker having a closing resistor includes a fixed part having a fixed contact, a movable part having a movable contact, a closing resistor unit connected to the fixed part and having a closing resistor unit contact, a closing resistor movable part connected to the movable part and having a closing resistor movable contact, and a support structure slidably coupled to the closing resistor unit in a direction parallel to a movement direction of the closing resistor movable part, thereby enabling impact and vibration applied to the closing resistor unit to be absorbed by the support structure.

A vacuum circuit breaker includes: a vacuum valve accommodated in a tank having a cylindrical shape; a movable-side shield installed on a movable side of the vacuum valve; a movable-side main contact point having a tubular shape to cover the vacuum valve and the movable-side shield from radially outside; a contact point driver that moves the movable-side vacuum contact point and the movable-side main contact point in conjunction with each other; and an insulating rod that transmits a force to the contact point driver. The contact point driver includes: a low gas pressure section lever connected to a contact via a contact pressure applier that applies a contact pressure to the contact; a rotary seal shaft fixed to the low gas pressure section lever; and a high gas pressure section lever fixed to a portion of the rotary seal shaft exposed to the high gas pressure section.

Provided is a relay switch device including a relay housing, a first upper fixing terminal and a second upper fixing terminal arranged side by side over an inside and an outside of the relay housing, a first lower fixing terminal electrically connected to the first upper fixing terminal and arranged under the first upper fixing terminal to be apart a predetermined distance from the first upper fixing terminal, and a second lower fixing terminal electrically connected to the second upper fixing terminal and arranged under the second upper fixing terminal to be apart a predetermined distance from the second upper fixing terminal, and a circuit mode switch module provided to selectively contact the first and second upper fixing terminals or the first and second lower fixing terminals by moving a predetermined distance.