Gas circuit breaker

A gas circuit breaker, comprising:

• a first arc contactor electrically connected to a first lead-out conductor connected to a power system;
• a cylindrical second arc contactor electrically connected to a second lead-out conductor;
• a bar-shaped trigger electrode arranged to be movable between the first arc contactor and the second arc contactor, an arc generated between the first arc contactor and the trigger electrode is ignited along with a movement in a first half of a current breaking action, and moves in the second arc contactor during a latter half of the current breaking action to commutates the arc to the second arc contactor;
• and
• a guide portion having an inner diameter larger than an outer diameter of the trigger electrode, and the inner diameter smaller than an inner diameter of a portion of the second arc contactor close to the trigger electrode, and arranged in a cylinder of the second arc contactor so as to circulate around the trigger electrode;
• wherein the guide portion is arranged to be separated from an end in a first-arc-contactor side of the second arc contactor to an opposite side of the first arc contactor by at least a distance obtained by multiplying the inner diameter of the end of the second arc contactor which is close to the trigger electrode by 0.2, and
• arranged in the cylinder of the second arc contactor so as to circulate around the trigger electrode when the trigger electrode is in a closed state with the first arc contactor.