An insulating molded body to be used for an arc extinguishing device of a gas circuit breaker is provided. The insulating molded body includes a fluororesin mixture which contains a fluororesin and an oxygen generator configured to generate oxygen through thermal decomposition at 450 C. or more and 1,150 C. or less with an arc generated when a conduction current is interrupted. The oxygen generator is dispersed in the fluororesin. Also provided is a gas circuit breaker including an insulating nozzle formed of the insulating molded body.

A gas circuit breaker of an embodiment includes a sealed container, a first contact part and a second contact part, an operation mechanism, an insulating nozzle, a pressure accumulator, and an electric field shield. The insulating nozzle is displaced in conjunction with the first contact part in a separation process of the first contact part and the second contact part. The insulating nozzle surrounds arc discharge generated between the first contact part and the second contact part. The electric field shield is attached to the insulating nozzle. The electric field shield has a floating potential during a period of at least part of the separation process. The electric field shield is electrically connected to the second contact part such that the electric field shield has the same potential in a completely open electrode state in which separation between the first contact part and the second contact part is terminated.

An interrupter unit for a circuit breaker has two electrically conductive arcing contact pieces, which can be moved relative to one another along a switching path. An insulating nozzle has a nozzle channel through which the switching path runs. A heating volume is connected to the nozzle channel. A separating housing divides the heating volume into a cold gas region and a hot gas region. A cold gas duct runs through a nozzle channel end section of the nozzle channel and is connected to the cold gas region. A hot gas duct runs through the nozzle channel end section and is connected to the hot gas region.

An interrupter unit for a circuit breaker has two electrically conductive arcing contact pieces, which can be moved relative to one another along a switching path. An insulating nozzle has a nozzle channel through which the switching path runs. A heating volume is connected to the nozzle channel. A separating housing divides the heating volume into a cold gas region and a hot gas region. A cold gas duct runs through a nozzle channel end section of the nozzle channel and is connected to the cold gas region. A hot gas duct runs through the nozzle channel end section and is connected to the hot gas region.

A circuit breaker, comprising an enclosure comprising: at least two arcing contacts that are movable axially relative to each other, between an open position of the circuit breaker in which the arcing contacts are separated from each other and a closed position of the circuit breaker in which the arcing contacts are in contact with each other; and a gas inlet configured to blow an arc-control gas in order to interrupt an electric arc that is likely to form during movement of the arcing contacts from the closed position to the open position of the circuit breaker, wherein the arc-control gas comprises at least 80% of carbon dioxide; wherein the enclosure further comprises a catalytic material, which converts carbon monoxide that forms after ionization of the carbon dioxide during arcing, into carbon dioxide, said catalytic material comprising ceria and a precious metal.

A circuit breaker, comprising an enclosure comprising: at least two arcing contacts that are movable axially relative to each other, between an open position of the circuit breaker in which the arcing contacts are separated from each other and a closed position of the circuit breaker in which the arcing contacts are in contact with each other; and a gas inlet configured to blow an arc-control gas in order to interrupt an electric arc that is likely to form during movement of the arcing contacts from the closed position to the open position of the circuit breaker, wherein the arc-control gas comprises at least 80% of carbon dioxide; wherein the enclosure further comprises a catalytic material, which converts carbon monoxide that forms after ionization of the carbon dioxide during arcing, into carbon dioxide, said catalytic material comprising ceria and a precious metal.

A gas circuit breaker includes: a fixed arc contact extending along an operating axis; a moving arc contact allowed to move to a position where the moving arc contact contacts the fixed arc contact and a position where the moving arc contact is separated from the fixed arc contact; a frame forming a puffer chamber around the moving arc contact; a nozzle having a cylindrical shape centered on the operating axis, the nozzle being fixed to the frame and projecting in a direction toward the fixed arc contact from the moving arc contact; and an arc extinction assisting portion provided on an inner surface of the nozzle and made of an ablation material. The nozzle and the arc extinction assisting portion are provided with a fall-off preventing portion to prevent the arc extinction assisting portion from falling off the nozzle.

A low-voltage multipolar circuit breaker includes a moulded housing including a main body that is divided into interior compartments, each associated with one pole of the circuit breaker, and a cover that is mounted on the main body covering a main face of the body. The circuit breaker includes, for each pole, electrical contacts that can be separated by a device of a switching mechanism and an arc-extinguishing chamber. For at least two of the poles, the main face includes an additional aperture, each placed directly above the spark guard of the corresponding pole and placing the arc-extinguishing chamber of this pole in communication with the interior volume delimited by the cover and the main face, and the cover is attached to the main body while leaving a peripheral opening between the cover and the main body, placing the interior volume in communication with the exterior of the housing.

A low-voltage multipolar circuit breaker includes a moulded housing including a main body that is divided into interior compartments, each associated with one pole of the circuit breaker, and a cover that is mounted on the main body covering a main face of the body. The circuit breaker includes, for each pole, electrical contacts that can be separated by a device of a switching mechanism and an arc-extinguishing chamber. For at least two of the poles, the main face includes an additional aperture, each placed directly above the spark guard of the corresponding pole and placing the arc-extinguishing chamber of this pole in communication with the interior volume delimited by the cover and the main face, and the cover is attached to the main body while leaving a peripheral opening between the cover and the main body, placing the interior volume in communication with the exterior of the housing.

This electric switch comprises an arc-blasting unit with a compression cylinder (25) enclosing a compression chamber (27) mobile together with the mobile contacts (2), and a stationary piston (13) at an end of the compression chamber, provided with a support rod made up as a blowpipe (9) which channels the gas compressed in the chamber when the contacts separate to a nozzle (10) that directs the flow to a separation place (12) of the contacts so as to efficiently blast electric arcs. The arrangement is lightweight and occupies little space.