A gas-insulated low- or medium-voltage load break switch includes: a housing defining a housing volume for holding an insulation gas at an ambient pressure; a first arcing contact and a second arcing contact arranged within the housing volume, the first and second arcing contacts being movable in relation to each other along an axis of the load break switch and defining a quenching region in which an arc is formed during a current breaking operation; a pressurizing system having a pressurizing chamber arranged within the housing volume for pressurizing a quenching gas from an ambient pressure p.sub.0 to a quenching pressure p.sub.quench during the current breaking operation; and a nozzle system arranged within the housing volume for blowing the pressurized quenching gas in a subsonic flow pattern from the pressurization chamber onto the arc formed in the quenching region during the current breaking operation. The nozzle system includes at least one nozzle arranged for blowing the quenching gas from an off-axis position predominantly radially inwardly onto the quenching 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 dielectric fluid (i.e., dielectric composition) that includes a perfluorinated 1-alkoxypropene compound represented by the following general Formula (I): R.sub.fOCFCFCF.sub.3 wherein R.sub.f is CF.sub.3 or CF.sub.3CF.sub.2. Such dielectric fluids may be useful in various electrical devices.

The use of a gas as a medium for electrically isolating and/or extinguishing electric arcs, the gas including 1-chloro-2,3,3,3-tetrafluoropropene. Also, an electrical device including a sealed chamber containing electrical components and a gas for electrically isolating and/or extinguishing electric arcs, in which the gas includes 1-chloro-2,3,3,3-tetrafluoropropene. The gas may be only 1-chloro-2,3,3,3-tetrafluoropropene.

An insulating medium for an electric energy transmission device is a fluid at room temperature and atmospheric pressure and has at least the following components 50% by volume to 98% by volume of synthetic air, and 2% by volume to 50% by volume of an organic fluorine compound. An electric arc extinguishing medium and a fluid-insulated electric energy transmission device are also provided.

A method and a facility for filling a high- or medium-voltage gas-insulated electrical apparatus in which the insulating gas comprises a mixture of heptafluoroisobutyronitrile ((CF.sub.3).sub.2CFCN) and carbon dioxide. The method and the facility using a mixture of (CF.sub.3).sub.2CFCN and CO.sub.2 in pressurised liquid form which is heated to a temperature no lower than the critical temperature of the mixture.

An arrangement includes a gas-insulated switchgear which is configured for filling with a first electrical insulation fluid. A surge arrester is provided to reduce the protection level of the gas-insulated switchgear such that the switchgear has insulation spacings of at most the same size as those of a switchgear insulated with a second electrical insulation fluid which has a higher dielectric strength than the first electrical insulation fluid.

A switching device for an encapsulated electric power distribution switchgear and an electric power distribution switchgear with at least one such switching device are disclosed. The switching device has a first electrically conducting housing which encloses an actuator mechanism for a first contact assembly and a second electrically conducting housing which encloses a second contact assembly. The first electrically conducting housing is arranged at a distance from the second electrically conducting housing. The switching device further has a third housing which is electrically insulating and arranged between the first electrically conducting housing and the second electrically conducting housing. The switching device is a puffer type switch.

A gas-insulated low- or medium-voltage switch for system voltages within 1 to 52 kV and for up to 2000 A rated current includes first and second contacts being movable in relation to each other along an axis of the switch and defining a quenching region in which an arc is formed during a current breaking operation; and an arc-extinguishing system for extinguishing the arc during the current breaking operation. The arc-extinguishing system may include a pressurization system with a puffer chamber, and a nozzle system connecting the pressurization system with the quenching region, the nozzle system having a nozzle at its outlet for blowing the pressurized quenching gas onto the arc formed in the quenching region during the current breaking operation; and a swirling device configured for generating a subsonic swirl flow of a quenching gas onto the quenching region during the current breaking operation, wherein the swirling device is arranged at an entrance of the nozzle system. The arc-extinguishing system further includes a swirling device configured for generating a subsonic swirl flow of a quenching gas onto the quenching region during the current breaking operation, wherein the swirling device is arranged at an entrance of the nozzle system.

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.