Patent ID: 7289309

Claim:
An apparatus for disconnection of a live electrical conductor having an enclosure; two power connections which are passed out of the enclosure; and a low-impedance conductor section which electrically conductively connects the two power connections to one another in an enclosure interior, and a propellant means, which are arranged in the enclosure interior for producing an amount of compressed gas which is sufficient to disconnect the conductor section when a fault current occurs, wherein there is provided a spark gap which is connected in parallel with the low-impedance conductor section in the enclosure interior, and into which a current exceeding a limit value is branched from the low-impedance current section, and wherein the propellant means is kept free of combustible substances and is chosen in such a manner that the amount of compressed gas which is required for disconnection can be thermally released from the propellant means by the electrical work produced by a fault current occurring between the two power connections, and comprises at least one of an additive which can develop the compressed gas as a result of vaporization, and a material which can form the compressed gas as a result of chemical decomposition, wherein the spark gap comprises a hollow electrode having a section for receiving a root of an arc, which section has a wall thickness that allows the arc to act on the propellant means when the arc work is above a predetermined value.