High-voltage electrical circuit breaker device with optimised automatic extinction

A self-blast electric interrupter device (1), such as a circuit breaker (1) or a disconnector, the device comprising:

• a first contact (3) and a second contact (4) extending in line with each other, at least one of the contacts being movable in translation relative to the other contact between a closed position in which the two contacts press against each other, and an open position in which the two contacts are spaced apart from each other;
• an arc-control chamber (11) surrounding the two contacts in order to define a space that is closed when the contacts are in the closed position;
• a central channel (12, 13) in at least one of the contacts (3, 4), each central channel (12, 13) opening out towards the other contact (3, 4) while being designed to enable the gas coming from the arc-control chamber (11) during a stage of opening the device to be discharged;
• and
• an insulating member (14) carried by the other contact and engaging in the channel (12, 13) in the closed position, this insulating member (14) extending between the two contacts (3, 4) in the open position;
• and
• wherein the insulating member (14) is made of a material that ablates under the effect of the heat generated by an arc (A) that becomes established between the contacts (3, 4) during an opening stage so as to increase the rise in pressure that occurs in the arc-control chamber (11) in the event of such an arc (A) appearing during a stage of opening the circuit breaker.