Self-blowout circuit breaker having a filling and overpressure valve

A self-blowout circuit breaker is disclosed which includes contacts for connecting or disconnecting a circuit, a heating volume, a compression volume and an exhaust volume. The compression volume can be connected to the heating volume by at least one first valve, which heating volume is in turn connected to an arc zone. Upon the disconnection of the circuit, while a first arcing contact is being disconnected from an associated second arcing contact, an arc is produced between the two arcing contacts in the arc zone. The compression volume is separated from the exhaust volume by a combined filling and overpressure valve which is formed as at least one plate, and has at least one tab which is formed in the plate.