Self-extinguishing breakers of the HB range are used for current from 630 A to 2500A and for rated breaking currents up to 40 kA. During the opening operation the current flows through a cylindrical coil, the magnetic field of which causes the arc to rotate on the quenching contacts in the breaker pole. The temperature of the arc causes the gas pressure in the extinction chamber to rise, and the resulting stream of gas extinguishes the arc in accordance with the current flow.