Abstract: Disclosed is a circuit breaker switch configuration in which a conducting member in the switch for connecting a switch terminal to a switch contact is shaped to form a loop current path, such that when a current flows in the switch, a magnetic field is established in the vicinity of the switch contacts. Such a magnetic field, which is appropriately oriented, serves to confine a plasma generated by an arc discharge which occurs between the switch contacts when the switch is initially opened. The confinement of the arc discharge plasma by the magnetic field reduces the extent of the plasma and permits the use of smaller arc-extinguishing means in the switch and affords more rapid extinguishment of the arc discharge.