Phoenix Contact 0915033 A thermal-magnetic circuit breaker is a type of electrical switch that automatically trips to disconnect power when it detects excessive heat, suitable for two-pole operation. It features one normally open (N/O) and one normally closed (N/C) contact, allowing for the connection or disconnection of circuits as needed. The universal foot on this device enables it to be mounted on either NS 32 or NS 35 surfaces, providing flexibility in its installation.