Abstract: A heat generating device, such as an oven, includes a heating element connected to a power source and a fuse interposed therebetween. The fuse is effective, when the magnitude of the current flowing thereto exceeds the fuse rating, to disconnect the element from the source. A thermostat is included in the circuit to control the current flow and, thus, the temperature level. In the event of a malfunction of the thermostat, temperature responsive means are effective, when the temperature sensed thereby exceeds a given level, to increase the current flowing through the fuse beyond the fuse rating. The temperature responsive means includes a temperature sensitive switch and a resistive element which may be a second heating element. When the switch is closed by excessive temperature, the resistive element is placed in parallel with the heating element, thus lowering the effective resistance of the circuit to increase the current.