A controller for a safety shut-off system is taught. The controller is for a system that interrupts a supply of electricity to an electrical appliance upon detecting a trigger. The controller includes a housing having a cover with an electrical socket, which is configured to receive an electrical plug electrically coupled to the appliance. The controller also includes interrupter circuitry contained within the housing, which is electrically coupled to a power supply and to the socket, and which is configured to decouple the power supply from the socket upon receiving a trigger signal. The trigger signal is generated in response to a safety hazard associated with the electrical appliance.