Abstract: Safety back-up and alarm circuit for loads such as electrical heaters and the like comprising a back-up substitute load for the primary load, e.g., an electric heater, switching circuits responsive to outputs from the primary and back-up loads, and which automatically replace the primary load with the back-up load upon failure of the primary load, said switching circuits including a circuit which reliably reads the output from the primary load and distinguishes failure of the primary load from mere non-load -- including impedance in the primary load circuit, a primary alarm element, e.g. a lamp, bell, or buzzer responsive through said switching circuits to a failure of the primary load and an energizing of the back-up load and a secondary alarm element, e.g. a bell or buzzer responsive to a failure of said back-up element.