Abstract: An electric heater fault detector for a rail of a railroad track is disclosed. The detector includes a power resistor electrically connected to the rail and a voltage breakdown device connected in series with the resistor to ground. The voltage breakdown device has resistance characteristics of high resistance at low voltages and low resistance at high voltages, and is preferably a metal-oxide varistor. In the event that an electric heater case applies a high voltage from a short in the electric heater to the rail, then the voltage breakdown device conducts and the power resistor and voltage breakdown device provide a path to ground for the rail. The electric heater fault detector may further include a ground fault circuit interrupt attached to the heater, whereby the ground fault circuit interrupts the application of voltage to the heater when it detects a difference in the current to the heater.