A manually switched Testguard circuit with auto-monitoring and end-of-life circuitry is provided. The manually switched Testguard circuit interrupts the flow of current through a pair of lines, wherein one of the pair of lines extends between a line input and a line output and the other line extends between a neutral input and a neutral output. The manually switched Testguard circuit includes a monitoring module for detecting an end-of-life condition. The monitoring module includes a simulated ground fault generator for simulating a ground fault; an auto-monitoring logic module; a relay synchronized switch; and an end-of-life switch for disabling the manually switched Testguard circuit if certain Testguard component failures are detected.