A fail safe feature for long life reduced voltage lamps including diodes id disclosed. As known, a low wattage lamp may designed for longer life by using a lower root mean square design voltage. The root means square voltage of the alternating source current may be lowered by including a rectifying element, and a fuse may be included in series with the lamp to safely interrupt the circuit. By further including a one-way shunt oriented oppositely to the rectifier, in parallel with the lamp, and intermediate the rectifier and fuse, on failure of rectifier, unrectified current blows the fuse. If the rectifying diode fails, substantially all of the current is shunted to the fuse during the failed half of the current cycle, thereby blowing the fuse, and safely failing the lamp.