POWER SUPPLY INTERRUPTION SYSTEM

PURPOSE:To prevent inadvetent turn ON of power after removal of housing cover by optically detecting the fixing state of the housing cover and interrupting power supply according to the detection results. CONSTITUTION:When a cover 7 is fixed to a housing body, optical energy emitted from the light emitting section 311 of a photoreflector 31 is reflected on the housing cover 7 to be fed to the light emitting section 312 of the photoreflector 31. Upon removal of the housing cover 7 from the housing body 8, optical energy is not fed from the light emitting section 311 to the light receiving section 312 of the photoreflector 31 and the light receiving section 312 is brought into nonconducting state. Consequently, the terminals T46, T47 of the switching control circuit 41 in a DC stabilized power supply circuit 4 are brought into nonconducting state and no power is outputted therefrom.