Abstract: An electrical power cord disabling jack for preventing unauthorized use of an electrical appliance. The disabling jack may be provided in a kit and is a symmetrical device having an electrical cord with a male electrical plug at each end thereof. The electrical appliance is modified by removing a conventional male plug from the end of its cord, and installing a female receptacle in place of the male plug. The appliance may be activated by connecting the female receptacle of the appliance to one end of the disabling jack, and plugging the opposite end of the jack into a conventional female receptacle or outlet. A ground fault interrupter device may be installed inline between the two male plugs of the disabling jack as a safety feature. Alternatively, the jack may be provided with an automatically extending safety guard which covers the otherwise exposed electrical contacts of the jack when it is not plugged in to an outlet or other female receptacle.