Abstract: An electric plug including a disabling mechanism to preclude unauthorized use of the plug. The disabling mechanism includes a key cylinder lock assembly including a cam member rotated in response to rotation of the key cylinder, a pair of conductive track strips extending from a cord inlet to a location proximate the prongs of the plug, an insulative block mounted for linear sliding movement within the hollow of the housing of the plug between open and closed positions, and a pair of conductive contact strips carried by the insulative block and each including a portion slidably engaging a respective track strip and a portion movable into electric contact with a contact portion of a respective prong in response to movement of the insulative block to a closed position in response to rotation of the key cylinder lock.