Abstract: A wafer-like body of electrical insulating material having three prong-receiving apertures therethrough configured and disposed to receive the two power line prongs and the ground prong of a standard three-prong electrical plug. Embedded within the wafer-like body is a contact device of resilient electrically conductive material, part of which is exposed in the ground prong aperture so as to yieldably interfere with the ground prong and make sustained electrical contact therewith when the prongs of the plug, which are insulated from one another, are passed through their respective receiving apertures enroute to being inserted into corresponding sockets of a grounded power outlet. A connection can thereby be made from the outlet ground to the contact device via the ground prong of the plug.