There is disclosed a wall plate for a wiring device. The wall plate has a single opening for receiving one or a gang of two or more wiring devices within the single opening. The wall plate has along its vertical axis, a surface of positive first differential and zero second differential, comprised of a combination of splines drawn between points of varying distance from a datum plane. The surface has zero second differential when the rate of height increase of individual splines is constant. The wall plate, when composed of non-conducting material, has a conductive coating on its front surface, on its back surface or on both its front and back surfaces. When the wiring device is a switch, the surface of the switch face follows that of the wall plate. When the wiring device is a receptacle, the surface along the receptacle face is flat in one plane to allow for the proper seating of an inserted plug.