The instant invention discloses a receptacle where the surface of the face along its width is flat in one plane and along its length has a constant radius. The shape of the face of the receptacle allows for the proper seating of an inserted plug. The receptacle is adapter to be located in a wall plate having a vertical axis of positive first differential and zero second differential, comprised of a combination of splines drawn between points of varying distance from a datum plane and zero second differential when the rate of height increase of individual splines is constant. The receptacle can be placed next to a switch, the front face of which follows the shape of the wall plate.