Abstract: A molded plastic electrical outlet box having improvements relating to a plurality of webs for attaching a cable entry aperture knockout panel to the box wall structure defining a given aperture, a strip of flashing connected about the knockout panel, and a pattern of protrusions defined on the exterior face of each knockout panel. The attachment webs are located in a four point, balanced arrangement adjacent to the respective corners of the generally rectangular panel. Thus, any knockout force applied to the panel by the tip of an instrument, such as a screwdriver, will always be directed between the locations where the panel is anchored to the wall structure and tend to result in detachment of the panel. The protrusions can take any one of a variety of patterns, such as a knurled pattern or a multiplicity of cylindrical-, pyramidal- or tetrahedral-shaped projections, to define non-skid surfaces which prevent the tip of the instrument delivering the knockout force from slipping upon impact with the panel.