Patent ID: 8026443

Claim:
An electrical enclosure comprising: a plastic housing having a wall member defining an inner surface and an outer surface; a knockout opening formed in the wall member, wherein the wall member defines an annular recess that surrounds the knockout opening, wherein the annular recess is defined in part by an outer wall and a floor; an annular rim defined by the wall member, wherein the annular rim is located within the recess and surrounds the knockout opening and extends outwardly from the floor of the recess at a location spaced inwardly from the outer wall of the recess; and a plug removably engaged with the wall member within the recess, wherein the plug is configured to cover the knockout opening and defines an outwardly facing surface and an inwardly facing surface, wherein the inwardly facing surface includes an annular groove within which the annular rim is engaged, and wherein the plug and the annular recess define a serpentine interface, which includes an interface between the annular rim and the annular groove, between the outer surface of the wall member and the inner surface of the wall member at the knockout opening.