Electrical boxes are often required to be installed within a wall surface such that the front face of the electrical box is generally flush with the finished wall surface. For example, electrical codes may limit the distance that the front face of an electrical box can be recessed from the finished surface of a wall to no more than one-quarter of an inch. To meet these requirements, electrical boxes may be required to be installed in different configurations depending on the thickness of a metal stud, thickness of a wall surface, and distance from the metal stud (or other mounting surface).
USPTO Backgrounds
USPTO Backgrounds