Plastic enclosure box for electrical apparatus

A plastic load center box economically provided by duplicate molded end sections joined by an intermediate section of uniform cross-section which is readily provided in selected lengths in either molded or extruded form. End walls receive metal inserts electrically interconnected to provide grounding when attached to grounded conduit, or plastic inserts where the load center application does not require grounded conduit. Molded end sections have formed knockouts and wire clamping tabs. A metal cover for the box is grounded to the metal inserts or to the interconnection. Additional plastic inserts in the end walls provide forwardly open pockets in which cable may be laid, and closing inserts overlying the pockets to grip the cable and retain it in the pockets.