The present invention provides an engineered closed wall system that includes one or more preinstalled conduits installed during fabrication of the closed wall system and an associated box that is positioned to intersect the preinstalled conduit at a standard connection port of the box and in a predetermined location. The location of the conduit and/or box can vary according to job-specific requirements. Advantageously, the conduit can be installed equidistant from the first and second outward layers. Specific boxes, and any ring extensions mounted to the boxes, can be sized to flexibly mount from either outward layer and still be substantially flush with the face of the outward layer and still intersect the conduit at a standard connection port provided on the box.