- Box openings should match the conduit diameters, and flush-mounted distribution box covers should fit closely to the wall with intact coatings. - Boxes should be made of non-combustible materials. Covers wiring, placement, standards, and expert tips for a compliant setup. Accessibility is one of the most. In modern electrical systems, cable distribution boxes (also known as electrical distribution boxes or distribution boxes) play a crucial role as the key hub for managing, distributing, and protecting circuits. It receives power from the main electrical supply and divides it into separate circuits, each. In just a few steps you will find the wiring and assembly plan, including complete documentation in accordance with standards.