Octagon and Round Electrical Boxes The Spruce / Margot Cavin Octagon and standard-size round boxes range from 1 1/2 to 3 inches deep and are the standard box for ceiling- or wall-mounted light fixtures weighing up to 50 pounds. They provide much more room for wiring than shallow round pan boxes and can be used as junction boxes.Can you use PVC conduit with metal boxes?
Yes . you can put a PVC pipe into a metal box. Like said above, you must run a ground wire in this circuit. Whenever you use plastic conduit you need a ground wire, and it must be attached to the metal box unless it just passes thought it.What are electrical junction boxes used for?
Junction box can do a whole lot of functions. It is used for joining wires, add lighting points, attach extra sockets to circuits, and expand circuits as well. It provides a safe passageway for getting power from an electrical circuit and taking it to another point safely.