What are Junction Boxes for? Junction boxes are designed to contain wires such as neutral (white), hot (black), and grounding (green or copper). By: Thor, Senior Electrical Engineer at Weisho Electric Co. Thor specializes in R&D and overseas technical support for high-voltage cable junction boxes and other power distribution equipment. Single screw terminals: these terminals bring all the cables (e. coaxial cables) into one connector point, joined together by a single screw (using a good. This guide explains junction box types by use, material, shape, installation method, and environment, while highlighting safety codes and selection considerations.