Enclosed busbar trunking (or simply busbar trunking) is a busbar system composed of a metal plate (steel or aluminum plate) as the protective shell, conductive bars, insulation materials, and related accessories. It can be manufactured as a plug-in type enclosed busbar with junction boxes at intervals, or as a feeder type enclosed busbar without junction boxes in the middle.
In the power supply systems of high-rise buildings, power and lighting circuits are often installed separately. Busbar trunking, as the main power supply line, is installed vertically along the wall in electrical shafts, one or more runs. Depending on its purpose, a typical run of busbar trunking consists of a starting busbar, a straight-through busbar (with and without sockets), an L-shaped vertical (horizontal) bend busbar, a Z-shaped vertical (horizontal) offset busbar, a T-shaped vertical (horizontal) tee busbar, an X-shaped vertical (horizontal) four-way busbar, a variable-capacity busbar, an expansion busbar, terminal end caps, a terminal junction box, a plug-in box, related accessories, and fastening devices. Busbar trunking can be classified into three types according to its insulation method: air-insulated plug-in busbar trunking, compact insulated plug-in busbar trunking, and high-strength plug-in busbar trunking. According to its structure and application, it can be classified into compact insulated, air-insulated, air-supplemented insulated, fire-resistant, resin-insulated, and sliding-contact busbar trunking. According to its outer shell material, it can be classified into steel-shell, aluminum alloy-shell, and steel-aluminum hybrid-shell busbar trunking.
