Bus ducts can be equipped with plug-in junction boxes at regular intervals for plug-in enclosed busbars,or they can be made into feeding enclosed busbars without junction boxes in the middle.In the power supply system of high-rise buildings,the power and lighting lines are often set separately,and the bus duct is installed vertically along the wall in the electrical shaft as the main power supply line.Due to the shell being made into a tile groove form,the pit groove position intentionally separates and fixes the busbars,with a spacing of 18mm between the busbars.The ventilation between the lines is good,which significantly improves the moisture-proof and heat dissipation functions of the busbar trough,making it more suitable for the southern climate.

　　The manufacturing process of busbar trunking is not limited by sheet metal,and the shell is made in the form of tile grooves,which increases the mechanical strength of the busbar.The horizontal section of the busbar can be produced up to 13m long.Due to the gap between the wires,the temperature rise of the wires decreases,which increases the overload capacity and reduces magnetic oscillation noise.However,the stray current and inductance generated by it are much larger than those of dense bus ducts.Therefore,when comparing with the same specifications,its conductive cross-section must be larger than that of dense insulated plug-in bus ducts,which have poor moisture-proof and heat dissipation effects.

　　Due to the use of copper sheet soft joints for transition between busbars,oxidation is prone to occur between the joints in humid weather in the south,resulting in poor contact between the joints and busbars,making the contacts prone to heating.Therefore,it is rarely used in the south.And the volume between the joints is too large,the horizontal bus segment size is inconsistent,and the appearance is not aesthetically pleasing.During construction,busbars are prone to moisture and water seepage,causing a decrease in insulation resistance between phases.The heat dissipation of the busbar mainly relies on the shell,resulting in a high temperature rise in the busbar duct.The dense insulation plug-in bus duct is limited by the shell plate and can only produce horizontal sections no larger than 3m.

　　Due to the small air gap between the busbars,a strong electric force is generated when the busbars pass through high currents,causing the magnetic oscillation frequency to form a superimposed state and resulting in excessive noise.Plug in busbar trunking belongs to the trunk system,which has the advantages of small volume,compact structure,reliable operation,high transmission current,easy tapping and feeding,convenient maintenance,low energy consumption,and good dynamic and thermal stability.It is widely used in high-rise buildings.The sub interface of the bus duct can add sub circuits,and the cables need to be laid from the distribution room.Bus ducts can be controlled at a location close to the equipment,while cables need to be controlled in the distribution room.