Copper bars or aluminum alloy bars are generally used as conductors for bus ducts.To prevent oxidation on the surface of the bus bar,tin plating or silver plating is applied to the surface of the bus bar.The surface treatment of the busbar trunking is carried out by flash plating,which reduces the treatment cost,but does not significantly improve the corrosion resistance of the busbar.As a result,the busbar trunking undergoes corrosion and oxidation within a few years of electrical use,greatly reducing its electrical performance.Bus duct is a bus system composed of metal plates as protective shells,conductive bars,insulation materials,and related accessories.

　　Bus ducts can be made into plug-in enclosed busbars with plug-in junction boxes at regular intervals,or 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.The resistance cannot meet the requirement of conductivity,so it is necessary to use copper,and the higher the content,the better.The busbar trunking has poor electrical performance,and during use,it is also prone to excessive temperature rise,even short circuits,and accident losses.

　　When selecting and applying bus ducts under different environmental conditions,different types and materials of bus ducts should be considered.For various bus ducts,the section of the bus duct should usually be selected according to the long-term operating current.Due to factors such as the resistance of conductors and the AC current meter effect when multiple conductors approach each other,heating can occur when current passes through the bus duct.The allowable temperature for heating during long-term operation of copper and aluminum bare bus ducts is 70℃,but when there is reliable tin coverage at their contact surfaces,the temperature can be increased to 85℃.

　　Due to the limitation of the allowable temperature for continuous heating,bus ducts of different materials and cross-sections are given corresponding long-term allowable current values.When selecting the section of the bus duct,the actual long-term operating current of the bus duct should be lower than the long-term allowable current value of the selected section of the bus duct.Use a channel steel bracket to support the bus duct,and use round steel as a hoop to fix the bus duct on the channel steel bracket.The two ends of the channel steel bracket are connected to the embedded parts on both sides of the transformer room wall with bolts.When the bus duct is improperly installed and subjected to twisting stress or the influence of bus short-circuit electric force,there is a possibility of the bus duct shaking left,right,or up,which will cause damage to the low-voltage bushing of the transformer connected to the cable tray bus duct or oil leakage at the rubber sealing ring at the root of the bushing.