Busbar trunking is a busbar system composed of metal plates as protective shells,conductive bars,insulation materials,and related accessories.It 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 busbar trunking system has been included in the IEC international standards,which play an important role in regulating the design and testing basis of busbar trunking products.Copper conductors for bus ducts should be made of purple copper because the purity of T3 copper is generally not high(T3 copper is usually made from recycled copper waste),and the resistance cannot meet the requirements of conductivity.Therefore,it is necessary to use purple copper,and the higher the content,the better.With the intensification of market competition,some manufacturers use high-purity brass as a substitute to reduce costs.Such bus ducts have poor electrical performance and are prone to high temperature rise,short circuits,and even accident losses during use.

　　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.However,the vast majority of manufacturers on the market use flash plating for surface treatment when the coating thickness is not specified.Although the treatment cost is reduced,there is no significant improvement in the corrosion resistance of the busbar,resulting in corrosion and oxidation of the busbar in just a few years of use,greatly reducing its electrical performance.Even some manufacturers use tin plating on both ends and no plating in the middle to deceive consumers.Using this method,the busbar has no significant effect on anti-oxidation.

　　The interchangeability of bus ducts is often poor.If the joints are not smooth and the space for tightening the connecting bolts is too small,the installation will be more time-consuming and laborious;In addition,the installation requirements for bus ducts are quite strict.During installation,collision and knocking should be avoided,and the connecting bolts should be tightened appropriately.Over tightening or loosening can cause hidden dangers and also affect the service life of bus ducts.Therefore,experienced technical workers must be present to complete the installation.During the operation of the bus duct,it is hot and cold,and the insulation layer releases moisture when it is hot.When it cools down,it absorbs moisture,which can lead to a decrease in insulation quality.