A closed busbar duct,also known as a busbar duct,is a busbar system composed of metal plates,steel plates,aluminum plates,etc.,insulation materials and related accessories to protect the shell.It can be made into a plug-in type enclosed busbar with plug-in junction boxes at regular intervals,or a feeding type enclosed busbar without a junction box in the middle.With the development of technology and the extensive application of copper resources,the development direction of enclosed bus ducts may shift towards copper aluminum or aluminum enclosure.Of course,with the emergence of new materials,there may also be products that can replace copper bars,greatly reducing the amount of copper used and the cost of enclosed bus ducts,making them more widely used.

　　The outer shell of a closed bus duct is generally made of aluminum alloy or steel.The main function of the outer shell is to protect the bus inside the shell.The outer shell is treated with multiple processes such as acid washing,phosphating and drying,powder coating and solidification.The outer shell is sprayed with polyester epoxy powder,which has strong surface adhesion and can maintain insulation for a long time.Copper bars are made of pure oxygen free copper to form busbars,and the end surfaces of the busbars are treated with special tin or silver plating to maintain good conductivity and contact surface.The interphase insulation material is composed of polytetrafluoroethylene,polycarbonate high-strength insulation plastic blocks,polyester imine,etc.

　　The enclosed busbar trunking was introduced and introduced from China in the 1980s.Based on the air type busbar trunking,the conductive copper bars were insulated with polytetrafluoroethylene tape to form the initial enclosed busbar trunking.However,PTFE has a fatal disadvantage,that is,it can tap toxic gas at high temperature,and the quality also varies greatly.The products produced sometimes fail to meet the standard.Later,radiation cross-linked flame retardant tape appeared.This material has a working temperature of 150 degrees,good waterproof performance,elasticity,and compactness of wrapping.A new type of insulation material is polyester imide,with an insulation grade of H,which is good for aging resistance and long life.

　　In order to avoid factors such as excessive cable laying and coordination difficulties in the use of enclosed cable trays in power,a one-time method should be adopted to transfer DC power from the power room to the load room side.The use of enclosed bus ducts in the DC power supply system of the computer room is an effective way to reduce the use of cables.It has the characteristics of strong heat dissipation,environmentally friendly products,and flexible wiring.It has practical application significance in the comprehensive building of centralized power supply mode.Its structure and usage are divided into dense insulation,air insulation,air additional insulation,fire-resistant,resin insulation,and sliding contact bus ducts;According to its shell material,it is divided into steel shell,aluminum alloy shell,and steel aluminum mixed shell bus duct.At present,this solution has been increasingly applied in operational business rooms.