The material of the conductor for busbar trunking accessories generally includes copper,aluminum plated with copper,aluminum,and copper-clad aluminum.Nowadays,most of the projects in our country choose copper,while in South Korea,Europe and America,the use of aluminum conductors has been increasing in the past two years.The cost difference between using copper and aluminum for busbar trunking accessories is very small.Due to the fact that using aluminum conductors requires nearly twice the size of the shell and insulation materials,the price difference is also very small.Using copper and aluminum does not make much sense,so at that time,most projects chose copper conductors as the correct choice.However,with the soaring price of copper,it is now three times the price of aluminum,and the weight of copper is also three times that of aluminum.

　　The major difference in busbar trunking accessories refers to the differential circuit composed of all branch currents except for the bus tie switch and section switch.The small difference of a certain section of busbar refers to the differential circuit composed of all the branches connected to the busbar,including the busbar and section switches,and the current.The large difference ratio differential of the busbar is used to distinguish between faults within and outside the busbar area,while the small difference ratio differential is used for the selection of fault busbars.Usually used in dual mother protection,the large difference is used as the initiating component to distinguish the shortcomings within the area;As a component for selection,distinguish the shortcomings on which bus.The difference between the large and small differential actions in the differential protection of the busbar is that in the small differential action,the busbar switch will be tripped at the first limit,and then all switches connected to the same busbar as the defective equipment will be tripped.

　　The major action is to trip all switches within the same time limit,regardless of which bus the equipment is attached to.Under normal dual mother operation,the input is small and selective.During the process of reversing the busbar,the busbar difference is set to a large difference to avoid the protection misoperation caused by the circulating current during the operation of the parallel knife switch.The major difference is more of a starting component,and the key is to choose the faulty busbar based on the minor difference,and then take action.As for the protection plan,the major difference is non selective.The protection plan consists of two busbars,while the minor difference is selective,which can distinguish which busbar has a disadvantage.The protective action will trip all switches and bus tie switches on the defective busbar.

　　The fire-resistant busbar trunking accessories are equipped with highly fire-resistant insulation and non combustible epoxy resin powder sprayed on the busbar.The accessories are fire-resistant insulation parts.Specially processed parts such as busbar connectors,plug-in boxes,and busbar trunking accessory shells have fire-resistant properties that comply with fire resistance standards.Low voltage distribution main lines such as fire pumps,fire elevators,and emergency generators should be equipped with fire-resistant busbar trunking fittings to ensure power supply in case of fire and facilitate fire recovery.