During long-term operation of the bus duct,the temperature rise of the joints should be regularly checked once a year.The temperature rise of the joints should not exceed 70K according to the standard(the ambient temperature is 40 degrees)to be qualified.We check whether there is any looseness in the connecting bolts and conductive contact parts of all bus duct joints to prevent the increase in resistance caused by looseness from causing the joints to heat up.Check whether the insulation material has aged,and whether the conductive part of the continuous mixer has melted and deformed.

　　If we find that there is phase to phase grounding or insulation breakdown,we should dismantle them in sections and use a voltage tester to inspect them in sections to find the fault,or replace the bus duct,or re coat the insulation.Check if the plug box pins of the bus duct system are in good contact with the busbar.During the operation of the busbar trunking,it is necessary to continuously check whether there are leaks,water sprays,potential sources of moisture around the entire system,whether there are any organisms that pose a threat to the system,and whether there are heat sources that affect the temperature rise of the busbar trunking system.The cone screw mixer should be checked for foreign objects entering the inside of the busbar trunking,whether the components of the busbar trunking system are damaged or corroded,and whether the support springs have appropriate elasticity.If any problems are found,they should be replaced immediately.

　　Under the same load,the material cost of branch cables is significantly reduced compared to bus ducts.Especially for bus ducts of 630A and below,using branch cables of the same current level can significantly reduce material costs.Combined with convenient installation,it saves on-site construction labor and greatly reduces the overall construction cost.Of course,branch cables can currently only achieve a cross-sectional area of 1000mm and a rated current of around 1600A,while bus ducts can achieve a rated current of 5000A.Moreover,branch cables with current levels of 800A and above will not have a price advantage.So,for large capacity distribution lines,the application of branch cables also has its limitations.

　　When connecting bus ducts with bolts,it is necessary to ensure a moderate joint torque,which requires high demands on installation workers.Ordinary bus duct manufacturers do not have any requirements for this aspect during on-site installation,and installation personnel only use ordinary wrenches to tighten bolts based on feeling.In fact,on-site bolt connections that are too tight or too loose can potentially affect the intrinsic performance and quality of the busbar.Due to the flexible structure of branch cables and the rigid nature of bus ducts,the installed bus ducts may feel overwhelmed by the swaying and shaking of the building.When there is a large deviation,it may affect the quality and safety of the bus ducts.However,when dealing with this phenomenon,branch cables may appear to have excess flexibility.