Compared with ordinary cables,bus ducts have shown strong advantages as the main power supply line.However,over time,operational practice has shown that bus ducts themselves have many irreparable defects,so bus ducts are not ideal power supply products as the main power supply line.Before the maintenance of the busbar trunking,it is necessary to conduct a power outage inspection of the busbar trunking system,completely block all power sources of the busbar trunking,and use a multimeter to measure whether there is voltage in the conductive body.Routine maintenance can only be carried out after confirming that the busbar trunking system is not electrified.Avoid high voltage causing physical injury to operators.

　　Busbar trunking is expensive,requires a large installation area,has a long installation cycle,and is labor-intensive,resulting in a significant initial investment.It is widely recognized that plug-in bus ducts are expensive,such as a set of three-phase four wire system with a layer height of 3m and a main current of 100A.A plug-in bus duct with a branch connection costs around 2000 yuan.Due to the special installation environment and requirements for busbar trunking,a dedicated electrical shaft should be left in the building.For a high-rise building,the area occupied by the electrical shaft from top to bottom is considerable,which increases the investment in civil engineering;The bus duct is installed section by section,with each section weighing nearly 100 kilograms.The installation and positioning rely entirely on manual labor,and the labor intensity can be imagined;Due to different floor heights and current levels,the interchangeability of bus ducts is often poor.If the joints are not smooth and the space for tightening the joint 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.The production method of busbar trunking is mostly manual,and the product quality cannot be controlled and guaranteed.In addition,there are too many joints,resulting in many fault points,so its power supply reliability is poor.There are many manufacturers of bus ducts in China,mostly in southern provinces and cities,especially Yangzhong City in Jiangsu Province,which can be called the hometown of cable trays and bus ducts.But among many manufacturers,there are only a few that can truly achieve scientific management and high-quality production of bus ducts,and the vast majority are shoddy.

　　When the bus duct operates for a long time,the joint temperature rise should be checked regularly once a year.The joint temperature rise should not exceed 70K according to the specifications to be qualified(the ambient temperature is 40 degrees).Check if there are any signs of looseness in the connection bolts and contact areas of all bus duct joints.Avoid causing the connector to generate heat due to increased resistance caused by looseness.Check if there are signs of aging in the insulation material and if there are signs of melting and deformation in the conductive area.If there is a phenomenon of phase to phase grounding or insulation breakdown,it should be removed in sections and checked in sections with a voltage tester to find the problem,or the bus duct should be replaced from scratch,or insulation coating should be carried out from scratch.Check if the plug box pins of the bus duct system can touch the busbar.