The low copper content of copper bars is indeed related to the current carrying capacity of bus ducts.If the copper content is low,the resistivity will be high,and only by increasing the conductor specifications can the current carrying capacity and temperature rise be ensured.Otherwise,the temperature rise will be too high.For some projects with overload operation,as the equipment increases and the load increases,or the originally designed busbar cannot meet the on-site needs,it is generally necessary to not only select the busbar,but also pay attention to the selection of related components of the busbar when selecting the busbar.Some projects use variable capacity section when ordering for construction,but do not take effective protective measures.When operating under overload,the temperature rises,and the switch at the beginning of the variable capacity cannot ensure the overload of the small current after the variable capacity,thus posing hidden dangers.

　　The insulation material and shell structure have good heat dissipation and processing technology.The conductors of bus ducts with good insulation material heat dissipation can meet the current carrying requirements after discounts according to the design manual or electrician's manual.However,some products use resin casting insulation materials or other insulation materials with poor heat dissipation,as well as air type bus structures.Dense bus structures with poor heat dissipation require more discounts.Some product structures and insulation materials have poor heat dissipation,and the conductors are selected according to the electrician's manual at an ambient temperature of 30℃,misleading users.It is understood that some of these products can only achieve a current cutoff capacity of 60%to 70%.

　　The internal conductivity,resistivity,and copper plate purity of the bus duct are shown in the table.All insulation materials are made of high-quality polyester film,fully formed and wrapped,with no interface or air bubbles in the middle.The insulation is pressure resistant and has a heat resistance level of B.A third-party inspection report and relevant proof materials are required.The insulation withstand voltage parameters and heat resistance levels of the bus duct are shown in the table.The shell and side plate of the busbar trunking system are made of high-quality aluminum magnesium alloy material,and the surface should be treated with anti-oxidation.The shell should protect the continuity resistance of the circuit,and a third-party inspection report and relevant supporting materials should be provided.Before the maintenance of busbar trunking accessories,it is necessary to conduct a power outage inspection of the busbar trunking system,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 energized.Avoid serious accidents where high voltage can cause physical injury or even death to operators.

　　During the operation of busbar trunking accessories,it is necessary to continuously check whether there are any leaks,water sprays,or potential moisture sources near the entire heating frame system.Are there any heavy objects that pose a threat to the system,as well as heat sources that affect the temperature rise of the bus duct system.Unstable connection of the connector,increased electrical resistance of the connector,unstable connection of the connector,poor contact of the connector,and increased electrical resistance can all cause an increase in temperature rise of the bus duct.Check for any damage or rust on the components of the busbar trunking system,and ensure that the support springs have appropriate elasticity.Replace them immediately if any problems are found.During the temporary operation of the busbar trunking accessories,check the temperature rise of the joints once a year and inspect all busbar trunking joint connecting bolts and conductive contacts for any signs of looseness.