If the measures adopted in the bus duct can ensure that the circuit has long-lasting good conductivity,and the current carrying capacity is sufficient to withstand the grounding fault current flowing through the complete equipment,then the various metal components of the assembled complete equipment are considered to effectively ensure the continuity of the protective circuit.Cables are represented by cross-section,while bus ducts are represented by rated working current(generally referred to as 400A bus ducts).Similarly,domestic products with 400A have a cross-section of 240mm,while some only have 180mm.The difference is too large,so there are some that cost 1.4 yuan/ampere x meters,2.0 yuan/ampere x meters,and there are also good ones.It is recommended to request the manufacturer to provide an explanation of the insulation method and label the busbar specifications to avoid being deceived.

　　The traditional protective earth wire PE line is placed on one side of the bus duct.Due to electromagnetic induction,the fault current induced on the protective earth wire is 50%higher than calculated by actual measurement.At the same time,the distance between the three-phase conductive rows and the PE line is uneven,and the inductance is also uneven.When the line is long,the three phases are severely unbalanced under fault current.Using non-magnetic material aluminum alloy shell with good conductivity as the protective ground wire,it is surrounded by the conductive busbar.Due to its proximity to the three-phase busbar as much as possible,it can achieve low reactance,and the distance between the protective ground wire and the three-phase busbar is equal,with the same reactance.In this way,whether it is a short-term or continuous relative ground short circuit fault,this grounding method is better than setting up a separate PE row.Therefore,the International Electrotechnical Commission has announced and advocated the use of enclosures as grounding conductors for electrical busbars(bus ducts).

　　Reinforced aluminum alloy shell design,the shell is made of aluminum magnesium alloy profiles,consisting of two side plates and upper and lower cover plates.The side plates are designed with heat dissipation fins and dovetail grooves,which not only facilitate the heat dissipation of the bus duct,but also enhance the rigidity of the shell and facilitate installation.At the same time,it reduces the weight of the bus duct,allowing for large-span design and reducing installation brackets.Screw free assembly technology,the connection between the upper and lower cover plates of the shell and the side plates does not require screws,rivets,or welding,but instead uses hooks and grooves.Due to the lack of holes on the shell,water,gas,and dust cannot enter,which improves the protection level and has a very beautiful appearance.The aluminum profile shell has much better anti-corrosion performance after anodizing for 10u and galvanizing.Long term atmospheric exposure tests on different grades of aluminum alloy sheets and galvanized copper plates in Japan show that the corrosion depth of the former is about one twentieth of that of the latter.

　　The reliable insulation method of the bus duct includes an insulation layer on the conductive busbar,with a certain air gap between phases.There is also an insulation pad made of DMC material pressed between the conductive busbar and the shell,with triple insulation,ensuring that the insulation of the bus duct is foolproof,especially when used in humid environments,which shows its superiority.Large span design,the length of straight busbar trunking is not limited by transportation capacity,and its design and production capacity are not limited by length,which can meet the needs of engineering,especially modern factories,for large-span busbar trunking.Due to its good rigidity,there is no need to install hangers between 6m spans.