Dense insulated fire-resistant enclosed bus duct is a new generation of bus duct developed by introducing high and new technology. The insulating parts of this bus duct are made of special insulating thermal materials, such as high temperature resistant mica tape and glass fiber inorganic reinforcement materials, which have the advantages of non combustion, non explosion and good mechanical strength.The shell of the bus duct is sprayed with high temperature resistant and fireproof materials, with a fire endurance of ≥ 30min and a protection grade of IP40. When the bus duct is exposed to fire, the relative phase and ground insulation resistance of the bus duct is not less than 1.0 Ω. It can withstand power frequency withstand voltage of 1000V, without breakdown or flashover within 1min, and can work normally under rated voltage. Therefore, it can be widely used in high-rise buildings, computer circuits, densely populated areas and other places with fire resistance requirements.