The traditional medium and small capacity low-voltage electrical power transmission and distribution mode is mainly based on cables, with the help of cable trenches, cable trays, steel pipes and other facilities. At present, the cross-sectional cap of the manufactured cable is 500mm2, therefore, the current carrying capacity cap of the cable is 800A (which is also specified in IEC standards). Due to the long length and heavy weight of large cross-section cables, in order to avoid damaging the cable insulation layer, the mechanical force of the middle fixing device cannot be too strong during vertical layout. Therefore, when laying large cross-section cables vertically in high-rise buildings, their overweight slipping and cable cross-section deformation have always been difficult to solve construction problems. The enclosed Bus duct does not have this problem, because it is rigid, so the mechanical fixing method can be very firm. In addition, the top section of the conductor in the enclosed Bus duct can exceed 1000mm2, and the double conductor can exceed 2000mm2. In addition, the bus is rectangular with large surface area, weak Skin effect, large heat dissipation area and low temperature rise, which means that the current carrying capacity of the cable with the same section is much higher (can exceed 1000A).