The body structure design is the same as that of XLV series Bus duct. The "sandwich" phase line compact laminated structure design is adopted, which is compact in shape and small in size. The bus has the advantages of low impedance, low voltage, good dynamic stability, no hysteresis eddy current loss, and will not produce "Stack effect" in case of fire. The internal shell is made of aluminum magnesium alloy drawn profiles, which can reach T6 state after aging to ensure the structural strength of Bus duct. The main refractory layer of the external shell adopts the PROMA of the preservation company- TECT-N series fiber reinforced calcium silicate fireproof board, the product does not contain asbestos and formaldehyde, and the thermal conductivity of the board is low. It is an A1 grade non combustible material. The busbar is wrapped with fiber reinforced calcium silicate fireproof board as a whole, and the gaps are filled with 1250 ° C boiler sealant to prevent high temperatures from directly entering the interior of the busbar.