The cable tray is mainly used to protect the cable. It can prevent the cable line from problems caused by other reasons. The cable tray is divided into trough type, tray type, ladder type, grid type and other structures, which are composed of supports, corbels and installation accessories. The bridge in the building can be erected independently or attached to various buildings (structures) and pipe gallery supports. It should reflect the characteristics of simple structure, beautiful appearance, flexible configuration and convenient maintenance. All parts should be galvanized. If the bridge installed in the open air outside the building is near the sea or belongs to the corrosion area, the material must have the physical characteristics of anti-corrosion, moisture resistance, good adhesion and high impact strength.