1. As a supporting project of wiring engineering, cable tray has no special specification guidance at present, and the specification form of each manufacturer lacks universality. Therefore, the design and selection process should reasonably select the appropriate cable tray according to the cable type and quantity of each electrical system.
(1) Determine the direction according to the building layout plan, combined with the setting of air conditioning pipelines and electrical pipelines, convenient maintenance, and cable route density to determine the route of cable tray. Indoor, it is best to install along the walls, columns, beams, and floors of the building. If using a comprehensive pipe gallery for installation, it should be installed parallel on one side or above the pipeline, and consideration should be given to avoiding the intersection of down conductors and branch lines as much as possible. If there are no other pipe racks to borrow, self installation (support) columns are required.
(2) Load calculation calculates the weight of cable per unit length on the vertical section of cable tray trunk line.
(3) Determine the width of the cable tray. Determine the model, specification, arm length, pillar length, spacing, width and layers of the cable tray according to the number of cables laid, cable diameter and cable spacing.
(4) Determine the installation method based on the setting conditions of the site to determine the fixing method of the bridge. Choose the suspension type, vertical type, side wall type, or hybrid type, and the connectors and fasteners are generally supplied together. In addition, select the corresponding cover plate according to the bridge structure.
(5) Plan and section drawings of cable tray shall be drawn, and space drawings and material lists shall be drawn for local parts.
2. If it is used together with the power cable tray, the power cable and weak current cable shall be separated by a partition on each straight side.
3. When using a bridge with weak current cables and other low-voltage cables, strict selection of weak current cables with external shielding layers should be carried out to avoid mutual interference.
4. Other installations
(1) When the cable tray enters the building from the outside, the outward slope of the cable tray shall not be less than 1100.
(2) When the cable tray crosses the electrical equipment, the clear distance between them shall not be less than 0.5m.
(3) When two groups of cable tray are laid in parallel at the same height, the clear distance between them shall not be less than 0.6m.
(4) Draw the route of the cable tray on a parallel diagram, indicating the coordinates or positioning dimensions and elevations of the starting point, ending point, turning point, branch point, and lifting point of the cable tray. If a cable tray laying axis side diagram can be drawn, the material statistics will be more accurate.