(1). Visual inspection
Upon arrival of the cable tray on the construction site, it is important to provide certain documentation such as the factory certificate, periodic inspection report from provincial and municipal quality supervision stations, and relevant technical appraisal documents. The thickness of the cable tray plate must adhere to specified requirements. For hot-dip galvanized cable trays, it is crucial that the coating surface is even, with no flaws such as over-burning, ash hanging, or partial non-galvanization. Furthermore, electrostatic spraying should be smooth, uniform, without peeling, bubbles, or blisters. The cable tray bridge should be flat with no distortion, a smooth inner wall, and no burrs. Welding seams on the bridge's surface must be uniform with no signs of leakage, cracks, or burn-through.
(2). The installation position of the cable tray
It is important to note that when laying the bridge horizontally, the clearance from the ground should never be less than 2.5m. When multiple layers are required for the cable tray, appropriate spacing must be maintained to facilitate the dissipation of heat, maintenance, and minimize any interference. As for parallel laying of cables and pipes, it is important to adhere to the relevant regulations specified to maintain proper distance between cable tray and pipes.
(3). Installation of support and hanger
Compliance with current technical standards is crucial when it comes to the quality of the support and hanger of the cable tray. The recommended span for supporting the cable tray when laid horizontally ranges between 1.5 to 3 meters. On the other hand, when it is mounted vertically, the distance between fixtures should not exceed 2 meters. For the cable tray arms, the horizontal height difference of any two neighboring arms should not surpass 10mm, while the vertical deviation of the vertical midline of two adjacent bridge arms ought not to go above 20mm.
The cable tray is a supplementary project to the wiring project and lacks specific normative guidelines. Likewise, the specifications presented by manufacturers are quite limited in terms of versatility. Thus, the design and selection of cable trays should depend on the quantity and type of cables needed for each weak current system. A thorough selection process is necessary to identify the best bridge for effective application.
To determine the optimal route for cable trays, one should consider the building's floor plan, location of air conditioning and electrical pipelines, ease of maintenance, and cable density. Ideally, cable trays should be installed along the walls, columns, beams, and floors of the building's interior. If an integrated pipe gallery is utilized, the tray should be erected parallel to the pipeline, while avoiding crossing with down-conductors and branch lines. In the absence of other pipe racks, it may be necessary to erect supporting columns.
(2) Cable weight per unit length calculation for the main line of the cable tray on the longitudinal section needs to be determined. This calculation will help in finding out the weight that the cable tray can bear and carry with it. Ensuring accurate calculations will provide a reliable estimate of the strength and durability of the cable tray to support the weight of the cables.
To determine the width of the bridge, several factors need to be considered. One of these is the type and specification of the cable bridge. The length of the support arm, as well as the length and spacing of the pillars, also play a role in determining the bridge width. The number of layers of the bridge and the width of the bridge will also be influenced by the number of cables laid, the diameter of the cable, and the spacing of the cables. All of these factors must be carefully calculated to ensure that the bridge is strong and capable of supporting the weight it is intended to carry.
To ensure the stability of the bridge frame, it is necessary to determine the appropriate installation method based on the site's setting conditions. There are various options to choose from such as suspension type, vertical type, side wall type or hybrid type, depending on the bridge frame design. Connectors and fasteners are typically provided with the bridge frame for installation purposes. Moreover, it is essential to select a suitable cover structure for the bridge frame to protect it from external elements. Making the right installation method choice is crucial for the bridge to withstand the test of time.
To illustrate the cable tray accurately, it is necessary to create plane and section drawings. Additionally, space maps for some of the parts should be drawn to provide a clear idea of the tray's dimensions and the space required for installation. The material table should list the specific materials used.
Firstly, plane and section drawings of the cable tray should be created to provide a visual representation of the tray and its components. Doing so will help ensure that the tray is correctly designed and manufactured.
Moreover, space maps need to be drawn for some of the parts to better understand how the cable tray can be installed in a given space. The space maps should include all required dimensions to enable proper installation and functioning.
Finally, the material table should be included, listing all of the materials used to construct the cable tray. This table will not only give an overview of the materials used, but it can also provide information about the tray's strength, durability, and susceptibility to damage. Careful selection of the materials can improve the quality and longevity of the cable tray.
When the power cable tray is used in conjunction with it, it is necessary to ensure that the power cable and the weak current cable are arranged in a straight line on one side, and separated by a partition in the middle for proper organization.
