When selecting the type and type of cable tray, it is necessary to shield the cable network from electrical disturbances or to protect against external influences (such as corrosive liquids, flammable dust, etc.), the FB type slot type composite anti-corrosion shielding cable tray (with cover) should be selected. For strong corrosive environments, the F type composite epoxy resin anti-corrosion flame-retardant cable tray should be selected. Brackets and brackets should also use the same materials to improve the service life of cable trays and accessories.
Cover plates should be added in simple dust accumulation and other environments or outdoor areas that need to be concealed. In addition to the above situations, tray type, trough type, stepped type, glass anti-corrosion flame-retardant cable tray or steel ordinary type tray can be selected according to the on-site environment and skill requirements. Cover plates should be added in simple dust accumulation and other environments or outdoor areas that need to be concealed. In public passages or outdoor crossing sections, it is advisable to add a pad at the bottom of the bottom step or use a pallet at that section. When crossing a public passage with a large span, the load capacity of the bridge can be increased or a gantry can be selected according to user requirements. Composite cable trays (FB) should be used for large spans (>3m). Composite epoxy resin bridge (F) should be selected for outdoor use.
The width and height of the standard selection cable tray should be selected according to the following table, and the cable filling rate should not exceed the specified values of relevant standards and specifications. The power cable can be taken as 40-50%, the control cable can be taken as 50-70%, and a margin of 10-25% should be reserved for other types of cable development. The standards for various bends and accessories should meet the engineering placement conditions and be matched with the bridge. The selection of support and hanger standards should be based on conditions such as bridge standards, number of floors, and span.
And it should meet the requirements of the load. The selection of the cross-sectional area of the bridge can be seen in the matching of indoor supports and hangers. The short span of supports and hangers is generally 1.5-3m. The span of outdoor columns generally adopts the support and hanger configuration of 6m non linear sections, following the following guidelines. When the width of the bridge is less than 300mm, a support and hanger should be installed on the side of the straight section 300-600m away from the junction of the non straight section and the straight line. When the width of the bridge is greater than 300mm, in addition to meeting the following conditions, a support and hanger should also be added in the middle of the non linear section. The Centre-to-centre distance between layers is 200250300350mm when the cable tray is set in multiple layers. 20-30mm Expansion joint (metal bridge) shall be reserved every 50m in the straight section of the bridge. It is necessary to use steel or non combustible and flame retardant materials for the fire protection requirements of the bridge section. The BJ III series cable trays produced by our company are all fireproof trays.
The bridge system should have reliable electrical connection and grounding (For metal cable trays only. When a cable tray system is allowed to form a grounding main circuit, the following requirements should be met. The connection resistance between the cable tray ends should not exceed 0.00033 ohms, and the grounding hole should be cleaned of insulation coating. In a 1KV and below neutral point direct grounding system, the grounding of the receiving equipment is connected to the neutral line grounding of the system. When a dynamic blocking power supply device is installed, the cross-sectional area of the metal in the longitudinal direction of the cable tray should not be less than the specified value.) When laying another grounding main line along the entire length of the bridge, each section (including non linear sections) of the bridge should have at least one point firmly connected to the grounding main line. For oscillation sites, spring coils should be installed at the connection of the grounding part. The planning content of the bridge system engineering should be closely coordinated with civil engineering, technology, and related disciplines to determine the optimal placement. The planning content may include relevant cross-sectional drawings of the bridge system. Layout plan of the bridge system.