1. Cable trays are classified into steel plates, aluminum alloys, stainless steel, fiberglass, and inorganic materials according to their material types; Classified by structure, there are ladder type, perforated tray type, non perforated tray type, etc; Classified according to fire protection requirements, there are ordinary and fire-resistant types; There are regular and energy-saving types in terms of performance classification. Steel cable trays are classified into three types based on surface protection layer: hot-dip galvanized type, composite corrosion-resistant type, and composite high corrosion-resistant (color steel) type. Among them, composite high corrosion-resistant (color steel) cable trays are a new generation of products made of color steel plates, which have the characteristics of fast installation, energy conservation, light weight, and high strength. They have been developed and produced by Shanghai Zhangxiang Electrical Complete Set Co., Ltd. The surface protection layer should be selected based on the usage environment.
When installing cable trays horizontally, it is advisable to select the optimal span as the support according to the load, and the spacing between support points should be 1500-3000mm, based on the cable tray deflection not exceeding 1/200 of its length under rated load. When installed vertically, the spacing between fixed points should not exceed 2000mm. When the requirements cannot be met, large-span cable trays should be used.
3. Except for technical interlayer and special occasions, the height of the horizontal section of the cable tray from the ground should not be less than 2500mm, and the height of the vertical section from the ground should not be less than 1800mm. When the requirements cannot be met, measures to prevent mechanical damage should be taken, except in and outside electrical rooms.
When installing cable trays in multiple layers, the clear distance between layers should comply with the following regulations: 1) The distance between power cable trays should not be less than 300mm.
5. The distance between the telecommunications (control) cable tray and the power cable tray should not be less than 500mm. When there are shielding measures, it should not be less than 300mm
6. The distance between control cable trays should not be less than 200mm.
7. 电缆桥架上部距顶棚、楼板或梁等其他障碍物不宜小于300mm。8. 当两组或两组以上电缆桥架在同一高度平行安装时，各相邻电缆桥架之间应留有满足维护、检修的距离。
7. The distance between the upper part of the cable tray and other obstacles such as the ceiling, floor slab, or beam should not be less than 300mm. When two or more sets of cable trays are installed in parallel at the same height, there should be a distance between adjacent cable trays that meets maintenance and repair requirements.
9. 在电缆桥架内可以无间距敷设电缆。电缆总截面积与电缆桥架内横断面面积之比，电力电缆不应大于40%,控制电缆不应大于50%。10. 下列不同电压、用途的电缆，不宜敷设在同一层的电缆桥架上:1
9. Cables can be laid without gaps within the cable tray. The ratio of the total cross-sectional area of cables to the cross-sectional area inside the cable tray should not exceed 40% for power cables and 50% for control cables. 10. The following cables with different voltages and purposes should not be laid on the same layer of cable trays: 1
）Cables above 1kV and below 1kV. 2) Two circuit power cables supplying power to the same load.
3) Emergency lighting and other lighting cables. 4) Power cables and telecommunications cables.
11. 当受条件限制需敷设在同一电缆桥架上时，应采用金属隔板隔开。12. 电缆桥架不宜安装在热力管道的上方及腐蚀性液体管道的下方。对于腐蚀性气体的管道，当气体的密度大于空气时，宜安装在其上方;当气体的密度小于空气时，宜安装在其下方。13. 电缆桥架转弯处的弯曲半径，不应小于桥架内电缆更小允许弯曲半径的值。
11. When laying on the same cable tray due to limitations, metal partitions should be used to separate them. 12. Cable trays should not be installed above thermal pipelines or below corrosive liquid pipelines. For pipelines with corrosive gases, when the density of the gas is greater than that of air, it is advisable to install them above it; When the density of the gas is less than that of air, it should be installed below it. The bending radius at the turning point of the cable tray should not be less than the maximum value of the minimum allowable bending radius of the cable inside the tray.
14. Cable trays shall not be connected at points where they pass through floors or walls.
15. When cable trays pass through firewalls and fireproof floors, fire blocking measures should be taken.
When the straight section length of steel cable trays exceeds 30m, and the length of aluminum alloy or fiberglass cable trays exceeds 15m, expansion joints should be installed.
When cable trays cross deformation joints in buildings, compensation devices should be installed.
18. The dedicated grounding main line inside the metal bridge and bracket, as well as the fiberglass cable bridge, should be reliably connected to the grounding protective conductor (PE line) at no less than 2 places along its entire length.
19. The two ends of the connecting plate between hot-dip galvanized cable trays may not be connected to the grounding wire, but the two ends of the connecting plate should have at least two connection fixing bolts with locking nuts or washers.
20. The two ends of the connecting plate between non hot-dip galvanized cable trays should be connected to a copper core grounding wire, and the minimum allowable cross-sectional area of the grounding wire should not be less than 4mm2.
When cables of the same voltage are laid in parallel and exposed indoors, except when laid inside and outside the cable tray, the clear distance between the cables should not be less than 35mm and should not be less than the outer diameter of the cable. Power and control cables of 1kV and below should be laid separately from power cables of 1kV and above. When parallel laying is required, the clear distance should not be less than 150mn.
22. (21) Power cables should be laid inside the bridge, with a plot ratio not exceeding 40%, and control cables not exceeding 50%.