The difference between cable trays and wire ducts
1. The dimensions and specifications are different. The cable tray is relatively large (200×100 to 600×200), and the wire duct is relatively small. If there are many cables and wires, it is recommended to use a bridge.
2. Material thickness is different. According to JGJ16-2008-5.1, metal cable ducts are also called trough-type bridges. They are generally trough-shaped components made of bent steel plates with a thickness of 0.4-1.5mm. Conceptually, they differ from bridges in that the height and width ratios are different, and the trays are shallow. While wide, metal trunking is of certain depth and containment. However, the cable tray is stronger than the cable trough and is more commonly used to place cables. Of course, it can also be used to place wires. It is usually used for strong current systems.
3. The filling rate is different. According to JGJ16-20088.5.3, the total cross-section of wires and cables in the trunking should not exceed 20% of the cross-section in the trunking, the current-carrying conductors should not exceed 30, and the total cross-section of the cables in the bridge should not exceed 40% of the cross-section. This is due to different installation heights. Lower installation heights require a cover. Covers do not provide good heat dissipation, so the filling rate is smaller.
4. The sealing properties are different. Metal wire troughs have better sealing and do not necessarily need bracket support. They can be laid in cable trenches and building mezzanines. Some trough-type bridges are semi-open and must be supported by brackets. They are generally erected along the air inside or outside the house.
5. Different strengths. The cable tray is mainly used for laying power cables and control cables. The strength of the cable trough is low and is usually used for laying wires and communication cables, such as Internet phones.
6. The turning radius is different. The bending radius of the bridge is relatively large, and most of the cable ducts are turned at right angles.
7. The span is different. The span of the bridge is relatively large and the trunking is relatively small. Therefore, the fixed brackets vary greatly, and the number of supports and hangers varies greatly.
8. The spacing between supports and hangers is different. According to JGJ16-2008, the cable trough is not larger than 2m, and the bridge is 1.5~3m.
9. The installation methods are different. There are special specifications for cable trays (see CECS31.91 for details), but there are no special specifications for fixing cable ducts.
10. The problem of adding cover plate. In the CECS31 "Steel Cable Tray Engineering Design Code", the definition is that the bridge is a general term, and the cover is an accessory. It is mentioned in JGJ16-20088.10.3 that when the installation height of the bridge cannot meet the requirements, a cover should be added for protection. In other words, the definition of the word bridge does not include cover plates. However, in GB29415-2013 "Fire-resistant Cable Trunk Box", the cable trough contains a cover and is an integral part of the cable trough.