What's the difference between a bridge and a trunking?

Abstract: Bridge is a bracket for supporting and laying cables. Bridges are widely used in engineering. As long as the cable is laid, the cable tray is used, and the cable tray is a supporting project of the wiring project. Trunk, also known as trunking, distribution trunking and trunking (varies from place to place), is an electrical appliance used to sort out the specifications of power cables, data cables and other wires and fix them on the wall or ceiling. Generally, there are two kinds of plastic materials and metal materials, which can play different roles. Let's take a look at the difference between bridge and trunking! Cable tray is divided into trough, tray, ladder and net structure, which consists of bracket, support arm and installation accessories. The trunking can be divided into: insulated trunking, exposed trunking, mini trunking, separated trunking, indoor decorative trunking, integral insulated trunking, telephone trunking, Japanese telephone trunking, open wire trunking, circular distribution duct, partition trunking for exhibition, cover trunking, etc. People often confuse bridges with trunking. Next, I will tell you the difference between them.

First, what is a bridge?

Bridge is a bracket for supporting and laying cables. Bridges are widely used in engineering. As long as the cable is laid, the bridge is needed. As a supporting project of wiring engineering, there is no special specification guidance at present, and the specifications and procedures of several manufacturers lack universality.

Basic categories of bridges

1, cascade cable tray

According to the relevant information at home and abroad, the CQ 1-T stepped cable tray is improved. It has the advantages of light weight, low cost, unique shape, convenient installation, good heat dissipation and ventilation. It is suitable for laying general large-diameter cables, and also suitable for laying high and low voltage internal chain power cables.

2. Tray cable tray

Tray cable tray is one of the most widely used in petroleum, chemical industry, light industry, telecommunications and other industries. It has the advantages of light weight, large load, beautiful appearance, simple structure and convenient installation. It is not only suitable for the installation of power cables, but also suitable for the laying of control cables.

3. Trough cable trough

Trough cable tray is a fully enclosed cable tray, which is most suitable for laying computer cables, communication cables, thermocouple cables and control cables of other highly sensitive systems. It has a good effect on shielding interference of control cable and protecting cable in severely corrosive environment.

4. Long-span cable trough

Long-span connecting bridges can be divided into ladder type, tray type and trough type. Cascade bridge has good ventilation performance, and it is not dustproof, so it is better to interfere. The surface treatment of tray cable bridge can be divided into three types according to users' needs: zinc plating, electrostatic plastic spraying and hot-dip zinc plating, which can be used for special anti-corrosion treatment in severely corrosive environment. Trough cable tray is a fully enclosed cable tray, which is equipped with a cover plate and uses the least connecting bolts. It is most suitable for laying computer cables, communication cables, thermocouple cables and control cables of other highly sensitive systems, and has a very good effect on shielding interference of control cables and protecting cables in severely corrosive environments.

Second, what is a relay?

Trunk, also known as trunking, distribution trunking and trunking (varies from place to place), is an electrical appliance used to sort out the specifications of power cables, data cables and other wires and fix them on the wall or ceiling. According to different materials, trunking can be divided into many types, such as PVC trunking, halogen-free PPO trunking, halogen-free PC/ABS trunking, steel-aluminum trunking and so on.

Characteristics of relay

1, suitable for long-span installation.

The shell of bus duct is formed by rolling, with small volume and beautiful appearance, which greatly improves the bearing capacity of the factory. It can bear the weight of 60kg, with a span of 6m and a deflection of less than10mm.

2, the installation is very convenient

Automatic compensation connection and single bolt clamping terminal are adopted, which makes the bus duct very convenient and flexible in the installation process and greatly saves the installation time.

3, extremely safe and reliable

It adopts separated air insulation type, and the safe clear distance and creepage distance between phases are far greater than the standard requirements.

Flexible wiring

The sockets of the bus duct are modular in design, and a large number of sockets can be reserved in the whole system. Ensure that the load can be connected to the bus duct unit in the shortest path, and there is no need to change the bus system due to the increase, movement and transformation of workshop equipment.

5, strong interchangeability

The bus duct is designed with seven current levels, and only three levels of housings are used, so that when the system changes capacity according to the adjacent current levels, it is not necessary to replace the housings.

Third, the general difference between bridge and trunking.

1. The bridge is used for laying power cables and control cables, and the trunking is used for laying wires and communication cables.

2, the bridge is relatively large, and it is widely used between floors of general buildings and various power distribution rooms. The trunking is relatively small.

3. The turning radius of the bridge is relatively large, and most of the trunking is right-angled.

4. The bridge span is relatively large, the trunking is relatively small, and the fixed installation method is different.

5. In some places, the bridge has no cover plate, and the trunking is almost completely closed with cover plate. Trough is widely used in various power distribution cabinets and instrument cabinets.

6. The trunking is used for wiring and the bridge is used for cables.

Fourthly, the concrete difference between bridge and trunking.

1, with different sizes and specifications. The bridge is relatively large (200× 100 to 600×200) and the trunking is relatively small. If there are many cables and wires, it is recommended to use a bridge.

2, the material thickness is different. According to JJ16-2008-5.1,metal trunking is also called trough bridge. Generally, it is a trough-shaped member formed by bending a whole piece of steel plate with a thickness of 0.4- 1.5 mm, which is conceptually different from the bridge in terms of height-width ratio. The bridge is shallow and wide, and the metal trough has a certain depth and tightness. However, the bridge is stronger than the trunking, and it is more used for placing cables and, of course, wires, usually used in high-voltage systems.

3. The filling rate is different. According to JJ16-20088.5.3, the total cross-section of wires and cables in trunking should not exceed 20% of that in trunking, and there should be no more than 30 current-carrying conductors, while the total cross-section of cables in bridge should not exceed 40% of that in trunking. This is due to different installation heights. If the installation height is low, there must be a cover plate. If there is a cover plate, the heat dissipation is not good and the filling rate will be smaller.

4. The sealing performance is different. Metal trunking is well sealed and can be laid in cable trench and building interlayer without support. Some trough bridges are semi-open and must be supported by brackets, which are usually erected indoors or outdoors in the air.

5, the strength is different. Bridge is mainly used for laying power cables and control cables, and the strength of trunking is low, so it is usually used for laying wires and communication cables, such as VoIP.

6. The turning radius is different. The turning radius of the bridge is relatively large, and most of the trunking is right-angled.

7. The span is different. The span of the bridge is relatively large, and there are fewer trunking. Therefore, the number of fixed brackets and supports and hangers varies greatly.

8. The spacing between supports and hangers is different. According to JGJ 16-2008, the trunking is not more than 2m, and the bridge is 1.5~3m.

9. Different installation methods. The bridge has special specifications (see CECS3 1.9 1 for details), but the trunking is not fixed with special specifications.

10. Cover plate problem. In CECS3 1 Code for Design of Steel Cable Tray Engineering, it is clear that the tray is a generic name and the cover plate is an accessory. As mentioned in JJ16-20088.10.3, when the installation height of the tray can't meet the requirements, the cover plate should be used for protection. In other words, the definition of bridge does not include the cover plate. However, in GB294 15-20 13, the trunking is a whole with a cover plate.