What should be paid attention to in the selection and selection of bridge?

Selection of cable tray type and variety:

1. When the cable network that needs to be shielded from electrical interference or has the requirement of protecting the external (such as corrosive liquid, combustible dust and other environments), the (FB) trough composite anti-corrosion shielded cable tray (with cover) should be selected

2.In highly corrosive environments, (F) composite epoxy resin anti-corrosion and flame-retardant cable trays should be used. The same material should be used for the bracket and bracket to improve the service life of the tray and accessories, and the cable tray. In the environment or outdoor places that are prone to dust accumulation and other needs to be covered, it is advisable to add a cover.

3. In addition to the above conditions, tray type, trough type, stepped type, glass anti-corrosion flame retardant cable tray or steel ordinary cable tray can be selected according to the environmental and technical requirements of the site. In the environment or outdoor places that are prone to dust accumulation and other needs to be covered, it is advisable to add a cover.

4. In the public passage or outdoor crossing road section, the bottom of the bottom step should be added with a backing plate or a tray should be used in the section. When the large span spans the public passage, the load capacity of the bridge can be increased according to the user's requirements or the row frame can be selected.

5. Composite bridge (FB) should be selected for large span (>3m).

6. Composite epoxy resin bridge (F) should be used outdoors.

1.Selection of cable trays.

1. In the engineering design, the layout of the cable tray should be comprehensively compared according to factors such as economic rationality, technical feasibility, and operational safety to determine the best plan, and fully meet the requirements of construction and installation, maintenance and cable laying.

2. The height of the cable tray from the ground when laid horizontally is generally not less than that, and the part below the ground from the ground when laid vertically should be protected by a metal cover, except when laid in a special electrical room. The cable tray is laid horizontally on the mezzanine of the equipment or on the sidewalk and is lower, and protective grounding measures should be taken.

3. Cable trays, trunkings and their hangers are used in corrosive environments, and should be made of corrosion-resistant rigid materials or treated with anti-corrosion, and the anti-corrosion treatment methods should meet the requirements of the engineering environment and durability. For places with high requirements for corrosion resistance or clean requirements, aluminum alloy cable tray should be selected.

4. In the section with fire protection requirements, the cable tray can be added with fire-resistant or flame-retardant plates, nets and other materials to form a closed or semi-closed structure in the cable ladder and tray, and take measures such as brushing fireproof coating on the surface of the cable tray and its support and hanger. Its overall fire resistance should meet the requirements of relevant national norms or standards. In places with high engineering fire protection requirements, aluminum alloy cable tray should not be used.

5. When it is necessary to shield the cable line with electromagnetic interference or have environmental requirements such as outdoor sunlight, oil, corrosive liquids, flammable dust, etc., the non-porous tray cable tray should be selected.

6. In places where dust is easy to accumulate, the cable tray should be covered plate; In the public passage or outdoor crossing road section of the bottom bridge should be added to the backing plate or the use of non-perforated pallets.

Cables with different voltages and different purposes should not be laid in the same layer of cable trays

1) Cables above 1kV and 1kv and below;

2) Dual-circuit cable with the same path supplying power to the primary load;

3) Cables for emergency lighting and other lighting;

4) Power, control and telecommunication cables.

If different grades of cables are laid in the same cable tray, a partition should be added to isolate the middle.

8. When the length of the straight section of the steel cable tray exceeds 30m, and the aluminum alloy cable tray exceeds 15m, or when the cable tray passes through the building expansion (settlement) joint, there should be an o-30mm compensation margin, and the connection should be connected with a telescopic connecting plate.

9. The selection of the width and height of the cable ladder frame and tray should meet the requirements of the filling rate, the filling rate of the cable in the ladder frame and tray is generally 40%-50% for the power cable, and the % for the control cable can be taken and the l0%-25% project development margin should be reserved.

10. When selecting the load level of the cable tray, the working uniform load of the cable tray should not be greater than the rated uniform load of the selected cable tray load class, if the actual span of the support and hanger of the cable tray is not equal to 2m.

Pay attention to the quality of the cable tray:

The quality of the cable tray is also an important factor when we choose it, and the quality of the cable tray will cause great losses in the later use, so special attention is needed. The quality of the cable tray can pay more attention to the following requirements.

1.The raw materials of the cable tray **, when choosing the cable tray, the manufacturer can take us to see how the raw materials for the cable tray are made, and whether there is a special purchase channel.

2.There are many kinds of surface treatment of cable tray, and whether the surface treatment of the manufacturer is in accordance with the relevant standards during production is also necessary to pay special attention to, so that the manufacturer can provide relevant information to prove it.

3.Whether the manufacturer cuts corners at the time of production, you need to carefully check the order form when receiving the goods, and check it clearly on the spot so that you don't need to trouble in the future.

4.There are also many installation accessories for cable trays, some of which are distributed by the manufacturer, and this needs to be explained clearly to the manufacturer in advance, which ones are paid and which ones are sent.

1) When the cable tray enters the building from the outside, the slope of the cable tray to the outside shall not be less than 1 100.

2) When the cable tray crosses with the electrical equipment, the net distance between them is not less than.

3) When two groups of cable trays are laid in parallel at the same height, the net distance between them is not less than.

4) Draw the route of the bridge on the parallel diagram, and indicate the coordinates or positioning rulers of the starting point, end point, turning point, branch point and lifting point of the bridge.

inch, elevation, if the bridge laying axis side diagram can be drawn, the material statistics will be more accurate.

Straight line section: indicate the full length, number of bridge layers, elevation, model and specification.

Bend point and branch point: indicate the model and specification of the turning adapter used.

Lifting section: indicate the elevation change, which can also be represented by a local sample or section drawing.

5) Bridge support points, such as columns, brackets or non-standard supports, frame spacing, installation methods, model specifications, elevation, can be agreed in the plane.

The above list is illustrated, and it can also be marked in sections and represented by different sections, single-line drawings or large drawings.

6) The position of the cable lead down point and the way of lead down, generally speaking, a large number of cable leads down can be used vertical bending plate and vertical lead on the shelf, and a small number of cable leads.

The guide plate or guide can be used to indicate the way of leading.

7) The cable tray should be more than one meter above the ground, the top of the bridge should not be less than one meter from the ceiling or other obstacles, and the width of the bridge should not be less than.

meters, the filling rate of the cross section inside the bridge should not exceed 50%.

8) When the cable tray is laid vertically, it should be fixed on the bracket of the bridge at the upper end of the cable and every interval meter, and when laid horizontally, it should be fixed at the beginning, tail, turn and every 3 5 meters of the cable.

9) When set up in the ceiling, the opening surface of the groove cover should maintain a vertical clearance of 80 (mm), and the utilization rate of the trunking section should not exceed 50%.

groove, in the cable in and out of the trunking, the turn should be tied and fixed. Vertical trunking cables should be fixed to the cable bracket every meter apart.

11) When laying wires in horizontal and vertical trays and vertical trunking, the cables should be tied. 4 pairs of cables are bundled with 24 wires, 25 pairs or more.

Upper trunk cables, optical cables and other signal cables should be bundled according to the type of cable, cable diameter, and number of cable cores. The spacing of lashing should not be appropriate.

More than meters, the buckle spacing should be even, and the tightness should be moderate.

12) When the bridge is laid horizontally, the support spacing is generally as follows, and the spacing fixed on the building structure should be less than 2m when laying vertically.

13) When the metal trunking is laid, it shall be set up to the frame or hanger under the following circumstances: at the joint of the trunking; Spacing 3m; Leave both ports of the trunking.

At the turn.

The relevant specifications are:

CECS31:2006 Code for engineering design of steel cable trays.

CECS106:2000 Technical specification for aluminum alloy cable tray. gb

Code for construction and acceptance of cable lines for electrical installation projects.

GB50217-2007 Code for design of cables in power engineering. gb

Code for acceptance of construction quality of building electrical engineering.

Cable tray installation standards:

When the cable tray is installed, it should be installed firmly, horizontally and vertically, and the left and right deviations of the support and hanger along the horizontal direction of the cable tray should not be greater than -lomm, and its height deviation should not be greater than 5mm.

When the cable tray is installed with the process pipeline, the cable tray should be arranged on one side of the pipe frame, and when there is a flammable gas pipeline, the cable tray should be set on the side of the power supply with a lower degree of danger.

When the design is not specified, the distance between the layers of the cable tray, the distance from the top layer of the cable tray to the top of the trench or the floor and the bottom of the cable tray to the bottom of the trench or the ground should not be less than the value in Table 3.

1) The cable tray should be above the pipe with corrosive liquid.

2) The cable tray should be under the thermal pipe.

3) When the flammable and explosive gas is heavier than air, the cable tray should be above the pipeline.

4) When flammable and explosive gases are lighter than air, the cable tray should be under the pipeline.

The cable tray should not be laid in parallel with the following pipes, and when it cannot be avoided, the position of the cable tray should comply with the following provisions. or take appropriate precautions.

The minimum distance between the cable tray and the pipe should meet the requirements of Table 4.

The cable tray should be covered with a cover plate or protective cover in one of the following situations.

1) When the cable tray is installed under the iron grate plate or similar perforated device, the uppermost cable tray should be covered with a cover plate or a protective cover, if the width of the upper cable tray is less than that of the lower cable tray

2) When the cable tray is installed in a place that is prone to mechanical damage, a protective cover should be added.

When the cable tray is installed through the wall, the sealing device should be used according to the environmental conditions. When the cable tray passes through the wall from the indoor to the outdoor, rainproof measures should be taken on the outside of the wall.

When the cable tray is led from the outdoor higher place to the indoor, the cable tray should be tilted downward first, and then led horizontally to the room. When the cable tray is trayed, it is advisable to use a cable ladder in the outdoor horizontal section to prevent rainwater from flowing into the room along the cable tray.

The fixation of the cables in the cable tray shall comply with the provisions of the relevant standards and specifications.

There are mainly ladder bridges, pallet bridges, trough bridges, energy-saving corrugated bridges, energy-saving molded reinforced bottom bridges, ladders, pallets, and trough bridges.

The main materials of the cable tray are: galvanized cable tray, hot-dip galvanized cable tray, sprayed cable tray, fireproof cable tray lead pants, aluminum alloy cable tray, stainless steel cable tray, FRP cable tray;

Usually the models of cable tray are divided into: trough type, tray type, ladder type.

The different materials of the cable tray are divided into: galvanized tray, stainless steel 304 tray, aluminum alloy 1060 tray.

The surface treatment process is divided into: fireproof baking paint, electrostatic spraying, hot-dip galvanizing (hot-dip galvanizing) Common specifications are: (width * height * thickness is: national standard thickness).

300mm*100mm*

400mm*100mm*

500mm*100mm*

600mm*200mm*

800mm*200mm*

1000mm*150mm*

1200mm*200mm*, etc.

A tray is a bracket that supports and puts cables. Bridge is very common in engineering, as long as the cable is laid, the cable tray as a supporting project of the wiring project, there is no special specification guidance at present, and the specifications of the manufacturer lack of universality, therefore, the design and selection process should be based on the type and quantity of each system cable of weak current, and the applicable bridge should be reasonably selected. The cable tray has the characteristics of complete variety, wide application, high strength, light structure, low cost, simple construction, flexible wiring, standard installation and beautiful appearance.

Cable tray: the weak current system of intelligent buildings, usually has a plurality of information monitoring and communication facilities such as BA (building automation), OA (public automation), CA (communication automation) and other corresponding systems, cable tray is divided into trough type, tray type and ladder frame type and other structures, composed of brackets, brackets and installation accessories. When selecting, attention should be paid to whether all parts of the bridge meet the requirements of serialization, generalization and standardization.

The bridge frame in the building can be assumed independently, and can also be attached to various buildings (structures) and pipe gallery supports, which should reflect the characteristics of simple structure, beautiful shape, flexible configuration and convenient maintenance, all parts need to be galvanized, and the bridge installed in the open air outside the building, if it is near the sea or belongs to the corrosion area, the material must have anti-corrosion and moisture resistance. Classification of cable tray 1, cascade cable tray CQ1-T type cascade cable qiao is based on the relevant data at home and abroad and improved design. It has the advantages of light weight, low cost, unique shape, easy installation, heat dissipation and good ventilation.

It is suitable for the laying of cables with large diameters, and is suitable for the laying of high and low voltage power cables. 2. Tray cable tray tray cable tray is one of the most widely used in petroleum, chemical industry, light industry, telecommunications, etc. It has the advantages of light weight, large load, beautiful shape, simple structure and easy installation.

It is suitable not only for the installation of power cables, but also for the laying of cables. 3. Trough cable tray trough cable tray is a fully enclosed cable tray. It is most suitable for laying computer cables, communication cables, thermocouple cables, and other control cables for highly sensitive systems.

It has a good effect on the shielding interference of control cables and the protection of environmental cables in heavy corrosion. 4. The cascade line bridge of the large-span cable tray has good ventilation performance, and is not dustproof and interference-proof. Trough and tray busbar bridges are dust-proof