1, cable tray as a wiring project supporting the project, at present there is no special instruction, the manufacturer's specifications programs lack of generality, therefore, the design selection process should appear type and quantity of each system according to the weak cable, reasonable selection of suitable bridge.

(1) determine the direction: according to the building floor plan, combined with air conditioning pipelines and electrical pipelines and other settings, convenient maintenance, as well as the density of cable routing to determine the best route cable bridge. In the room, as far as possible along the walls of the building, columns, beams and floor erection, so the comprehensive utilization of pipe rack erection, should be set up in parallel side or above the pipeline, and consider the lead line and a branch line to avoid cross, such as no other pipe frame borrowing, is required since the establishment (Branch) column.

(2) load calculation: calculate the weight of the unit length on the longitudinal section of the cable bridge main frame.

(3) to determine the width of the bridge cable laying: according to the number and diameter of the cable and cable spacing to determine the type and size of the cable tray, arm length, strut length, spacing, bridge width and number.

(4) determine the installation: according to the fixed place conditions to determine the bridge, suspensory, upright, side wall or mixed type, connectors and fasteners are generally supporting the supply, in addition, according to the bridge structure, choose the corresponding cover.

(5) draw a flat section of the cable bridge, and draw a space map as well as a material list for the local part.

2 if the power cable bridge is used, both the power cable and the weak cable should be directly separated from each other by the clapboard.

3, weak cable and other low voltage cable in bridge, should strictly implement the selection system with weak external shielding layer of the cable is weak, to avoid mutual interference.

4 、 cable bridge installation requirements

(1) when the trough type large span cable bridge enters the building from the outside, the slope outside the bridge shall not be less than 1/100. (2) the net distance between the cable tray and the electrical equipment is not less than 0.5m.

(3) when the two sets of cable trays are laid in parallel at the same height, the net distance shall not be less than 0.6m. (4) in parallel graph drawn on the bridge route, to indicate the starting point and end point bridge, turning point, bifurcation points and lifting the coordinates of the point size, location or elevation, such as drawing laid axonometric drawing, the material will be more accurate statistics.

Straight line: indicate the length, the number of the bridge, the elevation, the type and specifications. Turning point and branch point: indicate the type and specification of the turning panel. Lift: marked elevation changes, also available local drawing or profile said.

(5) the bridge support, such as a column, or non standard, frame spacing, installation methods, specifications, elevation, may agree to that list in the plane, can also be sub mark expressed in different sections, isometric or drawing.

(6) cable lead down point position and lead down mode; in general, a large number of cables can be drawn down and can be used as vertical bending plates and vertical lead shelves. A small amount of cables can be used for guiding or guiding pipes, indicating the way to be taken down.

(7) the cable tray shall be more than 2.2 meters above the ground, and the top of the bridge shall not be less than 0.3 meters away from the ceiling or other obstructions. The width of the bridge shall not be less than 0.1 meters, and the filling rate of the cross section in the bridge shall not exceed 50%.

(8) when the cable is vertically laid in the cable tray, it shall be fixed on the support of the bridge at the upper end of the cable and at every 1.5 meters apart. When it is laid horizontally, the cable shall be fixed at the first, tail, turn and at intervals of 3~5 meters.

(9) when setting in the ceiling, the opening of the groove cover shall be kept 80 mm vertical clearance, and the utilization ratio of the cross section shall not exceed 50%.

(10) the cable of the cloth placing groove can not be tied up; the cable in the groove shall be straight; the cable in the groove shall be straight and as far as possible without crossing; the cable shall not overflow the slot; the cable shall be bound and fixed at the turning point of the cable inlet and outlet. The cable for the vertical slot shall be fixed to the cable bracket at 1.5 meters per hour.

(11) wiring shall be carried out in horizontal and vertical bridge and vertical groove. 4 pairs of wire cables shall be 24 beams, and 25 or more main cables, cables and other signal cables shall be tied and tied according to the type of cable, cable diameter and cable core number. Lashing space should not be greater than 1.5 meters, the spacing should be uniform, elastic tightness.

(12) when the bridge is horizontally laid, the support spacing is generally 1.5-3m, and the spacing on the building structure should be less than 2m when laying vertically.

Selection and laying standard of cable tray type and variety

I. selection of cable tray types and varieties

Cable network 1, shielding electrical interference or external protection (such as: a corrosive liquid Hugh, flammable dust and other environmental effects) requirements, should choose (FB) type groove type composite type anti-corrosion shielding cable tray (with cover)

2, strong corrosive environment should adopt (F) composite epoxy resin anti-corrosion flame retardant cable tray. The bracket will choose the same material, improve the service life of the bridge and annex, cable tray. Cover panels in easy ash and other environment or outdoor areas that need to be covered.

3, in addition to the above circumstances, according to the site environment and technical requirements, choose pallet, trough, step type, glass anti-corrosion flame retardant cable bridge or steel ordinary type bridge. Cover panels in easy ash and other environment or outdoor areas that need to be covered.

4, in public or outdoor crossing the road section, the bottom of the bottom of the ladder should be added to the plate or in the use of pallets. When large span spans the public channel, the load capacity of the bridge or the frame can be improved according to the requirements of the users.

5, large span (>3m) to choose a composite type bridge (FB).

6, outdoor use of composite epoxy tree refers to the bridge (F).

Two 、 selection of cable tray specifications

1. The width and height of the composite epoxy resin cable bridge will be pressed