Cable Bridge Installation Requirements and Specification Guide
1. The cable bridge is an accessory project of the cabling project. Currently, there is no specific specification guidance. The specification program of a manufacturer lacks universality. Therefore, the design selection process should be based on the types and quantities of weak cables. Applicable bridges.
(1) Determine the direction: According to the floor plan of the building, combine the setting conditions of air-conditioning pipelines and electrical pipelines, convenient maintenance, and the density of cable routes to determine the best route for the cable tray. Indoors, erect as much as possible along the walls, columns, beams and floors of a building. If they are erected using an integrated pipe gallery, they should be erected on one side or above the pipeline in parallel. Consider taking down the line and the branch line to avoid crossover as much as possible. Without other pipe racks, you need to set up (branch) columns.
(2) Load calculation: Calculate the cable weight per unit length on the longitudinal section of the main cable trunking.
(3) Determine the width of the bridge: According to the number of cables to be laid, the cable diameter and the distance between the cables, determine the type and size of the cable tray, the length of the brackets, the length and spacing of the pillars, and the width and number of layers of the bridge.
(4) Determine the installation method: Determine the fixing method of the bridge frame according to the setting conditions of the site, select the suspension type, vertical type, side wall type or hybrid type, and the connection pieces and fasteners are generally supplied in an auxiliary manner. In addition, according to the bridge The structure selects the corresponding cover.
(5) Draw the flat and sectional drawing of the cable bridge, and draw a space diagram for the local parts and list the materials.
2. When used in conjunction with a power cable tray, the power cable and the weak cable should be straight and separated by a partition.
3. When weak cables and other low-voltage cables are used in combination with the bridge, weak cables should be strictly selected for weak systems with outer shields to avoid mutual interference.
4. Installation requirements for cable trays (1) When the slot-type large-span cable trays enter the building from outside, the slope of the trays should not be less than 1/100. (2) The distance between the cable bridge and the electrical equipment is not less than 0.5m.
(3) When two sets of cable trays are laid in parallel at the same height, the net distance between them is not less than 0.6m. (4) Draw the route of the bridge on the parallel diagram, and indicate the coordinate or positioning size and elevation of the starting point, the end point, the turning point, the branch point and the lifting point of the bridge. If you can draw the side view of the laying of the bridge, calculate the material statistics. Will be more precise.
Straight section: indicate the full length, number of bridges, elevation, model and specifications. Turning point and branch point: Specify the type and specification of the turning board used. Lifting segment: Note the change of elevation, which can also be represented by a partial large sample or a profile.
(5) Bridge support points, such as pillars, support arms or non-standard supports, frame spacing, installation methods, model specifications, and elevations, may agree to be listed on the plane, or may be marked in sections with different profiles, single lines Figure or large sample diagram.
(6) The location of the cable lead-in point and the way to pull it down. In general, a large number of cables can be used to guide the vertical bending plate and the vertical lead frame. A small number of cables can be used to guide the guiding plate or the guiding pipe, indicating the way to lead.
(7) The cable tray should be more than 2.2 meters above the ground. The top of the bridge should not be less than 0.3 meters from the ceiling or other obstacles. The width of the bridge should not be less than 0.1 meters. The filling rate of the cross section in the bridge should not exceed 50%.
(8) When cables are laid vertically in the cable tray, they should be fixed on the bracket of the bridge at the upper end of the cable and at intervals of 1.5 meters. When laying horizontally, the cable heading, tailing, turning and each interval of 3~5 The meter is fixed.
(9) When set in the ceiling, the open face of the tank cover should maintain a vertical clearance of 80 mm, and the utilization ratio of the cross section should not exceed 50%.
(10) The cables laid in the trunking may not be tied, the cable in the groove shall be straight, the cable in the groove shall be straight, as far as possible not crossing, the cable shall not overflow the slot, at the place where the cable enters and exits the slot, Bends should be fixed at the turn. The vertical trunking cable should be fixed to the cable bracket at intervals of 1.5 meters.
(11) When laying lines in horizontal, vertical bridges, and vertical slots, tie the cables. 4 pairs of wire cables are bundled in 24, and 25 or more trunk cables, optical cables and other signal cables should be bundled according to the type of cables, the cable diameter and the number of cable cores. The lashing distance should not be more than 1.5 meters. The spacing between the buckles should be even and moderate.
(12) When the bridge is laid horizontally, the distance between the supports is generally 1.5-3m, and the spacing fixed on the building body during vertical laying is preferably less than 2m.
Cable Bridge Type and Variety Selection and Laying Specifications
First, the choice of cable tray type and variety
1. When it is required to shield the cable network of electrical interference or to protect the external (such as: corrosive liquid leakage, flammable dust, etc.) requirements, (FB) type compound corrosion-proof shielded cable tray (with cover) )
2, strong corrosive environment should use (F) composite epoxy resin flame-retardant cable tray. The same material is used for the supporting arm and bracket to increase the service life of the bridge and accessories, and the cable tray. It is advisable to add cover plates in areas where there is a tendency to collect dust and other areas that need to be covered.
3. In addition to the above conditions, the tray type, trough type, step type, glass anti-corrosion and flame-retardant cable tray or steel ordinary type tray can be selected according to the site's environment and technical requirements. It is advisable to add cover plates in areas where there is a tendency to collect dust and other areas that need to be covered.
4. In the public access road or outdoor crossing road section, the bottom of the bottom step should be padded or used in the section. When a large span spans a public passage, the load capacity of the bridge can be increased or a stand can be selected according to user requirements.
5, large span (> 3m) to use composite bridge (FB).
6, outdoor use composite epoxy resin finger bridge (F).
Second, the cable bridge specification selection
1. The width and height of the composite epoxy resin cable tray are selected according to the following table, and should comply with the true charging rate of the cable not exceeding the specified value of the relevant standard specification, the power cable may take 40-50%, and the control cable may take 50-70%. In addition, 10-25% of the development margin needs to be reserved.
2. The specifications of various bends and accessories should be in accordance with the conditions of project layout and be matched with the bridge.
3. The selection of support and hanger specifications shall be based on the specifications of the bridge frame, the number of layers, the span, and other conditions. And should meet the requirements of the load.
4. For the bridge cross-sectional area selection, see the rated current value or setting value of the maximum automatic over-current protection of any circuit in the cable network on the watch bridge (A) Bridge cross-section allowable minimum (mm2) 0-6012961-100258101- 200452201-400645401-600968
Third, the cable bridge support, hanger configuration
1, the indoor branch, hanging short span generally take 1.5-3m. The mid-span of the outdoor column is generally 6m.
2. The following principles are followed in the configuration of the non-linear section support and hanger. When the width of the bridge is less than 300mm, a branch and hanger shall be installed on the side of the straight line between 300-600m away from the non-linear section and the straight line. When the width of the bridge is more than 300mm, in addition to the following conditions, a branch and hanger shall be added in the middle of the non-linear section.
3, pultruded fiberglass cable bridge multi-layer setting when the center distance between the layers of 200,250,300,350 mm.
4. The bridge section should be left with expansion joint 20-30mm (metal bridge) every 50m straight line section.
Fourth, fire prevention: The fire protection requirements of the bridge must be made of steel or non-flammable, flame-retardant materials.
Fifth, pultrusion FRP cable bridge grounding
1, the bridge system should have a reliable electrical connection and ground (only metal bridge).
2. The following requirements shall be met when the use of the bridge system to form a grounded mains loop is permitted. The connection resistance between the ends of the bridge should not be greater than 0.00033 ohms, and the grounding hole should be clear of the insulating coating. In a system with a direct neutral point of 1KV and below, the ground of the powered device is connected to the neutral ground of the system. When the equipment is installed to shut off the power supply, the cross-sectional area of ​​the bridge in the longitudinal direction shall not be less than the specified value.
3. When laying another grounding trunk along the full length of the bridge, each section (including non-straight section) of the bridge should be reliably connected to the grounding trunk at least one point.
4. For the vibration site, the spring ring should be installed at the connection of the grounding site.
Six, bridge system design content
The bridge system engineering design should closely cooperate with the civil engineering, crafts, and related specialties to determine the best layout. The design content can include:
1. The relevant section of the bridge system. 2. The floor plan of the bridge system. 3. Details of the specifications and quantities of straight sections, bends, supports, and hangers required for the bridge system and necessary explanations. 4. Non-standard technical descriptions or schematic drawings with special requirements.
Seventh, install
Please refer to the JSJT-121 National General Building Standard Design-Electrical Installation Standard Atlas “Installation of Cable Bridges†issued by China Building Standard Design and Research Institute during the security cable bridge midnight.
Eight, design requirements
1. The path layout of the bridge system;
2. The relevant section of the bridge system.
3, the anti-corrosion material used in the bridge system and the required specification, quantity list, etc., of the straight-through, bend-through, support (hang) frame, etc., as well as the necessary explanations. The connection plate, screws and protective cap shall be filled by the manufacturer according to the above requirements. 4. Non-standard technical instructions or diagrams with special requirements.
1. The cable bridge is an accessory project of the cabling project. Currently, there is no specific specification guidance. The specification program of a manufacturer lacks universality. Therefore, the design selection process should be based on the types and quantities of weak cables. Applicable bridges.
(1) Determine the direction: According to the floor plan of the building, combine the setting conditions of air-conditioning pipelines and electrical pipelines, convenient maintenance, and the density of cable routes to determine the best route for the cable tray. Indoors, erect as much as possible along the walls, columns, beams and floors of a building. If they are erected using an integrated pipe gallery, they should be erected on one side or above the pipeline in parallel. Consider taking down the line and the branch line to avoid crossover as much as possible. Without other pipe racks, you need to set up (branch) columns.
(2) Load calculation: Calculate the cable weight per unit length on the longitudinal section of the main cable trunking.
(3) Determine the width of the bridge: According to the number of cables to be laid, the cable diameter and the distance between the cables, determine the type and size of the cable tray, the length of the brackets, the length and spacing of the pillars, and the width and number of layers of the bridge.
(4) Determine the installation method: Determine the fixing method of the bridge frame according to the setting conditions of the site, select the suspension type, vertical type, side wall type or hybrid type, and the connection pieces and fasteners are generally supplied in an auxiliary manner. In addition, according to the bridge The structure selects the corresponding cover.
(5) Draw the flat and sectional drawing of the cable bridge, and draw a space diagram for the local parts and list the materials.
2. When used in conjunction with a power cable tray, the power cable and the weak cable should be straight and separated by a partition.
3. When weak cables and other low-voltage cables are used in combination with the bridge, weak cables should be strictly selected for weak systems with outer shields to avoid mutual interference.
4. Installation requirements for cable trays (1) When the slot-type large-span cable trays enter the building from outside, the slope of the trays should not be less than 1/100. (2) The distance between the cable bridge and the electrical equipment is not less than 0.5m.
(3) When two sets of cable trays are laid in parallel at the same height, the net distance between them is not less than 0.6m. (4) Draw the route of the bridge on the parallel diagram, and indicate the coordinate or positioning size and elevation of the starting point, the end point, the turning point, the branch point and the lifting point of the bridge. If you can draw the side view of the laying of the bridge, calculate the material statistics. Will be more precise.
Straight section: indicate the full length, number of bridges, elevation, model and specifications. Turning point and branch point: Specify the type and specification of the turning board used. Lifting segment: Note the change of elevation, which can also be represented by a partial large sample or a profile.
(5) Bridge support points, such as pillars, support arms or non-standard supports, frame spacing, installation methods, model specifications, and elevations, may agree to be listed on the plane, or may be marked in sections with different profiles, single lines Figure or large sample diagram.
(6) The location of the cable lead-in point and the way to pull it down. In general, a large number of cables can be used to guide the vertical bending plate and the vertical lead frame. A small number of cables can be used to guide the guiding plate or the guiding pipe, indicating the way to lead.
(7) The cable tray should be more than 2.2 meters above the ground. The top of the bridge should not be less than 0.3 meters from the ceiling or other obstacles. The width of the bridge should not be less than 0.1 meters. The filling rate of the cross section in the bridge should not exceed 50%.
(8) When cables are laid vertically in the cable tray, they should be fixed on the bracket of the bridge at the upper end of the cable and at intervals of 1.5 meters. When laying horizontally, the cable heading, tailing, turning and each interval of 3~5 The meter is fixed.
(9) When set in the ceiling, the open face of the tank cover should maintain a vertical clearance of 80 mm, and the utilization ratio of the cross section should not exceed 50%.
(10) The cables laid in the trunking may not be tied, the cable in the groove shall be straight, the cable in the groove shall be straight, as far as possible not crossing, the cable shall not overflow the slot, at the place where the cable enters and exits the slot, Bends should be fixed at the turn. The vertical trunking cable should be fixed to the cable bracket at intervals of 1.5 meters.
(11) When laying lines in horizontal, vertical bridges, and vertical slots, tie the cables. 4 pairs of wire cables are bundled in 24, and 25 or more trunk cables, optical cables and other signal cables should be bundled according to the type of cables, the cable diameter and the number of cable cores. The lashing distance should not be more than 1.5 meters. The spacing between the buckles should be even and moderate.
(12) When the bridge is laid horizontally, the distance between the supports is generally 1.5-3m, and the spacing fixed on the building body during vertical laying is preferably less than 2m.
Cable Bridge Type and Variety Selection and Laying Specifications
First, the choice of cable tray type and variety
1. When it is required to shield the cable network of electrical interference or to protect the external (such as: corrosive liquid leakage, flammable dust, etc.) requirements, (FB) type compound corrosion-proof shielded cable tray (with cover) )
2, strong corrosive environment should use (F) composite epoxy resin flame-retardant cable tray. The same material is used for the supporting arm and bracket to increase the service life of the bridge and accessories, and the cable tray. It is advisable to add cover plates in areas where there is a tendency to collect dust and other areas that need to be covered.
3. In addition to the above conditions, the tray type, trough type, step type, glass anti-corrosion and flame-retardant cable tray or steel ordinary type tray can be selected according to the site's environment and technical requirements. It is advisable to add cover plates in areas where there is a tendency to collect dust and other areas that need to be covered.
4. In the public access road or outdoor crossing road section, the bottom of the bottom step should be padded or used in the section. When a large span spans a public passage, the load capacity of the bridge can be increased or a stand can be selected according to user requirements.
5, large span (> 3m) to use composite bridge (FB).
6, outdoor use composite epoxy resin finger bridge (F).
Second, the cable bridge specification selection
1. The width and height of the composite epoxy resin cable tray are selected according to the following table, and should comply with the true charging rate of the cable not exceeding the specified value of the relevant standard specification, the power cable may take 40-50%, and the control cable may take 50-70%. In addition, 10-25% of the development margin needs to be reserved.
2. The specifications of various bends and accessories should be in accordance with the conditions of project layout and be matched with the bridge.
3. The selection of support and hanger specifications shall be based on the specifications of the bridge frame, the number of layers, the span, and other conditions. And should meet the requirements of the load.
4. For the bridge cross-sectional area selection, see the rated current value or setting value of the maximum automatic over-current protection of any circuit in the cable network on the watch bridge (A) Bridge cross-section allowable minimum (mm2) 0-6012961-100258101- 200452201-400645401-600968
Third, the cable bridge support, hanger configuration
1, the indoor branch, hanging short span generally take 1.5-3m. The mid-span of the outdoor column is generally 6m.
2. The following principles are followed in the configuration of the non-linear section support and hanger. When the width of the bridge is less than 300mm, a branch and hanger shall be installed on the side of the straight line between 300-600m away from the non-linear section and the straight line. When the width of the bridge is more than 300mm, in addition to the following conditions, a branch and hanger shall be added in the middle of the non-linear section.
3, pultruded fiberglass cable bridge multi-layer setting when the center distance between the layers of 200,250,300,350 mm.
4. The bridge section should be left with expansion joint 20-30mm (metal bridge) every 50m straight line section.
Fourth, fire prevention: The fire protection requirements of the bridge must be made of steel or non-flammable, flame-retardant materials.
Fifth, pultrusion FRP cable bridge grounding
1, the bridge system should have a reliable electrical connection and ground (only metal bridge).
2. The following requirements shall be met when the use of the bridge system to form a grounded mains loop is permitted. The connection resistance between the ends of the bridge should not be greater than 0.00033 ohms, and the grounding hole should be clear of the insulating coating. In a system with a direct neutral point of 1KV and below, the ground of the powered device is connected to the neutral ground of the system. When the equipment is installed to shut off the power supply, the cross-sectional area of ​​the bridge in the longitudinal direction shall not be less than the specified value.
3. When laying another grounding trunk along the full length of the bridge, each section (including non-straight section) of the bridge should be reliably connected to the grounding trunk at least one point.
4. For the vibration site, the spring ring should be installed at the connection of the grounding site.
Six, bridge system design content
The bridge system engineering design should closely cooperate with the civil engineering, crafts, and related specialties to determine the best layout. The design content can include:
1. The relevant section of the bridge system. 2. The floor plan of the bridge system. 3. Details of the specifications and quantities of straight sections, bends, supports, and hangers required for the bridge system and necessary explanations. 4. Non-standard technical descriptions or schematic drawings with special requirements.
Seventh, install
Please refer to the JSJT-121 National General Building Standard Design-Electrical Installation Standard Atlas “Installation of Cable Bridges†issued by China Building Standard Design and Research Institute during the security cable bridge midnight.
Eight, design requirements
1. The path layout of the bridge system;
2. The relevant section of the bridge system.
3, the anti-corrosion material used in the bridge system and the required specification, quantity list, etc., of the straight-through, bend-through, support (hang) frame, etc., as well as the necessary explanations. The connection plate, screws and protective cap shall be filled by the manufacturer according to the above requirements. 4. Non-standard technical instructions or diagrams with special requirements.
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