Construction technology of six kinds of lines in integrated wiring system

The transmission rate of the Category 6 cabling system can provide high-speed bandwidth about three times higher than that of the Category 5e cable, and the ACR value is 300% higher than that of the Category 5e cable at 100MHz. In terms of construction and installation, Category 6 is much more difficult than Category 5e. The construction of the six-category wiring system must be carried out in accordance with the specifications required by international standards. Because "the more advanced the copper wire is, the more sensitive it is to the external environment. As the transmission rate increases, the correctness of the installation and construction will have a greater impact on the system performance."

Unreasonable line arrangement, non-standard installation steps, and inadequate management agencies will all have an impact on the test results (including physical and electrical properties) of Category 6 wiring, and some will become difficult-to-repair faults, or even only Re-route a link to replace.

1. Matters needing attention in the construction of the six-category wiring system

Since the outer diameter of the Category 6 cable is thicker than that of the general Category 5 cable, in order to avoid cable entanglement (especially at the elbow), you must pay attention to the filling degree of the pipe diameter when laying the pipeline. Generally, the cable with an inner diameter of 20mm It is advisable to put two Category 6 lines in the tube.

Strictly abide by the construction specifications of the trunking to ensure an appropriate cable bending radius. When going up, down, left, and right around other wire slots, the turning slope should be gentle. Pay attention to whether the cables at both ends can still be covered with the cover plate after the cables are drooped and stressed without damaging the cables.

During the pay-off process, attention is mainly paid to the control of the tension. For cables packaged with reels, the reels should be placed on the self-made pull rods, and a part of the cables should be pre-pulled from the reel box at the pay-off end for use in other parts of the pipeline. One end is extracted, and the pre-drawn wires should not be too much, so as to avoid multiple wires being entangled on the field.

After the wire drawing process is completed, the redundant cables left at both ends should be organized and protected. When coiling the wires, the original rotation direction should be followed. Mark it up. When arranging, tying, and installing cables, the redundant cables should not be too long, and the cables should not be subjected to superimposed stress.

2. Several problems that need to be paid attention to in construction

Before construction, you must carefully consult other professional construction drawings, especially civil structure construction drawings, water, electricity, ventilation construction drawings. Because the length of the horizontal route will have a certain impact on the level of the system, and the civil structure construction drawings, water, electricity and ventilation construction drawings have the greatest impact on the direction of the horizontal wiring subsystem pipe lines.

When reviewing the drawing, the scale is carefully measured on the drawing to find out the most reasonable routing direction for the horizontal wiring subsystem, which not only saves the length of the horizontal cable, but also avoids conflicts with other professional pipelines. Because the electrical professional pipelines inevitably overlap with other professional pipelines, The horizontal pipeline of the horizontal wiring subsystem accounts for the largest proportion in the integrated wiring system, and if it is not handled properly with other professional pipelines, it will bring great inconvenience to the electrical construction, and the phenomenon of contradiction will bring high ground and other problems to the civil construction profession.

Before the pipeline of the horizontal wiring subsystem is buried, the joint examination of the drawings should be carefully done, and the technical disclosure should be made to the construction, and the cross-overlap and contradiction with other professional pipelines should be avoided as far as possible. AutoCAD can be used to draw 3D large drawings, indicating the direction and elevation of other professional pipelines and the specifications and models of various pipelines on the large drawings, and formulating the optimal pipeline construction scheme to meet the requirements of the shortest pipe line and easy installation.

At present, there are three methods for horizontal wiring: steel pipe laying method, cable trough in the suspended ceiling, steel pipe connection method between the cable trough and the information point, and the ground cable trough laying method, of which the ground cable trough laying method is suitable for high-grade intelligent buildings. The office space arranged in the building with dense information points and large open rooms that need to be partitioned is characterized by relatively large investment, high technological requirements, and difficult construction.

Integrated wiring is generally responsible for installation and debugging by professional companies, the construction party only do pipeline embedment, cable laying, if we in the construction perfunctory, do not follow the "pipe line by the shortest" principle, it will increase the length of the horizontal wiring subsystem pipeline, is not conducive to improving the communication capacity of the integrated wiring system, is not conducive to the stability of the communication system, is not conducive to the improvement of communication transmission rate.

Design margin should be satisfied in construction. Because in the actual construction, it is impossible to keep the horizontal cable straight route, so in the actual installation, the cable needed is always much larger than the amount of statistics on the drawing, which needs to consider a certain margin. The margin is calculated by adding the length of the cable drawing at the farthest information point from the distribution frame on a plane drawing (the length measured by a scale on the drawing) and the length of the cable drawing at the nearest information point, dividing by 2, and the resulting value is the average drawing length of the information point, taking 20% of the average length as the margin. Otherwise, unnecessary material waste will be caused.

In most designs, the horizontal wiring subsystem is designed in the ceiling, wall or bottom plate, so it can be considered that the horizontal subsystem is an unchangeable, permanent system. In the installation, the pipes and cables with excellent performance and reliable quality should be used as far as possible to ensure that the user does not damage the building structure in the future. Good installation quality can make the horizontal wiring subsystem always ensure good working condition and stable working performance during its working cycle, especially for high-performance communication cables and optical fibers, the installation quality has a particularly significant impact on the opening of the system, so the author believes that in the installation of cables, EIA/TIA569 specifications should be strictly complied with.

The cables, information sockets, jumpers, connecting cables and other components used in the integrated wiring system must be consistent with the types selected. If the type 5 standard is selected, the components such as cables, information sockets, jumpers, and connecting cables must be of the type 5. If the system adopts shielding measures, all the components selected by the system are shielding components, only in this way can the shielding effect of the system be guaranteed and the design performance indicators of the entire system be achieved.

3. Ground metal trough construction technology

The ground metal trough wiring is a new type of wiring method which is introduced in order to adapt to the complex weak current system of intelligent building and the variable position of the outlet. The ground metal groove is divided into single groove, double groove, three groove and four groove. When laying metal cable troughs on the ground, electrical professionals should closely cooperate with civil engineering professionals, and determine the location of the distribution box based on the location of the outlet of the construction drawing and the direction of the cable troughs. The cable trough should be provided with a distribution box at the intersection, turn or branch.

The line led to the cable trough by the distribution frame, hub, distribution box and other devices between the equipment is connected to the cable trough with the terminal deformation connector. A fixing bracket and adjusting support are arranged at every 2 meters of the wire slot, and are connected with the steel bar to prevent displacement. The protective layer of cable troughs should be at least 35mm. After cable troughs are connected, adjust them as a whole. Use a measuring tool to check the cable troughs.

Apply sealing strips to connectors, distribution boxes, and cable trough joints to prevent mortar from penetrating into and corroding the inner wall of the cable trough. Waterproof protective covers should be added to the cable outlet and distribution box during cable trough connection. When the concrete strength of the bottom plate reaches 50%, remove the protective covers and replace them with identification covers. In construction, the burr of the metal wire groove is filed with a steel file, otherwise it will scratch the outer skin of the twisted pair wire, reduce the anti-interference of the system, data confidentiality, data transmission speed, and even lead to the system can not be opened smoothly.

4. Laying cables

The horizontal wiring subsystem requires a distance range of 90m, which refers to the actual length from the distribution frame between the floor wiring to the information point in the work area. Other cables related to the horizontal wiring subsystem, including jumpers on the distribution frame and lines in the work area, should not exceed 90m in total. Generally, the length of the jumper is less than 6m, and the length of the information cable is less than 3m.

Because the metal groove is concealed in the ground, its heat dissipation condition is better than that of the open groove. The control and signal lines are non-current-carrying cables, and there is no problem of cable damage due to poor heat dissipation effect. Therefore, the filling rate in the online slot of the twisted-pair cable can reach 50% of the section of the slot. All twisted-pair cables of the same loop can be routed in the same slot. Strong and weak cables should be laid in slots, and a distribution box with a shielded distribution board should be provided at the intersection of the two lines. The cable must not have a connector, and the connector should be handled in the distribution box or cable trough outlet box.

The cable installation method under the floor of the distribution subsystem should be selected according to the environmental conditions under the floor bridge wiring method, honeycomb floor wiring method, elevated (active) floor wiring method, under the floor pipeline wiring method and other four installation methods. The cables of the distribution subsystem should be laid through steel pipes or along the metal cable bridge, and the shortest path should be selected. The vertical channel of the trunk subsystem has three options, such as cable holes, pipelines, and cable shafts, and it is appropriate to use cable holes. The horizontal channel can be pipe or cable bridge.

A pipe should be routed through a comprehensive wiring cable. When the amplified logarithmic cable is routed through the pipe, the pipe diameter utilization of the straight pipe should be 50% to 60%, and the pipe diameter utilization of the curved pipe should be 40% to 50%. When four pairs of twisted cables are routed in the pipe, the section utilization rate should be 25% to 30%.

Integrated wiring cables, cable TV cables, fire alarm cables, monitoring system cables are allowed to use metal cable trays, but they should be separated from cable TV cables by metal partitions.

Dark wiring in buildings can generally use metal wiring materials or plastic pipes. Because the metal wiring material has a shielding effect, parallel or cross with the strong current (more than 220V) pipeline can reduce the separation requirements, so it is the first way.

5. Protective grounding system for integrated wiring

Grounding technique

When the integrated wiring system adopts shielding measures, it should ensure that there is a good grounding system, and the grounding body can be set separately, and the grounding resistance is less than 4Ω. When the combined grounding body is used, the grounding resistance must be less than or equal to 1 ohm. The shielding layer used in the integrated wiring system must maintain continuity, and ensure that the relative position of the cable is unchanged, and the end of the distributing device of the shielding layer should be grounded.

When a shielded integrated wiring system is adopted, if the shielded wiring device (FD or BD) end of the shielded layer must adopt a shielded wiring system, the wiring cabinet on each floor should be separately wired to the grounding body with appropriate section of copper wire, or the centralized copper bar or thick copper wire in the shaft can be led to the grounding body. The section of the wire or copper conductor should meet the standard.

The ground conductor should be connected to a ground network with a tree structure to avoid DC loops. The grounding of the information socket can be connected to the distribution cabinet of each layer by using the cable shielding layer. The shell grounding of the workstation should be connected to the grounding body separately, and several workstations in an office can share the same grounding wire, and an insulating copper wire with a cross-section of not less than should be selected. Shielded cable Shielded layer grounding at both ends Measure the difference between the current of the link shielded cable, the shielded layer and the ground at both ends ≤5v.

When cables for integrated wiring are laid in metal troughs or steel pipes, the troughs or steel pipes should maintain continuous electrical connections and be well grounded at both ends.

The location of trunk cables should be close to the vertical ground conductor (such as the steel structure of a building) and located as far as possible in the central part of the network of the building.

Each layer of the distribution frame should be separately wired to the ground body, the grounding of the information socket is connected to the distribution frame on each floor by using the cable shielding layer, and the metal shell of the weak current device of the workstation is separately connected to the dedicated ground body.

When laying cables using steel pipes or metal Bridges, reliable connections should be made between steel pipes, Bridges, and Bridges, and cross-ground cables should be made. The positive electrode or metal shell of the active equipment related to the integrated wiring system, and the trunk cable shield layer should be grounded. If there is a pressure balancing ring in the same layer (higher than 30 meters and above, each layer should be set), it should be connected to make the grounding system of the entire building form a cage voltage balancing network. Good grounding can prevent the damage of weak current equipment by sudden voltage shock and reduce the influence of electromagnetic interference on communication transmission rate.

Protection technique

When the cable enters the building from the outside, it is vulnerable to external influences such as lightning strike, power supply touching the ground, power supply induced potential or ground potential floating, and so on, a protector must be used. In any of the following cases, the line is in a dangerous environment and should be protected against overvoltage and overcurrent.

The positive pole or shell of the active equipment of the integrated wiring system, the cable shield layer and the connected grounding line should be grounded, and the joint grounding method should be used, as if the layer has a lightning protection belt and a voltage equalizing net (each layer is set higher than 30m), it should be connected with this, so that the grounding system of the entire building constitutes a cage voltage equalizing body.

Fire-proof and anti-virus cables should be used for laying cables or optical cables in inflammable areas and building shafts; Flame-retardant wiring equipment should be used between adjacent equipment. Ordinary outer sheathing can be used for cables or optical cables through steel pipes. The network composed of integrated wiring system should prevent electromagnetic pollution generated by radio frequency and affect the normal operation of other surrounding networks.