Computer room wiring planning method


If we talk about the decoration project of the computer room, then we have to talk about the integrated wiring. As we all know, integrated wiring is a modular, highly flexible information transmission channel within a building or between buildings. So, what are the specifications for the wiring in the computer room? What are the planning methods for the wiring in the computer room?


What are the specifications for the wiring in the computer room?

Specifications for wiring in the computer room: In order to ensure the safe operation of communication lines, facilitate routine maintenance, and prevent accidental communication accidents caused by messy line layout. The wiring specification will now be briefly described as follows: 1. Wiring channel selection. 1. Weak electricity, strong electricity and Fibre Channel should be separated.


2. Selection of the main wiring channel of the computer room: usually choose the four sides along the wall of the computer room.


3. Selection of wiring channels in the computer room: usually choose the space between the equipment racks. <Note> Avoid cabling channels crossing the equipment rack or occupying the location for future equipment expansion.


What are the wiring planning methods of the computer room?

First, the transmission bandwidth of the integrated wiring system

The integrated wiring system in the computer room is mainly used to transmit high-speed information transmitted between computers, including text, static data, dynamic data, web pages, static images, dynamic images, voice, video streams and so on.


These information have different requirements for transmission, and some of them also involve requirements such as delay, so the corresponding computer networks also have heavy and light loads. For example, for industrial control systems and building automation systems, it must be ensured that the data can reach the designated location on time during the transmission process, and the amount of data is not large. work under load.

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It is conceivable that when an emergency comes, the control host needs to issue a large number of commands at the same time. If one of the commands is delayed, the consequences will be inestimable. At this time, the bandwidth requirements for cabling need to be very high.


So, is it appropriate to increase all the cabling transmission bandwidth to the highest level? In fact, this is not possible due to the price. For example: for network equipment, the price of single-mode fiber optic modules must be higher than that of multi-mode fiber optic modules (light-emitting diodes for emission and phototransistors for reception) because they include a laser emission tube (transmitting end) and avalanche photodiodes (receiving end). ). If the transmission level of the integrated wiring is the highest, it will inevitably cause the network equipment to use high-end equipment, which is inappropriate from the perspective of investment calculation.


According to the provisions of TIA 942-2005, the following transmission grade cabling products can be used in the computer room:

1. Category 6 horizontal twisted pair is recommended;


2. OM1 multimode fiber (62.5/125 micron) and OM2 multimode fiber (50/125 micron) can be used, and OM3 10 Gigabit multimode fiber (50/125 micron) is recommended;


3. Single-mode fiber.


Therefore, the transmission bandwidth of cabling products can be comprehensively evaluated based on this. As the basic platform of the computer network system, the integrated wiring system needs to balance the cost of the application system, that is, the transmission protocol of the computer network needs to be considered. Looking at the IEEE 802 series of standards, we can see that the main computer network protocols currently in use are:


1. Copper cable system: Fast Ethernet, Gigabit Ethernet, 10 Gigabit Ethernet to be used;


2. Optical cable system: 100 Gigabit Ethernet, Gigabit Ethernet, 10 Gigabit Ethernet, the upcoming 40 Gigabit Ethernet and 100 Gigabit Ethernet.


It can be seen that various network protocols have very different requirements on the transmission bandwidth of integrated wiring. If a single bandwidth product is used, the network product will be limited to a small selection range. To this end, the following recommendations are made:


1. Copper cable system:

Category 6 is the main category, and Category 6A or Category 7 twisted-pair cables (shielded or unshielded) can be properly considered in the HAD area. On the premise of ensuring Gigabit Ethernet transmission, there is room for 10 Gigabit Ethernet. For the EDA area, because the twisted-pair cable is nearby and can be replaced at any time, it can still be mainly Category 6 at present, and if necessary, it can be replaced with Category 6A or Category 7 with network equipment.


2. Optical cable system:

Due to the difficulty of construction, whether it is the MDA area, the HDA area or the EDA area, the OM3 optical cable (10 Gigabit multi-mode optical cable) and the OS1 optical cable (single-mode optical cable) are laid at the same time. A product line of different types of cores, so this design has no impact on engineering. The advantage is that all kinds of fiber optic modules can be allowed to access the system.


The purpose of this consideration is: when the transmission traffic requirements are not high, cheap network equipment can be installed, and when the transmission traffic in any area increases in the future, high-end network equipment can be installed at any time, and cheap network equipment can still be used. Move to another area to continue using it. Since network equipment is rapidly updated, it is possible to add the most suitable network equipment according to needs without wasting existing equipment.


In addition, among single-mode optical cables, it is worth considering single-mode zero-water peak optical cables. According to the ITU-T G.652 standard (single-mode fiber standard), G.652A and G.652B are single-mode fibers, G.652C and G.652D are single-mode zero-water peak fibers, and G.652D can Support future 40 Gigabit Ethernet and 100 Gigabit Ethernet requirements.


With the development of optical fiber production technology, many foreign optical fiber production factories no longer produce low-end single-mode optical fibers, but only produce single-mode zero-water peak optical fibers (grade G.652D). Domestic optical fiber factories also already have single-mode zero-water peak fibers. The product line of Shuifeng Optical Fiber. In order to ensure that the integrated wiring system can still meet the upgrading of network equipment in the future, it is necessary to partially adopt single-mode zero-water peak optical fibers in the MDA area and the HDA area.


Second, the laying position of the integrated wiring system

In various computer rooms, the laying position of the integrated wiring system is divided into two categories: upper wiring and lower wiring. The so-called upper wiring refers to the space where the cables are laid and then higher than the height of the equipment, while the lower wiring is laid Under a raised floor, this says two things about top- and bottom-entry lines of equipment.


When it comes to the laying position of the integrated wiring system, there are many factors involved in the design of the computer room, such as: the degree of relaxation of the computer room space (in China, there are many computer rooms that are relatively rich and are not subject to the pressure of cost accounting), computer room equipment (Including the incoming cable direction of the server, etc.), the laying position of the strong power cable, the air duct of the air conditioner and the shape/function of the rack/cabinet, etc.


In the computer room, the most cables belong to two series: strong current and weak current, and the weak current is dominated by integrated wiring. In the past, the wiring design of the computer room mostly laid all the strong and weak currents under the raised floor, in order to facilitate the adjustment in the future. After investigation, it is found that the wiring under strong current has a fire hazard (for example, when the air conditioner leaks, it may cause a short circuit, sparks, and fire). To this end, the telecommunications system has carried out a large-scale computer room renovation for several years, and all the strong current lines that were originally routed under the line are "relocated" to the upper line by order. accepted.


For computer room air conditioners, there are two types of side air supply and downward air supply. When a raised floor is installed, most computer rooms use the downward air supply method, which forms an air transmission channel between the raised floor and the ground. , so that the cold air can be sent into the cold corridor in front of the equipment from the side and bottom of the equipment, and the air heated by the equipment is sent to the hot corridor behind the equipment using fans, and finally returned to the air conditioner for cooling.


Since the air-conditioning system is the transmission channel under the raised floor, when the weak current is routed downward, a "wind resistance" will be formed, which will increase the transmission resistance of the wind.


Therefore, strong current cables and weak current cables can form three common combinations:

1. All strong and weak currents are routed below

At this time, the strong current and weak current can only be installed from the two sides of the machine room with a fork structure, and the direction of the air duct should be carefully analyzed to minimize the resistance to the wind.


At the same time, because the strong current cable is relatively close to the ground, it is necessary to prevent the possible impact of water leakage of the air conditioner in the design, and of course, it should also prevent the damage of the strong current cable caused by human beings.


2. The strong and weak currents are all wired up

When all the strong and weak currents are routed on top, it is necessary to form a multi-layer bridge in the space, because it is best not to lay the strong and weak currents in the same bridge (except for the base station of the mobile company) to avoid introducing electromagnetic interference.


The premise of all wiring is that the floor height of the equipment room is required. In addition, since the cables of the weak current system often need to be adjusted, although the raised floor does not need to be opened when wiring, there is still a work of cable maintenance and adjustment. difficulty.


3. The upper wiring is used for strong current, and the lower wiring is used for weak current

When the strong current adopts the upper wiring and the weak current adopts the lower wiring, the safety of the strong current cable can be guaranteed, and the height requirement of the equipment room is not high, and the weak current cable often needs to be adjusted. It can be ensured that the transmission of wind will not encounter large resistance.


For some users who are reluctant to open the floor, they may prefer to use the upper cable rather than the suction cup to open the floor.


4. Threading organization planning

The key to organizing the wiring is the construction organizer. The construction organizer should: understand the overall structure of the wiring system, and do not cross the wrong route; be able to clearly distinguish the various cables to be laid, and do not use the wrong cable; be familiar with the pipelines that the cables will pass through. Rich threading experience;


Know how to prevent typical problems that affect the quality and progress of threading; understand the special requirements for cable laying of integrated wiring systems; clear thinking, group information points, and lay them in groups, not too much wear, no leakage;


There should be no more than 20 information points in each group, otherwise the amount of cables to be put on and put at the same time will be large, which will easily lead to cable damage, easy to entangle and knot, which will greatly affect the progress; make labels strictly and record the length scale; strictly Organize the test, and use the testing instrument to measure the on-off status of each cable.


The threading should be carried out according to the process requirements, the pipe groove should be checked, the steel pipe should be guarded, and the buried steel pipe should be tried on. Explain the structure of the wiring system, the threading process, the quality points and the protection of cables to all those involved in the threading. Plan the grouping, route the cables group by group, and for one of the groups, select the starting point for the threading. Transport the cable to the starting point, mark it, mark the scale at the end of the patch panel, thread this group to the patch panel, and leave the remaining length as required. Measure the length from the starting point to the socket end, truncate, label, and mark the socket end scale. The socket end is coiled within the socket box. Conduct on-off test for each cable, make up wear, and correct labeling errors. Finally, organize the threading report and buckle the cable slot cover.


At the wiring box, the excess length from the entrance of the wiring cabinet is the length of the wiring cabinet (length + width + depth). Cabinets and cable management troughs should be well organized. The remaining lines should be grouped according to the grouping table, straightened and tied from the outlet of the trunking, and the spacing between the binding points should not be greater than 50cm.


Do not bind with iron wire or hard power cord. The turning radius of the 50-core cable should not be less than 162mm. When the vertical cable is transferred into the vertical steel pipe through the cable box and goes to the next layer, it should be tied and suspended in the cable box to avoid the weight of the cable being fully pressed on the cable on the inner side of the corner, which will affect the transmission characteristics of the cable. The cables laid in the trunking should be straight, without entanglement, and without varying lengths.


The cables are labeled according to the design plane diagram, each label corresponds to a 4-pair cable, and the corresponding room and socket location cannot be mistaken. The position of the labels at both ends is 25 cm away from the end, paste light-colored plastic tape, write the label with an oil-based pen or stick the quality label on it, and then wrap the transparent tape. In addition, from the end of the distribution frame to the entrance of the distribution cabinet, every 1 meter should be used to stick the label paper on the cable sheath and write the label with an oily pen. The 4 pairs of twisted-pair cables shall be put through the spare line according to the proportion of 3%, the spare line shall be placed in the trunk trunk, and at least one spare line shall be placed on each layer.


After threading is complete, all 4-pair cables should be fully tested for continuity. Test method: Strip all the core wires of the cable at both ends to expose the copper core. At one end, turn the digital multimeter to the on-off test gear, and the two test pens are stably connected to a pair of cable cores; at the other end, briefly touch the pair of cable cores. If you can hear intermittent sound on the watch end, it is OK. The 4 pairs of core wires of each cable are tested. The problems that this test can find are broken wires, short circuits and label errors.


5. Guarantee measures for construction quality:

1. To do a good job of detailed drawings in the design stage, drawings are very important. Don't think it's very simple, a good integrated wiring design drawing can save your wiring time and some on-site problems encountered in the wiring process, because not only weak electricity, but also strong electricity, fire protection, air conditioning and so on.


2. During the construction process, the construction plan should be well prepared to cope with the constant changes. Because sometimes the plan can't keep up with the changes.


3. It is necessary to keep abreast of the progress of other parts of the entire project in order to adjust the construction plan in time.


4. Strict construction is required, and the lines must be neat and clear.


5. Make a good label, otherwise it will be miserable in the back.


The above is all about the specifications of the equipment room wiring and the planning methods of the equipment room wiring. Due to the different objects faced by the equipment room, the bandwidth requirements for the wiring cables will be different, and the requirements for the routing methods will also be different. The above description can only be used as a reference, and the practice in the actual project still needs to determine the most suitable method according to the designer's efforts.



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