Discussion on cable selection method of integrated wiring system

Integrated wiring is one of the key links in the information network system. In order to ensure the high-speed and stable operation of the information network system, it is particularly important to select high-quality and high-performance cables. The choice of cable should be based on the requirements of the system, technical performance, Investment estimates and other factors, but in the wiring system should first determine the type of cable and the structure of the wiring ( Unshielded cable, shielded cable, optical cable or a mixture of several). Cables usually use wires with insulating layers and one or more layers of plastic skins. The cable usually consists of 2 to 3600 wire pairs. Large logarithmic cables are commonly used in backbone cabling systems and are suitable for voice and low-rate data transmission. These cables are on the trunk and level (Hub to desktop) Maximum length in cabling system applications in the latest GB50311-Detailed instructions in 2007. It should be noted that these maximum length restrictions apply to all media. They do not consider the impact of performance differences due to different cable types and protocol types used by the network. In fact, the maximum cable length will depend on the application of the system, network type and cable quality. The method of selecting cables for integrated wiring systems, according to '2013- According to the data from the analysis report on the development prospect and investment strategy planning of China's intelligent building industry in 2017, the market of China's intelligent building industry has also developed with an annual growth trend of more than 200 after breaking through 20% yuan for the first time in 2005, the market size reached 861 yuan in 2012. Judging from the data, intelligent buildings have developed rapidly in China in recent years, which also shows that intelligent buildings are a major trend in the development of buildings in the future. Since it is a building, a large number of communication cables will definitely be used. As the nervous system integrated wiring system in intelligent buildings, it is the key part and infrastructure of Intelligent Buildings. It is closely related to the planning and design, construction, installation, maintenance and use of construction projects. It is like an information highway in a building, on which people can communicate conveniently, quickly and effectively. It can be said that the integrated wiring system connects the communication, computer and various facilities and equipment in the intelligent building to form a complete whole to meet the requirements of high intelligence. But then we have to consider a problem: fire prevention. Because in the event of a fire in the building, the heat and toxic gas released by these cables will become a major safety hazard. Throughout the several large fire accidents happened in recent years in China, many of them are because the victims can not escape, the burning of cables emits toxic acid gas, plus a lot of heat and smoke released by the burning, causing the victim's breathing difficulties, leading to tragedy. Therefore, when we choose the cable of the integrated wiring system, in addition to considering the performance, fire prevention and environmental protection are also particularly important reference factors. China's 'code for Design of Integrated wiring engineering GB50311-' promulgated in 2007- 2007 'introduces the grade of cable fire prevention and environmental protection for the first time. The standard suggests that domestic users choose different grades of fire prevention or environmental protection cables according to different occasions. At present, the communication cable sheath materials in the domestic market are mainly divided into three types: 1. Ordinary (PVC)Type; 2, low smoke halogen-free type (LSZH/LS0H); 3, fire-resistant type (fireresistant). The selection of fire prevention or environmental protection grade of integrated wiring cable should be considered comprehensively according to the actual situation on site: if the overhead floor or ceiling building overhead floor or ceiling is PVC trunking/pipe and air conditioning and ventilation system is installed, in overhead floor or ceiling nei yi the flame retardant level (CMP or OFNP)Cable; If metal trunking/pipe or fire-resistant PVC trunking/pipe is used in the overhead floor or ceiling of the building, random fire rating ( CM//CMR/CMP or OFN/OFNR/OFNP)Cable. For buildings with environmental protection needs, such as crowded occasions ( Airports, subways, stations, hospitals, exhibition centers, etc) When designing the integrated wiring project, cables conforming to LSZH grade should be selected, and metal trunking/pipe with fire prevention function or flame retardant PVC trunking/pipe should be adopted at the same time. Vertical Shaft building if the vertical shaft is PVC trunking (Conduit), Vertical shaft should adopt vertical level (CMR or OFNR)Cables or optical cables of the above grade; If the vertical shaft is a metal trunking/pipe (Or flame retardant PVC trunking/pipe) , The vertical shaft can use random fire rating ( CM/CMR/CMP or OFN/OFNR/OFNP)Cable. Based on the above analysis, in addition to the factors such as the technical performance index and routing mode of the cable, the designer must also ensure that the construction and installation personnel organize the construction according to the design requirements and specifications, acceptance personnel must also test and accept in strict accordance with the specifications and design, so as to ensure the operation of the information network with high quality and high performance. If there is no integrated wiring system in intelligent buildings, all kinds of facilities and equipment will not operate normally because there is no information transmission medium, and intelligence is difficult to realize. The choice of system cables has also become an element that cannot be ignored. Here, we also remind everyone that in addition to performance, fire prevention and environmental protection should also be taken into account when choosing integrated wiring system cables, improve the safety index in the building.