Integrated Wiring standards Promote the Development of the cabling Industry

1. The cabling standard classifies shielded twisted pair wires.

Compared with the version 2000 standard, the current debate on the shielded wiring system is basically absent, and the discussion of engineering applications and methods is underway. With shieldingTwisted Pair wiresIn the new standard, four representative shielded twisted pair structure are defined, which makes the shielded twisted pair no longer a general concept, and began to enter the rational application stage of shielding performance.

In the past, the codes used to shield twisted pair wires were ScTP, STP, FTP, and SFTP. When the shielded structure of twisted pair wires was only added with wire mesh or (and) Aluminum Foil outside the core wires of the twisted pair wires, these symbols can describe the shielding structure, but the four symbols become blurred when the shielding layer is armed to each core line, because they cannot accurately describe the new shielding structure.

In order to solve this problem, the new version of the national standard cited the definition of the shielding structure in ISO11801-2002, the use of "/" as the four core line overall shield and each core line separately shield separator, u, S, and F are used to correspond to unshielded, wire mesh shielded, and aluminum foil shielded respectively. By combining separators and letters, a true description of the shielded structure is formed. For example, the unshielded structure is U/UTP. The four most common shielding structures are F/UTP (total aluminum foil shielding) and U/FTP (aluminum foil shielding) SF/UTP (screen + total aluminum foil shielding) and S/FTP (total screen shielding + aluminum foil shielding ).

In principle, the reasonable combination of wire mesh and aluminum foil can give full play to the combined shielding performance of two different materials and two different shapes of metal materials. In this sense, the new four groups of shield symbols represent four different levels of shielded twisted pair wires.

2. the cabling standard puts forward a new idea for the layout principle of information points.

In the new version of the International Standard, the workspace definition is no longer 6 ~ 10m2, but according to the actual layout, from several square meters to hundreds of square meters. Different configuration schemes are also proposed for the information points of each work area based on different work types.

In actual engineering design, the workspace definition is sometimes very vague, but the number of information points corresponding to each job is regular, and there are certain rules for various purposes. Its quantity sometimes far exceeds the new national standard. But in general, the provisions of the new national standard still have a wide range of practical value.

3. The number of information points that can be installed in each chassis should not be greater than two

In the current product sequence, we often see three or four 86-type panels, which means that three or four modules and the corresponding twisted pair wires can be installed in the space of an 86-type chassis. From the perspective of plane space, a 86-type panel does have four modules installed, but from the perspective of the bottom box capacity, if you want to accommodate four modules and all the twisted wires retained on the rear of the module, there are some problems in the project.

For the module end on the panel, whether the module is installed from the rear side of the Panel or from the front of the Panel, a pair of twisted wires must be retained after the module, enable the module to be mounted on the hand and attached to the Panel (or wall) for end connection, and then inserted back into the panel. Therefore, if no twisted pair wires are left behind the module, it is almost impossible for the construction personnel to do so. At the same time, the reserved twisted pair wires can also be used to redo the end connection in case of a terminal connection failure.

In the regulations, 150 ~ should be reserved for electrical panels ~ 200mm of wires, so after the panel of the Integrated Wiring System, a similar number of twisted wires should be reserved, and the reserved twisted wires mean that there is enough space in the chassis. The general depth of the 86-type chassis is 44 ~ 46mm, it is more appropriate to accommodate two modules in the bottom box and their corresponding twisted pair wires.

4. The cabling standard provides clear quantitative indicators for Engineering Performance Testing

The performance test of the Integrated Wiring System has been in China for more than 10 years. More than a decade ago, the pass rate of the Integrated Wiring System was relatively low, and the construction staff's attention was mainly focused on passing tests. However, more than a decade later, the performance testing has become inevitable, in some contracts, the qualification rate is even 100%. In this case, it is necessary to apply mathematical statistics to determine quantitative indicators of engineering quality. At the same time, the determination of quantitative indicators shows that today's construction workers are no longer worried about passing the test, they have begun to move to a new height-neat and beautiful.

5. The cabling standard makes meaningful modifications to the length definition of the trunk system

In the new design standard, the definition of the permanent link length of a complex trunk line, a building trunk line and a horizontal cable cannot exceed 2000 m, and a horizontal cable cannot exceed 90 m is put forward. The actual meaning is: the total length of the complex trunk line and the building trunk line is determined, but the specific length of the two trunk lines is not divided.

In fact, building complex trunk lines can be seen as an extension of building trunk lines outside. The electrical and optical properties of the cables they use are the same, but they differ in protection materials. Therefore, in engineering design, designers have never been interested in the length division between the two trunk lines, the maximum length of the trunk line used is analyzed from the transmission distance of the computer network and the transmission distance of the telephone line. In a large building like an airport, the length of the building trunk line is often far greater than the m length specified in the original standard. If the standard is used for restrictions, it will increase the complex structure of the system for engineering design, without any beneficial effect.

6. The wiring standard puts forward grade requirements for flame retardant, but does not put forward fire resistance requirements

In the new version of the standard text, the general requirements for fire prevention and fire resistance are put forward. In the description of the provisions, the fire retardant performance of indoor Integrated Wiring cables is set to a level requirement, which is basically consistent with the relevant international standards, it is also an inevitable path for the future of flame retardant cables. However, there is no fire resistance level requirement in the description of the Provisions. Perhaps because of the standard division of labor, the specific requirements for flame retardant and fire resistance are already included in the jurisdiction of other special standards.

In the international IEC standard, the flame retardant standard belongs to the IEC60332 series and the fire resistance belongs to the IEC60331 series. Their functions are completely different. Flame Retardant refers to the length of the cable that allows the fire to spread along the cable in the standard flame. It represents whether the cable will become the fire-spreading wire; fire Resistance refers to the time when the cable can continue to work in the standard flame. It represents the time when the device can continue to work after the fire.

From the purpose of application, the focus of the flame retardant series cables is to minimize the probability of death caused by cables and reduce the spread of fire after a fire, for this reason, the maximum operating temperature is mostly lower than 500 ℃. The focus of the refractory series cables is that the cables can still work normally in the flame at a temperature above 750 ℃ ~ 90 minutes.

For the fire emergency broadcast system and computer backup system in the data room, if they want to save or save data through transmission, the cables they need should comply with IEC60331 standards. Of course, there is already a cable that can comply with both the IEC60331 standard and the IEC60332 standard. Naturally, two different requirements are taken into account at the same time.

For the fire emergency broadcast system, there are two types of cables that may require continued work under the flame: first, the cables connecting the speakers (although domestic speakers do not have fire resistance at all, but not all the speakers in the fire are in the flame). Second, for a distributed broadcast system, the communication cables between modules need to be refractory, otherwise, an emergency broadcast of the fire may be interrupted.

7. The cabling standard puts forward the level requirements for industrial-level cabling

When looking at the foreign Integrated Wiring standard, I always noticed that its title name often has a qualified word: "Commercial Building ". In fact, the integrated cabling systems we use are often commercial products that can be used in the most extensive civil and commercial buildings, it can also be used in industrial or military fields with low environmental requirements. However, in electronics, electronic devices and electronic products are clearly divided into commercial, industrial, and military levels. Their use range is significantly different, and their prices are also very different. For harsh application environments, they have the best military level, followed by industrial level, and the lowest level for commercial use.

In the Integrated Wiring System products, there have been products specifically designed for harsh environments, which are referred to as industrial-level cabling systems in standards. They have the ability to defend against various harsh environments, such as strong electromagnetic fields, oil stains, water, dust, and smoke (of course, for specific products, it may only defend against one or more of these harsh environments ). This is clearly beyond the limits of the commercial environment, bringing the Integrated Wiring System to harsh factories, seaside and ships.

8. The cabling standard puts forward clear requirements on the cabling of buildings, but there are operational difficulties.

In the new standard, mandatory provisions are adopted: "When the cable enters the building from outside the building, the adaptive signal line surge protector should be selected ,......" This will play a significant role in line lightning protection. This article is very effective for buildings such as commercial buildings and office buildings, but it brings a practical problem for residential buildings (especially multi-storey and high-rise residential buildings in the South, is it necessary to set up telephone lines for lightning protection in each residential building?

When passing through the outdoor wall-mounted telecommunication distribution box in the residential area and the telephone distribution box in the residential building, I have noticed that the lightning protection module is invisible on the distribution frame. So does it mean that lightning protection should be installed on the general distribution frames of China Telecom in residential areas in the future, and lightning protection should be installed on each telephone line in residential buildings to protect those telephones worth 20 yuan?

When I made a bidding in the end of 1990s, an expert asked the author a question: why does the telephone in the park use a large logarithm of cable to protect against thunder, is Lightning Protection enabled on the computer and DDN data lines? To this end, I have asked small telephone switch manufacturers, they replied: first, the telephone switch board is equipped with a lightning protection circuit; second, the telephone do not have to install lightning protection, because the value of the telephone is not as high as the cost of lightning protection, the telephone can be changed directly after it is damaged.

The new revision of the cabling standard seems to be more interested in the value of leading the technology and play a leading role in the development of integrated cabling systems in China, it also makes the products, design, construction and acceptance of the Integrated Wiring industry more standardized.