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Common construction quality problem solving methods for integrated wiring engineering
Time：
2018-04-06 13:11
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Foreword:
The quality of the integrated wiring system directly affects the normal operation and use of the intelligent building system, so the implementation quality of the integrated wiring project is crucial.
The factors affecting the quality of integrated wiring engineering include: people, materials, machinery, methods and environment. The following paper combines the experience of actual integrated wiring engineering to talk about some common quality problems and prevention methods of integrated wiring engineering. Discuss with relevant personnel engaged in integrated wiring engineering.
During the construction of the online slot, the following situations are usually encountered: the cable trough is also changed after the decoration is changed.
As a result, some of the cables are not long enough; the ceiling of the decoration cannot be opened until the trunking cover is closed, the fixed ceiling cannot be laid, and there is no inspection port; there is not enough space between the channels and other professional pipes.
The reasons for the above situation are: after the completion of the work, due to changes in the use of the room, the decoration needs to be changed. Before the construction, there was no coordination with the decoration and other professions. After the completion of the decoration, the trunking could not be laid. The modified trunking needed to bypass the decoration obstacles, which increased the construction difficulty and the cable was not good. The elevation of the ceiling and other professional pipelines was not suitable for the system. The requirements for the trunking; the construction of the trunking is not standardized, and sufficient operating distance is not reserved as required.
To prevent the above situation from occurring, the prevention measures are:
First, it is necessary to look at the drawings and familiarize yourself with the on-site construction environment before construction.
Second, the construction of the cable trough is coordinated with the decoration and other professions.
Third, problems found during construction should be promptly reported to the general contractor or coordinator. In case of difficulties in coordination, some effective remedial measures should be taken actively. For example, when a cable trough is to be shared with a strong cable, a metal partition should be added. Board to prevent electromagnetic interference.
Second, the problem of metal wire tube installation defects
In the installation process of the metal wire pipe, the pipe wall is thin, the pipe pipe bender and the pipe pipe are not matched, the structure and construction specifications of the building are not fully understood, and the construction personnel cut corners during the implementation process. For other reasons, the common quality problems are as follows: the bending radius of the conduit is too small, the bending is severely concave and cracked; the kerf is not burr, the connection of the sleeve is not strong, and the installation of the tube is out of specification; The pipe has no grounding or grounding protection, and the electrical continuity is unqualified; the surface mounted pipe is not treated with anti-corrosion treatment.
To prevent the above situation from occurring, the prevention measures are:
First, metal wire pipe cutting generally uses hacksaws and special pipe cutting knives. It is strictly forbidden to cut with gas welding. The burrs of the inner diameter are flattened with a boring tool to keep the pipe mouth smooth and horn shaped. When the pipe is laid, the pipe clamp is fixed, generally 1.5m, and a pipe clamp card is added at both ends of the pipe joint and about 20cm at the elbow. The elbow should be equipped with a suitable pipe bender. When bending the pipe, first place the front end of the pipe to be bent in the pipe bender to prevent the pipe from bending, use the foot to press the pipe, bend the pipe bender, and gradually bend. Move the bender and slowly pull it to the desired camber. When conditions permit, the bent pipe will be filled with sand before the pipe is bent.
Second, the metal tube connection tube hole should be aligned firmly and the sealing performance is good. The thin-walled metal pipe connection should be constructed by JDG process, which is simple and convenient. Connections and grounding of galvanized metal conduits are strictly prohibited by electric or gas welding.
Third, before the construction and installation of the metal line pipe, the anti-corrosion paint should be brushed or checked to ensure that the anti-corrosion is correct, and then installed. After installation, check it again. It is found that there is a place where local anti-corrosion damage should be remedied in time to make anti-corrosion paint.
Third, the coaxial cable connection problem
In the video surveillance system, the output impedance of the analog camera is 75Ω unbalanced, and the input impedance of the console and monitor is also 75Ω unbalanced. For the impedance matching of the whole system, the transmission line often adopts 75Ω characteristic impedance. The TV monitoring system is generally a medium and small-sized system with medium and short distance. The coaxial cable is the most widely used video transmission line in the current monitoring system. The coaxial video transmission technology is also one of the most basic transmission methods in the monitoring system.
If the characteristic impedance of the coaxial video transmission cable does not match, it is usually the case that the image has vertical bars with equal spacing. On the screen of the monitor, several vertical bars with equal spacing are sometimes generated. When the waveform of the interfered image is viewed with an oscilloscope, the frequency of the interference signal is found to be substantially an integer multiple of the horizontal frequency.
The interference signal is superimposed on the back shoulder of the line sync head with a higher amplitude line frequency harmonic oscillation waveform, and the vertical line interference is caused by this. If the "starting end" or "terminal" impedance of poor quality coaxial cable or signal transmission of more than 250m is seriously mismatched, it may cause the above interference.
The solution to the above interference is to connect a 75Ω resistor at the “start” and a 75Ω resistor at the “terminal” to avoid impedance mismatch and excessive distribution parameters. At the same time, the use of high-quality coaxial cable, that is, the outer shielding net is copper, not less than 96 series, the core wire is also a multi-strand copper.
Fourth, the information socket installation is not standardized
In the integrated wiring project, it is often seen that the information point module short wiring head is too long, the wire pair lay length is too long, the information module has dust and moisture, and the information socket cable is reserved too long, the panel The installation is not in place, and the information socket under the office screen is not installed properly.
The reasons for the above are as follows: no special network termination tool is used for termination, and it is convenient to unscrew the wire pairs for termination. The construction personnel of the network termination did not receive professional training, and the information point panel and the dust cover were reversed, or the quality of the socket panel was too poor. There is no attention in the construction installation whether the screen is matched with the panel.
To prevent the above situation from occurring, the prevention measures are:
First, the stripping of the cable sheath should be carried out with a special wire stripper. The insulation layer must not be stripped and the cable should not be disconnected. One-to-one twisting is performed when crimping, and placed in the port corresponding to the information module.
Second, when installing the information socket under the screen, pay attention to the top of the panel of the panel to the bottom plate. The panel should be close to the screen partition, and the fixing should be firm until the hand cannot be turned.
Third, we must pay special attention to the actual situation on the spot. Some screen partitions and information socket panels are not matched.
Fourth, the quality of the panel should be strictly controlled. At the time of construction and installation, attention should also be paid to the closing of the joint between the bottom box and the surface of the building or the surface of the decorative layer.
Fifth, the tip of the cable tie is left
Installers who often use small cable ties may not know that it is dangerous to use long cable ties. For a 4-inch cable tie, it is okay to cut the cable tie at the tie-tab knot with a side knife or a lineman's pliers. However, if the long cable tie made of vertical hard material is cut like this, it will leave a pointed tip. Its sharpness is surprising enough.
It is a solution to bend away rather than cut it. In fact, no matter what type of cable tie, this practice is a good habit.
The specific procedure is:
First, do not cut the cable tie cleanly at the head or the knot, but leave a nibble about half an inch long from the knot.
The second is to use the pliers used by the lineman or a pair of hard needle-nose pliers, insert the nose into the prominent position of the tie, and grasp the strap.
The third is to hold the pliers handle while bending the band until the tie falls. It can be bent seven to ten times. The fourth is to use the finger to touch the knot, feel the edge, and no longer poke people.
Integrated wiring systems have become an important part of modern architecture. Any installation errors in the integrated wiring may result in the project being barely qualified or unqualified, thus affecting the normal operation and use of the building.
Therefore, in the integrated wiring construction, it is necessary to strictly abide by the installation method specified in the wiring standard documents, and adopt a high-quality installation method, in order to build a high-quality integrated wiring system, in order to make the integrated wiring system play its due role.