Common problems of indoor and outdoor optical cables

Below we introduce the related issues of implementing indoor and outdoor optical cable wiring. Usually, in integrated wiring, we will encounter the laying of indoor and outdoor optical cables. The laying of indoor optical cables is mainly used in the laying of horizontal subsystems and vertical backbone subsystems. Indoor and outdoor optical cable wiring

1. Laying of indoor optical fibers

In order to prevent sagging or slipping, the optical cables must be firmly fixed at the top, bottom and middle of the channel on each floor. Usually, nylon cable ties or steel clips can be used for effective fixing. Finally, the linseed sealing material should be used to block and seal all the slots and pipe holes where the optical cables pass through in each floor of the building, and fire prevention measures such as adding fireproof materials should be taken to achieve the effect of moisture resistance and fire prevention.

When laying the optical cable, an appropriate length should be reserved according to the design requirements. Generally, 5m-10m should be reserved at the equipment end, and it can be extended appropriately if there are special requirements.

Second, the laying of outdoor optical fiber

The laying of outdoor optical fibers is divided into the laying of duct optical cables and the laying of direct buried optical cables

Laying of duct cables

1. Clean and test. Before laying the optical cable, the tube holes should be cleaned and tested section by section. When cleaning, use a special cleaning tool, and use a test stick for a test pass inspection after cleaning. The inner diameter of the plastic sub-tube should be 1.5 times the outer diameter of the optical cable. When laying more than two sub-pipes in a cement pipe hole, the equivalent total outer diameter of the sub-pipes should be less than 85% of the inner diameter of the pipe hole.

2. Lay out the plastic sub-pipes. When putting more than two plastic sub-pipes, if the pipes are of different colors, the ends may not be marked. If the pipes are of the same color or have no color, the ends shall be marked separately.

3. Optical cable traction. The pulling length of the optical cable at one time should generally be less than 1000m. When the distance is exceeded, segmental traction or auxiliary traction should be added at the middle position to reduce cable tension and improve construction efficiency. In order to protect the appearance of the optical cable from damage during the traction process, protective measures such as guiding devices or bell mouth protection tubes should be used when the optical cable penetrates into the pipe hole, the corner of the pipe, or crosses with other obstacles.

4. Reserve margin. After the optical cables are laid, the optical cables should be placed on the specified pallets one by one in the manhole or hand hole, and an appropriate margin should be left to prevent the optical cables from being too tight. When the optical cable in the manhole or hand hole needs to be spliced, the reserved length should meet the minimum value specified in the table.

5. Joint treatment. Optical cables must not have joints in the tube hole in the middle of the tube. When the optical cable has no connector in the manhole, the optical cable is required to be bent and placed on the optical cable pallet for fixing and binding, and it is not allowed to pass directly in the middle of the manhole, otherwise it will not only affect the construction and maintenance, but also easily cause damage to the optical cable. When the optical cable has a joint, it should be protected by a serpentine hose or a soft plastic tube, and placed on a pallet for fixing and binding.

6. Blocking and identification. The outlet end of the tube hole where the optical cable is threaded should be tightly sealed to prevent water or debris from entering the tube. The optical cable and its connection should have identification marks, and indicate the serial number, optical cable model and specification, etc. Antifreeze measures should also be taken in severe cold areas to prevent optical cables from being damaged by freezing. In the event that the optical cable may be damaged by touching, an insulating plate can be set on or around it for partition protection.

Laying of direct buried optical cables

1. Burial depth. Since the direct buried optical cable is directly buried under the ground, there must be a certain distance from the ground. With the help of the tension of the ground, the optical cable will not be damaged. At the same time, the optical cable should also be protected from freezing.

2. Cleaning and backfilling of cable trenches. The bottom of the ditch should be flat, free of debris such as gravel and hard soil blocks that hinder the laying of optical cables. If the ditch is rocky or semi-rocky, 10cm thick fine soil or sandy soil should be paved and leveled at the bottom of the ditch. After the optical cable is laid, it should be backfilled with 30cm thick fine soil or sand as a protective layer. It is strictly forbidden to mix gravel, bricks, hard soil, etc. into the protective soil layer. The protective layer should be gently stepped on manually.

3. Optical cable laying. When laying optical cables or cables in the same ditch, they should be pulled and laid separately at the same time. If it is laid in the same ditch as the direct buried cable, the cable should be laid first, followed by the optical cable, and arranged in parallel at the bottom of the ditch. Just like laying optical cables in trenches, they should be laid separately at the same time, and they should not be crossed or overlapped at the bottom of the trench. The optical cable should be placed flat on the bottom of the ditch or bent naturally to release the stress of the optical cable. If it is bent or arched, try to lay it flat, but it is absolutely not allowed to use strong methods such as foot stepping.

4. Identify. Marks should be set at the joints, turning points, reserved lengths or intersections with other pipelines of directly buried optical cables for future maintenance and repair. The sign can either use an autocratic logo, or borrow a permanent building near the optical cable, measure the distance between a certain part of the building and the optical cable, and record it for future reference.

3. Points for attention in optical fiber construction

In addition, in integrated wiring, the main reasons affecting the attenuation of optical fiber signals are internal factors and external factors. The attenuation of internal factors is related to the fiber material, which can be purchased by purchasing high-quality fiber products. The external factors are related to the construction of optical fiber wiring, because during the construction, the optical fiber is caused by deformation, coupling loss between optical fiber and light source, and connection loss between optical fibers, which can be reduced during the construction process. Therefore, it is reminded that you should pay attention to the following when laying optical fibers:

1. When bending the optical cable, the minimum bending radius cannot be exceeded.

2. The traction force of laying optical cable should not exceed the maximum laying tension. At the same time, the optical fiber should be prevented from being subjected to transitional external forces (side pressure, impact, bending, twisting, etc.).

3.The termination and maintenance of optical fiber should be carried out by technical personnel who have received strict training. When optical cables are used in the backbone, at least 6-core optical cables should be used in the wiring room of each floor, and 12-core optical cables should be used for advanced applications. This is considered from three aspects: application, backup and capacity expansion.