The Laying Of Outdoor Optical Fiber Is Divided Into Pipeline Optical Cable Laying And Direct Buried Optical Cable Laying

- Jun 13, 2020-  

Laying of pipeline optical cable

1. Clean and try. Before laying the optical cable, clean the pipe holes section by section and try to pass. Use an autocratic cleaning tool when cleaning, and use a test rod to check after cleaning. The inner diameter of the plastic tube should be 1.5 times the outer diameter of the optical cable. When placing 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 plastic sub-tubes. When putting more than two plastic sub-pipes, if the pipes are of different colors, the ends need not be marked. If the pipe has the same color or no color, it should be marked separately at the ends.

3. Optical cable traction. The hauling length of the optical cable should generally be less than 1000m. When this distance is exceeded, section traction or auxiliary traction mode should be added in the middle position to reduce the cable tension and improve construction efficiency. In order to protect the appearance of the optical cable from damage during the towing process, when the optical cable penetrates into the pipe hole, the pipe bends or crosses with other obstacles, protective measures such as guiding devices or bell mouth protection pipes should be adopted.

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

5. Joint processing. The optical cable shall not have any joints in the hole in the middle of the pipeline. When the optical cable does not have a joint in the manhole, the optical cable is required to be bent and placed on the optical cable support plate to be fixed and tied. It must not pass directly in the middle of the manhole, otherwise it will affect the construction and maintenance, and easily cause the optical cable to be damaged. When the optical cable has a joint, it should be protected by a serpentine hose or soft plastic tube, and placed on a pallet for fixing and binding.

6. Blocking and marking. The outlet end of the pipe hole where the optical cable is put should be sealed tightly to prevent water or debris from entering the pipe. The optical cable and its connection shall have identification marks, and indicate the number, optical cable model and specification, etc. Anti-freezing measures should also be taken in severe cold areas to prevent frost damage to optical cables. In the event that the optical cable may be damaged by collision, insulating plates can be installed on or around it for protection.

Directly buried optical cable laying

1. Embedding depth. Since the directly buried optical cable is directly buried under the ground, it must be at a certain distance from the ground. With the help of the ground tension, the optical cable is not damaged. At the same time, the optical cable should not be damaged by freezing.

2. Cleaning and backfilling of optical cable trench. The bottom of the ditch should be flat and free of debris and hard soil that hinder the laying of the optical cable. If the trench is stone or semi-lithic, 10cm thick fine soil or sand should be laid on the bottom of the trench and smoothed. After the optical cable is laid, 30cm thick fine soil or sand should be backfilled 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 leveled manually.

3. Optical cable laying. When laying optical cables or cables in the same trench, they should be towed and laid separately at the same time. If it is laid in the same trench as the directly buried cable, the cable should be laid first, and then the optical cable should be laid in parallel at the bottom of the trench. Just like laying optical cables in trenches, they should be laid separately at the same time, and they should not be placed across or overlapped at the bottom of the trench. The optical cable should be laid flat at the bottom of the trench or bent naturally to relieve the stress of the optical cable. If it is bent or arched, try to lay it flat, but never use strong methods such as stepping on it.

4. Perform identification. Signs should be set up at the joints, turning points, reserved lengths, or intersections with other pipelines of directly buried optical cables for future maintenance. The signs can either use authoritarian signs or borrow permanent buildings near the optical cable to measure the distance between a certain part of the building and the optical cable, and record it for future reference.

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