What are the main points of indoor and outdoor optical cable construction?

With the development of technology, higher and newer requirements have been put forward for optical fibers. The old wiring standards have been tested in practice and are now being revised. In addition to the revision of the original specification, some new requirements will be added. I believe that fiber will play a more important role in it. It is not difficult to predict the bright future of fiber-optic communication and fiber-optic wiring. Below we introduce the issues related to the implementation of indoor and outdoor optical cable wiring.

Usually, in the integrated wiring, we will encounter the laying of indoor and outdoor optical cables. The indoor optical cable is mainly used for laying horizontal subsystems and vertical trunk subsystems. The laying of the horizontal subsystem cable is very similar to that of the twisted pair, except that the cable has a lower tensile performance, so it should be more careful when pulling and the radius of curvature should be larger. The vertical trunk subsystem cable is used to connect the equipment room to the wiring closet of each floor, usually in the cable shaft or ascending room. The outdoor optical cable is mainly used for wiring of the building group subsystem. When implementing the wiring of the building group subsystem, the pipe optical cable should be selected, and the direct buried optical cable or the overhead optical cable should be selected only when it is unavoidable.

★ Related issues related to indoor and outdoor optical cable wiring

(1) Laying of indoor optical fiber

In order to prevent sagging or slipping, the cable must be firmly fixed at the upper, lower and middle of the channel on each floor. In general, nylon cable ties or steel clips can be used for effective fixing. After the zui, the linseed plugging material is also used to block and seal the gaps of all the slots and pipe holes through which the optical cables of the various floors in the building pass, and fireproof measures such as adding fireproof materials should be taken to achieve the effects of moisture proof and fire prevention.

When laying the optical cable, the appropriate length should be reserved according to the design requirements. Generally, the equipment should be reserved 5m-10m, and if necessary, it should be extended.

(2) The laying of outdoor optical fibers is divided into the laying of pipeline optical cables and the laying of direct buried optical cables.

• Pipeline cable laying

1. Clean up and try. Before laying the fiber optic cable, the pipe hole should be cleaned and tested one by one. Use a special cleaning tool when cleaning, and apply the test stick after cleaning to test. The inner diameter of the plastic sub-tube should be 1.5 times the outer diameter of the cable. When two or more sub-tubes are placed in a cement pipe hole, the equivalent total outer diameter of the sub-pipe should be less than 85% of the inner diameter of the pipe hole.

2. Lay the plastic sub-tube. When two or more plastic sub-tubes are worn, if the tubes are of different colors, the ends may not be marked. If the tubes are the same color or have no color, they should be marked separately at their ends.

3. Cable traction. The length of one cable traction should generally be less than 1000m. When the distance is exceeded, the sectional traction should be adopted or the auxiliary traction mode should be added at the intermediate position to reduce the cable tension and improve the construction efficiency. In order to protect the appearance of the cable from damage during the traction process, protective measures such as guiding device or bell mouth protection tube should be adopted when the cable penetrates into the pipe hole, the bend of the pipe or intersects with other obstacles.

4. Reserve margin. After the cable is laid, the fiber optic cable should be placed on the specified pallet in the manhole or hand hole one by one, and appropriate margin should be left to prevent the cable from being too tight. When the cable in the manhole or hand hole needs to be connected, the reserved length should meet the small value of zui specified in the table.

5, joint processing. The cable shall not have a joint in the pipe hole in the middle of the pipe. When the optical cable has no joints in the manhole, the optical cable is required to be bent and placed on the optical cable tray for fixing and binding, and must not pass directly in the middle of the manhole, otherwise the construction and maintenance are affected, and the optical cable is easily damaged. When the cable has a joint, it should be protected by a pipe such as a serpentine hose or a soft plastic pipe, and placed on the pallet for fixing and tying.

6, blocking and identification. The outlet end of the tube hole through which the cable is placed should be tightly sealed to prevent moisture or debris from entering the tube. Optical cables and their connections shall be marked with the identification number, cable type and specifications. Anti-freezing measures should also be taken in severe cold areas to prevent damage to the cable. In case of damage to the cable, the insulation plate may be placed on or around the partition for protection.

• Laying of direct buried cable

1. Buried depth. Because the direct buried optical cable is directly buried under the ground, it must be at a certain distance from the ground. The cable should not be damaged by the tension of the ground. At the same time, the optical cable should not be frozen.

2. Cleaning and backfilling of cable trenches. The bottom of the ditch should be flat, and there are no debris such as gravel and hard clods that hinder the laying of the cable. If the groove is stone or semi-stone, the bottom of the ditch should be padded with 10 cm thick fine soil or sand and flattened. After the cable is laid, 30cm thick fine soil or sand should be backfilled as a protective layer. It is strictly forbidden to mix gravel, bricks and hard clods into the protective soil layer. The protective layer should be gently leveled by hand.

3. Cable laying. When laying optical cables or cables in the same trench, they should be laid separately during the same period. If it is laid in the same trench as the direct buried cable, the cable should be laid first, then the optical cable should be laid and arranged in parallel at the bottom of the trench. If the cable is laid in the trench, it should be placed separately at the same time, and the bottom of the trench should not be crossed or overlapped. The cable should be placed flat on the bottom of the trench or bent naturally to release the cable stress. If it is bent or arched, try to level it, but you should never use a tough method such as foot.

4. Carry out the logo. At the joints, turning points, reserved lengths or intersections with other pipelines of direct buried cables, signs shall be provided for future maintenance. The sign can be used either by a dedicated sign or by borrowing a permanent building near the cable, measuring the distance between a part of the building and the cable, and recording it for inspection.

In addition, in integrated wiring, the main factors affecting the attenuation of the fiber signal are internal factors and external factors. The attenuation of internal factors is related to fiber optic materials by purchasing high quality fiber optic products. The external factors are related to the construction of the fiber-optic wiring, because the construction time, the fiber is deformed, the coupling loss between the fiber and the light source, and the connection loss between the fibers, which can be reduced during the construction process.

★ So remind you to pay attention when laying fiber:

1. When bending the cable, do not exceed the small bending radius of zui.

2. The traction of the laying cable should not exceed the large laying tension of Zui. At the same time, external forces (side pressure, impact, bending, distortion, etc.) that cause the fiber to be subjected to transition should be avoided.

3. The fiber should be terminated and maintained by highly trained technicians. When the optical cable is applied to the trunk, at least 6-core optical cable should be used in each floor wiring closet, and the advanced application Zui can use 12-core optical cable. This is considered in terms of application, backup and expansion. As for the networking mode of optical fiber, it is also very flexible. can be realised:

A. Point-to-point: Establish a high-speed channel between two computers. The transmission rate ranges from a few Mbps to several hundred Mbps, and the distance can be up to 2 km (multimode) to 5 km (single mode).

B. Star network: Establish a star-shaped network topology through fiber-optic network equipment.

C. Ring network: The signal regenerators are connected by optical fibers to form a loop. (Original title: Issues related to the construction of indoor and outdoor optical cables)