Requirements for the installation and layout of the leather cable
Leather cable is commonly known as indoor hanging wiring cable. With the domestic optical fiber access market showing a good momentum of development, optical fiber access has become a hot spot in the field of optical communications. In the optical fiber access project, the indoor wiring close to the user is the most complicated link. The bending performance and tensile performance of conventional indoor optical cables can no longer meet the needs of FTTH (fiber-to-the-home) indoor wiring. Presumably you are not unfamiliar with the leather cable, so do you know the laying technical requirements for the installation of the leather cable?
Fiber optic cable installation
1. What are the laying technical requirements for the installation of leather cable
1. The laying of the leather cable should be straight, without twisting and crossing, and should not be squeezed by external forces and damaged by operation. Power cords, household leather cables and cables for other weak current systems in the building should be laid out separately. If it cannot be satisfied, corresponding isolation protection measures must be taken. For steel wire reinforced leather cable, attention should be paid to grounding the metal parts in the junction box.
2. For important users or users with special requirements, consideration should be given to providing protection, and different protection methods should be selected according to different situations.
3. The laying of the leather cable should fully consider and strictly meet the requirements of "fire prevention, rodent prevention and extrusion prevention".
4. Both ends of the leather cable should have a unified mark, and the mark should indicate the location of the connection between the two ends. Label writing should be clear, correct and correct. Labels should be made of materials that should not be damaged.
5. The bend of the leather cable should be even and smooth. The radius of curvature of the ordinary G.652 fiber should be greater than 30mm, and the radius of curvature of the anti-bending G.657 fiber should be greater than (A type) 10mm, (B type) 7.5mm , (C type) 5mm.
6. When laying the leather cable, manual traction is generally used, and the traction force should not exceed 80% of the maximum allowable tension of the leather cable. The instantaneous maximum pulling force shall not exceed the maximum allowable tension of the leather cable 100N. The main traction force should be added to the cable strength member. After the cable is laid, the tension should be released to maintain a natural bending state.
7. The leather cable reel should be used to carry the leather cable, and the cable release bracket should be used when laying the cable, so that the cable reel can automatically rotate to prevent the cable from being entangled.
8. During the laying process of the leather cable, the tensile strength and bending radius of the optical fiber should be strictly paid attention to, so as to avoid the optical fiber from being entangled, twisted, damaged and trampled.
The minimum bending radius of the cable laying shall meet the following requirements:
(1) The bending radius of the leather cable should not be less than 40mm during the laying process;
(2) After fixing, the bending radius of the cable should not be less than 15mm.
9. Requirements for shafts and bridges in the building:
(1) The telecommunications shaft should pass through each floor uniformly up and down, the internal width should not be less than 600mm, and the operating distance in front of the wiring box installed in the cable shaft should not be less than 0.6m.
(2) A grounding device should be reserved in the telecommunication shaft.
(3) The installation of the trunking in the shaft should be more than 50% of the total cable utilization rate.
(4) The vertical part of the home optical cable in the shaft should be bundled and fixed every 1.5 meters to prevent the damage to the fiber core caused by the falling force.
10. Horizontal piping requirements (weak current well to user end):
(1) The diameter of the pre-embedded pipe should be φ20 mm - φ25 mm, the length of the straight embedded pipe of the hidden pipe in the building should be controlled within 30 meters, and a passage box should be added when the length exceeds 30 meters. When the hidden pipe must be bent and laid, its routing length should be ≤ 15 meters, and there should be no S-bend in this section. When it is continuously bent for more than 2 times, a wire box should be installed. All turns are done with pipe benders and are standard turning radii. Three-way, four-way, etc. shall not be used.
(2) The bending radius of the hidden pipe should be 10 times larger than the pipe diameter. When the outer diameter is less than 25 mm, the bending radius should be 6 times larger than the pipe diameter, and the bending angle should not be less than 90 degrees. The bending radius of the hidden pipe shall not be less than 6--10 times the outer diameter of the pipe.
11. When laying the leather cable, the reserved length at both ends of the leather cable should meet the following requirements: about 1m is reserved at one end of the floor optical splitter box; about 0.5m is reserved at one end of the user leather cable terminal box.
12. After the household leather cable is laid, the light source and optical power meter should be used to test it. The optical attenuation value of the household leather cable section at the wavelength of 1310nm and 1490nm should be less than 1.5dB. If the optical attenuation value is greater than 1.5dB, it should be repaired. If the repair has not been improved, it is necessary to re-make the optical fiber mechanical connection plug or re-lay the leather cable.
13. If the span of outdoor leather cable exceeds 40 meters, consider adding a soft hanging method.
14. When laying the dark (open) tube type leather cable, first, when laying the dark (open) tube, the connection at the turning angle should be connected with a hose or a passing box cannot be directly applied to the turning angle; when the straight line distance exceeds 10 meters, it should be Install the pass box.
15. In principle, the laying of the leather cable in the shaft should be from top to bottom. For high-rise buildings or long-distance laying, it needs to be bundled and fixed every 1.5 meters to reduce the long-term self-weight of the leather cable. damage to come.
16. Power cords, home leather optical cables and cables of other weak current systems in the building should be laid out separately.
2. What are the ways to enter the home with the leather cable?
User indoor wiring
In the FTTH project, the user's indoor wiring is the most complicated link, and many factors are considered. It is necessary to ensure the safety of the line, take into account the indoor beauty, and at the same time facilitate the construction. The traditional single-core indoor optical cable can no longer meet the indoor wiring requirements of the current FTTH project. As a substitute for traditional indoor optical cables, leather cable can adapt to most indoor wiring conditions, for example, it can turn with a bending radius of 20mm, can bear the lateral pressure of people stepping on the optical cable, and the pulling force caused by engineering construction. At the same time, with a variety of on-site connectors, on-site termination and docking can be realized in the shortest time. Therefore, the leather cable is the best choice for FTTH indoor wiring.
In-building vertical and horizontal wiring
Like the user's indoor wiring, the leather cable is also suitable for vertical and horizontal wiring in the building. The horizontal wiring is not very demanding on the optical cable, but the vertical wiring must require the optical cable to have a certain tensile strength. The leather cable can withstand the short-term 200N and long-term 100N tensile force, so it can ensure the construction safety and stable performance of the vertical wiring of the leather cable within a certain height range.
Self-supporting overhead access wiring
Since the self-supporting "8" wiring optical cable has a metal hanging wire unit, it has stronger tensile performance and can withstand a span of 50 meters. The optical cable is laid outdoors in an overhead manner. Before entering the house, the metal suspension wire unit is cut off and fixed on a special fixture. After the remaining optical cable is stripped of the metal suspension wire, the leather wire optical cable is introduced into the room.
Compared with the leather cable, the pipeline mapping optical cable is harder and has higher tensile strength. At the same time, the optical cable contains water-blocking materials, which can reduce the erosion of outdoor rainwater, so it is more suitable for long-distance outdoor pipeline laying. The pipe-mapping optical cable adopts an all-non-metal structure, thus avoiding the introduction of lightning into the room. After the optical cable enters the house, strip its outer sheath, water blocking material and reinforcements, and directly use the middle leather cable for indoor wiring, which inherits all the advantages of indoor wiring of the leather cable, while reducing the connection of outdoor and indoor optical cables.
About the little knowledge of leather cable, today Xiaobian will explain it here for everyone. In fact, most of the sheathed optical cables are single-core or double-core structures, and can also be made into a four-core structure. The cross-section is in a figure-8 shape. The reinforcement is located in the center of the two circles. center. The optical fiber in the leather cable adopts G.657 small bending radius optical fiber, which can be laid with a bending radius of 20mm.