Drop cable is commonly known as indoor hanging wiring cable. 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 drop cable, so, do you know the laying technical requirements for the installation of the drop cable?
1. What are the laying technical requirements for the installation of drop cable
1. The laying of the drop cable should be straight, without twisting and crossing, and should not be squeezed by external forces and damaged by operation. Power cords, household drop 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 drop 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 drop cable should fully consider and strictly meet the requirements of "fire prevention, rodent prevention and extrusion prevention".
4. The two ends of the drop cable should have a unified mark, and the mark should indicate the position where the two ends are connected. Label writing should be clear, correct and correct. Labels should be made of materials that should not be damaged.
5. The bend of the drop cable should be even and smooth. The curvature radius of the ordinary G.652 fiber should be greater than 30mm, and the curvature radius 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 drop cable, manual traction is generally used, and the traction force should not exceed 80% of the maximum allowable tension of the drop cable. The instantaneous maximum pulling force shall not exceed the maximum allowable tension of the drop 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 drop cable reel should be used to carry the drop 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 drop 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) During the laying process, the bending radius of the drop cable should not be less than 40mm;
(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 telecommunication 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 laying of the home optical cable in the vertical part of 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 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 drop cable, the reserved length at both ends of the drop 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 drop cable terminal box.
12. After the household drop cable is laid, the light source and optical power meter should be used to test it. The optical attenuation value of the household drop 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 drop cable.
13. If the span of the outdoor drop cable exceeds 40 meters, consider adding a soft hanging method.
14. When laying the dark (open) tube type leather wire optical cable first, when laying the dark (open) tube, the connection at the turning angle should be a hose or a passing box should not 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 drop cable in the shaft is from top to bottom. In 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 drop cable. damage to come.
16. Power cords, home drop optical cables and cables of other weak current systems in the building should be laid out separately.
If you want to learn more about drop cable or technical problems pls feel free to contact us by email: sales@gl-fibercable.com.