When an optical fiber is subjected to tensile forces that exceed its tensile limit, it breaks. Reinforcement components are added to the structure of the optical cable, and the tensile strength required by the optical cable is mainly borne by the reinforcement components. During construction, the traction force cannot exceed the allowable rating of the optical cable, so that the optical fiber does not produce tensile strain as much as possible. The allowable traction of the cable has different ratings depending on the cable manufacturing process, and this must be paid attention to during construction. The tensile strength of the general optical cable is 100~300kg.
Communication Cable Engineering Overview:
Communication optical cable engineering is mainly divided into overhead optical cable engineering, direct buried optical cable engineering, pipeline optical cable engineering, waterline optical cable engineering and submarine optical cable engineering.
Optical cable length is long: the standard manufacturing length of general optical cable is 2km, when laying optical cable, do not cut off the optical cable at will, increase the optical cable joint.
Fiber optic cables have less tensile capacity: when the optical fiber is subjected to tensile forces that exceed its tensile limit, it breaks. Reinforcement components are added to the structure of the optical cable, and the tensile strength required by the optical cable is mainly borne by the reinforcement components. During construction, the traction force cannot exceed the allowable rating of the optical cable, so that the optical fiber does not produce tensile strain as much as possible. The allowable traction of the cable has different ratings depending on the cable manufacturing process, and this must be paid attention to during construction. The tensile strength of the general optical cable is 100~300kg.
The cable has a smaller diameter and is lighter in weight.
The connection technology of optical fiber is high and the connection is more complicated: the connection of optical fiber, it needs to melt the end face of the optical fiber at high temperature, and then bond it together by the viscosity of quartz glass. Therefore, the tools required for connection are more complex and technically demanding.
Overhead optical cable installation specifications:
Pole mounting:
Cable pull, hanging wire connection:
Connector box use:
Optical cable into the home:
Pipe and cable installation specifications:
According to the material pipeline, it can be divided into: concrete pipe, plastic pipe, steel pipe, cast iron pipe, asbestos cement pipe, ceramic pipe…
Plastic pipes are mostly used.
Characteristics of plastic pipe: light qualityPipe wallSmooth jointSimple watertightnessGood corrosion resistanceGood insulation performanceGood transportationPoor cold resistancePoor thermal stabilityPoor price.
Pipeline construction:
Pipe slope:
Human handholes:
Cabling:
Optical cable line acceptance criteria:
Pipeline Optical Cable:
(1) The optical cable in the handhole should be protected by a serpentine hose (or soft plastic pipe), and the laid optical cable should be close to the wall of the handhole, and tied to the bracket with plastic cable ties or treated according to the design requirements; At the same time, it is necessary to ensure that the direction of the optical cable in the handhole is smooth and there is no cross-twisting phenomenon.
(2) The optical cable is generally reserved for 15 meters in the base station lead well, if there are more old optical cables reserved in the lead well, the reserved optical cable this time will be reserved to the previous hand well; Straight sections are reserved for 15 meters every 500 meters or so; The joint well is reserved for 15 meters; The line passes through the bridge or sewer and adds a reserve of 15 meters; The reserved optical cable is tied and fixed according to the regulations.
(3) IN THE HANDHOLE, HANG A OPTICAL CABLE IDENTIFICATION PLATE ABOUT 35CM OUT OF THE HORN OF THE OPTICAL CABLE; A cable identification plate should also be hung at the reserved place and the connector of the optical cable.
(4) The pipeline optical cable joint box is in the human (hand) hole, about 20-30 cm from the wellhead, and the connecting disk surface and the ground level; The joint box is fixed with expansion bolts; The optical cable reservation ring is fixed on one side of the well wall; The installation of the connector box and the remaining cable tray position should not affect the deployment of other optical cable connectors in the manhole.
(5) Within the length of 15cm of the subtube hole of the optical cable, bending is not allowed.
(6) The laying of sub-pipes should be laid with three-color or four-color full capacity according to the requirements of various cities and cities, multiple sub-pipes are arranged in color order and the whole path is consistent, the sub-pipes are cut off at the well (PVC large pipe hole) not exceeding 10 cm, and the plug drum is set, and the empty sub-pipe that does not lay the optical cable should be put on the end cap of the sub-pipe.
(7) When laying optical cables through railways, highways, rivers, ditches, underground pipelines and other obstacles, specific location marks or effective protective measures should be taken, and the location of manholes should be safe.
(8) Check whether the routing direction and length of the pipeline are consistent with the drawings.
(9) During acceptance, if it is found that there are wells and well rings damaged, manhole covers are lost, uneven piles and other ancillary facilities are insufficient, etc., they should be put forward in the acceptance report or meeting, and a rectification plan should be formulated.
90*120 through the hand well:
60*90 straight to the hand well
Overhead optical cable:
(1) Check whether the direction of the pole, the buried position of the pole cable (strut), the height of the pole and the distance between the poles, the pulling thread, the position of the optical cable joint, the position of the remaining optical cable, and the total length of the pole are consistent with the engineering design.
(2) The optical cable through the pole must have a certain bend (and sleeve hose protection – depending on the design), and the angle rod position optical cable must be protected by a plastic hose.
(3) The upper and lower parts of the overhead lead should be tied firmly, and protected by steel pipes (required to be more than 2.5 meters).
(4) The place where the overhead optical cable and the power line cross and are parallel (the interval that does not meet the requirements of the specification) must be protected by a three-wire cross protection sleeve for insulation protection.
(5) When the overhead optical cable crosses the intersection through which the vehicle passes, it must ensure that the crossing height reaches more than 7 meters, and hang a sign or sign plate that pays attention to safety on the hanging line; Short-distance poles and wires affect the line and traffic safety, and reflective marking should be done, and the pole pier should be protected if conditions permit.
(6) The pole road built together with the optical cable requires that the pole must not be seriously skewed or decal, and the pole body must not be broken or exposed.
(7) The pull wire should be diagonally deep, and the ground anchor should be excavated no more than 0.5 meters.
(8) The hook is uniform and does not move out of position, the hanging wire sag meets the specifications, and the optical cable and the hanging wire do not cross.
(9) The optical cable joint is installed firmly, and the remaining lashing is neat and beautiful, which meets the design requirements.
(10) Every other pole or according to the design requirements of the pole optical cable tied to the sign plate, the content of the plate requirements is the same as that of the pipeline optical cable, within 500 meters of the entry and exit bureau, on each overhead pole on the optical cable tied to the sign plate.
Incoming optical cable:
(1) Optical cable in and out of the line room has a reservation in line with the regulations (generally reserved for 15 meters), the cable binding on the cable frame (groove) is neat, safe, beautiful, no crossing, no suspension, the optical cable is separated from other optical cable lines in each floor, turning, through the wall, into the distribution frame to hang signs, the turning place should be wrapped with plastic fiber pipe protection, multiple cables are arranged and placed, the same point is listed side by side.
(2) There shall be no optical cable left on the floor routing frame (groove) and the routing frame of the computer room.
(3) The first connector box out should disconnect the electrical connection of the reinforcement core.
(4) The optical cable should be blocked by fireproof mud or other materials that conform to the design at the floor or between walls.
Fitting requirements:
(1) The optical cable distribution frame (ODF) must be installed firmly and neatly, the optical cable stripping section to the welding plate must be protected by hoses, the fiber core welding plate of the optical cable is placed stably, the core welding point is in the center of the heat shrinkable protection tube, and the fiber core disk is neat and without damage.
(2) Optical cable handover box: After the construction of the optical cable is completed, the optical cable import and export of the optical cable must be blocked; The optical cable must be fixed with a steel hoop in the optical delivery box, and cannot be replaced by a plastic cable tie; The optical fiber from the open end of the optical cable to the terminal box part is connected with a plastic hose, and the wiring should be reasonable and beautiful.
(3) Next to the connector, the printed optical cable name label (the name of the starting terminal and the number of cores, length), the optical fiber coupler bayonet should be installed neatly and firmly, and the bare fiber in the connection box should be threaded through a small hose to the welding plate and tied well.
(4) The optical cable connector box should be installed firmly, tied neatly, and there should be no water leakage.
(5) Grounding requirements for the metal reinforcement core at the end of the optical cable terminal: The metal reinforcement core and metal armor layer at the end of the ODF frame optical cable must be well grounded.
(6) The pigtail in the ODF frame is neatly arranged and safe, the core number is accurate, and the spare core pigtail connector should be covered with an end cap to prevent dust.
Transmission performance indicators:
(1) Test method: test the total loss value with the light source optical power meter, and test the average loss of the optical cable and the joint loss with the backscatter meter (OTDR);
(2) The average loss requirements of single-mode optical cable throughout the whole process: the average decay is 0.25db/km at 1550nm wavelength, and 0.36db/km at 1310nm wavelength;
(3) Loss of the middle joint of single-mode optical cable: the loss per fiber of the scattered optical cable is below 0.08db, the loss per fiber of the ribbon is below 0.1db, and the maximum is not more than 0.15db.
(4) Fiber core end loss of optical cable: Each core loss including the active coupler should not be more than 0.5db.
(5) The attenuation average of the optical fiber trunk segment (tested with a light source optical power meter) must meet the indicators specified in the design, and the optical fiber backscatter curve should meet the requirements (the curve is printed with OTDR).
Line acceptance criteria:
(1) The buried depth of the optical cable line does not meet the standard requirements;
(2) The routing selection of some lines is unreasonable, and some routes need to be migrated;
(3) Both sides of the line hanging along the bridge are basically exposed, there are no protective measures, and there is a hidden danger of illegal cutting and burning;
(4) The line separation distance does not meet the requirements, and there are potential safety hazards in the three-line crossover protection;
(5) The joint pipeline line is jointly built by multiple operators, and the mobile lines are mixed, and the optical cable and pipeline line are chaotic;
(6) The mechanical and electrical properties of poles, pipelines and optical cables do not meet the requirements. Specifications such as poles and signs are not uniform;
(7) The crossing height of the optical cable line does not meet the requirements.
This article comes from the Internet, compiled and edited by HVAC South News Agency.
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