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Introduction of optical cable splicing box enclosure
What is an optical cable splice box?
Fiber optic splice closures permanently connect two fiber optic cables together and have a splice that protects the components. The optical cable connection part, that is, the optical cable joint, is the part that protects the connection between two or more optical cables by the optical cable splice sheath, and meets the requirements of transmission characteristics and mechanical properties.
It is mainly used for straight-through and branch connections of overhead, pipeline, direct burial and other laying methods of optical cables of various structures. The box body is made of imported reinforced plastic, which has high strength and corrosion resistance. The terminal box is suitable for the connection in the terminal room of the structural optical cable. The structure is mature, the sealing is reliable, and the construction is convenient. Widely used in communications, network systems, CATV cable television, optical cable network systems and so on. The right side is a two-in-two-out splice box; it is used for protective connection and optical fiber distribution between two or more optical cables. It is one of the common equipment for user access points. It mainly completes the distribution of optical cables and household line optical cables outdoors The connection function, and the box or simple optical splitter can be installed according to the needs of FTTX access.
Cable Enclosure Category
- According to the shape and structure, it can be divided into two types: cap-type optical cable joint box and horizontal optical cable joint box;
- According to the laying method of optical cable, there are overhead, pipeline (tunnel) and direct burial;
- According to the optical cable connection method, it is divided into two types: straight-through connection and branched connection;
- According to the sealing method, there are heat shrinkable sealing type and mechanical sealing type.
Dome type optical fiber cable splicing enclosure
Horizontal type optical fiber cable splicing enclosure
Cable Splicing Enclosure Composition
The horizontal optical cable splice box is roughly divided into 3 parts, as shown in the figure.
- Outer sheath and sealing part (housing)
The outer shell is the outermost layer of the splice box, which is mainly responsible for the sealing function.
- Sheath support part (support)
The sheath support part is the skeleton of the splice box, including brackets, optical cable fixing clips and optical fiber accommodating trays. They give the splice closure some mechanical strength to resist the effects of lateral stress on the fibers in it.
- Cable inner connecting part (connector)
The connecting part in the cable is some auxiliary components that serve for butt joint, such as the metal sleeve or connecting splint for connecting the strengthening core, the bridge wire connecting the aluminum sheath of the optical cable at both ends of the joint, etc.
Requirements of the optical cable joint box
General requirements
- Has the ability to restore the integrity of the cable jacket and the mechanical continuity of the cable strength members.
- Provides the function of electrical connection, grounding or disconnection of metal members in optical cables.
- Features that protect fiber optic connectors from the environment.
- Provides the function of placing optical fiber connectors and storing the remaining optical fibers.
- When required, the cable splice closure should also be termite resistant.
Performance requirements
- Compatible with the program and laying method of the connected optical cable, there are many optical cable programs. The structural form of the joint sheath is also diverse.
- Has good sealing. It is generally required to effectively maintain the performance of waterproof, moisture-proof and harmful gas intrusion within 20 years.
- Have a certain mechanical strength. It is required to stress the cable splice closure to 70% of its strength without affecting the performance of the fiber in it.
- Long-term corrosion resistance. At present, the shell of the joint box is made of plastic products. In addition to ensuring wear resistance, the aging resistance and insulation properties of the material should also meet the requirements of 20 years of life.
- Detachable and reusable. If the connector needs to be repaired during construction and maintenance, it is not necessary to cut off the optical cable, but only need to open the connector sheath and re-encapsulate it after inspection. It is of great significance to improve economic efficiency and ensure smooth communication.
Containment and treatment of the remaining length of optical fibers
After the monitoring and evaluation of optical fiber splice and optical fiber connection loss, the remaining length of optical fiber is processed, and its storage method depends on the structure of the splice sheath of the optical cable used. Pay attention to the curvature radius and stacking strokes when the optical fiber is accommodated and coiled. After the long coil is left, the OTDR instrument is generally used to re-measure the connection loss. If the loss is found to be larger, the sealing of the sheath should be checked and analyzed and the fault has been eliminated.
The effect of the remaining length of the optical fiber
(1) The need for reconnection;
(2) The need for transmission performance.
How to accommodate the remaining length of optical fibers
As shown in the figure, there are four ways to accommodate the remaining length of the fiber:
How to accommodate the remaining length of optical fibers
- (1) The approximate direct method is shown in Figure (a).
- (2) The flat coil method is shown in Figure (b).
- (3) The winding drum storage method is shown in Figure (c).
- (4) The cylindrical winding method of the storage bag is shown in Figure (d).
Sealing treatment of optical fiber connector sheath
The sealing methods of connection sheaths of different structures are different. Before sealing, the sealing part of the optical cable should be cleaned and finely ground. Note that the sanding direction of the sandpaper should be rotated horizontally, and should not be sanded back and forth along the axial direction.
After the optical cable sheath is encapsulated, the air-tight inspection and the re-test of the optoelectronic characteristics are carried out to confirm that the optical cable is connected well, and the connection work is completed.
Installation and fixation of optical cable joint box
The general installation and fixing method has been clarified by the engineering design. During the construction, attention should be paid to the design drawing, so that the joint installation can be standardized, neat, beautiful and attached with signs.
Installation of direct buried optical cable splice box
The joint pit of the directly buried optical cable should be located on the right side of the route. If it has to be located on the left side of the route due to terrain restrictions, it should be indicated on the route construction drawing. The bottom of the pit should be covered with 10cm of fine soil or sandy soil, and the top of the joint box should be covered with about 20cm of fine soil or sandy soil and then covered with cement board or red brick.
Installation of overhead optical cable splice box
The connector of the aerial optical cable is generally installed next to the pole, and should be telescopically bent. The reserved optical cable at both ends of the aerial optical cable connector should be placed on the adjacent pole. The picture shows the installation diagram of the aerial optical connector box.
Installation of pipeline optical cable joint box
The joint box for laying the optical cable in the pipeline should be installed in the higher position of the manhole to prevent it from being soaked by the accumulated water in the manhole during the rainy season. Stick to the manhole wall or manhole shelf, form an "O" ring, and fix it with a cable tie. Note that the curvature radius of the "O" ring should not be less than 20 times the diameter of the optical cable. The picture shows the installation diagram of the pipe manhole joint box.
