Installation Guide of Fiber Optic Closure

How To Install The Fiber Optic Splice Closure?

What is the installation process? What issues you should notice?

1. Check the construction of the fiber optic cable before starting the installation. Different optical fibers cannot be spliced together.
2. Seal the articulated parts to reduce the effect of moisture on the fiber, and do not apply any pressure to the articulated parts.
3. Keep a dry and dust-free environment, do not apply external force to the fiber optic cable, and do not bend and wind the cable.
4. In the process of fiber optic cable removal and splice closure installation, use the appropriate tools according to the local specifications for fiber optic splicing.

To ensure no damage to the optical fiber, do not use the destroyed fiber, and when removing the outer cover of the fiber optic cable, do not cut, kink or damage the inner sheath. If anything happens, the back of the fiber optic cable sheath can be removed to ensure regular maintenance and repair.

Installation Instruction

Optical Fiber Preparation

1. Remove the outer cover of the fiber optic cable, (if there is, please remove the shield and armor) and then remove each wrapping layer to reveal the loose tube, and please follow the steps recommended by the fiber optic cable manufacturer. Please note that the preparation length is 3 m.
2. Clean the loose tube and strengthen the core-sheath with detergent, remove the excess filler tube, and sand the outer cover of the fiber optic cable with the sandpaper provided.

Optic Fiber Installation

1. Select the sealing ring with minimum diameter according to the outer diameter of the fiber optic cable, and set the two sealing rings on the fiber optic cable.
2. Put the fiber optic cable into the corresponding entry hole.
3. Connect the cable shield and ground.
4. Wrap the two sealing rings with self-adhesive sealing tape so that the sealing tape is wound flush with the outside diameter of the sealing ring to form a sealed end of the fiber optic cable.
5. Put the optical cable sealing end into the optical cable hole.
6. Reinforce the holder and cable core support with a hose clamp, and fix the cable in the connector box base, then tighten the hose clamp screws.
7. Tie the nylon ties, and cut the excess parts.
8. Use the plug to seal the rest part of the unused fiber optic cable and also wrap the plug with sealing tape.
9. Wrap the reinforcing parts on the countersunk screw of the fusion tray support and press it tightly.

Fiber Optic Splicing

1. Prepare the fiber after coiling 1.5 turns on the tray, and then coiling all the remaining fibers in the box.
2. Use a single-core buffer tube for single-core fiber on the tray, and use a ribbon buffer tube for ribbon fiber on the tray. Tie the inlet of the fusion splice tray with a nylon tie.
3. Docking two fibers in the prescribed method, put the splice into the fusion unit slot, and coil the remaining fiber in the tray.
4. Cover the fusion splice tray and place it.
5. The number of stacked trays of fusion splice tray depends on the capacity of the splice box required. The stacked fusion splice tray must meet the inspection and maintenance requirements of fiber optic splice. When you stack two splice trays, you can put these two trays by three buttons on each splice tray. And stack five splice trays in the same way. If you want to observe the condition of one splice tray, you can just remove the splice tray at the first layer.

Sealing Instruction

1. Enclosure sealing: Before sealing, tighten the valve nozzle with the ground screw. Embed the sealing strip into the sealing slot and put the sealing strip into the “U” slot at both ends of the splice closure. (Please note that do not pull the sealing strip artificially to avoid leakage.)
2. Gently close the top cover of the splice enclosure, screw it in the fastening bolts, fasten them in the order of the numbers indicated on the cover, and forbid the fastening with a torque wrench to reach 25N-m.
3. After 5 minutes, tighten them again in the order of the torque wrench, and the torque will still reach 25N-m.

Cover Remove

1. Loosen the 10 fastening bolts in order, and at this time the cover and base are still combined.
2. Take four fastening bolts and insert them into the four corners of the box, screw them symmetrically and evenly in the four corners of the top cover, so that the cover and the base are separated up to 6mm.
3. Wait for 5 minutes until the cover and base are separated up to 6mm and you can easily separate them by hand. (Note: The cover must be gently removed when separating to avoid damage to the optic fiber.)
4. If the capacitance or inspection is done, you need to re-close the cover. You should remove the old seal stripe, and put the seal to the seal slot again including the “U” slot cable entrance end of the seal.

Important Points to Consider

1, Pay attention to the depth of feed when stripping fiber optic cable. The key to stripping the outer sheath of fiber optic cable is to master the depth of the sheath cutting, otherwise, it is easy to break the fiber. In practice, you should rotate the sheath cutter while observing the cut. If you can see the white polyester tape, you should stop feeding and remove the cutter. This step requires several practices to master the depth of feed.

2, Fix the fiber optic cable and strip the core bundle tube. After stripping the fiber optic cable, fix the cable to the fiber optic splice closure and strip the core bundle tube. Do the preparatory work before the fiber optic splicing. 3 things you need to pay attention to during fiber optic splicing:

• The core bundle tube should not be twisted. Before fixing the fiber optic cable, you should pay attention to the position of the fiber bundle tube. The filler tube must be under the rebar instead of the fiber bundle. when the rebar is passed through the set screw, the fiber bundle tube must be on the same side of the rebar and cannot be twisted around the rebar. If the rebar is pressed on the core bundle tube, the deformation of the core bundle tube will cause excessive loss and the fiber inside the core bundle tube will break due to long-term stress, which may bring safety problems.
• The length of the rebar should be appropriate. After the position of the core bundle tube is determined, the fiber optic cable can be fixed. Fiber optic cable must be fixed so that the fiber optic position in the fiber optic splicing closure is not loose, which can avoid the problem of fiber optic loss or fiber breakage. The fixing of fiber optic cable is divided into the fixing of reinforcement and the fixing of the rest of the fiber optic cable. Pay attention to the length of the reinforcement. If it is too long, it cannot be put into the splice closure; while if it is too short, it does not repair the fiber optic cable. The distance between the clamp plate fixed fiber optic cable and the screw that fixes the reinforcement should be equal to the remaining length. The rest of the fiber optic cable is fixed after the reinforcement. Tighten the cleat and fix it firmly at the entrance of the fiber optic cable of splicing closure.
• The stripping length of the core bundle tube should be appropriate. After the fiber optic cable is fixed, the core bundle tube can be opened. If the stripping length is too long, it will reach the placement slot of the fiber optic heat shrink tube, which will damage the rest of the fiber when winding the fiber; if the stripping length is too short, the fixing clip will be stuck on the fiber and easily damage the fiber. So it is generally recommended to strip through two fixed clips. Within this length, the fiber bundle tube will not cause damage to the fiber and can be fixed well. However, when fixing, the clips should not be too tight, otherwise, the fiber of the fiber core bundle tube will be lost under stress, and the fiber will break over time, leaving safety problems to the project.

3, The fusing of optical fiber

Fiber optic splicing is directly related to the quality and life of the project, and the key lies in the preparation of the fiber end face. If the fiber end face is smooth, burr-free, and defect-free, the fusion splicer can accept the confirmation well and can make a joint that meets the requirements of the project. If the fiber end face is not qualified, the fusion splicer will refuse to work, or the connected joint will lose a lot that cannot meet the requirements of engineering. In the process of making a fiber optic end face, first of all, when stripping the coating of fiber, the stripper should be perpendicular to the fiber axis to ensure that the stripper will not scratch the fiber; when cutting the fiber, you should operate strictly according to the regulations. When using the end cutter, the cutting length should be accurate, the action should be fast and the force should be deft, to ensure that the fiber is broken but not crushed. When taking the fiber, make sure the fiber does not touch any object and avoid end face bruising to make it smooth and qualified. A fusion splicing machine is key equipment for fiber optic fusion splicing, as well as a machine with high precision and high price. In the process of use, you should operate strictly according to the instruction, otherwise, it may cause great loss. Pay special attention to the operating procedures of the welding machine and the length of the heat shrink tube needs to meet the requirements.

4, After the protection of the remaining fiber optic fusion splicing, you need to protect the fiber with a heat-shrinkable tube, and wrap the remaining fiber.

Do’s and Don’ts

• In the fiber winding process, the bending radius of the fiber cannot be too small, generally not less than 4mm. If the bending radius is too small, it can easily lead to excessive refractive loss and increased dispersion. After a long time, it may also occur in fiber breakage.
• When winding, pay attention to the twisting direction of the fiber, which is usually in the shape of an inverted “8”. Be careful not to break the fiber. After winding, place all fibers under the baffle that holds the tray to avoid damage to the fibers during packaging.

5, The sealing of the splice closure is very important in the project. If the splicing closure gets wet, the fiber inside can easily be broken. Over time, the splice closure will be broken and it should be carefully sealed as it is buried in the ground. The sealing of the splice box is mainly between the upper and lower covers of the fiber optic cable and the splice closure, splice enclosure sealing. During the sealing of fiber optic cable and fiber optic splicing closure sealing, you should first polish the cable sheath, and use gauze vertical cable axial to polish the outer sheath, so that the cable and sealing tape can be combined tightly. The sealing between the upper and lower covers of the splice closure is designed to make the sealing tape evenly into the sealing slot of the splice closure and tighten the screws.

The fiber optic splice enclosure is suitable for ribbon fiber optic cable and common fiber optic cable, the internal splice tray can be flipped according to the installation requirements, and it can leave enough space for the fiber optic tray so that each fiber optic cable and fiber can be constructed separately.

A high-quality fiber optic splice box is small in size, large in capacity, and can install fixed modules with different adapters, which is convenient for installation and maintenance. It can be installed on walls and poles.

If necessary, the cover can be equipped with an extraction tool that can make the metal components inside the fiber optic splicing closure and fiber optic cable connections to the ground, but it is not recommended to be installed when they leave the factory.

If necessary, the cover can also be installed with a valve nozzle, which is used to inflate and measure the air pressure during the sealing inspection of the fiber optic splice closure, but it is not recommended to be installed when they leave the factory.