What Is Fiber Optic Splice Closure and How to Choose the Right one

1. What’s fiber splice closure

The fiber optic splice closure, also know as fiber optic joint enclosure, is a device that used to connect two or more optical cables together and provide space of the connection point. Fiber optic splice enclosure is a necessary and very important fiber optic equipment in the construction of optical cable line engineering. The fiber optic closure can connect and store optical fibers safely whether in outside environment or indoor building. It has excellent mechanical strength and a sturdy shell which ensure the connectors and splice point inside the fiber splice closure are not damaged by harsh environments. The quality of the fiber splice enclosure directly affects the quality of the fiber optic line and the service life of the optical cable.

2. Why we need to research the fiber splice closure

The external fibre splice enclosure is an indispensable and important component in the optical cable line. It plays a vital role in the protection of the optical cable, the protection of the optical fiber connection and the communication transmission quality of the optical cable line. At present, there are a lots of different optical fibre cable joint closure suppliers. The grade trunk line basically uses the joint closure from big company such as 3M, Corning, Tyco, AFL, Commscope or other companies. The secondary trunk lines are all sent by Chinese manufacturers. There are more than 60 factories. Their structures are even more diverse and their performance varies greatly. From the current application situation, the communication line is malfunctioning (except for the freshness of the optical cable). If people are not damaged by construction or natural disasters, most of them are not on the optical cable, and most of the faults occur in the fiber optic splice enclosure. If the sealing performance is poor, the water intake loss of the optical splice closure is increased, or even the aperture of the broken ring is bad, either the loss is large, or the strength is insufficient. The overhead optical cable is affected by the external environment, caused by the expansion of the joint closure in the winter and the summer, and frequent failures during the season. It happened reasonably on the street. In addition, the fiber optic joint enclosure was struck by lightning, wind and flood. The influence of external forces such as the pomegranate earthquake often causes a variety of faults.

The current outdoor fiber splice enclosure has the following problems.

2.1 Design issues

The external fibre splice enclosure of some manufacturers do not meet the requirements of local operators and cannot meet industry standards and network access requirements. Some fiber optic closures have no anti-termite infestation function. Most fiber splice enclosures cannot reach the tensile strength of 1000N on the structure, and some fiber splice enclosures are resistant to High temperature difference, poor sealing performance, complicated operation and installation of individual optical fibre cable joint closure, poor construction craftsmanship and other issues. In addition, there are problems in the design and structure. The metal reinforcing cores and plastic-coated steel or aluminum tapes of the fiber optic cable in the optical splice closure and the fiber optic cable in the outdoor fiber splice enclosure should be insulated from each other. However, there are a considerable number of manufacturers whose brackets in the external fibre splice enclosure are completely integrated. The metal plate, the metal reinforcement core and the metal plate are not designed to use insulating washers, so the electrical performance is in a short-circuit state. The reinforcing core and the bracket of the fiber optic cable entering and exiting the fiber optic closure should be able to withstand a tensile force of 1000 N, but the structure of some manufacturers can only call it “installation”, which can not achieve the fixed effect of being able to withstand the tensile force at all. The radius of curvature of the connecting plate of some manufacturers is less than 37.5 mm.

2.2 Material and process issues

In order to reduce costs, some manufacturers use inferior materials or recycled plastics for the shell material of the fiber optic joint enclosure, causing the fiber optic splice closure to severely crack after the low temperature impact, and the outer sheath of the optical cable in the fiber optic splice enclosure has poor workmanship or improper material selection. , The fiber splice closure shell has no rounded corners or the rounded corners for the optical cable are too small. When the optical cable is repeatedly bent, the outer sheath of the optical cable is damaged and leaks. Most of the joint closure sealant does not prevent termites. It cannot withstand the high temperature requirement of 60 degrees. In summer, it will flow under direct sunlight, causing serious problems such as the loss of sealing of the optical fibre cable joint closure and the common phenomenon of water ingress.

2.3 The actual construction operation of the line paving

The quality of the construction team is poor and lack of serious and responsible spirit. The installation of the optical splice closure sealant is very irregular, which makes the sealant fail to seal. In practice, most of the outdoor fiber splice enclosure enters water, which is one of the main reasons. Optical fiber fusion splicing is not standardized, and even if the loss is large, it is still discharged randomly. In the optical fiber splice tray, even the optical fiber has a dead bend or small bend in the splice tray. In order to save effort and trouble when installing the external fibre splice enclosure, the bolts and nuts are neither tightened nor added with spring washers. After one or two winters and summers, the springs and nuts are cold-shrinked and heat-expanded. In summer, the thermal expansion can not go back, causing frequent failures of the time cable lines during the season, and the problems will not be listed one by one.

As mentioned above, it is necessary for the purchaser to have a full understanding of the fiber optic closure when purchasing the fiber optic joint enclosure.

3. How to choose right fiber optic splice closure for your project

3.1 Choose the material of the fiber optic splice enclosure

The shell of the fiber splice closure can be divided into plastic fiber splice enclosure and metal fiber splice enclosure. Metal fiber splice enclosures are relatively few in the market. Generally, PC plastic resin or ABS plus PC resin is used with heat-resistant, flame-retardant and other characteristics.

3.2 Choose types of optical fibre cable joint closure

At present, there are mainly two kinds of joint closures with different appearance structures in the communication field, inline fiber optic splice closure and dome fiber optic splice closure, which are used for all kinds of direct or branched optical cable connections in the field, aerial, wall mount, manholes, and underground. . As shown in below image, it is a inline type joint closure 48 fibre, and as shown in below image, it is regarded as a dome splice closure. The main difference between the two types of optical fibre cable joint closure is the sealing performance. The inline optical splice closure is composed of two upper and lower shells. The sealing area is large and the seal is irregular. The shell is sealed with a sealing strip. Relatively speaking, The sealing area of the inline type is small, the sealing place is regular, the sealing groove is circular sealing, and a circular sealing ring is used, so the sealing of the dome fiber optic splice closure is easier to achieve than the inline type, and the dome splice closure inlet and outlet adopts heat shrinkable tubing , The sealing performance is good and firm, the inline type adopts waterproof insulating glue, the sealing performance is good, and the firmness is not as good as the dome type (reflected in the tensile performance).

3.3 Select the number and diameter of the fiber optic cable ports

The size and quantity of the incoming and outgoing cables of each fiber optic splice closure are different. Before purchasing, be sure to determine the needs of the project, and then confirm the technical specifications of the product with the supplier to avoid using it back after purchasing.

3.4 Select the number of cores of the fiber splice enclosure

The number of cores in the external fibre splice enclosure on the market ranges from 12 cores to 2880 cores. The user selects the appropriate number of cores according to the needs of the project, and pays attention to the needs of subsequent expansion.

4. How to check the quality of fiber optic closure

In order to ensure the quality of communication equipment and the safety of users, we must choose optical fiber products that meet the standards. Many project managers like to use splice closure from TELHUA because they meet the standards. It is necessary to distinguish the difference between a high-quality fiber optic joint enclosure and a poor-quality fiber optic splice closure. Enhancing the quality of communication equipment such as fiber optic splice enclosure also brings a certain degree of safety to users.

4.1 Check the material of the enclosure

The high-quality fiber splice closure is injection molded from new material PC, which is corrosion-resistant and aging-resistant, has a long service life, and has a smooth and beautiful surface. The mechanical structure is durable and can resist different climate changes and harsh working environments.

4.2 Check the applicability of the optical cable

The high-quality fiber splice enclosure is suitable for ribbon optical cables and ordinary optical cables. The internal splicing tray can be turned over according to the installation requirements, and there is enough space to place the optical fiber trays, and each optical cable and optical fiber can be constructed separately.

4.3 Check the volume and capacity

The high-quality joint closure is small in size, large in capacity, and can be installed with fixed modules of different adapters, which is convenient for installation and maintenance. Can be installed on walls and poles.