Fiber Optic Splice Closure Selection Guide

What Is Fiber Optic Splice Closure?

Fiber Optic Splice Closure, also known as fiber Splice Closures, fiber splice enclosure,or fiber optic splice enclosure,is designed to protect fiber optic facilities.The Fiber optic splice closures provide space for optical fiber fusion splicing. There are lots of different designs and options on Fiber Splice Closures. Some are designed for concatenation of long distance cables where two identical cables are spliced together. Some Fiber Optic Splice Closures are designed for connecting several smaller cables to a larger one for breaking out the larger cable to several destinations.Small fiber splice enclosure for FTTH pre-terminated cables may have connector mating adapters inside the closure to create a patch panel.

Types of Fiber Optic Splice Closures

According to different applications,there are two main varieties of fiber optic splice closures, vertical and horizontal; many are used for Aerial-mounted splicing,pole-mounted splicing,buried or hand hole splicing.

• Horizontal Type Fiber Optic Splice Closures

Horizontal type Fiber Splice Closures is like a flat or cylindrical case. This type of fiber enclosure is the most commonly used one in mounted aerials or buried underground. Horizontal type Fiber Optic Splice Closure usually contains one or more fiber splice trays to provide space and protection for fiber optic splices. Fiber splice trays used in different fiber optic splice closures may have different designs and fiber counts. The common fiber counts of flat fiber splice closure are 12 and 24 fibers.

Horizontal fiber optic splice closures are designed to be waterproof. They have good adaptability and compression resistance. If attached to a pole or hung from wiring, these fiber splice closures need to be held firmly in place, to fight the bad environment.

The following picture shows a 96-fiber horizontal fiber optic splice closure. It has two input ports and two output ports providing space for 96 fiber splices. There are four standard 24-fiber splice trays stacked together inside the fiber optic splice closure.

• Dome/ horizontal Fiber Optic Splice Closures

Vertical Fiber Optic Splice Closure looks like a dome, thus it is also called dome fiber optic splice closure or fiber dome closure. The dome shape makes it easy to be buried in many applications, though it also can be used above-ground as well.

Due to the growing network demands, there is a wide range of models and configurations of vertical fiber optic splice closures. High-capacity versions and variations in the number of splicing trays are also available in the market to meet the complex needs of today’s fiber-optic networks. The number of inlet/outlet ports of the dome Fiber Optic Splice Closure also varies with application needs. Dome fiber optic splice closure requires high-levels seals and waterproof technology, due to its underground applications. Besides, keeping insects and dirt out is also important for underground closures.

The following shows a vertical fiber splice closure FOSC-mini 48 fiber, which has a capacity of  four 24-fiber splice trays. Max. closure splice capacity is 96 cores. IP waterproof-68.

How to choose right Fiber Optic Splice Closures？
The long term survival of a network depends on the integrity of fiber optic splice closures to protect the splices and cables at that location. Choosing a Fiber Splice Closure is a matter of solving the problems of protecting the splices and installing the closure plus choosing a design that the tech knows how to use. The following factors will help you to choose the right fiber optic splice closures and protect the fiber optics in your network.

1. Cable Compatibility

A good Fiber Optic Splice Closure shall be capable of accepting any fiber optic cable as specified in the tender document. Thus, it is vital to figure out cable compatibility before selecting the right closure type. The design of fiber optic splice closure changes with the application areas. Therefore, a fiber optic splice closure for aerial will have a different design from that used for the underground application.

2. Numbers of cables ports/fibers/splices

The first consideration is how many cables with what number of fibers are to be joined with splices at the closure.

The cable port is also known as the cable entrance capacity. The number of ports in a Fiber Optic Splice Closure reflects its capacity to handle the number of cables. The cable entrance capacity of a fiber optic splice closure refers to the number of ports available for terminating cable within the closure.

3. Material of Fiber Splice Closures

4. According to different usage environments choose  different Fiber Splice Closures made of different materials. There are PP,PC and ABC plastics.

5.Location of the closure

According to different applications, you had better consider the following factors.

Outdoors: aerial, underground or integrated into a pedestal, Indoors: wall/rack mount or integrated into patch panel.
6.Fiber Splice Closures Quality

The ruggedness and sealing of the closure are of primary concern since moisture/water, dirt, etc. entering the closure can compromise the quality and lifetime of the cables, fibers and splices. Most Fiber Optic Splice Closures will be rated IP68 according to IEC 60529 or Telcordia GR-771-CORE.

7.Special needs

Many options, including cable types (armored requires grounding), adding other components like splitters for PON networks, hard ribbon cables requiring  splice trays that are thicker, breakouts to connectors for FTTH drops, etc.
8. Hardware and Accessors

Aerial Fiber Optic Splice Closures may need to hang on the messenger wire depending on the network configuration. Or they may be attached to the pole. In both cases, extra hardware is required along with the closures. The hardware or accessories to attach and secure should be able to bear wear and tear and also environmental stresses.