Buying Guide: What is the Fiber Optic Closure?

Fiber Optic Cable Closures are crucial in building and maintaining optical fiber networks. These devices connect multiple optical cables, ensuring continuity, sealing, and mechanical strength.

What are fiber optic cable closures?

Fiber optic closures serve as protective boxes encasing the sensitive joints between interconnected cables. As their name implies, these enclosures ensure the patency of fiber optic connections by maintaining a tight seal over the optic cable junctures. The seal helps keep contaminants like dirt or moisture at bay, preventing external elements from corrupting the integrity of the data cables.

As such, the quality of the fiber optic splice boxes directly impacts each network’s performance and lifespan.

Are these enclosures necessary?

The short answer is yes. Fiber optic cables transmit light pulses (data) over great distances. They span across cities (even continents) and are often laid out in various terrains (underground, underwater, or over air) and under extreme weather conditions.

Without adequate protection, optical fiber connections, especially the parts spliced together, are most at risk of severing at any time. As optical fibers rely on the patency of the connection to send and retrieve data from one end to another, it is a priority to ensure the cables are safe from any mechanical or environmental damage.

Key Features of fiber optic splice closures:

• Waterproof, dustproof, and weatherproof
• Durable and built to last
• User-friendly and easy to install
• Tamper-resistant
• High performance and maintains signal integrity under various conditions
• Supports a variety of cable types and sizes

Benefits of fiber optic splice closures:

• Improves longevity of fiber optic networks
• Ensures the network’s high performance
• Protects cable from hazards including damage from moisture and extreme temperature
• Helps prevent signal degradation
• Ease of maintenance and future upgrades

Types of fiber optic enclosures

There are three main classes of optic fiber closures: horizontal (also known as inline or cylindrical), vertical (or dome-shaped), and hybrid. Each fiber optic network is unique and has varying needs, depending on factors like the location or the splice count.

1. Horizontal – Commonly shaped as a cylinder or a flat box, this setup is the most popular due to its adaptability. Horizontal enclosures can buried or hung, and are waterproof, dustproof, and compression-resistant. Most horizontal boxes support fiber counts of 12 to 24 per tray and come in various shapes, sizes, and tray counts.
2. Vertical – These dome-shaped enclosures are built mainly for underground placement. However, depending on the optic network’s needs, the splice closures may also be utilized for above-ground use. They usually share similar specifications as the horizontal boxes and protect the cables from water, pressure, or dirt damage.
3. Hybrid – Used in FTTH (fiber to the home) networks for internet service, hybrid closures are boxes that house cable ends and a patch panel. These enclosures are usually made for cables with special ends and do not require splicing. Like the two other types, these enclosures keep moisture and dirt from invading the connections.

Compoments of an optic fiber splice closure

A fiber optic cable enclosure typically consists of several essential parts:

• Outer housing. This is the main body of the enclosure, typically made from durable materials like plastic or metal.
• Cable entry ports. These are openings where the fiber optic cables enter and exit the enclosure. They keep the enclosure sealed and well-protected.
• Splice trays. Inside the enclosure, these trays hold and organize the spliced fibers and ensure each fiber connection is in place.
• Sealing mechanism. These include gaskets or sealants to ensure the enclosure is waterproof and dustproof.
• Locking mechanism. This could be a latch, screw, or other securing method to keep the enclosure closed and tamper-resistant.
• Grounding and bonding components. For enclosures with metallic components, these protect the cables against electrical surges.
• Strength member clamps. These components secure the central strength members of the cables, providing stability and reducing strain on the fibers.
• Cable management features. Clamps, ties, or guides to ensure that cables are neatly organized and bent at safe radii, preventing damage or signal loss.
• Accessories for mounting. Brackets or other features for mounting the enclosure on poles, walls, or below ground.

Things to consider when choosing a fiber optic cable enclosure

When choosing your box, here are a few things to keep in mind:

1. Cable compatibility. Check the compatibility of the fiber optic cable against the box specs. Make sure that the box can fit the size of your cable and is compatible to support it.
2. Port capacity. Look into the box’s number of ports and get the one that’s most suited to your networking needs, whether it’s a box that can handle fewer or more ports.
3. Splice types. The way the cables are joined will also affect the choice of the kind of enclosure. Mechanical or ribbon splices are usually larger and take up more space. Closure trays for splices like this must be able to hold the splices in place.
4. Termination system. The termination system should be able to handle changes such as thermal expansion and contraction without stressing the cable. Additionally, it should minimize any movement between different parts of the cable so they stay put.
5. Box placement. The choice of closure box will also depend on where the cables are located (e.g., attached to a wall or pole or buried underground). It must be secure enough to keep away the elements and endure everyday wear and tear while maintaining the cables’ integrity.
6. Easy access and expansion. Depending on the location, some boxes tend to be reopened more often than others. Look for boxes designed to be easy to open and shut if they need to be accessed from time to time. It’s also important to note how the network might grow, as it might need a box that can adjust to more cables later.

Final Thoughts

The longevity and performance of fiber optic networks depend on many factors, including the quality of the enclosures protecting the spliced connections. As simple as these boxes of plastic and metal may seem, they play an indispensable role in ensuring uninterrupted data transfer, whether small-scale or large-scale applications. Hence, the selection, design, and maintenance of these enclosures are crucial elements in the broader context of network infrastructure, directly impacting the efficiency and reliability of fiber optic communication systems.