Fiber Optic Cable

Common Fiber Optic Cable Types for Outdoor Application

Taking the advantages of fast transmission and high bandwidth, fiber optic cable is being heavily deployed in most networking applications. It comes in lots of different types, depending on the number of fibers and how and where it will be installed, normally for indoor or outdoor applications. Outdoor fiber optic cable takes more responsibility to protect the optical fiber to operate safely in a complicated outdoor environment than indoor cable. This post aims to introduce some common fiber optic cable types for outdoor applications.

What Is Outdoor Cable?

As we all know, indoor cable is we call “tight-buffered” cables where the glass fiber has a primary coating and secondary buffer coating that enlarge each fiber to 900 microns—about 1 mm or 1/25 inch to make the fiber easier to works with. It is designed for flexibility, tensile strength, ease of handling, and flame retardancy. Different from indoor cable, outdoor cable structure contains a water blocking, which prevents the accumulation of water from freezing and transferring stress to the glass fiber, making the cable withstand the rigors of outdoor installation for a lifetime of 20 or 40 years.

Common Types of Outdoor Cables

For different outdoor environments, such as moisture, sunlight exposure, or underground, there are different outdoor cable types being applied.

Outdoor Loose-Tube Cable

Loose-tube cable is composed of several fibers together inside a small plastic tube, which is in turn wound around a central strength member, surrounded by aramid strengths and jacketed as shown below, providing a small, high fiber count cable. It is designed to endure outside temperature and high moisture conditions. The fibers are loosely packaged in gel filled tubes to repel water. Recommended for using this type of cable between buildings that are unprotected from outside elements. Loose-tube cable is restricted from inside building use, typically allowing entry not to exceed 50 feet(check your local codes).

structure of loose-tube cable

Indoor/Outdoor Tight-Buffered Cable

By eliminating the need to splice outdoor cables to flame-retardant indoor cables, indoor/outdoor fiber optic cable can achieve the connection between and within buildings, which saves many labor hours and reduces material costs. Indoor/outdoor tight-buffered cable is the most commonly used type, which often comes in two versions—fiber distribution cables and breakout fiber optic cable. This type of outdoor cable is flexible, easy to handle and simple to install. Since they do not use gel, the connectors can be terminated directly onto the fiber without difficult to use breakout kits. The image below shows the structure of indoor/outdoor tight-buffered cable.

indooroutdoor tight-buffered cable

Aerial Fiber Optic Cable

Aerial fiber optic cable as shown below is usually used for outside installation on poles. Due to its installation environment, the design of aerial fiber cable must consider to protect it from the destruction of the nature and man-made damage or theft. It is easily affected by the natural disasters, such as typhoons, ice, floods, as well as the influence of an outside force and the mechanical strength weakening in themselves. Therefore, the failure rate of aerial fiber cable is higher than the pipeline or direct buried fiber optic cable.

aerial fiber cable

Direct Buried Fiber Optic Cable

Direct Buried cable is a kind of communication or transmission cable which is especially designed to be buried under the ground without any kind of extra covering, sheathing, or piping to protect it. Unlike standard telecommunications and power cable, which have only a thin layer of insulation and a waterproof outer cover, direct buried cable consists of multiple layers of heavy metallic-banded sheathing, reinforced by heavy rubber covers, shock absorbing gel, wrapped thread-fortified waterproof tape, and stiffened by a heavy metal core as shown below. Direct buried cable is cheaper and easier to lay than other kinds of cable that require protection from the earth. However, direct buried cable is also easily cut during digging or other excavation. As a result, most direct buried cable is found on side roads, not main thoroughfares.

Direct-buried_cable

Summary

Outdoor cabling environment is so complicated that we should choose right bulk fiber optic cable to keep the good performance of the whole transmission network. FS.COM provides affordable fiber optic cable price for the outdoor cable that we have discussed above.

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