The Fiber Optic Cable Plant

The FOA generally focuses on the fiber optic cable plant.

What is a "fiber optic cable plant"? It's a term we use all the time in fiber optics to cover the installed fiber optics that transmits communications signals. It's permanently installed between the two points which you require communications between. It's what you connect your communications electronics to with patchcords on each end.

The cable plant includes all the fiber optic cable between those two points. That cable may be buried underground or installed aerially on utility poles. It may even have segments that run under water - streams, rivers, lakes or oceans. Cables come in a maximum length of about 5km on a spool from the factory, so longer lengths will require splicing cables together. Splicing is also required if points along the route require connections (drops) as well as from end to end. At the ends, the cable plant will be terminated in connectors to allow making connections that can be changed as needed. Hardware is required for every splice and termination to protect the cable plant and the joints between cables. These may require underground storage in manholes or above ground storage in pedestals. Indoors they are in racks or enclosures that hold and protect patch panels for interconnections.

Fiber optic cable may be installed indoors or outdoors using several different installation processes.  Outdoor cable may be direct buried, pulled or blown into conduit or innerduct, or installed aerially between poles. Indoor cables can be installed in raceways, cable trays above ceilings or under floors, placed in hangers, pulled into conduit or innerduct or blown though special ducts with compressed gas. The installation process will depend on the nature of the installation and the type of cable being used.

Here are examples of fiber optic cable plants.

underground cables
Underground cables may installed in conduit or ducts or, if the cable is armored, directly buried underground. Cables are spliced in manholes or handholes (smaller than manholes) and may be new and neat as on the left or older and crowded from the addition of many cables over the years.

aerial cable
Aerial fiber optic cable often shars poles with telecom wire and CATV coax, but is usually marked with orange fiber labels. Low voltage cables are mounted on poles in the "telecom space," well below power cables.

Optical power ground wire (OPGW) is an electrical power ground with fiber optics in the center of the conductor. The coil on the tower is where fibers are spliced and the building houses communication equipment.

premises cabling
Premises cable plant with connection racks and storage loops

More on Outside Plant Construction and Installation

Table of Contents: The FOA Reference Guide To Fiber Optics


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