As technology advances, the demand for improved data bandwidth increases. So, fiber optics are gradually replacing copper wires as the network backbone. These cables are installed in overhead ducts, conduits, or buried underground. Hence, they are prone to damage from bending under excessive physical strain or gnawing by rodents and pests. To ensure the cable laid out for extreme environments is protected against them, cable manufacturers also created a special line of Armored Fiber Optic Cable. The fiber core is protected with an aluminum armor helically covering the fiber or kevlar strands to protect the cable from crush force. An armored fiber optic cable with a helically wrapped aluminum armor and usually installed in the plenum area of the building is called Interlocking Plenum Armored Fiber Optic Cable.

The Construction

Standard fiber optic cables have a glass core surrounded by a denser cladding and a PVC jacket for protection. Armored fiber optic cables go a step ahead and have a fire-retardant Aramid yarn between the cladding and the outer PVC covering. An aluminum covering is helically woven across the PVC jacket. As seen in the image below, the aluminum covering has ridges that offer crush protection to the cable without restricting the cable flexibility. Due to the way the ridges “interlock” with the preceding ridge, these cables are termed ‘interlocking armored fiber optic cable.’

How to terminate the cable

Due to the construction of the cable, you cannot implement traditional termination methods directly. Instead, a specialized tool called the BX & Armored Cable Cutter is used to slice the outer aluminum armor to access the inner fiber.

Once you have removed the outer jacket, exposing the aluminum armor, the tool is clamped into place. Then, by rotating the spindle, a small circular cutting blade cuts through the armor to make a small slit.

By gently flexing the cable, the armor separates, exposing the inner PVC jacket that can be terminated for attaching connectors.

Benefits & Applications of Armored Fiber Cables

The benefits of using armored fiber optic cable are:

Excellent attenuation performances

Protected from water or moisture penetration

Crush protection

Protection against rodents gnawing the cable

Flexible yet sturdy

Fire-resistant

Places where armored fiber cables are best suited are:

Surveillance

Data centers with underground cable laying.

Specialized cables with water block gel are used for underwater networks near shores.

Places where the cables need to be run in tight areas such as overhead conduits, ducts, or plenum area.

Video broadcasts

Fire & safety alarm systems.

Wrapping Up

Interlocking plenum armored fiber optic cable resulted from the need to have a network that provides high speed and bandwidth of the traditional fiber optic with additional protection measures for the harsh conditions. You buy them in bulk and have them terminated on the field or eliminate extra work by opting for pre-termination from the factory.