Considerations About Fiber Optic Cable Installation

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It’s true that fiber optic cable, based
on optical technology to carry information between two points, have become
increasingly important in fiber optic systems. This cable is often attached
with the same or different connectors on the ends to connect devices, for
example, LC LC
multimode patch cord (LCs on both ends). When used in premises, fiber
optic cables can be used as backbone cabling in a standard structured cabling
network, connecting network hardware in the computer room. And when applied in
optimized fiber optic networks, they go directly to the work area with only passive
connections in the links. They can be installed indoors or outdoors using
several different installation processes. One of my recent blogs has talked
about safety issues about fiber optic cable installation. Today, this article
still focuses on its installation, but from other aspects, including the
general guidelines, its pulling tension, bend radius, and so on.

 

When deployed outside, fiber optic
cables may be direct buried, pulled or blown into conduit or innerduct, or
installed aerially between poles. When used outside, they can be e installed in
raceways, cable trays, placed in hangers, pulled into conduit or innerduct or
blown though special ducts with compressed gas. The installation process
depends on the nature of the installation and the type of cables being used.

 

Installation General Guidelines

First point to mention is that fiber
optic cable is often custom-designed for the installation and the manufacturer
may have specific instructions on its installation. So, it’s highly recommended
to follow the cable manufacturer’s suggestions. Often, it’s necessary to check
the cable length to make sure the cable being pulled is long enough for the
run, so as to prevent having to splice fiber and provide special protection for
the splices. Of course, it’s better to try to complete the installation in one
pull. Prior to any installation, one should assess the route carefully to
determine the methods of installation and obstacles that are likely to be
encountered.

 

Pulling Tension

Fiber optic cable is designed to be
pulled with much greater force than copper wire if pulled correctly, but excess
stress may harm the fibers, potentially causing eventual failure. Cable
manufacturers install special strength members, usually aramid yarn, for
pulling. Fiber optic cable should only be pulled by these strength members. Any
other method may put stress on the fibers and harm them. During installation,
swivel pulling eyes should be used to attach the pulling rope or tape to the
cable to prevent cable twisting during the pull.

 

Besides, cables should not be pulled by
the jacket unless it is specifically approved by the cable manufacturers and an
approved cable grip is used. Tight buffer cable can be pulled by the jacket in
premises applications if a large (~40 cm, 8 in.) spool is used as a pulling
mandrel. It’s right to wrap the cable around the spool 5 times and hold gently
when pulling.

 

It’s ill-advised to exceed the maximum
pulling tension rating. It’s suggested to consult the cable manufacturer and
suppliers of conduit, innerduct, and cable lubricants for guidelines on tension
ratings and lubricant use.

 

On long runs (up to approximately 3
miles or 5 kilometers), one should use proper lubricants and make sure they are
compatible with the cable jacket. If possible, an automated puller can be used
with tension control and/or a breakaway pulling eye. On very long runs (farther
than approximately 2.5 miles or 4 kilometers), one should pull from the middle
out to both ends or use an automated fiber puller at intermediate point(s) for
a continuous pull.

 

Bend Radius

When there are no specific
recommendations from the cable manufacturer, the cable should not be pulled
over a bend radius smaller than twenty (20) times the cable diameter. And after
completion of the pull, the cable should not have any bend radius smaller than
ten times the cable diameter.

 

Twisting cable

It’s known that twisting the cable can
stress the fibers, thus in no case should one twist the cable. (Tension on the
cable and pulling ropes can cause twisting.)

 

Use a swivel pulling eye to connect the
pull rope to the cable to prevent pulling tension causing twisting forces on
the cable.

 

Roll the cable off the spool instead of
spinning it off the spool end to prevent putting a twist in the cable for every
turn on the spool.

 

When laying cable out for a long pull,
use a “figure 8” on the ground to prevent twisting. The figure 8 puts a half
twist in on one side of the 8 and takes it out on the other, preventing twists.

 

Conclusion

Fiber optic cables have been widely
deployed for computer net- works (LANs), closed circuit TV (video), voice links
(telephone, intercom, audio), building management, security or fire alarm
systems, or any other communications link. With its installation in large
scale, it’s of great importance to know some basic points on cable installation
discussed in this text. As for the fiber optic cables chosen for project, you
can try Fiberstore, whose cables are available in many types, like SC fiber
optic cable, LC SC cable, MTP cable. All are test- and quality-assured,
suitable for both indoor and outdoor installation.