How To Do Fiber Optic Installation

In whatever space your optical-fiber cable is being installed, there are some basic guidelines that must be followed. Support the cable and avoid crushing, stressing and overbending it. Every cable will have values for minimum bend radius and maximum tensile loading; do not exceed these values. Cables should never be allowed to hang freely for long distances or to press against edges in an installation.

When pulling cable in conduit, all transition points, such as those going from conduit to pull box or exiting the conduit, should be kept smooth. Sometimes the addition of a piece of conduit beyond the transition will keep the cable from resting on a sharp edge. Bushings designed to fit the ends of conduit are also available.

Flexible conduit can be placed within boxes or at interfaces to prevent pressure against the cable or scraping on rough edges. Flexible conduit can also be added in areas open to frequent access, such as raised computer-room floors, where there is a higher potential risk to the cable.

Complying with the cable`s minimum bend radius cannot be overstressed. Some applications may present conditions where the configuration of the equipment will damage the cable by overbending it if precautions are not taken. Conduit bends, pull boxes and joints must be checked to verify that the bend radius is not too small. Innerduct or flexible conduit can be used to ease or sweep the cable around tight corners. The inside radius of conduit bends for fiber-optic cable should be at least 10 times the diameter of the cable. Pulls through tightly bent elbow fixtures should be backfed; in other words, the cable is not pulled from end to end, but to and out of an opened junction box, then coiled loosely on the ground and fed through the rest of the run.

Fiber Optic Installer Certification

In tray and rack installations, the minimum bend radius must also be monitored, because the cable will be routed around corners or through transitions. Where raceway or rack transitions expose the cable, flexible conduit should be used for protection.