Follow the box manufacturer's recommendations. Fiber optic box is often custom-designed for the installation and the manufacturer may have specific instructions on its installation.
Check the box length to make sure the box being pulled is long enough for the run to prevent having to splice fiber and provide special protection for the splices.
Try to complete the installation in one pull. Prior to any installation, assess the route carefully to determine the methods of installation and obstacles likely to be encountered.
When pulling box 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 box 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 box 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 box.
Complying with the box`s minimum bend radius cannot be overstressed. Some applications may present conditions where the configuration of the equipment will damage the box 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 box around tight corners.
The inside radius of conduit bends for fiber-optic box should be at least 10 times the diameter of the box. Pulls through tightly bent elbow fixtures should be backfed; in other words, the box 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.
In tray and rack installations, the minimum bend radius must also be monitored, because the box will be routed around corners or through transitions. Where raceway or rack transitions expose the fiber termination box, flexible conduit should be used for protection.