Handling Guide For Fiber Optic Simplex and Zipcord Cable
While optical cable may outwardly resemble copper cordage, the two are significantly different. A failure of optical cable may occur when improper methods of pulling and de-spooling are employed.
Too much tension on the fiber will cause several problems. If the glass is pulled, it may fracture causing light to be reflected resulting in high losses. If the cable jacket is pulled and stretched, it will eventually return to it's original state. If connectors are applied to the cable before it has had an opportunity to relax and return to this original state, the fiber and aramid fiber inside the jacket will be compressed and bunch up causing light to escape the cable.
Pulling only the outer jacket of the cable can cause a compression of the optical fiber that causes a significant attenuation increase. This condition, once initiated, is irreversible. In order to eliminate cable twist and pulling damage when installing optical cable, the following guidelines should be followed.
- Reel should be mounted horizontally on an axle.
- Remove 1 foot of outer jacket.
- Separate the kevlar aramid yard from the fiber.
- Cut the fiber even with the jacket.
- Knot the Kevlar to a pulling eye 2 inches from the end of the cable.
- Tape the remaining Kevlar to the jacket. This will assure the pull is on the Kevlar strength member and that the jacket does not slip back.
Simplex and Zipcord and pre-connectorized cable should always be pulled using a pulling rope and swivel. Should it become necessary to pull on the jacket due to space limitations a mandrel should be used. Using a 6-inch diameter mandrel, wrap 5 turns. Tape or allow a finger to maintain tension on the first wrap from the loose end. This will ensure that force is transferred to the aramid yarn strength member.
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