Tuesday, January 13, 2015

Protecting Your Fiber Optic Cables from the Elements

Fiber optic cables are installed in a wide variety of ways. They can be buried underground, pulled in conduit, strung aerially, and even laid deep underwater. Given the highly delicate and costly nature of fiber optic cables, much care must be taken to ensure that they are protected from the elements. The number of factors that must be considered are massive. Is the cable in danger of becoming wet or moist? Will it be exposed to chemicals or extreme temperatures? Could it be accessed by squirrels, woodchucks — or even sharks — that mistake it for a chew toy? Luckily, today we are sharing some types of cables that will not be vulnerable to the elements.

Cable Design Criteria:

  • Pulling Strength: In some cases, cables are laid into trays or ditches and do not experience much resistance. However, when cables are drawn over conduit, pulling tension tends to be very high. For simple installations, aim for a cable pull strength of 100-200 pounds, and closer to 800 for outside cables.
  • Bending Limits: If a cable is not experiencing bending tension, the recommended long-term bend radius is ten times the cable diameter. That number doubles for fiber optic cables under tension.
  • Water Protection: Any outdoor cable must be protected from water or moisture. When protecting your cable, the most common solution is to employ a moisture resistant jacket and a filling of water blocking material. However, most manufacturers now sell dry water-blocked cables.

Types of Protective Cables:

  • Armored Fiber Cables: The easiest way to feel confident about the safety of your fiber optic cable assemblies is to invest in armored fiber optic cables. Manufactured at an industrial or military grade, armored solutions are perfect in conditions where the cable is exposed to extreme temperatures or could possibly be compromised by heavy crush loads. With a jacket that is up to 100 times stronger than the average fiber optic cables, it promises to keep your cables protected without compromising flexibility.
  • Bend Insensitive CablesDue to the sensitive nature of their construction, fiber optic cables are very sensitive to sharp bends. If you exceed its maximum bending radius, light will escape from the fiber coil, causing significant power loss. Many facilities have a problem with this as wall- or ceiling-mounted cables require a bend at the corner of the room. Of all fiber optic cable types, bend insensitive cables are the best equipped to handle this tough task. The complex geometry allows for microbending and macrobending with little reflection energy loss, 
  • Undersea Cables: Often, applications are required where fiber optics must be installed under water. Earlier this year, Popular Science reported that Google was taking extra steps to protect their underwater fiber optic cables from sharks, who are “encouraged by electromagnetic fields from a suspended cable strumming in currents.” They do this by wrapping the cables in a Kevlar-like material or running the fibers through stainless steel tubes to thwart away these unlikely intruders.

The number of factors that must be considered when selecting a fiber optic cable can be overwhelming. Here at SanSpot, we have a team of specialized experts that are dedicated to helping you select the best cable for your environmental and installation requirements. Call us today at 1-800-720-3860.