Preparing Fiber Optic Cable For Splicing or Termination

I recently watched my coworker disassembling a computer using only one tool. Was it the right tool for the job? Yes and no. It was the tool he had… it worked, however, there is definitely more than one tool out there that would have made the task easier! This situation is definitely one that many fiber optic installers know all too well. As a gentle reminder, how many of you have used your Splicer’s Tool Kit (cable knife/scissors) to remove jacketing or even slit a buffer tube and then use the scissors to hack away at the Kevlar? Did you nick the glass? Did you accidentally cut through the glass and have to start over?

Correctly splicing and terminating fiber optic cable requires special tools and techniques. Training is important and there are many excellent sources of training available. Do not mix your electrical tools with your fiber tools. Use the right tool for the job! Being proficient in fiber work will become increasingly necessary as the importance of data transmission speeds, fiber to the home and fiber to the premise deployments continue to increase.

Many factors set fiber installations apart from traditional electrical projects. Fiber optic glass is very fragile; it’s nominal outside diameter is 125um. The slightest scratch, mark or even speck of dirt will affect the transmission of light, degrading the signal. Safety is important because you are working with glass that can sliver into your skin without being fiber optic cable manufacturer seen by the human eye. Transmission grade lasers are very dangerous, and require that protective eyewear is a must. This industry has primarily been dealing with voice and data grade circuits that could tolerate some interruption or slow down of signal. The person speaking would repeat themselves, or the data would retransmit. Today we are dealing with IPTV signals and customers who will not tolerate pixelization, or momentary locking of the picture. All of the situations mentioned are cause for the customer to look for another carrier. Each situation could have been avoided if proper attention was given to the techniques used when preparing, installing, and maintaining fiber optic cables.

With that being said, why don’t we review basic fiber preparation? Jacket Strippers are used to remove the 1.6 – 3.0mm PVC outer jacket on simplex and duplex fiber cables. Serrated Kevlar Cutters will cut and trim the kevlar strength member directly beneath the jacket and Buffer Strippers will remove the acrylate (buffer) coating from the bare glass. A protective plastic coating is applied to the bare fiber after the drawing process, but prior to spooling. The most common coating is a UV-cured acrylate, which is applied in two layers, resulting in a nominal outside diameter of 250um for the coated fiber. The coating is highly engineered, providing protection against physical damage caused by environmental elements, such as temperature and humidity extremes, exposure to chemicals, point of stress… etc. while also minimizing optical loss. Without it, the manufacturer would not be able to spool the fiber without breaking it. The 250um-coated fiber is the building block for many common fiber optic cable constructions. It is often used as is, especially when additional mechanical or environmental protection is not required, such as inside of optical devices or splice closures. For additional physical protection and ease of handling, a secondary coating of polyvinyl chloride (PVC) or Hytrel (a thermoplastic elastomer that has desirable characteristics for use as a secondary buffer) is extruded over the 250um-coated fiber, increasing the outside diameter up to 900um. This type of construction is referred to as ‘tight buffered fiber’. Tight Buffered may be single or multi fiber and are seen in Premise Networks and indoor applications. Multi-fiber, tight-buffered cables often are used for intra-building, risers, general building and plenum applications.