Published In December 2001
Last month’s fiber optics column focused on estimating. This month’s column targets a small but important part of installation costs: fiber optic cable termination. Surveys have said that ease of installation and high performance (e.g., low loss) are the top two desired qualities, but cost ranks close behind. Actually, all three are closely related. Easily installed connectors can be installed more quickly, which lowers labor cost. Low-loss connectors are less likely to fail testing, so they have higher yield. Labor and yield are important cost issues. When most people calculate fiber optic termination costs, they include the costs of the connector plus the labor required for installing it. Thus, an inexpensive connector that takes longer to install may be less cost-effective than an expensive connector that installs quickly. A difficult aspect of estimating costs is determining the actual time needed to terminate a fiber. How much time does it really take? The total time required for terminating fiber optic cable does not only include attaching the connector to the fiber. As part of our Fiber U training programs, we’ve analyzed the whole process, from showing up at the job site to leaving after cleanup. We have determined that about 20 separate steps are involved. The total time required depends on a number of factors, including job site conditions, connector termination type, cable type, number of terminations, and installer experience. On the average, work at one location will take 20 to 30 minutes of setup, test, and cleanup. It can take a lot more time if hardware, such as patch panels or boxes and dress cables, must be installed. Test time will be longer if cables are running between buildings or only one person is doing the testing. The time involved will also be longer if the work area is hard to reach or restricted in working space, especially overhead. If the work area is difficult to work in, the best bet is to bring excess cable out into a hallway or down to floor level and after termination coil the excess cable into service loops. The cable type is very important. Distribution cable is the simplest as the single-cable jacket and individual 900-micron buffered fibers require minimal preparation. Strip the cable once to expose all the fibers and strip each fiber as you make the individual termination. Individual terminations should take as long as a manufacturer quotes for its connector, only a couple of minutes per fiber. Breakout cables have each fiber in an individual cable inside a common jacket. You must strip the outer jacket, then strip each fiber as a separate cable, with termination times about the same as terminating single-fiber cable or zipcords. Add a minute or more per termination to allow stripping of the jacket, cutting of the Kevlar, fitting the connector to the jacket, and crimping. Terminating outside plant cables with connectors can be a long and arduous process. You must strip the cable, clean the gel off, cut the buffer tubes, clean the individual fibers, then thread them into breakout kits, which can add five minutes or more per termination! Once you do this, you can understand why dry water-blocked cables are rapidly gaining acceptance for outdoor applications! The actual termination takes only a couple of minutes. Even the “old reliable” epoxy-polish connector, which requires oven curing, takes no longer if you are doing several connectors. The curing time becomes irrelevant if you install one connector and let it cure while you install others. The curing will be complete on the first connector before a half dozen connectors are installed, so it will be ready to polish. If you are installing only one or two connectors, then add a few minutes for epoxy curing. Anaerobic or other quick-curing adhesives are more attractive if you are installing only a few connectors at each location, but set-up time becomes a significant element in the time equation. “Cleave and leave” connectors are attractive because of their shorter set-up time. Here, you only prep the cable, strip, and cleave the fiber and install the connector, usually with a special tool. No adhesives, plus simple setup and cleanup, can mean fast terminations. But here, the wild card is yield. What is your connector yield? With any termination process, the key cost factor is yield. Connectors that install quickly are useless if many of them fail. A 90 percent yield means each connector costs 11percent more than the standard cost. Cost increases further if replacing that connector includes setting up in the same work area again. This presents a strong argument for testing all connectors as you go along, rather than coming back later and testing all the connectors at once. There is no “secret” to connector yield, just maniacal attention to details. You must have the right tools and training. Most importantly, you must have experience with the connector you are installing. Only you should take that responsibility—never trust what someone tells you. HAYES is the founder of Fotec, the fiber optic test equipment company and the Cable U training programs. He can be contacted at Jh@jimhayes.com.