A previous article, “10 guidelines for qualifying and selecting fiber installers,” presented guidelines for selecting trained and certified installation personnel. These guidelines evolved from Pearson Technologies’ 32 years of training more than 7700 installation personnel and supporting attorneys in 38 lawsuits. This article presents 10 examples of the consequences of untrained and uncertified personnel.
1. Ignorance of dust’s impact. Trained and certified installers understand both the importance of clean fibers and connectors, and the consequences of dust. In this example, tens of thousands of “cleave-and-crimp” connectors were to be installed in a large facility under construction. The construction activities resulted in a dusty environment. The connectors required creating a cleaved fiber end and inserting that end into the connector. The dusty environment resulted in dust settling onto the cleaved fiber ends end/or connector ends. High loss resulted.
The installation personnel were day laborers without the knowledge and experience for successful installation. As a result, the installers did not consider creation of a clean volume for connector installation to avoid dust contamination. Such a clean volume is simple to create at an estimated cost of $250.
Consequences: Instead of a yield of ≥95%, the yield was <70% with an increase in labor and connector cost of ~43%, for an estimated cost increase of $840,000.
2. Importance of microscopic inspection. Avoidance of dust contamination and microscopic inspection are the well-known rules for trained and certified installers. Published studies of installation problems indicate dirty fiber ends have represented as much as 85% of installation problems. The connectors in Example 1 were installed without microscopic inspection of the ferrule end to assess contamination; installers and their supervisor did not recognize the need and benefit of inspection. Without this knowledge, high-loss connectors were replaced instead of cleaned. It is possible that some of the high loss and cost in Example 1 were due to dust on the ferrule end. Such dust would be simple and inexpensive to remove.
Consequence: Some of the $840,000 replacement cost could have been avoided by a cleaning and inspection process that takes several minutes with a ~$200 microscope.
3. Failure to follow manufacturer’s instructions. Trained and certified installers are disciplined to follow the manufacturer’s instructions. In Example 1, the connector instruction manual explicitly stated: “Do not clean the cleaved fiber end.” This author’s 14 years’ experience with cleave-and-crimp connectors strongly supports this instruction. Contamination from cleaning after cleaving can and does often result. The inexperienced installers consistently cleaned the cleaved end. The supervisor supported this violation of the stated instructions. This example, and the prior example, emphasize the need for both experienced fiber supervision in addition to experienced, trained, and certified installers.
Consequence: The lack of knowledge and/or training and/or understanding resulted in reduced yield, increased cost, a costly lawsuit, and a highly dissatisfied client.
4. Violation of NEC requirements. As cable systems are installed within buildings and such systems require compliance with the National Electrical Code (NEC), trained and certified installers know how to comply with these requirements. In this example, the inexperienced installers and supervisors routed patch cables in front of enclosures, in violation of the NEC Section 770.24.
The “NEC and Optical Fiber Cable and Raceway Rules” provide: “You must install equipment and cabling in a neat and workmanlike manner (NEC Section 770.24). One of the implications of this is the routing of your cables cannot interfere with access to equipment (NEC Section 770.21).” (Source: The NEC and Optical Fiber Cable and Raceway Rules, EC&M, June 11, 2013)
Avoiding interference has two benefits—convenience in accessing ports and avoidance of reduced liability. If a technician needs to move one cable to access equipment or a port, there is a risk of damaging cables or interrupting signals. Compliance with the NEC at patch panels will be the subject of another article.
Consequence: The lack of knowledge by supervisor and installers resulted in a lawsuit with significant dollar value.
5. Choosing the lowest-cost installer. Here are two examples of what can happen by choosing the low-cost installer. Trained and certified installers understand two specific aspects of splicing: how to splice fiber without gas bubbles, and how to interpret OTDR traces of such splices. In the first example, a fiber contractor, a friend of mind, lost a splicing bid to the low bidder. Several weeks later, the client called my friend and stated, “None of the fibers work.” The client asked my friend to redo the splicing. My friend’s technicians reported that OTDR testing indicated every one of the splices had low loss and high reflectance. The reflectance was due to a gas bubble in every splice. The excessive reflectance from gas bubbles corrupted the optical signal on every fiber.
Evidently, the low bidder knew how to measure loss properly with an OTDR but did not know two basic facts: a properly made fusion splice has no reflectance, and it has no gas bubble. The client’s request was amusing: “Will you redo the work at the same price as the low bidder?” Being polite, my friend thought, but did not say, “You got what you paid for.”
Consequence: Installation cost more than doubled.
Trained and certified installers know that following the rules for cable installation eliminates fiber breakage. Following these rules results in control of both the load and the bend radius. In this second example, against technical personnel’s recommendations, the purchasing department of a client hired a cable installer because of low cost. As a result, a significant number of cables had to be repurchased and reinstalled to replace cables with broken fibers at a cost to the client. Obviously, the low-cost installer did not control bend radius and load.
Consequences: Increased installation cost. A second concern is the potential for reduced reliability of those cables that did not break.
6. Inadequately trained installer. While OTDR testing a replacement cable for a client, this author noticed that many of the singlemode connectors had losses closer to the maximum than the typical values. From experience installing and supervising more than 50,000 connectors, I knew there were installation errors. Microscopic inspection of the connectors revealed that polishing scratches had not been removed completely. Upon further investigation, I learned that a salesperson trained the technician in polishing of multimode connectors. The technician used the multimode polishing procedure on singlemode connectors, not knowing either the significance of polishing scratches left from the multimode procedure, or the effect of scratches on singlemode loss.
Consequence: The power margin, power level reduction allowable before link failure, was reduced. As a result, the reliability of the link was reduced.
7. Inadequate training in connector inspection. Trained and certified installers know how to interpret microscopic appearance of connector ends, as microscopic inspection is the last step prior to connector insertion. A technician with 2 months of on-the-job experience arrived to install fiber to this author’s home. After installing connectors on both ends of the drop cable, there was no signal. Power level testing revealed insufficient power at the optical network terminal (ONT). The field installer inspected both connectors and deemed them good. Reinstallation of the connectors did not fix the problem.
The technician called another technician with several years’ experience. The experienced technician noted that the connector installation was defective in that the fiber, held by compression and without adhesive, had withdrawn into the ferule, resulting in high loss. Interpretation of connector appearance by a person without adequate training resulted in misinterpretation of microscopic appearance and inability to diagnose link failure.
Consequence: Increased installation cost; a half-hour task for one technician took 3 hours and 2 technicians.
8. Cable buried incorrectly. Trained and certified installers know to bury cables at a depth that prevents damage. This author has had two experiences of this incorrect installation. In the first experience, cable installers buried the fiber cable to my home at a depth of about 3 inches. Two days later, the landscaper put his shovel into and through the cable. (After the technician installed a second cable with connectors, I placed “buried cable” markers along the path.)
Consequence: A one-hour task had to be done twice, at twice the cost.
In a second experience, an attorney asked me to review a claim by a cable owner against a contractor working a heavy plow along the cable path. The plow damaged the fiber cable. The cable owner claimed negligence. However, the normal burial depth for fiber cable is approximately 30 inches or below the frost line, whichever is deeper. The normal depth of disturbance by the plow as 3 to 4 inches—the same depth at which the cable owner had allowed the cable to be buried.
Consequence: Significant cable repair cost, which I estimate at high five figures.
9. Inadequate cable installation training. Trained and certified installers know to attach cable tied without damage. Such knowledge is required for fiber certification. In this example, a client was called to troubleshoot a non-functioning Ethernet link installed by an electrical contractor. This client noted that the power light was on, but the “signal received” light was not. Suspecting a power loss problem, the client performed an OTDR test. The test revealed 42 power drops along the small-diameter, zipcord cable. The power loss at each drop was small, but 42 small losses resulted in significant total loss.
Visual inspection of the cable revealed cable ties installed with a cable tie tool. The cable tie tool created bend radius violations under each of the ties. Removal and replacement with hand-tightened ties restored link operation.
Consequence: Increased installation cost. Update: The recommended procedure has changed. Cable ties are not recommended for use on indoor fiber-optic cables; instead hook-and-loop ties are, as it is essentially impossible to violate a bend radius under a hook-and-loop tie.
10. Failure to monitor oven temperature. Trained and certified installers know that temperature control is required for proper curing of connectors installed with epoxy. After polishing connectors installed with epoxy, a client noticed 30% of the connectors had cracked fibers. This author provided a thermometer to check temperature. The thermometer indicated excessive temperature from thermostat failure. The installer did not follow the common practice of monitoring oven temperature.
Consequence: A 30% increase in installation cost.
As demonstrated by these examples, specific knowledge is essential for successful fiber installation. The trained installer may have some of this knowledge. The certified installer has been certified, by examination, as having the knowledge deemed essential for success. This author recommends and trains the Fiber Optic Association’s certification requirements for the Certified Fiber Optic Technician (CFOT) and the Certified Fiber Optic Specialist (CFOS).
In closing, there is a choice. The hiring authority pays for trained and certified installers, or for increased installation cost. Either way, the authority pays.