FOA reference for fiber optics (2023)

Installation of fiber optic cable installation outside the facility

Jump to:
The role of the contractor in the installation
Installation Checklist

Preparation for off-site installation

Pull and place the OSP cable

Hardware and equipment

Training and safety

Installation of fiber optic cable

Connection and
Testing of the installed fiber optic cable plant

Administration, management and documentation

See alsoConstruction of the TSOin the FOA guidelines

Optical fiber installation by the TSO
All fiber applications are not the same. At FOA, we mainly deal with communication fiber - telecom, CATV, LAN, industry, etc., but fiber is also used for medical or non-destructive testing, inspection andlighting.

Even in communication applications, we have applications that vary greatly in usage and installation methods. We have "outdoor" fiber used in telephone networks, CATV, city networks, utilities, etc. or "field" fiber that can be found in buildings and campuses. We have fiber optics on "platforms" like cars, planes and ships (and space stations). same. Since all these applications require different installation procedures, this section will focus on the installation of OSP in more detail.


After the fiber network design process is complete, the next step is installation. What do we mean by "installation process"? Assuming the project is complete, we look at the process of physical installation and completion of the network, making the project an operating system. This chapter covers preparation for installation, training and safety requirements, and then the installation process itself.

Because outdoor fiber networks can cover a wide range of installation types using different components in different geographical types, it is impossible to cover the details of a single installation. This chapter is intended to provide an overview of the various options available in TSO installations and general knowledge that should prepare those involved in each specific installation to understand how to proceed.

The role of the contractor in the installation
To begin work on a fiber installation, the owner or user of the network must choose a contractor, perhaps the most important decision in the entire process. The fiber contractor should be able to work with the customer on any installation project through the six phases: Design, Installation, Testing, Troubleshooting, Documentation and Renovation. The contractor must have experience with fiber optic installations of this type and must be able to provide references for similar work.

You should be able to trust a contractor who will not only carry out the installation, but also help with the design of the network and the selection of components and suppliers. Once commissioned, the contractor must be able to assist the customer with design, including selection of appropriate fiber types, cables, connectors and equipment for installation. The contractor should know which components meet industry standards to ensure interoperability and which state-of-the-art components will facilitate future expansion.
An experienced contractor should also be able to help with the selection of suppliers. Experience with specific product types and suppliers will enable the contractor to help the client select products that make installation faster and easier, often more efficient and more reliable. If the customer selects components that are unknown to the contractor, it is important that the contractor is aware of this early in the process so that they can receive appropriate training, often from the manufacturer, as well as any unique tools that may be required. .

In general, the client is not as familiar with fiber technology and practices as an experienced contractor. The contractor may need to discuss certain options with the client if it believes that alternatives may be better choices.

The actual installation process may involve more than simply connecting the cable, terminating it and testing it. If the contractor is knowledgeable and experienced, the user can ask the contractor to purchase, pick up, inspect and bring components to the construction site, which can be another good source of income for the contractor. Full control over the materials process can also make the contractor's life easier, as they have a better chance of staying on schedule than relying on a client with many other priorities. In addition, they are free to choose components that are more familiar to them, which facilitates the installation process itself.

The technicians who actually perform the installation must be trained and certified by organizations such as The Fiber Optic Association ( and/or the manufacturers of the products being installed. Certification ensures that installation technicians have the knowledge and skills necessary to do the job.

The last four requirements of the contractor, testing, troubleshooting, documentation and restoration, must be discussed before the project begins. Every fiber project requires testing the insertion loss of each link with a light source and a current meter or optical loss test kit according to industry standards. Some designs, such as long outdoor links with splices, may also require OTDR testing. The contractor and the customer must agree that testing includes fault finding and remediation, as well as documentation of test results for each link.

Similarly, it applies to the contractor that the documentation must start before the project begins, so that everyone knows the extent of the work and only ends when the final test data is in place. Copies of the documentation, along with redundant items left over from the installation, must be provided to the customer to facilitate future network recovery if necessary.


The fiber installation contract should include detailed requirements for the project, specifying what is to be installed, acceptable test results and documentation to be provided. All this should be discussed between the client and the contractor and agreed in writing. These are not trivial details as they are important that the client gets what they want and the contractor knows what is expected of them when they design the network, estimate costs, carry out the actual installation and provide documentation of performance to demonstrate the work is performed and needs payments to be made.

Project planning

After signing the contracts and giving the contractor a set of plans, what next? Planning work is the first task. Proper planning is important to ensure that the work is done correctly, on time and meets cost targets so that the contractor can make a profit.

This assumes that you have a project plan ready, know where and how everything will be installed, and have any special requirements such as permits ready. It can also be assumed that you have an end date, hopefully a reasonable one, that you can aim for. The first step is therefore to create a schedule that will be the focal point of the planning process.
To plan a job, you need a lot of information, much of which can be gleaned from estimates made when you bid for a job. When buyers price components to be used in a job, they should receive both lead times and prices. Some components used in fiber optic designs should be stock items such as connectors, patch panels, or splice closures. However, cables can be custom-made.

Many fiber optic cables are non-standard components, depending on cable type, number and types of fibers and color coding. Custom cables will often be cheaper because they don't have extra fibers to your specifications that you, for example, have. do not need, but will have a longer delivery time because they have to be made from scratch. When specifying a fiber optic cable, always try to have a few extra fibers available in case the fibers are damaged during installation.

A smart contractor always tries to use the same types of components on every job, so he knows not only the installation procedures, but also the typical costs, performance (ie, the number of joints or welds that will pass the tests on the first try). and any problems that may arise.

If some components are unfamiliar to installers, they must learn how to install them correctly by experimenting in the office in their spare time or by asking manufacturers for training. The need for training may also arise if new types of equipment are required, such as external cabling tools or new types of test equipment. The basic principle of installation is never to take an unfamiliar component or tool to work; it's a recipe for disaster.

Buyers must order components at the time of order collection, schedule on-site delivery to have everything available before installation, or for a large job with an extended schedule, depending on how long it will take to install that component. Here, too, you must plan where the components are to be delivered, for example to the warehouse or to the workplace.

Components delivered to the construction site may require protection. Theft can be a problem, especially with cables, as many thieves believe that all cables contain copper and the price of copper makes them worth stealing. But vandalism is another issue that requires components to either be unlocked or, if they are too large to be placed indoors, like large coils of cable or indoor fiber pipes, they may require night guards on site.

Then you have to plan the birth. Again, the estimate should tell you how many installers, what experience will be needed, and how long they will need to complete the installation. If training is required, additional time may need to be added to the schedule.

With labor and materials included in the schedule, planning is almost complete. Review the schedule with everyone involved to get them involved and start processes, starting with purchasing materials. Then add a safety briefing to your plan for foremen, installers and anyone expected to be on site. Also add notes to keep all used cables, connectors etc. in the packaging and present to the user if they are needed for future refurbishment.

If the start date is not tomorrow (because the customer wanted it yesterday!)

Installation Checklist

Installation planning is a critical phase of any project as it involves the coordination of many people and companies. The best way to keep everything in order is to develop a checklist based on the project. The checklist below is comprehensive, but each project will have its own unique requirements that must be added to the list.

Checklist before installation:

The main point of contact/project manager has been selected
Link communication requirements have been established
Requirements for equipment and components were defined and suppliers were selected
Connection route selected, permissions obtained
Components for cable installations and suppliers are selected
Coordination with plant and electrical personnel completed
Documentation completed and ready for installation, preliminary renovation plans ready
The test plan is ready
A schedule and start date for the installation has been set, and all parties have been notified
Ordered components and agreed delivery date, prepared plans for collection of materials (time, place,) organizes security in case of departure outside or on the construction site
A contractor/installer has been chosen and a start date has been set
Tour with artist(s)
Construction plans verified with contractor(s)
Selected components checked with contractor(s)
Schedule verified with contractor(s)
Safety rules discussed with the contractor(s)
Storage of surplus renovation materials with contractor(s)
Test plan verified with contractor(s)

Before starting the installation:

All permits available for inspection
Places prepared, power available
All components in place, checked, 24/7 security organized if needed
Contractor available
Relevant personnel notified
Safety rules posted at workplace(s) and reviewed with all supervisors and installation personnel

During installation:

Check performance at each step
Daily overview of process, progress, test data
Immediate notification and resolution of problems, deficiencies, etc.

After the installation of the cable installation is complete:

Check the build quality
Review the test data on the wires
Configure and test the communication system
Update and complete the documentation
Update and complete the recovery plan
Store renovation plan, documentation, components, etc.

Preparation for off-site installation

Outdoor fiber optic cable installations (TSO) can be much more diverse than on-site installations. TSO installations may include installing an overhead cable, direct buried cable, underground cable in a conduit, or installing a cable conduit or indoor pipe and then pulling the cable out or placing the cable under water. A single link can include several types of installation, such as an antenna in one section, pulling a pipe at a bridge crossing and burying the rest of the cable.

Cables can run out when they are pulled into buildings or end up at the top of poles where surveillance cameras or wireless access points are located. The splices in which the cables are assembled can be placed on plinths, buried underground or suspended from overhead splice covers.

The variety of OSP installations makes it extremely important for the contractor to know the exact route of the cable being laid. Like the estimator who must walk the road before beginning the estimating process, the contractor must see for himself the actual situations he will encounter. This inspection allows them to determine what problems they may encounter, what special equipment may be needed, and even double-check that all necessary permits are in order. Long cable runs in pipes may require greasing or intermediate runs, where installers must know how to lay the cables in a figure eight to prevent kinking, a procedure described later in this chapter.

Call me before you start digging

FOA reference for fiber optics (1)

The old story of the most likely failure of a fiber optic communications system to be caused by an "excavator fade" is no joke - it happens every day. But it reminds us that digging safely is extremely important. The risk is not only the interruption of communication, but the life-threatening risk of digging high-voltage cables or gas lines. There are several services that maintain underground service location databases that should be contacted prior to any excavation, but their mapping should be done at the design stage and double-checked before excavation to ensure the latest data.

At the same time as the cable is installed, such markers can also be installed to indicate its location and owner.

More about the construction of the TSO (underground and air)

Pull and place the OSP cable

TSO installations fall into four broad categories: underground, directly buried, aerial, and submerged (or underwater). Each of them used different procedures, tools and even cables.

Underground cables

FOA reference for fiber optics (2)

FOA reference for fiber optics (3)

Digging trenches to bury the fiber optic track and pull cables into the track

Underground cables are pulled into a conduit buried underground, typically 3–4 feet (1–1.2 meters) deep, to reduce the likelihood of accidental excavation. The process usually begins by digging a trench to bury the duct, which is usually a 4-inch plastic pipe, sometimes with a pre-installed inner wire (also called a wire liner) with a pull band to facilitate the actual process of pulling the wire. cable. Directional drilling can also be used to avoid digging up surfaces, such as at road or pavement intersections. If the line and cables are dielectric, conductive tape can be buried approx. 30 cm above the wire to help locate cables in the future and as a warning to anyone digging near the cable.

Due to the cumbersome nature of burying conduits, especially under roadways, many governments that issue permits for burying cables require the contractor to install additional conduits along the route to avoid re-burial for future cable installations. Since many cities already have extensive cable ducts buried for other services, or may have required additional ducts to be buried during previous installations, the ducts may be available to pull new fiber optic cables.

An internal channel inside the cord separates the cables and makes it easier to pull them through. Pipes can be purchased with internal ducts installed, usually with pull bands as well. If the inner duct does not have a pull strap installed, you can run a cable through the duct to pull a stronger pull strap or cable through the duct.

Unless internal wiring is installed in a conduit, only one cable may be installed in a conduit unless all cables are bundled together. Pulling a cable into a conduit that already has multiple cables in it can cause tangling, increased stress, and potential damage to the cables. Several cables can be pulled at the same time if the total cable load and tension does not exceed the recommendations.

Inderduct or duct liners come in several types, including flexible pipes with corrugated or smooth insides. Corrugated tubes with smooth inserts tend to flatten out more, limiting cable size, while corrugated internals can be more brittle. The new type of conduit liner is more like a fabric sleeve that lies flat until the cable is pulled through it, and takes up less space in the cable than a rigid inner conduit that allows multiple cables to be placed.

The length of cable that can be pulled through will depend on many factors, including the type of cable, wire or inner, temperature and smoothness of the course, all of which affect the coefficient of friction. Except for short hauls, lines should be lubricated to reduce friction, which increases drag. Lubricants must be of a type approved by the cable manufacturer, not copper communications or electrical cable lubricants, and should be used by the manufacturer of the lubricant and/or cable. Some lubricant manufacturers offer online calculators to assist in the selection and use of lubricants.

Most ropes can only be pulled safely by attaching a swivel eye to the rope's reinforcements. Twists are important to reduce twisting loads on the cable. For high tension loads, a break swivel is used to prevent damage if the tensile stress exceeds the cable specification. Some cables are made to be pulled from the sheath if a flexible wire mesh grip, commonly called a Kellems grip, is used. They are also usually attached to the strength elements of the cable. See later in this chapter for instructions on attaching wooden eyelets.

The tension to pull the cables is often high enough that a motorized winch will be needed, possibly for all but the shortest runs. The game should be equipped with a screen that can stop the game if the set voltage is exceeded. If the tension becomes too high, the cause of the excessive friction must be found and corrected.

As with any cable installation, it is important not to bend the cable too much, which can damage the cable or its fibers. Standard guidelines for cable are a minimum bend radius of 20 times the diameter of the live cable and 10 times the diameter of the cable when the tensile stress is removed. There may still be some tension in the cable when it is pulled, but with proper lubrication and gentle pulling it should be minimal.

The cables can be pulled out completely from one end if the length is short enough and there are no intermediate locations such as wells or vaults that the cable must be pulled through rather than braided at that location. There are mid-span aids that allow the cable to be pulled from one wire to the other at certain points, or the cable can be pulled to a point, laid on the ground in a figure-eight pattern to prevent twisting, and then through the next section. Alternatively, the cable can be pulled in one direction from an intermediate point, the remaining cable intact in a figure-of-eight pattern, turned and pulled in the other direction. See the section on lines in Figure 8 later in this chapter.

Cables can sometimes be installed by blowing special types of cables into conduits called ducts, microducts, or subducts that have been installed in larger conduits, or even pipes for water, sewage, or gas. High-pressure compressed air provides an aerodynamic effect by lifting the cable in the air flow and carrying it down the duct, enabling installations up to 2 km (6,500 ft) long.

At each end of the cable where splicing or termination is required, leave an additional 30-60 feet (10-20 meters) of cable for splicing. Most of the splicing will be done in the trailer or tent on the ground and additional cable is needed to reach the splice point and have extra length to be stripped for splicing. Before beginning installation, check the cable splicing instructions for cable lengths needed to splice or enter the span. Always leave extra length to cut the draw eye from the end of the draw.

As with any wiring installation, the work must be done neatly and professionally. Cables should be carefully secured in the appropriate places in manholes or vaults with cable ties, but never tighten the ties tightly, as this can cause problems with the cable or fibers. Service loops must also be carefully secured. In intermediate locations, it is extremely important to place identification marks on fiber optic cables to enable easy identification and prevent future damage if the cable is confused with a cable that needs to be cut and removed.

Cables terminated indoors must be laid carefully. Use cable ducts or cable trays to protect the cables. Most building, fire, or electrical codes limit the length of OSP cable that can be run inside a room unless the cable is in a conduit, so proper cable installation involves following the appropriate building codes.

Buried cables

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FOA reference for fiber optics (5)

Orca with d

direct buried (L) and directional drilled (R) cables

If the geographical conditions allow, fiber optic cables of suitable types can be buried directly in the ground by digging directly into the ground, directional drilling or burying and laying the cable in the trench. Where the ground is soft and relatively free of rock, and the terrain is flat and unimpeded by heavy equipment movement, the direct installation method is a quick installation method that allows several miles/km of cable to be laid in one day. In more built-up areas, digging may be easier because plowing requires large machines and a lot of space.

Heavy-duty cables can be laid directly in the ground, and cables in conduit can be installed using direct burial techniques for added protection. Cables can already be delivered in channels to be buried. An alternative technique is to bury the ducts and blow the cables into the ducts as in underground installations.

Typically, trunk cables in most areas are installed at a depth of 1–1.2 m (3–4 ft), but in residential or urban areas, cables may only be buried to a depth of 2 ft (0.6 m). Some cables can be laid directly in cut grooves in roads, but they are buried only a few centimeters deep, still in the roadway material and filled with sealant. If the cable is completely dielectric, a conductive marker tape can be buried about a foot above the wire to aid in future cable placement and as a warning to anyone digging near the cable.

Cable plowing can be done with large static plows or smaller vibrating plows, but they should be plows capable of pulling fiber optic cables. Copper cable plows may not meet fiber requirements for cable support, bend radius, tension or vibration. Sometimes the plowing of a cable is preceded by a plowing operation in which an initial plowing is done to prepare the ground and find underground obstacles.

Cable plowing requires careful insertion of the cable into the cable channel of the plow to relieve stress. Winch power is used on many plows to synchronize cable feed. The cable drum and the feed chute must also be isolated from vibrations.

Installing fiber optic cables is a process that requires attention and experience. Needless to say, the plow operator and crew must know what they are doing and be very careful. Inexperienced personnel should work with experienced personnel to learn proper procedures.

Excavation involves digging a trench with an excavator or backhoe, laying the cable and then backfilling the trench. Backhoes come in all sizes and do not need to be equipped with fiber handling equipment unlike plows. The contractor must be careful with sharp objects or stones in the trench or putty, as they can damage the cable. If the ground is stony, it will provide protection by burying the cable in sand before backfilling the trench.

FOA reference for fiber optics (6)

Micro-excavation is another method used for underground installations, usually on roads or in private yards, for residential fiber optic connections. Micro-digging involves digging a narrow and shallow trench approximately 25 mm (1 in) wide and 200–250 mm (8–10 in) deep with a special tool. Tools are available that can cut through asphalt or concrete roads or walkways or cut through bare soil. After cutting the trench, a special cable or micro-channels can be installed in which the cables can be laid by blowing. A typical trench can accommodate a microchannel with up to six channels, ensuring future expansion.

Blown cable installation refers to the method of installing small cables in microducts using compressed air and a machine to push the cable into the conduit. The cables are not actually blown into the duct, but the blown air lifts the cable in the duct and reduces friction so the machine can push the cable into the duct. This method works well in both TSO installations, often with micro trenches to install the ducts, and in local installations where the duct is installed first and the cable blown in. With today's microcables, it is easy to install high fiber count cables this way, as a typical 144 fiber cable is only 8 mm (0.3 in) in diameter. You can even install special ducts that allow you to blow only fibers, not cables, although this is not so popular anymore.
Cables can also be buried using directional drilling, a method often preferred when crossing roads or shallow watercourses as it does not require excavation of the surface. Hole size and length are related, as larger holes cannot be made to such lengths, and both can be determined by the type of soil encountered. Directional drilling also requires a thorough knowledge of other underground utilities to prevent them from being damaged during the drilling process.

Cables in the ground can be spliced ​​into joints that are buried along the cable route or placed above ground in a plinth. At each end of the cable where splicing or termination is required, leave an appropriate length of cable, usually an additional 30-60 feet (10-20 meters) of cable for splicing in a trailer or tent on the ground. Before beginning installation, check the cable splicing instructions for cable lengths needed to splice or enter the span. Always leave extra length to cut the draw eye from the end of the draw.

As with any wiring installation, the work must be done neatly and professionally. Cables should be carefully secured in the appropriate places in manholes or vaults with cable ties, but never tighten the ties tightly, as this can cause problems with the cable or fibers. Service loops must also be carefully secured. In intermediate locations, it is extremely important to place identification marks on fiber optic cables to enable easy identification and prevent future damage if the cable is confused with a cable that needs to be cut and removed.

Cables terminated indoors must be laid carefully. Use cable ducts or cable trays to protect the cables. Most building, fire, or electrical codes limit the length of OSP cable that can be run inside a room unless the cable is in a conduit, so proper cable installation involves following the appropriate building codes.

Antenna cables

FOA reference for fiber optics (7)

FOA reference for fiber optics (8)

Installing the antenna cable for the CCTV camera (L), connecting the OPGW to the underground fiber optic cable

In many areas, cables are still installed on electricity pylons. Antenna cables are subjected to constant stress as well as additional stress from temperature changes, wind and in some places the weight of ice. Most fiber optic cables are not strong enough to allow direct overhead installation, but there are overhead installation methods as well as special cables designed for overhead installation.

The simplest solution is to connect a regular OSP cable to the Communicator, usually a twisted metal cable used to support the cable, but sometimes another cable if strong enough. CATV sometimes retrofits fiber optic cables to existing coaxial cables, and even feeder cables can have fiber optic cables attached to them. The communicator must be selected so that it has sufficient strength to support the fiber optic cable over the spans between the supporting structures. When installing fiber optic cables with the communicator, allowance must be made for changes in the length of the communicator, e.g. due to wind drag or changes in temperature. Since fiber optic cables are designed not to stretch, as this would stress the fiber optic, slack must be provided, usually in supports, to reduce stress on the fiber optic cable when the length of the relay is changed. The National Electrical Safety Code and RUS provide guidance on the design of support structures, but manufacturers should always be consulted on appropriate support methods for cables selected for overhead installation.

The first step in the installation of the spiral antenna is the installation of the supporting communication cable. Typically, the string is laid on the ground along the span, pulled over the rods by pulleys, then the tension is adjusted and the messenger is securely attached. The fiber optic cable must be connected to the communicator separately on each span in the cable system. The fiber optic cable can be routed over temporary support rings and secured or alternatively routed along the ground under the Communicator and the air guide in front of the power tool to position the cable next to the Communicator for securing. Some methods also use a truck to lay out the cable and pull the whip.

Cables with embedded communicators, called "figure 8" cables (not to be confused with the process of coiling cables on the ground called "figure 8-ing"), can be installed directly when the support structure is built into the cable. The cable is supported by crimping on the cable strength element in a manner similar to the installation of a relay wire. You can also buy an antenna duct, a small fiber duct with a communicator attached as a figure 8 cable, then the OSP fiber cable can be pulled into the duct.

There is also a category of all self-supporting dielectric cables (ADSS), which are designed with more strength elements and a thicker sheath to have the proper strength to withstand the stress of overhead installation when installed with special equipment designed to grip the sheathed cable correctly, do not cause damage to the cable when exposed to high voltage for extended periods. Since each manufacturer generally has their own equipment and procedures, they should be consulted during the design phase for proper procedures for designing and laying cable installations.

ADSS cables have two types of grips, terminals or dead ends, where the cable is supported by the load caused by the installed cable, and bushings, where the cable can be attached to the rod but is allowed to move within the joint. The ends do not mark the end of the fiber optic cable, but the place where the cable is under a lot of tension. On a pole, the two ends can be used to divert the cable, provide slack for tension, or bring the ends to ground for splicing. Tensioning can be done using a chain hoist with a tension setting device.

Another type of antenna cable is the optical ground wire (OPGW). OPGW is a high-voltage cable with a hermetically sealed tube in the middle containing optical fibers. This cable is widely used throughout the world to provide communication and power. The OPGW is installed in the same way as a high voltage cable, but the ends are brought to the ground and spliced, or terminated, coiled on the tower. If communication equipment is required at this location, fiber optic cables are routed from splices to the local facility where the equipment is located. OPGW installation should be left to experienced electrical personnel, with the exception of splicing, which can be performed by fiber installation personnel.
For all antenna cable installations where splicing or termination is required, leave an additional 30-60 feet (10-20 meters) of splice cable. Even more may be required if splicing is done on the ground on cable installed on tall poles.

Careful planning is very important when installing antenna cables. Working high above the ground can be dangerous, and working on poles can mean working near power lines. If possible, disconnect power cables before installing other cables on utility poles. Be especially careful when installing the metal support for fiber optic cables; fiber optic cables may not be conductive, but equipment can. Install cables as long as possible to reduce the number of splice points. Have suitable equipment and a sufficient number of properly trained workers on site and, if possible, a local authority who can be responsible for the installation on your property.

Alternative installationsmetoder
Cable installation sometimes requires creativity.

Micro excavations
Excavation of roads to lay cables has been used in the past, but often leads to complaints about the condition of the road after the cable is installed. Micro trenchers cut grooves in the pavement and insert special cables and/or channels. The groove is refilled, often with the same material dusted off during cutting, for a simple and neat installation. This process is much faster than digging trenches.

FOA reference for fiber optics (9)

Cables in channels
This method was developed early in the history of fiber optics. Sewers and storm drains have air spaces at the top of the pipe to facilitate flow. Small remote controlled robotic vehicles like the one below are sent down the pipe to install special cable trays on top of the pipes to carry fiber optic cables. In large pipes, vehicles are large enough for technicians to drive on and perform installations. Like micro-excavation, it reduces the problems associated with laying cables in urban areas.

FOA reference for fiber optics (10)

Submarine/submarine cables

Fiber optic cables sometimes need to be installed underwater. The most famous of these installations are probably the transoceanic cables that provide worldwide telecommunications and Internet connectivity. The installation of these cables is a highly specialized process that requires special cable structures and customized cable-laying vessels to lay the cable over thousands of kilometers and place it on the seabed at great depths. Although these applications are interesting, they are beyond the scope of this book.
Other underwater installations include river or sea crossings, where it is more economical to lay fiber optic cable underwater than to detour around water, place the cable in a pipe attached to bridges or other structures, or run the cable through the air. Subsea crossings may require special permits due to the jurisdiction of various environmental groups.
FOA reference for fiber optics (11)

When cables are run under water, there is always a risk of getting stuck in the cable. In relatively shallow water, if possible, the cable should be buried several meters below the bottom of the stream or lake. For deeper water, special armored cables with one or more layers of wire armor should be used to prevent damage to the cable in the event of snagging. Because of the special connector covers needed for submersible cables, it will be much easier and cheaper to run a length through the water.
An underwater installation also brings its own security risks. Experienced divers may be needed to assist with cabling and troubleshooting.

Hardware and equipment

FOA reference for fiber optics (12)

TSO installations may require the installation of supporting structures before commencing cable installation. It may be necessary to bury a new conduit or internal conduit, or inspect an existing conduit, remove old cables, and install a new internal conduit. Some buried cables may even require the installation of pedestals, manholes or canopies with a controlled environment for the equipment as well as wiring.

Not only must the contractor consider all the equipment that may need to be installed, but he must plan for the special equipment needed: backhoes or cable plows, excavators, bucket trucks, cable winches, etc. and ensure that personnel are well trained in their handling.

Connection cables

FOA reference for fiber optics (13)

After the infrastructure is created and the cable is placed, the splicing of the optical fibers begins. Now the problem is planning the availability of suitable fiber optic equipment. If the cable is to be spliced ​​outdoors, a splicing trailer is usually used, unless splicing is done on a pole or in a bucket, where a tent may be needed in bad weather.

Prepare the cable for the connection process. This includes processes appropriate to the type of cable being installed, but typically involves removing the cable jacket, exposing buffer tubing of the correct length to connect to the splice trays, cutting away the reinforcements to attach to the splice closure, and cleaning any water blocking gel or powder. Finally, the respective fiber lengths are exposed and cleaned for splicing.

Care must be taken to ensure that each fiber is carefully placed in the welded closure to prevent damage, especially if the closure is to be reinserted in the future, and the closure must be carefully sealed to prevent long-term degradation. And, as welders always caution, careful identification marking inside the closure makes it much easier to identify the fibers if a later problem requires re-entry.

OSP cables are often terminated by splicing on short pigtails - terminated with "tight buffered" cables with a factory termination. An alternative is SOC connectors - welded connectors - where a factory connector with a very short pigtail is welded directly onto the fiber. SOC can be done without splicing when the terminations are inside the patch panel.

Each weld must be verified with an OTDR test. Testing is best done with each splice being made and placed in the splice tray, so to be efficient the welder will be on the job site and the test technician will be working on the other end of the cable with an OTDR to verify each splice. Splicing machines give an estimate of weld loss, but that's it, and come back later, opening the splice closure and rejoining is an expensive proposition!

Midspan Entrance

FOA reference for fiber optics (14)

Sometimes it is necessary to connect cables with a large number of fibers to smaller cables in a place other than the end of a larger cable. Instead of cutting the cable and splicing all the fibers, a midspan entry can be used to access only the fibers needed to splice smaller cables. To make a midspan entry, you must know the procedures recommended by the cable manufacturer and have the proper tools and other equipment required by the cable construction.

For mid-span entry, the cable jacket, which includes the jacket and armor or other protective layer on the cable, must be removed for a length of cable, typically about 2 meters (80 inches). The sheath is ring-cut first at the beginning and end of the section to be removed. Then one end of the sheath is shaved off with a special tool or utility knife to gain access to the cable release lines. Trigger lines are cut at the ring point and used to cut the casing up to the ring cut at the other end of the hole. When both trigger wires are used, the cable cover can be removed in two parts.

Then the reinforcing elements (aramid fibers) and ties (and water-blocking tape if the cable is a water-blocking dry construction) are cut and removed. The mid-strength member and the cable brace must then be cut to size so that the ends must be secured to close the splice if necessary.

Entry into the individual buffer tubes for access to the fibers to be spliced ​​must be done with a suitable medium voltage insertion tool that shaves the tube for access without damaging the fibers. Inside the pipe there must be a release wire, which is used to split the pipe to the desired length. The split tube is then cut off at both ends.

The remaining buffer tubes can be placed in the splice closure storage section, while the exposed fibers are bundled with other cables and stored in the splice tray. As with any splice closure, care must be taken not to damage the fibers or break the buffer tubes during the process, and store all fibers and buffer tubes properly to allow re-entry without damaging the fibers if necessary.


FOA reference for fiber optics (15)

The cables will be terminated inside the facilities where they connect to the communication equipment. OSP cables generally do not meet NEC flammability requirements, so a cable entering a building must be terminated or spliced ​​to internal cables shortly after entry, typically within 50 feet (16 meters), to meet fire codes. Some OSP cables have a double jacket, outside for outdoor use and inside for indoor use, so the outer jacket can be removed inside the building and routed to the utility room. Cables terminated in sockets or vaults do not have this requirement.

Generally, single-mode OSP cables will be terminated by braiding pigtails on each fiber, and splices will be placed in splice sleeves. Multimode fibers can be handled in the same way or terminated directly on the fibers. Most OSP cables will require the installation of a breakout kit that places each fiber in a conduit strong enough for direct termination.

Preparation of premises for fiber optic installations

Any off-site cabling project will include local cabling where the TSO cables are terminated, so any TSO contractor must be familiar with the local installation. Most building codes require OSP cable that is not fireproof to be terminated a short distance after entering the building or routed in an approved conduit. Before proceeding with the installation of fiber optic cables and equipment in the premises installation, the place of installation of fiber optic cables, equipment and transmission equipment must be properly prepared. During the design and planning phase, the site should have been inspected and all equipment necessary for the cable installation should have been included in the design.

Space-bearing structures

FOA reference for fiber optics (16)

There are many constructions for fixing fiber optic cables in residential installations, which makes generalizations difficult. The cable can be hung on suitable hangers, laid in cable trays or pulled into a pipe or tray. Cable terminations can be placed on racks in telecommunications rooms, in wall boxes or even in wall sockets. Preparation for installation includes planning to store cable service loops behind racks as shown here.

Before the fiber optic cable itself is installed, the support structures for the fiber installations must be installed. These structures should follow the guidelines of relevant standards such as TIA/EIA 569-A and NECA/BICSI 568-2001. Allow for future increase in cable quantity and size when dimensioning tracks. Comply with all cable bend radius requirements and avoid running cables around hazards if possible.

Sometimes new cables can be laid in existing cable trays. To prevent damage, do not install fiber optic cable in a conduit or conduit that already contains cables, regardless of cable type. Existing or new hollow ducts can be modified to allow for multiple different installations by positioning the interior ducts accordingly.

The load-bearing structures of the premises also include patch panels for terminations. They can be wall-mounted or rack-mounted and must be selected according to the type of cable used. Terminated simplex or zipper cables can be terminated on open panels, but tightly buffered 900 micron fibers from distribution cables require closed end panels for protection. Where possible, the design of load-bearing structures should provide sufficient space for cable termination and storage of service loops.


FOA reference for fiber optics (17)

Room wiring requires fire resistance at all penetrations through walls and floors. Fire protection of telecommunications must always comply with applicable codes and standards. All passages must be protected by type-approved fire barriers.

In most areas, a fire separation breach will require physical monitoring until it is repaired. Before commencing work, contact "Relevant Authorities" for detailed project requirements.

Electrical systems

All fiber optic devices will require sufficient power at the locations where the devices are located. The power supply must be of high quality, protected against power surges and spikes, and must generally have sufficient reserve capacity to prevent loss of communication during power failure. Data transmission equipment will require separate grounding and sufficient power for year-round air conditioning. Pay attention to the cooling capacity to reduce energy consumption. Consult with the facility owner, customer and appropriate user personnel to plan the electrical installation.

Grounding and connection

FOA reference for fiber optics (18)

All conductive cables and components must be grounded and connected. Grounding systems must be designed in accordance with the NEC or other applicable codes and standards. Although most fiber optic cables are non-conductive, any metal hardware used in fiber optic cabling systems (such as wall-mounted junction boxes, racks and patch panels) must be grounded. All conductive cables require proper grounding and connection of appropriate conductors.

Marking and identification of cables

Fiber optic cables must be specified with colored jackets in accordance with industry standards that identify the cables as fiber optic cables and indicate the type of fiber in the cable. All fiber optic cable terminations must be marked on racks or boxes where the cables are terminated. Cables must be marked identifying that they are fiber optic cables and proper handling is required.

Special care must be taken when upgrading local wiring. For nearly two decades, 62.5/125 micron multimode fiber has been the primary fiber in premises cabling. With the advent of gigabit networks, laser-optimized 50/125 fiber has become more popular. Mixing the two fibers can cause excessive splice loss, which can cause system failure. Color coding, labeling and even the use of incompatible connectors (SC or ST on 62.5/125 fiber and LC on 50/125 fiber) should be used whenever possible.

Removal of abandoned cables

Unless the owner or another agency recommends that unused cables be reserved for future use and labeled accordingly, it may be necessary to dispose of a discarded fiber cable (a cable that is not terminated at a device other than a plug and is not intended for future use with a label) as required by the National Electrical Code or local regulations.
At the landowner's discretion, the contractor may be required to remove additional cables (eg copper communications or power cables). Cable removal is much more time-consuming than installation, as each cable must be identified and carefully removed to prevent damage to other cables. No cable shall be cut for removal unless it is clearly identified as the cable to be removed.

All removed cables must be properly recycled. Most communication cables have a significant scrap value, not only for any copper conductors, but also for other metal components and even some plastics.

Installation of personnel equipment

Equip the installer with tools

As you get closer to the actual installation time, it's time to decide how to equip the crews that will do the work. Choosing the right installation and testing equipment is important as it will affect the time and quality of the installation and even determine the cost effectiveness of the job. The frequency of problems caused by tools is alarming: their poor design, incorrect use, poor technical condition or ignorance of their use.

Installation tools include large equipment such as forklifts, backhoes, cable winches or plows. The need for them will be determined at an early stage in the planning. Many contractors do not have such expensive equipment, so it is more profitable to rent it if necessary. If your crews are unfamiliar with your specific equipment, it can be much more cost effective to outsource the work to someone who has both the equipment and an experienced crew, as operating errors can be catastrophic – both expensive and dangerous.

Outdoor plant cables and on-site single-mode cables will generally require long lengths of cable to be spliced ​​together and spliced ​​at pigtails for termination. As fiber fusion splicers have become cheaper, more and more contractors are purchasing them. Other contractors who have fewer projects that require splicing prefer to hire them, knowing that they are getting a welder that is a newer model with the latest technology that has recently been serviced. The disadvantage of a rented unit is that installers may not be familiar with this model and may require training or time to become familiar with it. If you own your own welder, it is assumed that your employees are familiar with its operation and only need to check the apparatus to ensure that it is working properly and that the arc electrodes are in good condition.

Most contractors have termination equipment for multimode fiber as it is used in most jobs. Generally, contractors have a preferred finish method, either glued/polished or pre-polished/braided types. Each type requires dedicated tool sets. Epoxy or hot melt finishes require proper curing ovens and the two are completely different; The Hot Melt oven is much hotter. If you are using epoxy or anaerobic adhesives from your stock, check the expiration dates on all of them to make sure they are fresh. Also check out other consumables such as wipes, isopropyl alcohol, cable cleaning gel and of course plugs.

Pre-polished splice joints will be better and easier to use. Newer termination kits include a high-quality splicer, such as used with fiber splicers, and a visual fault finder to verify internal splicing. Since newer kits can now produce plugs with lower loss, around 0.5dB, a new kit with the latest plugs and perhaps training could be a good investment.

When inspecting end sets, pay particular attention to the condition of the tool. Missing tooling will of course need to be replaced, but hopefully that was done when the kits were inspected after the last job. Tools such as coat removers, fiber removers and splitters can wear or break, so it is important to test their performance with a few fiber samples to see if they are working properly.

It is mandatory to check any equipment you intend to bring to the job site to ensure that it is working properly and that the installation staff can become familiar with its operation again. This process should be completed with sufficient time to service or replace the unit and replenish supplies. It should also be obvious that equipment that has had problems in the field is never shelved. It must be replaced immediately or sent for repair so that it is ready for the next job.

Let me warn you about another problem we've seen recently with tools. Several recent complaints about low-quality tools, particularly lint removers, have led us to believe that low-quality imports are becoming more common. In one case, the tools appear to be counterfeit and bear a well-known American name. I suggest only purchasing tools from reputable sources and having them inspected upon receipt to ensure they function properly.

Finally, once the equipment is checked and ready for use, ensure that the correct protective equipment is provided with the tools. Anyone who works with fibers needs safety glasses, and a clean, unbleached one will make it much easier to see the hair-thin fibers. Black splicing and termination work mats also help the installer see the fibers and find fiber debris for easier cleaning.

Equip the installer with test equipment

Installers also need test equipment. There are many options in the sophistication and cost of fiber test equipment. Correct selection can reduce both equipment costs and testing labor costs. The types and quantities of test equipment required will also vary depending on the type of job.

All installation technicians should carry a visual marker or visual fault finder. A tracer is a visible flashlight or LED source used with multimode fiber to check continuity and trace the fibers to ensure proper connection. The Visual Fault Locator is a higher power visible laser source that can be used for singlemode or multimode fiber tracing, but also capable of detecting some faults such as strains or breaks in most simplex or zipcord or common buffer fibers. Both visual markers and fault finders are inexpensive but invaluable during the installation and troubleshooting process.

Each fiber in fiber cables requires a loss test with a light source and a current meter, also called an optical loss test set (OLTS). OLTS will confirm that the fiber has been installed and terminated correctly by testing end-to-end loss and comparing it to the loss budget created during the design phase. Large tasks may require more than one set to complete the task in a timely manner. Loss testers are available in several configurations, including a separate light source and power meter, usually sold as a test kit, OLTS which is a single instrument containing both a light source and a power meter, and modules to convert copper testers to OLTS. A single light source and current meter is usually the cheapest solution, especially for small jobs, because the meter and source can be separated so that two technicians can carry them to each end of the cable under test. If OLTS is used, two will be needed to test the cable end to end, but it can test two fibers at the same time, saving labor costs. OLTS adapters for copper testers are usually not cheap, but they can take advantage of the sophisticated data management of an expensive copper tester and generate complete reports. Contractors often choose these adapters if they have already invested in copper testers.

Each loss test kit requires reference test cables. They are just good fiber optic patch cables with a length of 1-2 meters that match the size of the fibers and connectors of the tested cables. Reference cables do not need to be special cables, only those tested for low loss. Bad patchcords will give bad test results, causing good fibers to pass the tests. Reference cables must be tested frequently to ensure they are still in good condition and low loss. It is wise for each test set to have several sets of reference cables as they wear or break and need to be replaced.

Long runs outdoors with intermediate splices will require OTDR testing. OTDRs are also good troubleshooting tools for long cable installations, but are generally not intended for use with short cable lengths such as those commonly used in facilities. OTDRs are expensive and complicated instruments. If you don't use it often, it may be hard to justify the cost. Users unfamiliar with the peculiarities of OTDR data interpretation cause many problems by damaging good cables and sending bad cables, often with costly consequences. OTDRs can be rented, but given the number of problems caused by inexperienced users, it may also be a wise move to have an OTDR tested by an experienced contractor.
OTDRs also require reference cables, especially a long starter cable long enough to allow the OTDR to stabilize after being overloaded by a test pulse. For single-mode fiber, a 1 km starter cable is recommended. 100 meters is sufficient for most multimode OTDRs. The new standards require a cable at the other end of the cable under test to allow testing of the connector at the other end, where a length of 100 meters is usually sufficient.

The most important thing to remember when it comes to test equipment is to know how to use it and always check it before taking it to your work site. Batteries need to be replaced or recharged, reference cables need to be tested, and most importantly, take a few minutes to refresh your memory on how to use the instrument. On the construction site, there is nowhere to say that the equipment is not ready for use.

Training and safety

Fiber training

Rule #1 for fiber installations Never, ever attempt to install a new type of component or make a new type of application without proper training. Lack of knowledge or skills related to this component or application makes it virtually impossible to ensure success on the job, and mistakes can be very expensive. At FOA, we have many examples of installations that went wrong with terrible consequences.

No one can know everything and no training can cover all aspects of fiber, all types of components and applications. In any case, technology is constantly evolving, so it is important to continue to gain knowledge from all available sources. Much of the technical knowledge you need can be gleaned from websites such as the FOA Online Reference Guide, but what about the skills needed to work with actual fiber components for installation, testing, troubleshooting and restoration? These skills can only come from training and experience.

More training

What kind of training is needed to become a successful fiber optic contractor or installer and where can you get that training? There are many options for continuing education, but first you need to find out what your needs are, what the education should include and who can provide the appropriate education. As a general rule, all fiber installer training must include hands-on practice with appropriate equipment, tools and components so that the student can develop skills appropriate to the activity.

Fiber optic technicians with some experience can often learn to install many new types of components or operate new equipment themselves. FOA's and many manufacturers' websites provide information on most aspects of installation, as well as FOA "virtual hands-on" tutorials (VHO) that show you how to do it step by step. Most manufacturers have good instructions and often online tutorials that can help. With the right tools and application knowledge, a knowledgeable technician should be able to learn new processes in no time. The secret, of course, is to do it in a quiet, clean office environment before trying it on the customer's seat while they're looking over your shoulder!

Sometimes it's better to take a course. Many FOA approved schools offer advanced or specialized courses in termination, splicing, testing, home fiber, etc., which provide several days of intensive training, equipped with tools, equipment and supplies, as well as instructors familiar with the processes taught. Manufacturers also offer product-specific training, but you should try to be trained by application engineers rather than by sales staff, who may not have the in-depth knowledge needed to properly train installers.

Learn how to install new components

There are hundreds of different types of fiber optic components that manufacturers have developed for specific applications or to simplify the installer's work. Many of these components are unique to this manufacturer and may require special tools and installation processes. Examples are pre-polished/spliced ​​connectors such as Corning Unicam, 3M HotMelt connectors, splice sleeves, all self-supporting dielectric cables, optical ground wire, prefabricated cable systems, etc.

In general, you should go directly to the manufacturer for such training, unless an independent trainer has been trained and recommended by the manufacturer and has the appropriate tools and components to teach the necessary processes. Some manufacturers offer short introductory courses on their new products that include limited hands-on time, and such training can be ideal for those interested in learning about the product before purchasing all the tools and components necessary to use it . Additional extensive training can be provided after these purchases are made.

Learning to use new equipment

Some of the equipment required for fiber optic installation is complex and can be difficult to learn without proper instruction on the same equipment. Examples are automated fiber splicers, especially ribbon splicers, cable pulling or plowing equipment, and OTDRs.

Some of these pieces of equipment are quite complex and include peripheral products that must be used correctly with them to achieve the desired results. For example, strip welders use strippers and cutters, which are essential to achieve consistently good splices. All automatic welders have unique programming features, so you should learn how to operate the welder itself, as well as how to weld with it.

OTDRs are also complex devices and learning to use them consists of two parts - learning to use the OTDR with all its capabilities and interpreting the data taken during fiber testing (path or signature as it is called). Although all OTDR manufacturers offer "automated test" capabilities, you cannot afford to rely on them for all applications as they can be easily confused by artifacts such as ghosting. The user should always manually check the OTDR trace to ensure that the conclusions drawn from the test data are correct.

Training should be conducted on the actual type and model of equipment of interest, as products from different manufacturers or different models from the same manufacturer may have unique characteristics. For the training to be effective, it must consist of two phases - how to configure and operate the equipment itself and how to perform the processes for which it is intended. Manufacturers generally offer training on these products, and independent trainers may use the same equipment or will be willing to train the user on their equipment if one has already been purchased.

Learn new apps

We often emphasize that there are many different uses of fiber optics and there are significant differences in how these applications are designed, installed and tested. For example, external technicians typically end up splicing on the factory pigtails, while local technicians end up directly on the fibers with glued/polished or pre-polished/braided connectors. FTTx technicians must only use prefabricated cable assemblies. Technicians moving from one application to another may require training as well as on-the-job training (OJT) to understand the application and develop relevant skills.

Finding the right education

Regardless of your interests, make sure the courses you choose are relevant to your interests or you will be wasting your time and money. Here are some options to consider:

Can you learn it yourself? Some of us just learn better on our own. Is information about this easily available, for example in FOA's online fiber guide? Good videos can also help, especially on practical topics like cable routing and termination. Can you get the right tools and components to use to develop the necessary skills? Is there someone you can call for help?

FOAU fiberoffers free online tutorials on a wide range of relevant topics.

Does the manufacturer offer training? Does it cover what you need to know? Does it provide lots of practice with equipment and components? Do you want to be certified as an approved installer by this manufacturer? This can help you get customers from that manufacturer.

Do independent trainers, such as FOA approved schools, offer training in this area? Does it cover what you need to know? Does the trainer have the latest version of the equipment needed for training? Will they train you on your equipment? Is the instructor experienced and well versed in products and technology? Can a trainer offer manufacturer certification as well as other certifications?

Where is the training offered? Travel costs can significantly increase the cost of education.
Note that FOA-approved schools often offer other types of instruction than just CFOT-certified classes. Contact your FOA school or the online list of FOA approved schools for more information.

Safety when working with optical fiber

OSP safety is a very important consideration that goes far beyond the usual fiber concerns of protecting your eyes from fiber splinters or working with potentially hazardous chemicals. Routes should be cleared using "One Call" or "Call Before Digging" services to ensure there are no buried cables or pipes on the proposed route. Installers working with cable laying machines must be well trained in their safe operation. Overhead installations are particularly dangerous because electrical cables are usually found near the poles. Each TSO station should have published safety procedures and all personnel instructed in their use.

Safety in the laboratory or workplace should be everyone's top concern. In addition to the common construction safety issues generally covered by OSHA regulations that all contractors and installers should be aware of, fiber optics is associated with eye safety, chemicals, fusion splice sparks, fiber rail disposal, and more. Before starting the installation, the safety rules should be posted on the wall of the classroom, laboratory or workplace and made known to all personnel on site. All personnel must wear standard construction safety equipment and all must wear safety glasses when handling fibers.

Eye safety

Many fear that the most dangerous part of working with fiber is the possibility of eye damage from the laser light in the fiber. They mistook communication fibers for fibers connected to the output of high-powered lasers used to cut metal, burn warts onto the skin of doctors, or perhaps they had watched too many science fiction movies.

In fact, most fiber optic systems do not have enough power to cause eye damage, and the light coming out of the fiber expands, so the further you are from the end of the fiber, the less exposure there is. That said, consider yourself warned. More recently, some fiber optic systems have enough power to be unsafe, and some fiber inspection techniques that can be used in operating systems increase the risk of damage. But it is not the biggest threat to installers.

The key to understanding the power problem is to understand the power levels, the wavelengths of light, and the nature of light transmission in a fiber.

Fiber medical laser systems used in surgery and laser treatment systems certainly have enough power to cause eye damage as well as burn warts or treat certain types of materials. These systems use very high power lasers, often CO2 lasers, that emit radiation at a wavelength that is actually heat rather than light, around 10 microns. This wavelength is easily absorbed by materials and can quickly heat them up for easy cutting.

Fiber optic communication systems use much less energy. First of all, most sources used in fiber optics are optimized for modulation rate, not absolute power. Utility cables with multimode fiber and LED sources have a very low current level, too low to be dangerous. Higher speed local links use VCSEL lasers, which are still fairly low power and generally harmless. Most telecommunications links use lasers with a power slightly higher than the VCSEL.

Two types of links are powerful, up to 100 times stronger than other communication systems, and are CATV or video links at 1550 nm and telecommunications long-haul links using dense wavelength division multiplexing (DWDM). fiber to the home (FTTH - read more) can use fiber amplifiers (read more) that boost power to very high levels, potentially dangerous to the eye. Telco DWDM links are used over very long distance links (read more). Not only do they use fiber amplifiers to increase power, they have many different signals operating at different wavelengths carried over a single single-mode fiber. Any single wavelength may not be a problem, but the sum of 16, 32 or 64 individual wavelengths can be very powerful.

The next issue is to focus the light from the fiber into the eye. The light emerging from the fiber propagates in a cone whose angle is determined by the transmission characteristics of the fiber determined by the numerical aperture. As the eye moves away from the end of the fiber, the amount of radiation received is inversely proportional to the square of the distance; double the distance and reduce the power by 1/4, ten times the distance reduces the power to about 1%. You don't have to be far from the fiber for the current to drop to a low, harmless level.

As the light leaves the fiber in a cone-shaped beam, the eye cannot focus it on the retina. This differs from a typical laboratory laser or laser pointer, which shines with a narrow, collimated beam that does not disperse; beam, your eye can easily focus on the retina, causing temporary blindness.

FOA reference for fiber optics (19)

Finally, there is the question of wavelength. Your eye cannot see many of the wavelengths used in fiber optics because the eye is sensitive to light in the blue to red spectrum, while fiber optic systems operate in the infrared. The fluid in your eye, which is mostly water, strongly absorbs infrared light. Light from most fiber optic sources will be absorbed by this fluid, so any potential damage is likely to the lens or cornea, not the retina.

While the expanding light beam emerging from the optical fiber makes this less of a problem for direct viewing, using a microscope to inspect optical fibers can be a problem. The microscope will focus almost all light back into the eye. Therefore, many microscopes used in fiber optics have filters that absorb infrared (IR) light, which can be harmful. Beware of cheap microscopes that may not have infrared blocking filters.

To ensure that the fibers are safe to inspect or work with, always check the fibers in a live network with a fiber optic current meter to ensure there is no light before inspecting a connector with a microscope.

Just Fiber Security

However, installing optical fibers is not without risk. A more common problem is fiber residue entering the eye when working with fiber. Although few fiber optic systems have harmful power levels, each termination and splice produces pieces of fiber that are potentially very harmful to eyes and skin, or that can stick to clothing and be transported to other locations where they can be harmful to others.

These fiber shards are small, thin and often very sharp where they have broken away from the fiber. They can easily pierce the skin and bury themselves deep enough that it becomes difficult to pull them out if you just see them. Since they are transparent, they practically disappear when they blend into the skin. In most parts of the body, they just become a nuisance, perhaps infecting or causing an annoying bump, until they eventually resolve on their own.

But around the eye they can be much harder to find and remove. Tears that wet the eyes make shards of clear glass virtually impossible to find and remove. The sharp ends of the fiber can cause it to dig into the eye or surrounding tissue, making it even more difficult to remove. Unlike metallic particles, they cannot be removed with magnets,

It is necessary to follow procedures to minimize the risk to the eye. Always wear safety glasses with side shields, even if you normally wear glasses, to prevent flying debris from entering your eyes. Be extremely careful when handling fibers, especially when removing fibers or scratching and breaking fibers protruding from the adhesive joint. Instead of breaking it, gently scratch it, then run your fingers over the connector sleeve, grab the fiber and pull it out. Then carefully throw it away.

Most crimpers used to splice or terminate prepolished/spliced ​​connectors retain the fiber after cutting, so the only problem is disposal. We recommend using disposable containers, such as those used for soups in takeaway restaurants. Use it on all fiber residues, seal and dispose of properly.

You can also configure your workspace to help you avoid problems. Use a black plastic mat as a work surface. A dark background will make it easier to see the fibers you are working with and handle them more gently. Any broken fibers that fall onto the mat can be easily found for disposal.

Some technicians like to place a piece of double-sided tape or a loop of black electrical tape on the mat and stick the fibers to the adhesive surface, then discard the tape when you're done. I prefer to just use a disposable container and put every bit of fiber in it, rather than leaving it exposed on the work surface.

Other security issues

Chemicals: Fiber splicing and termination uses various chemical cleaners and adhesives as part of the processes. Normal handling procedures should be followed for these substances. Even simple isopropyl alcohol used as a cleaning agent is flammable and should be handled with care. Manufacturers provide "Material Safety Data Sheets" (MSDS) upon request or can be found online.

Welding Hazards: Fusion welders use an electric arc to weld, so care must be taken to ensure that there are no flammable gases in the welding area.
No smoking: Smoking should also not be allowed near fiber optic works. Flue ash contributes to fiber pollution problems, in addition to the possible presence of combustibles (and of course health risks).

Electrical Hazards: Installation of fiber optic cables typically does not involve electrical hazards unless the cable contains conductors. However, these cables are often installed near electrical and conductive cables. When you are near these cables, there is always a potential risk of electric shock. Be careful! If you are not familiar with electrical safety, we recommend taking the NEC (National Electrical Code) and Safety Practices for Installers course!

Safety and building regulationsFor safety reasons, all installations must comply with building and fire regulations. All components must be suitable for the application (local or OSP) and properly installed. Internal applications require fire-rated components and fire-resistant seals for penetrations through walls or floors. All metal components in the wiring system must be properly grounded and bonded. The documentation must contain all the conditions required by the building regulations.
National electrical codes now require all "abandoned" wiring to be removed due to fire hazards. This should be considered as part of the installation planning as the cable should be removed first if possible to avoid interference with newer cables.

Safety rules for fiber optic installations

This is all very important, important enough to have a few workplace rules for all fiber optic technicians to prevent workplace accidents:

Work on a black work surface as this helps to find fiber residue.
Wear disposable aprons to minimize fiber particles on clothing. Particles of fibers on clothing can later get into food, drinks and/or otherwise be ingested.
Always wear safety glasses with side shields and protective gloves. Treat fiber optic shards in the same way you treat shards of glass.
Never look directly at the end of a fiber optic cable until you are sure there is no light source at the other end. Use a fiber power meter to make sure the fiber is dark. When using an optical marker or continuity check, look at the fiber at least 6 inches from the eye to determine if visible light is present.
Work only in well-ventilated areas.
Contact lens wearers should not touch the lenses before washing their hands thoroughly.
Do not touch your eyes when working with fiber optic systems until your hands have been thoroughly washed.
Keep all flammable materials away from electrical equipment, including welders, testers and curing ovens.
All cut pieces of fiber must be placed in a properly labeled container for disposal.
Clean the work area thoroughly when you are finished.
Do not smoke when working with fiber optic systems.
Keep all food and drinks away from the work area. Internal bleeding may occur if fiber particles are swallowed.

Installation of fiber optic cable

Collection of fiber optic cables and equipment on site

Fiber optic equipment and components can be damaged by improper handling or storage and should be handled properly.


Fiber optic cable, equipment and supplies must be delivered to the job site as close as possible to the time of use to minimize possible damage from other construction, weather or theft. Coordinating deliveries can be difficult, so arrange for delivery to an off-site staging area or provide a locked container for on-site storage. Upon initial receipt, all fiber components must be thoroughly inspected for damage and tested for continuity or loss if damage is suspected. Ensure that all components and parts have been shipped, received, are consistent with the quantities ordered (e.g. fiber optic cable includes ordered fiber number and type and length) and that any discrepancies or damaged items are noted, supplier notified and listed as required.


Handle spools of fiber optic cable with care. All coils, regardless of size or length, must have both cable ends available for continuity testing. Fiber indicator or visual fault finder and bare fiber adapters can be used for continuity testing.
Cable reels must be moved carefully to avoid damaging the cable. Handling of small, lightweight spools of fiber optic cable. Larger drums must be moved with suitable lifting equipment or with two or more installers trained in this operation. Lifting equipment should only handle drums with a matching set of straps or chokes attached to an appropriately sized tube inserted through a hole in the center of the drum. Slings and chokes should never be attached around the coiled area of ​​the roller cable.


All equipment and wiring must be stored in a clean and dry place, protected from harsh conditions such as extreme cold and heat. Due to the value of the cable and the possibility of theft, all components should be stored securely with covers when necessary.

General guidelines for the installation of fiber optic cables

Fiber optic cables are installed in so many different applications that it is very difficult to generalize how to install fiber, so in this book we will try to cover universal issues and mention details where necessary.

Fiber optic cable can be installed indoors or outdoors using several different installation processes. The outdoor cable can be buried directly, pulled or blown into a cable duct or indoor duct, or installed overhead between poles. Indoor cables can be laid in tracks, trays above ceilings or under floors, placed in hangers, pulled into conduits or internal ducts or blown through special ducts with compressed gas. The installation process will depend on the nature of the installation and the type of cable used.

The installation methods for wired and fiber optic communication cables are similar. Fiber optic cable is designed to pull with much more force than copper wire if pulled properly, but over-tensioning the cable can damage the fibers, potentially causing failure. During installation, special care must be taken not to exceed the cable's bending radius or kinks, which can damage the fibers.

Installation instructions
Follow the cable manufacturer's recommendations because no one knows how to handle a cable like the company that made it. Fiber optic cable is often specially designed for installation, and the manufacturer may have specific instructions for installation.

Check the length of the cable to ensure that the cable being pulled is long enough for the planned cable routing. If possible, try to complete the installation in one go. Before proceeding with the installation, carefully assess the route to determine the installation methods and possible obstacles.

Tension pull

Cable manufacturers install special reinforcements, usually aramid (Dupont Kevlar) yarn, to absorb the stresses of pulling the cable. Fiber optic cable should only be pulled by these strength elements unless the cable is designed to allow pulling by the handle on the sheath. Any other method can stress the fibers and damage them.
Use the swivel eyelets to secure the rope or tow strap to prevent the rope from twisting when pulling.

Cables should not be routed in the sheath unless specifically approved by the cable manufacturers and an approved cable grip, often called a "Kellems grip", is used. These handles are usually also attached to the power elements.

A dense buffer cable can be pulled through the sheath in plant applications if a large (~40 cm, 8 inch) spool is used as the pull pin. Wrap the line around the spool 5 times and hold it gently as you pull.

Do not exceed the maximum tensile stress. Consult the cable manufacturer and suppliers of tubing, inner tubes, and cable lubricants for guidance on voltage ratings and lubricant use.

When running long lengths of cable in pipes or indoor conduits (up to about 3 miles or 5 kilometers in an outdoor facility, hundreds of meters in on-site cables), use the correct cable lubricants, but make sure they are compatible with the cable vagina. If possible, use an automatic trigger with tension control and/or a draw eye. For very long stretches of OSP (more than about 2.5 miles or 4 kilometers), pull from the center to both ends, or use an automatic fiber stripper at intermediate points for a continuous pull.
When laying the fiber optic loops on the surface while pulling, use a figure eight loop to prevent the cable from twisting.

Cut cable

Do not twist the cable. Twisting the cable can strain the fibers. Cable tension and pulling on ropes can cause twisting. Use the swivel tow eye to connect the tow rope to the cable to prevent tensile stresses that cause twisting forces on the cable.

FOA reference for fiber optics (20)

Roll the line off the spool instead of unwinding it from the end of the spool to prevent the line from twisting with each turn of the spool. When laying the cable for a long run, use a "number 8" on the ground to prevent twisting. The figure 8 puts a half twist on one side of the figure eight and pulls it out on the other, preventing twists.

Installation of rotating eyelets on fiber optic cable

Cable manufacturers install special reinforcements, usually aramid yarn (Dupont Kevlar), for pulling. Fiber optic cable should only be routed over these reinforcements unless the cable is designed to allow the jacket to be routed. Any other method can stress the fibers and damage them.
Use the swivel eyelets to secure the rope or tow strap to prevent the rope from twisting when pulling.

Procedure for mounting swivel eyelets:

FOA reference for fiber optics (21)

Strip the cable sheath and cut all the fibers to the end of the sheath, leaving only the aramid reinforcements.

Divide the aramid yarn into two bundles and feed them through the swivel in opposite directions.
Tie knots in each bundle at the ear and loop the reinforcements back into the cable jacket.
Glue the reinforcement pieces along the jacket and to the draw eye.

How to make "Figure 8" cable for intermediate runs in OSP installations

For very long stretches of OSP, typically longer than about 2.5 miles or 4 kilometers, it may be necessary to use an automatic fiber stripper at intermediate points for continuous pull or mid-span pull. When laying the fiber optic loops on the surface while pulling, use a figure eight loop to prevent the cable from twisting. The figure 8 puts a half twist on one side of the figure eight and pulls it out on the other, preventing twists.

FOA reference for fiber optics (22)

Use this procedure to draw from one end:

Pull the cable out of the housing or inner tube and lay it on the ground in the shape of a large "eight". Size "8" will depend on the size and stiffness of the cable, but a common size is 6-12 feet (2-4 m). The end of the cable will touch the ground - you may need to use a tarp or plastic to keep the cable clean. Pull the cable slowly and carefully in a figure 8 fashion to avoid kinking.
Use several installers to pick up the cable and turn it so that the end to be pulled to the next location is at the top.
Attach the end to the tow rope with the appropriate swivel tow eyes and continue pulling.

For mid-span pulls, use these tips:

This procedure eliminates the need to reverse the figure 8 cable on the ground.
Place the cable drum in the middle of the long span (make sure the maximum pull length in any direction is not exceeded).
Pull one end of the cable through the channel to one end of the span.
Unroll the cable from the coil and lay the remaining cable on the ground. The end of the cable will be at the top of Figure 8.
Pull the other end of the cable through the channel to the other end of the span.

Bending radius

Do not exceed the bending radius of the cable. Fiber optic cable can break when bent or bent too much, especially when pulled. Unless specifically recommended by the cable manufacturer, the cable should not be pulled over a bend radius of less than twenty (20) cable diameters.
The rope shall have no bend radius less than ten (10) rope diameters when tension is complete.

Vertical cable routes

Run vertical cables down instead of pulling them up whenever possible. Support the cables at frequent intervals to prevent excessive sheath stress. Cable ties (tight but not tight enough to deform the cable jacket) or Kellems can provide support. Use service loops to help grip the cable for support and secure the cable for future repairs or rerouting.

Installation of cables indoors in cable trays

Fiber optic cable is often installed in cable trays in premises. Cable trays should not be shared with copper communication cables as their weight can damage fiber optic cables. Similarly, large amounts of fiber optic cables in a tray can put too much pressure on the cables at the bottom. In applications where cable trays are used for copper communication cables, it is possible to suspend light fiber optic cables under the cable trays.

Use of Innerduct

It may be wise to install critical indoor fiber optic cables inside a bright orange "inderduct" to facilitate the installation of the cables and protect them from future damage. The bright orange inner channel will identify the fiber optic cable for each worker at a later time and possibly prevent damage. The additional initial cost of the internal duct can be compensated for by simplifying the installation, saving the worker time.

Use of cable ties

Fiber optic cables are, like all communication cables, sensitive to compressive or crushing loads. Cable ties used with many cables, especially when tightened with an installation tool, are harmful to fiber optic cables, causing attenuation and potential fiber breakage. When used, cable ties should be hand-tightened so that they are tight but loose enough to be moved along the cable by hand. Then the excess length of the tie must be cut off to prevent further tightening. Velcro straps are preferred for fiber optic cables as they cannot exert sufficient crushing loads to damage the cable.


Internal cables must meet fire regulations and pass inspection, so any cable passing through a fireproof wall must be fire protected. All telecom security must comply with applicable codes and standards. All passengers must be protected by approved fire barriers. Fire protection measures and devices should be used when the installation is affected by fire separation. In most locations, a fire separation breach will require physical monitoring until it is repaired. Contact the "competent authority" for detailed project requirements before work begins.

Grounding and connection

Conductive cables require proper grounding and connection of suitable conductors. Although most fiber optic cables are non-conductive, any metal hardware used in fiber optic cabling systems (such as wall-mounted junction boxes, racks and patch panels) must be grounded. Grounding systems must be designed in accordance with the NEC and other applicable codes and standards. Most telecommunications rooms have a ground bus that has high-quality building grounding and connections to equipment that requires grounding.

Connection and termination

Finishing and gluing processes are described in detail in Chapter 7. Finishing and gluing in the field has no unusual requirements other than finding a suitable, dust-free room with moderate temperatures to work in.


Pooling plants outdoors is usually done in a special pooling trailer or truck. Inside the truck is an air-conditioned splicing lab with enough table space to work with cables and joints. Sometimes it is necessary to splice in the open, in a small tent or even in an air bucket. The installer must be able to cope with the conditions of the installation. In extremely cold weather, heating is likely to be necessary as the cables become stiff and the equipment difficult to handle. A warm climate may facilitate the processes, but it is equally inconvenient for the installer.

Ideally, splices should be tested with an OTDR as soon as they are made and before they are placed in the splice tray. Fiber splicers provide estimates of splice losses, but these are only estimates. The OTDR can confirm the quality of the splice, giving the installer confidence that the splice is good and that the splice closure does not need to be reopened to repeat a bad splice.
Special care must be taken when placing splices in the splice trays and when laying buffer pipes or fibers in the sleeve. A problem that occurs all too often is fiber breakage during tray assembly and closure. It is difficult to find fiber breaks inside the closure because they are too close to the splice to be resolved by an OTDR. If the plug is close enough to be traced with a visual fault finder, it can be found by visual inspection.

The cables must be attached to the joints and properly sealed. In general, loose tube cables will have tubes extending from the closure entrance to the tray where they are attached, and then after welding, approx. 1 meter of exposed fiber in the tray. Be careful to connect the electrical conductors correctly, such as the armor of some cables or the central metal reinforcements, to the closure and each end.

All closures must be sealed to prevent ingress of moisture. Closures must be properly secured, with the location determined by the type of installation, and excess cable must be properly coiled and stored. This may be on a plinth or vault, on a pole or tower, or buried underground.

More on splicing



At the very least, termination usually occurs indoors near communications equipment, whether terminating outside cable stations or local cables. The installer may still have problems finding the right place, for example in a telecommunications room with rows of patch panels and equipment cabinets. Hopefully the cable installer provided service loops for each cable so that the cables can be routed out into the open for termination. Many installers use portable folding tables or carts on wheels to create a work area where they can reach cable ends.

If the building is still under construction, dust can be a problem. Even in finished buildings, air conditioning systems can blow away dust. Beware of dust, and if it is necessary to work in a dusty environment, clean all tools, polishing foil and connectors as often as necessary.

When terminating single-mode cables with fiber splice pigtails on each fiber, the same precautions must be followed for placing splices or fibers in cable trays and closures to prevent damage. When directly terminating 900 micron buffered multi-mode fibers in the distribution cable, allow sufficient length to store excess fiber lengths and be careful to avoid tight bends that can cause future fiber failure loss problems. Splice connections (SOC) often do not require a separate splice tray or closure, but can be terminated and placed on the back of a patch panel.

As with splices, each connector must be inspected after the termination of the fiber is complete. Examine each polished joint under a microscope to ensure that the polishing has been done correctly. If possible, test each prepolished/spliced ​​connector with a visual fault finder. After terminating both ends of the fiber, end-to-end loss must be tested and documented. High loss connectors need to be re-terminated, saving time when the installer is already configured on site.

More about termination


FOA reference for fiber optics (23)

Labeling and documentation

Typically, the installer who terminates the cable is tasked with marking each end point. Ideally, the label should be created as part of a cable installation project and the installer only needs to match the fiber color codes to the label and, if not already located, stick the label to the patch panel in the correct location. This is an important process as the labeling on each fiber will be used to record test data, connect to equipment and will be respected during subsequent moves, additions and changes. Patch panel doors must be marked for use and contain warnings about permitted access.

Cleaning the workplace

After terminating or splicing the cables, the installer should thoroughly clean the work area, leaving it at least as clean as he found it, preferably cleaner. All cuttings, especially fiber cuttings, which must be sealed in disposable containers, must be removed from the construction site.

Storage of redundant components

Any redundant elements should be saved for future use, especially for renovation. Plugs and cables can be kept with the cable installation documentation so that any future refurbishment will include compatible components for use when bundling or terminating cables.

During installationCheck all installation work during the actual installation so that any problems can be identified and fixed before they become bigger problems. Daily supervisors and installers should review processes, workflows and test data. All affected personnel should receive immediate notification of problems and solutions, deficiencies, etc.
Be careful when installing cables to avoid stress, hazards that can cause cables to be caught and bent, or installation of cables where there may be heavier cables.
It's fine to bundle cables to keep things organized, but be careful when using cable ties. Tightening them can cause harmful stress on the fibers (or pairs in UTP copper cables), so tighten them by hand and cut off the excess length. Even better, use soft Velcro straps that can be opened again to move cables around.

Testing of the installed fiber optic cable plant

In the design phase, each cable run should have a loss budget calculated from the component specifications. After installation, it is necessary to test each fiber in all fiber cables to verify correct installation by comparing the measured losses with the calculated losses from the loss budget.

Typically, the installer will perform the following tests:

Continuity tests to determine if fiber routing and/or polarization is correct and documentation is correct.
End-to-end insertion loss using current meter and OLTS source. Test multi-mode cables using TIA/EIA 526-14 method B and single-mode cables using TIA/EIA 526-7, unless plug test equipment compatibility requires another reference method. The total loss should be less than the calculated maximum loss of the cable based on loss budget calculations using appropriate standards or customer specifications. If the tests show deviations from the expected losses, troubleshoot and correct them.
Optional OTDR testing can be used to check cable installation and splice performance. However, OTDR testing should not be used to determine cable loss. The use of an OTDR in local applications may be inappropriate if the cables are short. An experienced OTDR technician should determine appropriate use.
If the design documentation does not include the length of the cable installation and this is not recorded during installation, read the length from the distance markings on the cable jackets or test the length of the fiber using the length function available in OTDRs or some OLTS.

Continuity and polarity test

Perform fiber continuity tests with a visual fiber indicator, visual fault locator, or OLTS current meter and power source. Trace the fiber end-to-end through any connections to ensure the path is properly installed and that polarization and routing are correct and documented.

Loss of input

Insertion loss refers to the optical loss of installed fibers measured by a test source and a power meter (OLTS). Test multi-mode cables using TIA/EIA 526-14, preferably method B (but always document the method used) and single-mode cables using TIA/EIA 526-7 (single-mode).

Test multi-mode fiber at 850 and 1300 nm and single-mode fiber at 1310 and 1550 nm, unless otherwise required by other standards or customer requirements.
Please test reference test cables before testing to verify quality and clean them frequently.

Cables intended for use with high-speed systems using laser sources may be tested with appropriate laser sources to ensure that the tests verify operation of this type

Testy OTDR

An Optical Time Domain Reflectometer (OTDR) uses techniques similar to optical radar to create an image of the fiber in an installed fiber cable. The image, called a signature or trace, contains data about the length of the fiber, losses in fiber sections, connectors, splices and voltage losses during installation. OTDRs are used to verify installation quality or troubleshooting. However, the OTDR test alone should not be used to determine cable loss.

OTDR testing should only be performed by trained personnel using certified equipment designed for this purpose. Test technicians should be trained not only to operate the OTDR hardware, but also to set the OTDR test parameters and interpret the OTDR waveforms. OTDRs have limited distance resolution and can show misleading artifacts when testing short cables typical of local applications. If on-site testing of OTDR cables is desired, experienced personnel should assess the appropriateness of the testing.

More about testing

Administration, management and documentation

Documentation of fiber optic cable installations is an integral part of the design, installation and maintenance of the fiber network. Properly documenting your installation will make installation easier, allow for better upgrade planning, simplify testing and future porting, additions and changes.

Unless otherwise specified by the user, fiber optic documentation must comply with ANSI/TIA/EIA-606, Administrative Standard for Commercial Building Telecommunications Infrastructure.

Fiber optic cables, especially those used for backbone cables, can contain multiple fibers connecting many different links leading to multiple locations with connections on patch panels or splice closures. The fiber cable factory must document the exact path each fiber in each cable follows, including interconnects and each type of connector. The documentation should also include insertion loss data and optional OTDR traces.

See alsoConstruction of the TSOin the FOA guidelines

Download a free copy of the NECA/FOA-301 Fiber Installation Standard.

Read more about installation.

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Table of contents: FOA Fiber guide

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