Reference Guide To Fiber Optics
|Topic: Installing Premises Cabling Systems||Table of Contents: The FOA Reference Guide To Fiber Optics|
|Premises Cabling installation|
After the process of designing a premises cabling network is completed, the next step is to install it. What do we mean by the “installation process?” Assuming the design is completed, we’re looking at the process of physically installing and completing the network, turning the design into an operating system. The organization of this chapter is preparing for the installation, training and safety and then doing the actual installation work.
Preparing For Installation
The Role of the Contractor in an Installation
To begin work on a premises cabling installation, the network owner or user must choose a contractor, perhaps the most important decision in the entire process. The contractor should be able to work with the customer in each installation project through six stages: design, installation, testing, troubleshooting, documentation and restoration. The contractor must be experienced in premises cabling installations of the type involved and should be able to provide references for similar work.
One should be able to rely the contractor to not only do the installation but to assist in the design of the network and help choose components and vendors. Once the contractor has been given the assignment, they should be able to help the customer with the design, including choosing the right kinds of cables, connectors and hardware for the installation. The contractor should know which components meet industry standards to ensure interoperability and what state of the art components will facilitate future expandability.
The experienced contractor also should be able to help in the choice of vendors. Experience with particular product types and vendors will allow the contractor to assist the customer to choose products that make the installation faster and easier as well as higher performance and more reliable. Should the customer choose components that are unfamiliar to the contractor, it is important that the contractor know early in the process so they may obtain proper training, often from the manufacturer, as well as any unique tools that may be required.
Generally, the customer is not as familiar with premises cabling technology and practice as an experienced contractor. The contractor may need to discuss certain choices with the customer where they believe alternatives may be better choices.
The actual installation process can involve more than just putting in cable, terminating and testing it. If the contractor is knowledgeable and experienced, the user may ask the contractor to purchase, receive, inspect and bring components to the work site also, which can be another good source of revenue for the contractor. Having full control of the materials process can also make life easier for the contractor, as they have a better chance to keep on schedule rather than depending on a customer who has many other priorities. Plus, they may have the latitude to choose components they are more familiar with, facilitating the actual installation process.
The technicians actually doing the installation should be trained and certified by organizations like The FOA (www.thefoa.org) which offers the CPCT premises cabling technician certification and/or manufacturers of the products being installed. Certification provides a level of confidence that the installation techs are knowledgeable and have the skills needed for the work involved.
The final four requirements from the contractor, testing, troubleshooting, documentation and restoration, need to be discussed before the project ever begins. Every premises cabling project requires loss testing of every link according to industry standards. The contractor and customer must agree that testing includes troubleshooting problems and fixing them as well as documenting test results for every link.
Likewise, for the contractor, documentation must begin before the project starts so the scope of work is known to everyone and end only when the final test data is entered. Copies of the documentation, along with excess components left over from the installation, must be presented to the customer to facilitate future network restoration, should it be required.
The contract for a premises cabling installation should include detailed requirements for the project, spelling out exactly what is to be installed, acceptable test results, and documentation to be provided. All this should be discussed between the customer and the contractor and agreed to in writing. They are not irrelevant details, as they are important to ensure the customer gets what they expect and the contractor knows what is expected of them when designing the network, estimating costs, doing the actual installation and providing proof of performance in order to show the work is completed and payment should be made.
Planning For The Project
Once the contracts are signed and a set of plans has been handed to the contractor, what’s next? Planning the job is the first task. Proper planning is important to ensure the job is installed properly, on time and meets cost objectives, so the contractor can make a profit.
It is assumed you have a finished design for the project, know where and how everything will be installed and have any special requirements like permits ready. One can also assume you have a completion date, hopefully a reasonable one, to work toward. The first step then is to create a schedule which will be the centerpiece of the planning process.
In order to schedule a job, you need a lot of information, much of which can be acquired from estimates you did when bidding the job. When buyers price the components to be used on a job, they should get delivery times as well as prices. Some items used on premises cabling projects should be stock items, like UTP cables, connectors or patch panels. Fiber optic cables, however, may have to be made to order.
Many fiber optic cables are custom items, depending on the cable type, number and types of fibers and color coding. Custom cables will often be less expensive because they don’t have extra fibers for specifications you don’t need, for example, but they will have longer lead times since they must be made from scratch. Whenever specifying a fiber optic cable, always try to have a few extra fibers available, just in case fibers are damaged during installation.
The astute contractor tries to always use the same types of components on every job so they are familiar with not only the installation procedures but the typical costs, yield (i.e. number of links will pass testing first time) and any problems likely to be encountered.
If any components are not familiar to the installers, they need to learn how to install them correctly, either by experimenting in the office on off-time or getting manufacturers to train them. The need for training may also arise if new equipment types are required, such as new tools or new types of test equipment. The cardinal rule of installation is never take an unfamiliar component or tool on the job; it’s a recipe for disaster.
Buyers need to order the components when the job is acquired, scheduling delivery to the job site either to have everything available before the installation begins, or on a large job with an extended schedule, according to how long the installation of that component will take. Here you also need to plan on where the components will be delivered to, either a staging area in your warehouse, for example, or to the job site.
Components delivered to the job site may require security. Theft can be a problem with cable particularly, since many thieves know all cables contain copper and the price of copper is still high! But vandalism is another concern, requiring components be either locked up or if too large to put indoors like large spools of cable or innerduct, may require on site overnight guards.
Next, one needs to schedule labor. Again, the estimates should tell you how many installers of what experience will be needed and how long they are expected to need to complete the installation. If any training is needed, additional time may need to be added to the schedule.
Having covered labor and materials in the schedule, the planning is almost done. Review the schedule with everyone involved to get them on board and start the processes, beginning with acquiring materials. Then add to the plan a review of safety rules for supervisors, installers and anyone expected to be on site. Also add notes to keep all scrap cable, connectors, etc. to package and present to the user in case they are needed for future restoration.
If the start date is not tomorrow (because the customer wanted it yesterday!) and you have other projects in the interim, pull out this schedule regularly to check if everything is on schedule to prevent any last minute surprises.
Planning for the installation is a critical phase of any project as it involves coordinating activities of many people and companies. The best way to keep everything straight is to develop a checklist based on the design. The checklist below is comprehensive but each project will have some of its own unique requirements that need to be added to the list.
• Main point of contact/project manager chosen
Before starting the install:
• All permits available for inspection
During The Installation:
• Inspect workmanship at every step
After completion of cable plant installation:
• Inspect workmanship
Preparing For Premises Fiber Optic Installations
Before beginning installation of premises cabling and hardware, the site must be properly prepared for the installation of cables, hardware and transmission equipment. During the design and planning stages, the site should have been inspected and all the hardware necessary for the cable plant included in the design.
Premises Support Structures
There are numerous structures used for the securing of cabling in premises installations making generalizations difficult. Cable may be hung on appropriate hangers, laid in cable trays above the ceiling or below the floor or pulled into conduit or innerduct. Termination of the cables can be at racks in telecom rooms, in wall-mounted boxes or even wall outlets. Preparing for an install includes planning for storage of cable service loops behind racks such as shown here.
You must install support structures for cable installations before the installation of the cable itself. These structures should follow the guidelines of appropriate standards such as TIA/EIA 569-A and NECA/BICSI 568-2001. Allow for future growth in the quantity and size of cables when determining the size of the pathways. Follow all cable bend radius requirements and avoid pulling cables around hazards if possible.
Sometimes new cables can be laid in existing cable trays. Do not install a fiber optic cable in a conduit or duct that already contains cabling, regardless of the cable type to prevent damage. Existing or new empty ductwork can be modified to accept several different installations by the proper placement of innerduct.
Premises support structures also include patch panels for terminations. They may be wall- or rack mounted and must be chosen appropriately for the cable types being used. Terminated simplex or zipcord fiber optic cables can be terminated on open panels, but 900 micron tight-buffered fibers from distribution cables require closed termination panels for protection. If possible, the design of support structures should be such that adequate space is provided for termination of the cables and storage for service loops.
Premises cabling requires firestopping at all penetrations of walls and floors. Telecommunications firestopping must always comply with applicable codes and standards. All penetrations should be protected by type-approved firestops.
In most areas the breaching of a fire separation will require physical monitoring until it has been repaired. Check with the “Authority Having Jurisdiction” for specific requirements on the project before commencing work.
All communications equipment will require proper power at the locations of the equipment, generally the main equipment room and telecom rooms. Power must be high quality power, protected for surges and spikes, and generally must have appropriate backup capacity to prevent loss of communications during power loss. Data equipment will require a separate ground and adequate power for year-round air conditioning. Consideration should be given to efficiency in cooling to reduce power consumption. Consult with the site owner, customer and appropriate user personnel to plan electrical power installation.
Grounding and Bonding
All conductive cabling and components must be grounded and bonded. Ground systems must be designed as specified by the NEC or other applicable codes and standards. Any metallic hardware used in cabling systems (such as wall-mounted termination boxes, racks, and patch panels) must be grounded. All conductive cables require proper grounding and bonding for applicable conductors.
Marking and Identifying Cables
Cables should be specified with colored jackets per industry standards which identify the cables as fiber optic cables and indicate the type of fiber in the cable. UTP terminations in patch panels should have every jack identified. All fiber optic cable terminations should be marked on racks or boxes where the cables terminate. Fiber optic cables should be tagged with identification that they are fiber optic cables and proper handling is required.
Particular care should be taken in premises cabling upgrades. For nearly two decades, 62.5/125 micron multimode fiber has been the primary fiber for premises cabling. With the emergence of gigabit networks, laser-optimized 50/125 fiber has become more popular. Mixing the two fibers can result in excessive loss at connections that may cause systems to not operate properly. Color coding, marking and even using incompatible connectors (SC or ST on 62.5/125 and LC on 50/125 fiber) should be used whenever possible.
Removal and Recycling of Abandoned Cables
Unless directed by the owner or other agency that unused cables are reserved for future use and the cables are marked accordingly, it may be required to remove abandoned optical fiber cable (cable that is not terminated at equipment other than a connector and not identified for future use with a tag) as required by the National Electrical Code or local codes.
At the discretion of the owner of the site, the contractor may be requested to remove other cables (e.g. copper communications or power cables) in addition. Removal of cables is much more time consuming than installation, as each cable must be identified and carefully removed to prevent damaging other cables. No cable should be cut for removal unless it is positively identified as one to be removed.
All cables removed should be recycled properly. Most communications cable has significant scrap value, not only for any copper conductors but for other metallic elements and even some plastics. In order to maximize your return on selling scrap cable to recyclers, there are some guidelines that should be followed.
Separate cables by type. The best price is for electrical power cable, obviously, since the copper content is higher than for communications cable, so it should be separated from other cables. Recyclers grade cable by conductor size, basically larger or smaller than 12 gage wire. Also separate communications cables by jacket type. Not only is the copper recycled, but so is the plastic. Some recycled plastics can be reused while others are processed for use as fillers or to make structures like park benches. However, the different types of jackets on riser and plenum cable, for example, require segregation for recycling.
Do not try to remove jacketing on cables. As mentioned above, the copper and plastic can both be reused. Some “scrap dealers” tell people that the cable is worth more without the jackets and they can remove it by burning it off. That’s an environmental disaster, as many harmful chemicals are released into the air and may subject you to an EPA fine, plus it’s dangerous. One of the largest fires ever in New York City was caused by thieves stealing wire from abandoned buildings who tried to burn off the insulation. Legitimate recyclers use two methods to remove insulation, squeezing the cable until it cuts through the insulation or chopping it into fine particles and separating metallic and plastic pieces. The chopping process works on fiber optic cable too.
Remove and separate non-cable scrap. Try to cut off connectors, cable ties, steel hangers, etc. to leave only the pure cable. Likewise, scour the job site for other recyclables, as any metallic or plastic scrap is probably recyclable. Conduit is especially good to recycle but even patchcords and extension cords are recyclable. Try to separate anything containing lead or other hazardous metals like mercury and anything considered toxic. Be aware that some electronic materials must be properly recycled according to EPA regulations. In today’s world, we need to minimize the amount of material that goes to landfills because of the cost as well as the environmental impact.
Deal with legitimate recyclers. Many scrap dealers are middle-men, reselling to recyclers. Find a recycler, preferably one who owns the machinery to process cable locally, and you will get a better price and be assured the materials are properly handled. Local governments can help you find them. If you have a big enough load, they will often pick it up for you. And make certain they have a certified scale.
Cabling can be installed in many ways, under floors or above ceilings in cable trays, inside conduit, in J-hooks attached to walls or roof supports, inside walls, even inside special cable trays built into modular furniture. Installations need to be tailored to the property being cabled, the equipment being connected and local building codes, making generalizations about installations difficult. For all installations, however, certain cautions apply.
Mistakes in installation of cabling, particularly UTP cable, can be detrimental to final cabling performance and very difficult to detect. A mistake that could keep the entire system from working might not show up at all until the system is completely installed and turned on.
The installer needs to remember that while cabling systems have been thoroughly researched and standardized, the standards were created as universal performance standards for the manufacturers of cabling systems. The manufacturers interpret these standards in their product development, so while components from different manufacturers are designed to be interoperable, they may not have the same installation procedures. Thus it is imperative that the installer thoroughly understand the installation procedures provided by the manufacturer for the components being installed in order to obtain the specified performance.
Start With A Good Design
Proper installation depends on the proper design of the cabling system. The facility in which cabling is being installed should be designed according to industry standards which include all the pathways and spaces in which the cabling and communications equipment will be installed. Even where the cables are routed in the building is important. Cables should be kept dry and in moderate temperatures. Above the ceiling in some buildings in hot climates can get very hot, causing UTP cable to have higher attenuation so it will not support full standard link distances.
Cable should be installed on special hooks, bridle rings or cable trays that limit its bend radius and stress to preserve the performance. You cannot lay the cable on top of ceilings or hang from the drop ceiling hangers - in most places it's illegal - not allowed by code. Supports for the cables should be wide enough to support the cables without distortion, spaced close enough so the weight of cable supported (copper cable bundles are heavy) causes minimal sagging and have no sharp edges to cut or kink the cables. Fiber optic cables should be separated from heavy copper cables to prevent crushing; sometimes fiber cables are run in flexible orange innerduct which not only protects the cable but makes it readily visible.
Install and Terminate Cable Properly
The performance of the cabling network is also heavily dependent on the installation. The components used in structured cabling installation have been carefully designed and exhaustively tested to meet or exceed the requirements of EIA/TIA 568 or ISO 11801 when properly installed. If the cable is not properly installed, performance will be degraded. Terminations, both with UTP and fiber optic cables, must be properly made and tested.
Just like we keep reminding you about maintaining the pair twists right down to the terminations, there are other things you must realize to maintain the performance of Cat 5e/6/6a UTP cable. First of all, pulling tension must be less than 25 pounds. That's not very much tension. Pulling at higher tension can stretch the cable and affect the twists in the pairs, and it's those twists that make the cable perform well at high frequencies. Fiber optic cable can be pulled at higher tension than copper if it is properly attached to the pulling rope using only the strength members of the cable.
Puling cable in conduit is especially critical as you must deal with friction in the conduit and pulling around bends. Installing breakout boxes for intermediate pulls is often necessary and one may need to use pulling lubricants in the conduit. Only use an appropriate lubricant to prevent long term degradation of the cable. The lubricant must be compatible with the cable jacket which can vary according to cable types and ratings. Likewise, kinking any cable by letting it get twisted or pulled around sharp corners can cause permanent damage.
One should also avoid bundling the cables too tightly. Crushing the cables can affect the performance, since it can affect the twist and pair alignment in the cable which affects high frequency performance. If one uses regular plastic cable ties, they should be tightened only finger tight and cut off - do not use cable tie guns which may tighten tight enough to damage the cables. Preferably use "hook and loop" cable ties (shown above) which have an added advantage that they can easily be opened to add or remove cables.
Most UTP cable shipping boxes are designed to allow easy pulling directly from the box. Gather up several boxes and pull a bunch of cables at once. Tape them together and attach a pullstring or just feed them along by hand. There is usually 1,000 feet (about 300 meters) of cable in each box. Each cable is also marked with a distance every few feet so you can keep track of length by reading the distance off the cable. Before you pull any cable from the box, find the distance marked on the cable and write it down on top of the box. That way, you can calculate the length of each cable you pull and more importantly, the amount remaining in the box! It's not good to start pulling a cable and find out it's not long enough!
You can pull from the telecom room or to the room, whichever is more convenient in the install you are doing. You can also pull to consolidation points then out to individual outlets or vice versa, instead of pulling the bundle of cables all the way. Riser installations are more easily done by dropping cables down rather than pulling up. Riser installations need to be secured at regular intervals to prevent the weight of the cables suspended from causing long term problems.
In the telecom room, patch panels can have a large number of cables, so managing these cables can be quite a task in itself. It is important to keep all cables neatly bundled and labeled (write on the cable) so they can be moved when necessary. However, it is also important to maintain the integrity of the cables, preventing kinking or bending in too small a radius which may adversely affect frequency performance.
Power cables are also a safety hazard. Although premises cable is called "low voltage" and fiber optic cables are non-conductive, it runs in areas full of power cables that can be a shock hazard. If you are not familiar with electrical safety, fire safety and inspections, it is strongly suggested that you take a course on the NEC (National Electric Code) or similar local codes to learn about these important topics. It could save your life!
Other safety considerations:
Electrical inspectors do not always inspect communications wiring. Nonetheless, take a moment to check with local electrical inspectors before you do any work in their jurisdictions. In most cases, the inspector of your installation will be the same person who signs you contract, although in some cases, the inspector will be a third party. Make sure you know who will inspect your work before you give your customer a final price. You must know what the inspector will expect of you and what he or she will be looking for.
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