Curs PC si internet cap 9.4 Structured Cable Run Installation
9.4 Structured Cable Run Installation 9.4.1 Easiest procedure for routing cable Instructor Note Several less desirable methods for routing cable are described. First of all, stapling is unacceptable. Duct taping is unacceptable. Unattractive but easy is the method of tie-wrapping the cable together and then screw-mounting the tie-wraps to the wall. The easiest way to route cable is to mount it on a wall. However, this method should only be used in situations where you are sure the cable will not be bumped or pulled. Can you think of possible locations where this technique could be used? To wall mount cable you need to select a device that will secure it to a wall. One such device is the tie-wrap. If it is unlikely that a tie-wrap will need to be removed, you can use an adhesive tie-wrap. While it is easy to use, remember that it cannot be moved or repositioned later. If you think it is likely that the cable may have to be moved in the future, a tie-wrap, with holes punched in it, is a better choice. To use this type of tie-wrap, you need to drive screws into the wall. To drive screws into a masonry wall, the first thing you must do is drill holes into the wall. However, this can present problems. If you need holes smaller than 9.5 mm in diameter, you can use an electric drill equipped with a carbide bit. Be prepared for the work to go slowly. If you need holes larger than 9.5 mm in diameter, the electric drill will probably overheat. For this task, you need to use a tool called a hammer drill. A hammer drill resembles an oversized electric drill, but unlike an electric drill, it hammers rapidly while the bit is turning. (Note: By pushing the hammer drill firmly against your work, you can increase the hammering power and consequently the drilling speed.) Never use staples to attach cable to walls. The use of staples to secure cable does not conform to TIA/EIA-568A specification. Web Links Cabling Glossary Cable Termination and Installation 9.4 Structured Cable Run Installation 9.4.2 Mounting cable in raceway Instructor Note Raceway and gutter are introduced as two preferred ways of routing cable. However, this drives up cost as raceway can have considerable cost especially as your cable runs get long. In some areas of the world raceway is the only standards-compliant option. You can also route cable by mounting it in raceway. Raceway is a wall-mounted channel that has a removable cover. There are two types. decorative raceway - presents a more finished appearance. Decorative raceway is used to enclose cable on a wall inside a room where it might otherwise be visible. gutter raceway - a less attractive alternative to decorative raceway. Its primary advantage is that it is big enough to hold several cables. Generally, the use of gutter is restricted to spaces such as attics and spaces created by dropped ceilings. Raceway can be made of either plastic or metal, and can be mounted with adhesive backing or with screws. Can you think of a possible disadvantage of adhesive-backed raceway? Can you think of a possible advantage of adhesive-backed raceway? Disadvantages include: looks bad, can come loose or be pulled off, single use. Advantages include: easy to install, easy to remove. After you mount the raceway, lay the cable inside it, and attach the top. This will help to protect the cable. Web Links Cabling Glossary Cable Termination and Installation 9.4 Structured Cable Run Installation 9.4.3 Running cable through existing raceway Instructor Note There are generally two concerns with routing cable in existing raceway. First, is there room? The new bundle of cable you want to route in the raceway may exceed the capacity of the raceway. Second, it is preferabe not to route cable in a raceway with power wiring. This can potentially cause noise problems. You may already be familiar with raceway, since it is routinely used to hold other types of cable. It is not uncommon for raceway to exist in buildings where LANs are being installed or expanded. Because that is often the case, people often wonder if cable can be routed in existing raceway. The answer depends on the type of cables that are currently contained with the raceway. Can you think of any types of cable that you would not want to run next to CAT 5 UTP cable? This would include any type of power or electrical cable. Web Links Cabling Glossary Cable Termination and Installation 9.4 Structured Cable Run Installation 9.4.4 Personal safety precautions before installing cable Instructor Note Again, safety precautions are reviewed. Do not attempt cable installations until you have adequately trained and mature students and sufficient adult supervision. Cable installations can be incredibly fun and rewarding, but since they are essentially construction projects, there are many precautions that must be taken. Perhaps on the days you do your structured cabling project you could invite some parents to assist, some of whom may be employed in the electrical or construction trades. SAFETY RULESWhenever you work in walls, ceilings, or attics, the first thing you should do is turn off power to all circuits that might pass through those work areas! If you are not sure whether, or which, wires pass through the section of the building in which you are working, a good rule to follow is to shut off all power. Never, ever, touch power cables! even if you think you have cut all power to the area where you will be working, There is no way to know if they are "live". Before you begin work, learn the locations of all fire extinguishers in the area. Wear appropriate clothing. Long pants and sleeves help protect your arms and legs. Avoid wearing excessively loose or baggy clothing. If it is catches on something, you could be injured. If you anticipate working in a dropped ceiling area, survey the area. You can do this by lifting a few of the ceiling tiles and looking around. This will help you locate electrical conduit, air ducts, mechanical equipment, and anything that might possibly cause problems later.If you need to cut or saw, protect your eyes with safety glasses. It's also a good idea to wear safety glasses when you work in a crawl space or above a dropped ceiling. If something falls from above, or if you lean into anything in the dark, your eyes will be protected. Consult the building's maintenance engineer to find out if it there is asbestos, lead, or PCB where you will be working. If so, follow all government regulations in dealing with that material.Keep your work area orderly and neat. Do not leave tools lying in places where someone might trip over them. Use caution with tools that have long extension cords. Like tools, they are easy to trip over. Web Links Cabling Glossary Cable Termination and Installation 9.4 Structured Cable Run Installation 9.4.5 Building safety Instructor Note It is not only the individual who needs to take precautions to protect themselves and others. The building should also be considered. Always find out in advance what the local codes are. Some building codes may prohibit drilling or cutting holes in certain areas such as fire walls or ceilings. The site administrator or facility engineer will be able to help you determine which areas are off limits.When you install cable, if you find damaged insulation, do not run cable into that area. In some situations, if you drill through walls, you may have to fill holes completely with a non-combustible (meaning cannot catch on fire) patching compound. Again, the facility engineer will be able to help you identify where this will need to be done. Finally, if you find that you must route cable through spaces where air is circulated, you will need to use a fire-rated cable. Web Links Cabling Glossary Cable Termination and Installation 9.4 Structured Cable Run Installation 9.4.6 Supporting horizontal cabling Instructor Note Options for routing cable above dropped ceilings are discussed. The one unacceptable option is to simply lay the cable on top of the dropped ceiling. Many installers like to run cable in attics or dropped ceiling spaces because it is out of sight. When running cable in a dropped ceiling space, never lay the cable on top of the ceiling. You must provide some other means of support for the cable. As mentioned before, wall-mounted gutter offers one option for supporting the cable. Another option is to attach tie-wraps to the wires that suspend the dropped ceiling. If you use this option, string the cable from tie to tie. A third option for supporting the cable is to use a ladder rack. Ladder racks are hung from the ceiling and provide the best type of support for networking cable. Web Links Cabling Glossary Cable Termination and Installation 9.4 Structured Cable Run Installation 9.4.8 Fishing cable from above a wall Instructor Note Fishing cable through walls using fish tape is described. When you pull cable up through a wall - sometimes called fishing cable - you ordinarily work from an attic or dropped ceiling space. To fish cable through a wall:Locate the top plate of the wall, and drill a 19 mm hole through it. Slowly feed fish tape through the hole you drilled, down into the wall. Position another person (helper) next to the wall opening, below you. Tell your helper to signal you, and to grab the hooked end of the fish tape when it reaches the wall opening.Your helper should strip back about 25 mm of the jacket from CAT 5 UTP cable, and bend the wires around the hook of the fish tape, and use electrical tape to finish securing the cable. You can, then, pull the cable up through the wall to the wall plate. Be sure to leave enough excess cable at the jack end to reach the floor, and extend another 60-90 cm. Web Links Cabling Glossary Cable Termination and Installation 9.4 Structured Cable Run Installation 9.4.9 Fishing cable from below a wall Instructor Note Fishing cable from below a wall (as in the case of basement access) is described. When you run horizontal cabling in a building that has a basement, you can fish cable from there to the work areas on the first floor. To do this you must do the following:Drill a 3.2 mm hole, at an angle, through the floor, next to a baseboard. Push a coat hanger or stiff piece of wire into the hole to indicate the spot when you are in the basement. Go to the basement and locate the wire. Use a tape measure to mark a spot under the areas of the wall. This mark should be 57 mm from the hole. Drill a new hole in this spot. This hole should be 19 mm in diameter. Unlike the first hole that was drilled at an angle, drill this hole straight up through the subfloor and wall plate. Push the cable up through this second hole, to the wall opening where the work area outlet is to be located. Be sure to allow enough excess cable so that it can reach the floor and extend another 60-90 cm. Web Links Cabling Glossary Cable Termination and Installation
