Chapter 10 Cabling Rough-In

Chapter 10 Cabling Rough-In
Rough-in phase Rough-in support tools Horizontal cable installation Vertical cable installation Rough-in other cable types Firestop Overview Upgrades and retrofits Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Fundamentals of Voice and Data Cabling 1.2
Rough-in Steps Cable is pulled from staging area to another telecommunications rooms or work areas. In the work area, enough cable is pulled so that there is plenty to work with when terminating. At the telecommunications room, the cable is pulled until it reaches a termination device such as a punch-down block or patch panel. Each cable is labeled on both ends so it can be identified. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Types of Cable Installation Projects
New buildings under construction Older buildings that are vacant Older buildings that are currently in use In most cases, a new construction environment is less challenging than a remodeling project since there are fewer obstructions. Special planning is not usually required in this environment, since structures that will support cables and terminals are generally built as needed. Installing cabling in older buildings that are being remodeled can present challenges. If the remodeling takes place in an occupied building, accommodations must be made for the occupants, and the noise and mess made during the installation should be minimized. The work area must also be secured to protect the building’s occupants. It may be necessary to finish the job within a short timeframe in order to minimize the inconvenience to the building's occupants. Regardless of the type of installation project, proper planning is important before starting the rough-in process in all of these environments. Part of this planning is assembling the cable installation team and assigning their tasks. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Retrofit Installations
When working with older buildings, the cable installer should: Identify active circuits so as not to accidentally remove them. Remove abandoned cable to make room for new and future cabling. Plan the cut over process and notify building’s occupants when it will occur. Since the equipment used for pulling cable can pose a danger for both cable installers and onlookers, only members of the cable installation crew should be in the area. Pulling large cables with a capstan winch or cable pulling system creates a great deal of tension on the pulling rope. If this rope were to snap, someone in the area could be injured. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Safety Considerations
Ensure that only the cable installation crew are in the area where cable is being pulled. Warn the public that work is being performed in the area. Secure all equipment and materials to protect them and the public. Care must be taken to alert others in the building that work is taking place. In areas where there are a number of cable reels set up for a pulling operation, place traffic cones or warning tape around the area. This will let people know that they should avoid the area. It is often necessary to lay lengths of cable along a hallway prior to placing the cable in a raceway or above a ceiling. In this case, the cable should be laid along the wall rather than down the center of the hallway. Traffic cones can be used to direct people away from these cables to prevent them from tripping on them. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Rough-in Support Tools
Cable reels or boxes Cable trees, jack stands, and rollers Bullwheels and quadrant blocks Pulleys and swivels Kellem grips Raceways While network distribution cable comes on small reels or in boxes, backbone cable comes on large reels which require special equipment to support them, such as rollers or cable jacks. Backbone cables can range in count from 25 pairs to 2700 pairs. Cables sizes are often referred to as cable counts. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Cable Reel, Jack Stand, and Rollers
The cable reel is a large spool with cable spun around it. The cable unwinds from the reel with relative ease. When network distribution cable is installed, multiple cables are pulled in a bundle to information outlets or jacks. To set up multiple reels, a cable tree is used. A cable tree supports a number of small reels of cable. This allows the cable installer to pull multiple runs of cable simultaneously. Since all cables will terminate at the telecommunications room, a cable tree would be set up in the staging area. Cable jacks and reel rollers are designed for large reels holding backbone cabling. Since large reels are often too large and heavy to lift by hand, cable jacks provide the leverage that will allow two people to raise them. Once raised, the jacks allow the reel to rotate freely and safely during the pulling process. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Bullwheels and Quadrant Blocks
Bullwheels and quadrant blocks are two devices that are used when cable needs to make a turn of more than 45 degrees. They are used to maintain an arc or to change direction when a cable is fed into a backbone pathway. Bullwheels, in particular, are normally used to make the first or last turn in the path, but can be used to make an offset or turn in the center of the run. A bullwheel is a large diameter pulley that is used in a mechanical cable pulling process. A quadrant block is particularly useful for large and heavy backbone cabling. It is often used at the beginning of pulls to help guide the cable. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Horizontal cable installation
Horizontal cable installation is the process of installing network distribution cables and backbone cables horizontally. This includes cables in open ceilings, enclosed raceways, ladder racks, cable trays, and floor ducts. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Horizontal cable guidelines
Cables should always run parallel to walls. Cables should never be placed diagonally across a ceiling. When selecting the path for cabling, select the most direct path with the fewest number of turns. Do not have cables lying directly on top of ceiling tiles. Once the backbone cabling has been installed, network distribution cable must be installed. Network distribution cable provides users and devices with network connectivity from the backbone cabling. Generally, this type of distribution cable is from workstations back to the TRs where it is interconnected to the backbone cabling. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Cable Installation Without Support Structures
Ceiling tiles are removed along the route that the cable will be pulled. Permanent fasteners are mounted every meter and the temporary pulleys at intervals of approximately 3 m (9.8 feet). A pull rope is put in place across the ceiling. A meter of cable is pulled from each of the reels to form a bundle which is then taped together and to the pull rope. The cable bundle is now pulled from the far end. Pulling backbone cabling in an open ceiling also follows the same basic procedures as with horizontal cabling, with a few changes. When the staging area is first set up, cable jacks or a reel roller are used to handle the larger reel. Also, a large diameter pull rope is used due to the heavier cable. A bullwheel should also be used on the far side of the pull, since the installer will be pulling hard in a downward direction. It may also be necessary to use a quadrant block at the beginning side of the pull to help guide the cable. Extremely large cables will require the use of a winch or cable puller that must be securely fastened prior to pulling. This could include bolting it to structural building steel, or drilling holes and bolting it to the floor. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

An Open Space Pull Setup
An open space pull using pulleys and a bullwheel At least three people are needed on larger pulls. One person will be required to turn the reel while another will feed the cable up into the ceiling. Two or more installers may be needed to pull the cable on the other end. Pulling backbone cabling in an open ceiling also follows the same basic procedures as with horizontal cabling, with a few changes. When the staging area is first set up, cable jacks or a reel roller are used to handle the larger reel. Also, a large diameter pull rope is used due to the heavier cable. A bullwheel should also be used on the far side of the pull, since the installer will be pulling hard in a downward direction. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Pulling cable through a conduit
The conduit must be large enough to handle all of the cables that are being pulled. Conduits should never be filled to over 40 percent of their capacity. Cables are supported by the conduits or raceways so there is no need for other hardware. Generally accepted practices are that conduit runs will be no longer than 30 m (98 feet) without a pull box, and a run of conduit shall have no more than two 90-degree bends. Large cable pulls require long radius conduits for the bends. Getting pull rope into a long run of conduit can pose a problem. A specialized vacuum cleaner attachment can help with this. Special attachments for the vacuum can also allow the missile to be blown through the conduit. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Conduit Blowing System
A special foam rubber missile can be inserted into the conduit, with a light pull string tied to the missile. A high-powered vacuum cleaner, like those for commercial use, can draw the missile (with string attached) through an entire conduit run. For particularly difficult runs, one vacuum can be set up to blow on one end and another vacuum to draw on the other. Once the string has reached the other end of the conduit, it is used to pull the pull rope through the conduit. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Pulling Cable to the Jacks
If conduits are used to run behind the walls from the ceiling to the outlet boxes, a fish tape can be inserted into the outlet box at the end of the conduit and pushed up the conduit until it comes out into the open ceiling. If there are no conduits in the walls, the cable can be pulled behind the wall. First, a hole is cut into the drywall at the location of the jack. Care must be taken to avoid making the hole too large. Another hole is drilled into the top plate of the wall. This hole should be 1-2 cm ( in) in diameter. A fish tape is pushed down through the top hole, and the installer must try to find it at the lower hole. Once the end of the fish tape is captured at the outlet location, a pull string is tied to it. The fish tape is then pulled back up to the original location where the cables are tied to the pull string. Finally, the pull string is pulled down to the outlet location with the cables attached. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Pulling and fastening best practices
Ensure that if tie wraps are used, they should not be over tightened. Use hook and loop ties to prevent cables from being over-tightened and to provide a greater surface area to support the cable. Keep minimum bend radius in mind when using fasteners or pulling. Pull in a single smooth action. Pulling cable in conduit requires extra caution at the beginning of the pull. Extremely hard pulls around a 90-degree turn can cause cables to flatten. To avoid this, shorten the length of the pull and do it in stages. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Vertical pulls Risers are round holes in the floor, typically 10 cm (3.9 in.) in diameter, possibly with conduit sleeves installed. Vertical installations are generally done in conduits, in conduit sleeves through the floors, or in slots cut through the floor. A rectangular opening in the floor is often called a slot or a pipe chase. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Vertical pulls Vertical cable installation takes place either from an upper floor to a lower floor or from a lower floor to an upper floor. In most cases, pulling cables from an upper floor to a lower floor is easier since gravity assists in the effort and mechanical aids like winches or cable pullers are generally not needed. Since it is not always possible to bring large reels of cable to upper floors in a building, there are instances when vertical cables must be pulled from a lower floor. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Pull Cable From a Lower Floor
A winch or cable puller is required for this operation. It is absolutely essential that the cable puller be secured to a stationary part of the building. The pull should not be interrupted unless absolutely necessary. The pull rope and winch hold it in place until it is permanently fastened between floors. The cable reel is set up on reel jacks or a reel roller. (Note that the use of a reel brake is not essential when pulling in the upward direction.) A rope is then lowered from the winch to the bottom floor and attached to the end of the cable. Care must be taken with this attachment since this rope will bear the entire weight of the cable once it is pulled in place. If there is enough room in the floor openings, the rope can be tied directly to the cable with a series of half hitches. Cables can be ordered from the factory with a pulling eye installed, which is particularly useful for large heavy pulls. If this is not possible, a Kellem grip can be used. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Fastening Vertical Cables
While the winch or the reel brake supports the cable, the cable is gently lowered until it is supported by the grips. Vertical cables should be fastened at each floor. Strut systems, like Unistrut or the B-line, are sections of open face channel that can be cut to length. The channel or strut is fastened securely to the wall. The clamps are then inserted in the channel and tightened around the cable. Other support systems include friction clamps that are secured around the cable. The size of the clamp prevents it from falling through the opening in the floor. It is important to note that friction clamps or strut systems can cause sheath damage to large and heavy riser cables. They are not appropriate for bundles of network distribution cables. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Vertical Cabling Precautions
It is advisable to remove a small section of sheathing from the end of the cable and use that to wrap the sheath of the cable underneath the area that will be clamped. The winch must be secured properly and the pull rope should be in good condition. When lowering a cable to other floors, a properly functioning reel brake must always be used on the reel. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Tips for pulling vertical cable
Utilize a staging area that is close to the first 90 degree whenever possible. Use pulling lubricant for long difficult pulls to prevent damage to cables. Use a quadrant block at the beginning of the pull to help guide the cable. Orient the reel so that cable comes off of the top of the reel rather than from beneath it. Pull an additional piece of pull string with the cable for cables that may be needed later. If cable must be coiled on the floor for a secondary pull, coil the cable in a "figure 8" configuration to eliminate tangles when uncoiling. Use two safety cones or even buckets as guides for coiling the cable. Supporting cables vertically through multiple floors can be a challenge. Run a steel strand or messenger between the floors, and anchor it at both ends. Vertical cable runs can be tie wrapped to this steel strand for vertical support. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Fiber-Optic Cable Installation Considerations
A bend radius that is tighter than the manufacturers specifications could break the fibers or induce macro bends, which will increase the attenuation of the fiber. Fiber-optic cables require special care. The fibers within the cable are made of very thin strands of glass (125 microns) that are very fragile. Although the glass fibers have various coatings applied to them to give them flexibility and strength, they are still subject to damage. To strengthen the cables containing these glass fibers, strands of Kevlar or steel are added. Despite these additions, fiber-optic cables are still prone to damage during installation. Service loops are a couple of extra meters of cabling left coiled up inside the ceiling or other location. Service loops are generally not provided for copper cable installations, but are common in fiber-optic installations for both backbone and workstation pulls. Service loops for backbone cable can have as much as 20 feet of cable that is coiled and stored. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Aerial Cable Aerial cables should never be placed without a supporting structure unless they are specifically designed to support their own weight. Only cables specifically designed for outdoor installation should be used for the aerial. Indoor cables should never be placed outdoors. The shield on the aerial cable must also be bonded in a splice and grounded at the ends of the cable. The black polyethylene jacket on outdoor cables provides protection from harmful UV rays from the sun. PVC jacketed cables are only meant for indoor cables and will quickly deteriorate in an outdoor installation. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Direct-burial cable and underground cabling
Direct-burial cable is laid directly in the ground while underground cable is placed in buried conduits. Direct-burial cable is similar in construction to aerial cables. As with the aerial cable, both the direct burial and underground cables require lightening protection at the building entrances. When installing cable within buildings, follow all codes that pertain to the job site. Many countries have codes that require cable in some parts of buildings to be fire-resistant. In addition, there are regulations as to installation of this cable that must be followed. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Cables and Fire The choice of cabling materials and how they are installed can greatly affect how a fire moves through a building, the type of smoke and gasses emitted, and the speed at which the smoke and flames spread. Using plenum rated cables where required, minimizing penetrations through fire walls, and using proper firestopping when penetration is unavoidable can reduce and slow the spread of smoke and flames. Fire rated walls also limit the spread of flames from the area where a fire originates into areas that are not directly affected. If an area does catch fire, a fire rated wall will slow the spread of flames to new areas. These measures can protect building occupants and fire fighters from being exposed to toxic smoke as well as give them extra time to evacuate the building. Modern buildings depend on a system of firewalls and compartments, called fire separations, to delay the spread of fire and smoke. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

UL cable ratings for fiber-optic cable
OFC - General purpose conductive OFN - General purpose non-conductive OFNP - Plenum rated non-conductive OFCP - Plenum rated conductive OFNR - Riser rated non-conductive OFCR - Riser rated conductive Since many areas that contain cabling, such as a false ceiling, conduit, or heating duct, run from one end of a building to another, cabling that burns can quickly spread fire across the entire floor of a building or between floors. In addition, regular cable gives off poisonous fumes when burned, which can easily be spread throughout a building. Therefore, most countries have enacted cabling codes that require special types of cable be used for these areas. Since these areas are called plenum, the cabling type is called plenum cable. Plenum cable is designed to burn slowly and not produce toxic fumes. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Fire Walls When cable is to be pulled through a firewall, a hole must be drilled through the firewall. After the hole is drilled, the penetration is usually sleeved. After the cables have been pulled through the conduit, the conduit must be sealed with an approved firestop material. Penetrations can go all the way through the firewall, or can go through one side only. In this case, the penetration is called a membrane penetration. When cables are installed in an existing firewall penetration, the firestop material must be removed to clear space for the new cables. After the new cables have been pulled, the hole and conduits should be sealed with new firestop material. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Types of Firestop Systems
Elastomeric or flexible types of firestop systems are putties or caulks that are applied around the cable to fill any openings between the cable and the wall or the cable and the conduit. Mechanical firestops are generally used in conduit or floor sleeve applications. Cementatious firestop material is generally a dry powder that is mixed with water. Intumesant firestops expand when heated. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Firestop Material Traits
Ablative – This trait allows firestopping material to develop a tough charred surface where it is exposed to heat and flame. This gives it strength against the gas pressures of the fire. Endothermic – This trait allows a firestopping material to emit water vapor as it burns to cool the material prevent the transfer of heat to the far side of the firewall. Intumescent – Intumescent firestops swell up when heated in order to provide the greatest seal when it is needed the most. One additional element to most firestopping systems that involve using a sleeved conduit is mineral wool, or rock wool. This is a fireproof compound that has the appearance of fiberglass. Its function is to displace air from the inside of the sleeve, and to provide a physical barrier that can be inserted after the wires are routed through the conduit or sleeve. In horizontal penetrations, the rock wool is pushed into the middle of the conduit prior to covering the conduit ends with elastomeric putty. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Backfilling Backfilling is the placement of firestop solution products into the penetration after the cabling has been installed in the opening. All openings around a conduit and holes must be sealed completely. firestop pillows are designed to completely block any openings for ladder rack and cable tray wall penetrations. These pillows are removable and reusable. When additional cabling is to be added to a ladder rack penetration, the pillow is removed for cable placement. After the cables are placed, the pillow is again packed into place. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Outside plant (OSP) and aerial cables
When installing OSP or aerial cables: Check whether the cable must be installed in conduits or can be laid in an open trench. Lightning protection is required at building entrances. Those with a polyethylene jacket may not extend more than 15 m into a building, unless contained in a rigid conduit. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Identifying Active Circuits
Typical pieces of test equipment are a telephone test set and a digital multimeter. The telephone test set is used to check for dial tone on a specific cable. With the proper setting, the multimeter can be used to see if an AC outlet is active. When installing cables in an existing office or manufacturing environment, it is often necessary to identify active circuits. Circuits may have to be temporarily disconnected in the installation process. The customer should always be notified prior to disconnecting the circuit and then notified when the circuit is reconnected. It may also be necessary to clear space on an old termination block. Special care must be taken to avoid removing cross-connects from active circuits. Obtaining any network documentation the customer may have will help prevent accidental disconnects. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Cutting Over Guidelines
Keep detailed records of the installation. Test every cable that is installed. Develop accurate cut sheets. Schedule the cutover when it inconveniences the customer the least. Cutting over is the term used when transferring existing services to a new cable system or when installing new equipment on a newly installed cable system. Good cutovers require careful planning, organization, and meticulous attention to detail. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Removing Abandoned Cable
Before removing any abandoned cable, it must be verified that there are no live circuits on the cable. Care must be taken not to damage ceiling tiles or dropped ceiling support members. It is sometimes necessary to remove a working cable prior to the cutover to the new system. An existing cable may be occupying the space in a raceway that the new cable requires, so the existing cable must be removed. In this instance, the customer must be notified when this will take place. The old cable should be as close as possible to the raceway opening. Before it is pulled out of the raceway, the new cable should be attached to the end of the old, allowing the old cable to be used as a pull string to pull in the new cable. When the new cable is placed, it should be terminated and tested immediately, and all equipment should be reconnected. Copyright 2003 Fundamentals of Voice and Data Cabling 1.2

Chapter 10 Cabling Rough-In

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