Cisco Networking Academy ProgramCopyright 2003Fundamentals of Voice and Data Cabling 1.2 Chapter 10...

Copyright 2003 Fundamentals of Voice and Data Cabling 1.2 Cisco Networking Academy Program

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


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.


Types of Cable Installation Projects

• New buildings under construction• Older buildings that are vacant• Older buildings that are currently in use


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.


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.


Rough-in Support Tools

• Cable reels or boxes • Cable trees, jack stands, and rollers• Bullwheels and quadrant blocks• Pulleys and swivels• Kellem grips• Raceways


Cable Reel, Jack Stand, and Rollers


Bullwheels and Quadrant Blocks


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.


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.


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.


An Open Space Pull Setup

• An open space pull using pulleys and a bullwheel


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.


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.


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.


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.


Vertical pulls

• Risers are round holes in the floor, typically 10 cm (3.9 in.) in diameter, possibly with conduit sleeves installed.


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.


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.


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 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.


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.


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.


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.


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.


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.


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


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.


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.


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.


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.


Firewall


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.


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.


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.


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.

Cisco Networking Academy ProgramCopyright 2003Fundamentals of Voice and Data Cabling 1.2 Chapter 10...

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Transcript of Cisco Networking Academy ProgramCopyright 2003Fundamentals of Voice and Data Cabling 1.2 Chapter 10...