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
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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.
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Types of Cable Installation Projects
• New buildings under construction
• Older buildings that are vacant
• Older buildings that are currently in use
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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.
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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.
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Rough-in Support Tools
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Cable reels or boxes
Cable trees, jack stands, and rollers
Bullwheels and quadrant blocks
Pulleys and swivels
Kellem grips
Raceways
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Cable Reel, Jack Stand, and Rollers
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Bullwheels and Quadrant Blocks
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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.
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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.
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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.
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An Open Space Pull Setup
• An open space pull using
pulleys and a bullwheel
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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.
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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.
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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.
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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.
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Vertical pulls
• Risers are round holes in the floor, typically
10 cm (3.9 in.) in diameter, possibly with
conduit sleeves installed.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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UL cable ratings for fiber-optic cable
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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
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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.
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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.
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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.
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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.
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Firewall
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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.
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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.
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Cutting Over Guidelines
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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.
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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.
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