ELCM 254

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Cable Installation

©PRGodin @ gmail.com

Updated Jan 2014

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Cable Installation

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There are many situations and many methods for installing cable in a building.

This presentation will address a few basic installation issues.

Other issues, such as planning an installation, will be addressed at a later time.

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Measuring tapesquareSteel pull tape and

fish sticksDrillDrywall sawPencilOutlet bracketStud finderCamera

Toner/tracerBuilding planPull cordElectrical tapeMarker and masking

tapeCable greaseCable

support/payout reelCable gripsAir compressor, …

Cable installation requires many tools. Here are some typical tools and equipment for cable pulling:

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Basic Steps of Cable Installation

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Determine the destination of the cable.Determine the best pathway for the cable (often

this has been pre-determined)Use a fish tape, compressed air or other method

to install a pull string.Attach the appropriate number of cables to the

pull string using a method described by the manufacturer. Attach another pull string. Label the cable end and the spool.

Pull the cable using the pull string.Cut, label and record, leaving the extra pull

string in place.

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Cable Pulling

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Pull strings:For conduit and duct installations a string should be

pulled first.Lubrication (grease):

Cable lubrication may be required for conduit and duct.

Wheels and tension systems:Used for larger cables over longer distances

www.cable-lashers.com

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Installation Issues – Pull Strength

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Pull Strength: Maximum pull load on a cable. Measured in pound (lb) or Newtons (N).

Pull strength varies from cable to cable. The manufacturer’s specifications must be followed. Outdoor cable typically can handle much greater pull strength.Dynamic pull: During installationStatic load: After installation

The rule of thumb for 4pr UTP is 25 lbs, or about the strength of an arm without leaning the body.

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Pull Methods

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Methods of attachmentSimple attachment (bend and tape)Cable grips (“kellam” grip, “horse” grip)More complex (follow manufacturer instructions)

Layers include: Cable grip Tape Strength members Swivels and Break-away bolts Scales

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Pull Methods (Short Haul)

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Fishing:TapeSticksDrill bits with holes

Compressed Air and RatA plug or “rat” is tied to a pull string and placed in

a conduitCompressed air pushes the “rat” through the

conduitA “rat” is usually a piece of dry cloth

www.acehardware.com

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Pull Method (Ceilings)

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Ceilings and PlenumsString Toss MethodCable Casters

Special ConcernsCable support and suspensionRips, bends and kinksLadder and other Safety issues

Image: Greenlee

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Pull Methods (long haul)

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Long Distance (follow manufacturer recommendations)Pull to mid pointFigure 8 on ground. This virtually eliminates

torque on the cable.Pull next legAlternately, use mid-point pullers and pulleys

(specialized)

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Pull Methods (long haul)

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Outdoor issuesConduit/duct or direct burialInstallation equipmentCable locationAdministration issues (Right-of-Ways)

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Installation Issues – Cable Radius

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Bend radius: How much bend is permitted, measured from the center of the circle.

Bend radius is usually stated as a multiplier of the cable’s Outside Diameter (OD):Dynamic: During installation, usually the greater radius.

Typical is 20x the OD.Static: Once installed, usually the smaller radius. Typical is

15x the OD.

Cables also have a maximum cyclic flexing rating

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Installation Issues – Spools and Boxes

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Cables are supplied in boxes (such as UTP) or on a spool.

If the cable is not removed from the spool properly it may develop a serious torsion problem.

Cable must always be unspooled from a rotating spool (using a reel jack) and never from the end-face of the spool.

Unspool from the top of a rotating spool

Do not remove cable by the endface of the spool

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Installation Issues – Spools

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Great care must be employed when using cable spools.Strength members may cause the spool to unwind

itself. The cable end may strike someone with force (often in the face). Use a cable brake where required.

Spools are round and unstable. Use braking techniques for safety.

Reel Chocks In-Line Cable BrakeIntegrated Reel Brake

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Office issues

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Lighting and PowerPac polesUnder carpetHigh movement and vibration areasModular furnitureUser access ports

Planning to access the office spaceMoving about the office space

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Installation Issues: Crush resistance

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Cable may be damaged by weight from other cables or from traffic (foot, vehicular, etc). Performance degradation, physical damage and safety problems may occur.

Cables have crush and impact ratings, typically in ft-lbs or N-m.

Route the cable in a manner that avoids crushing“Pac poles”Underfloor systemsFloor racewaySpecialty configurations

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Installation Issues – Cable Supports

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Cables should not be laid directly on ceiling tiles. TIA/EIA 569 specifies 3in/75mm above the

ceiling tiles as a minimum.Cable supports must not distort the

cable’s shape or performance. Hooks: “J” hooks and support rings

Cable ties: Tie wraps should not be tight

www.mcwoods.com

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Installation Issues – Cable Supports

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Staples: Straight staples should never be used with cable. If staples are required use ones designed for cable.

Clamps: Cable clamps may be required for attaching to the ground of the cable. Follow manufacturer instructions.

Cable staple profile

Cable Shield Clamp (“Beaver

Clamp”)

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Installation Issues – Loops and Bends

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Service LoopsExtra length of cable that is left with the installation. This

is for cases where the cable needs future re-termination or splicing.

Drip BendsAn extra bend in the cable that creates a point on the cable

that is lower than the termination. Typically at the building entrance, drip bends keep fluids such as water from following the cable into the termination.

Termination Block

Drip Bend

Service Loop

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Wall and Room Issues

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Wallsgrommets and standoffsinsulation, inside and outside wallsfire walls and fire stopsdrilling and special drill bits

Roomsneatness versus efficiencyfuture additionselectrical devicescable weight and strain reliefBundling and service loops

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Firestopping

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Required to restore the integrity of fire-rated structures when they have been penetrated by cables and cable trays.

Although there are several mechanical and non-mechanical systems the most common for conduit is stuffing the aperture with ceramic/mineral wool and caulking both sides with fire resistant putty.

Firestopping is required by code.

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Firestop Cut-Away - Conduit

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Conduit

Firewall

Firewall

Firestop putty, caulking, mineral wool or other approved materials

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Firestop Cut-Away - Tray

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Firewall

Firewall

Tray

Firestop pillows, mineral wool or other approved materials

Cables

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Conduit

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Types include rigid/non-rigid, metal/non-metal

Fill rate (TIA 569) recommends approx. 40% max

No more than 2 x 90 degree bendsPull Boxes are required if

there are more.The bends must meet a

minimum bend radius.

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Conduit

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Installation methodsTapeStringusing existing cable to pull in a stringinstalling extra pull strings

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Tray, Duct, Raceway and Wireway

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TIA/EIA 569 specifies no more than 50% fill ratio in tray or wireway.

Images: legrand.com, panduit.com

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Installation Challenges

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Power cablesGroundingHeat and steam pipesBend radius at information outletBackboards and building entranceDirectional drilling and trenching

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Other Issues

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Communication between installersCable BundlesSlack and how it should be arrangedInstallation from top down in tall

buildingsShort runs and splicingEnvironmental issues

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Tips

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Use core of cable reel for tight cornersPulling multiple cablesWhen to make the room neatTesting and labelingLeaving pull stringsFun tips:

remote control truckfishing equipmentbaseballcompressed Air

WALL

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Planning

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schedule your time on the job siteplan for changeplan for quick fix and changesplan for adds, moves, changesdocumentation and planningservice loopsAdd the walls for length

More on installation planning later in this course.

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Identification of Cable

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TIA/EIA 606 standardlabeling and documentationAddressed later in this course

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From http://www.cablinginstall.com/ Aug2012. Images under CC license.

Before and after cable management.

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From http://www.cablinginstall.com/ Aug2012. Images under CC license.Before and after cable management.

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Extra Costs to Cabling InstallationUsing different manufacturers in an installation

may increase chances for technical performance, long term viability and supply chain problems.

Third-party verification may help ensure the installation has been done correctly.

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Safety

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LaddersEnvironment

Construction hazardselectricalmechanicalchemicalvehicles

Personnel hazardssecurityother safety concerns

End of presentation