CableGuide

TPC

MULTI-CONDUCTOR USERS HANDBOOK

There are many different types of Multi-Conductor cablesdesigned for a wide variety of applications. By definition,multi-conductor cables consist of two or more conductorsprimarily used for remote control, although power can beprovided in some applications.

Typical Multi-Conductor types are:

Small diameter Tray cables

High temperature Payout and retractile

Control Low temperature

The decision to use one type over another is dependentupon the application and the applicable codes.

Typical Multi-Conductor Applications include:

Forced Directional Reeling and Pulling applications

Bending applications such as Cat-Tracks

Robotic applicationsTwisting and Bending

Pendant ApplicationsPulling

General Guidelines for Cable Selectionand Installation:

1. DO NOT exceed the bend radius of the cable! 8-10 times the O.D. of the cable is an optimum bend radius.

2. DO NOT restrict the movement of the cable withwire ties or clamps.

3. Where possible, always use some type of Strain Relief.

4. ALWAYS use a cable with a reinforced jacket or strength member in reeling or pendant application.

5. Allow the cable to hang for 24 hours before installation

6. DO NOT confuse flex life with flexibility. A cablemay be very flexible but if it is not designed prop-erly for the application it may have a very shortflex life.

7. All things considered, use the smallest O.D. cable you can.

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ii) The primary symptom of too much tension on acable is called corkscrewing. This is characterizedby the conductors bunching or twisting under thejacket. In severe cases it is possible for the conductors to punch through the jacket. This condition will ultimately result in cable failure.

iii) The lower the reeling tension, the longer the cablelife, all other things being equal.

d) Reeling Speed and Temperature

i) Reeling speed and temperature are not as controllable as drum size and reel tension. If thereeling speed and/or temperature are extreme in any way, other considerations must be applied. Acold weather application might call for a larger drum diameter, whereas a high temperature may dictate a larger AWG size to reduce inner conductor temperatures.

ii) In general, the slower the reeling speed and/or thewarmer the temperature, the longer the cable life.

iii) Cable speed normally should not exceed 400 feetper minute.

Product Application GuideForced Directional Reelingis the single toughest applicationfor a multi-conductor cable. This application places tremendousstresses on the jacket and conductors. If the correct cable is notused and installed properly, the cable will quickly begin to corkscrew and ultimately fail.

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Application

Any type of reelingapplication where thecable is being pulled.

Cable DesignCharacteristics

Typically these cables have the following design characteristics: Reinforced jacket or

Strength member. Hard Durometer jacket. Constructed on a Planetary Cabler

to eliminate conductor stress. Conductor insulation

has a very low coefficient of frictionallowing the conductors to slide freely withinthe conductor jacket.

A short lay lengthA shorter laylength is preferred for bending applications.

These cables typically fail when the jacket begins to stretch because of thepulling tension. When the jacket beginsto stretch, the conductors are pulled outof their lay within the cable, and the cablebegins to corkscrew. When the jackethas stretched enough, the conductorsbegin bearing the weight of the pull tension. At this point the individual conductors begin to work harden and fail.

Installation Keys

Use a cable with a reinforced jacket orstrength member.

Do not exceedthe cables rated pull tension.

Do not exceedthe cables bend radius.

Use a MeshStrain relief atboth ends of the cable. Thiswill help spreadthe load on thejacket, helpingto prevent jacket stretch.

Engineered for maintenance to reduce usageand eliminate costly repairs and downtimethrough performance

Bending applications such as Cat-TracksConstant bendingapplications such as cat-tracks are abusive on multi-conductorcables because of both the bend radius of the application andthe repetition of the motion. This application places stresses onthe conductors as they are forced to move with the bend. If thecorrect cable is not used and installed properly, the conductorswill begin to quickly work harden and break.

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Application

Any type of bendingapplication, such asa cat-track.

Where there is aconstant bendingmotion but no directpulling of the cable.

Cable DesignCharacteristics

Typically these cables have the following design characteristics: Smaller Overall cable OD

is preferred. Reinforcement of the jacket

is not necessary. Softer jacket with a lower

Durometer. Constructed on a Planetary Cabler

to eliminate conductor stress. Conductor insulation that has a

very low coefficient of frictionallowing the conductors to slidefreely within the conductor jacket.

The construction cannot have a single center conductor or drain wire.

A short lay lengthA shorter laylength is preferred for bendingapplications.

Cables typically fail in bending applicationsfor two reasons: the movement of the cableis restricted or the bend radius is too smallfor the cable.

Wire tying the cables to the cable tray or toeach other restricts constricts the movementof the conductors within the jacket, resultingin premature conductor failure. Using toosmall a bend radius causes the conductorsto be overstressed, resulting in work hardening of the conductors and ultimatelyconductor failure.

Installation Keys

Allow the cableto hang freelyfor 24 hours so that anytensions frombeing storedon a reel arereleased.

Do not exceedthe cablesbend radius.

Use a MeshStrain relief atboth ends ofthe cable. Thiswill helpspread theload on thejacket, helpingto prevent jacket stretch.

b) Bend Radius See bend radius calculations for

Cat-Track Applications.

c) Cable Tensioni) Cable tension plays a very important role in

determining cable life in reeling and pendant applications. The copper conductors are the principal strength members in flexible cable construction. The following chart can be used as a guide in determining the proper cable tension and to prevent the cable from being overstressed.

Do not exceed 2.3 pounds per MCM times the number of conductors

Complete range of product sizes cut to order

Cable Size Maximum Continuous Cable Size Maximum ContinuousAWG/Cond. Tension in Lbs. AWG Cond. Tension in Lbs.

20/2 20/1 pr 5 16/30 17720/6 20/3 pr 16 16/31 18020/12 20/6 pr 33 16/36 21220/18 20/9 pr 49 16/41 239

20/24 20/12 pr 65 16/60 350

18/2 18/1 pr 10 14/6 5618/6 18/3 pr 25 14/7 6518/12 18/6 pr 51 14/8 7518/18 18/9 pr 76 14/10 9318/24 18/12 pr 102 14/12 112

16/6 35 14/16 15016/7 41 14/20 18716/8 47 14/24 22416/10 59 12/6 8916/12 71 12/8 11916/16 94 12/12 17916/20 118 12/16 23816/22 128 12/20 29716/24 141 12/30 446

c) Bend Radiusi) The minimum

cable-bendingradius for Cat-Tracks or Reelsis calculated as 8 times the cableO.D. Therefore, aSuper-Trex P&R cable with an O.D. of 1.61" wouldrequire a minimum Cat-Track radius of 8 x 1.61" or 12.88".

ii) The minimum cable bending O.D. for Cat-Track orReels is calculated as 16 times the cable O.D.Therefore a Super-Trex P&R cable with an O.D. of1.61" would require a minimum Cat-Track or ReelDiameter of 16" x 1.61" or 25.76".

iii) Ideally, the larger the radius or O.D. of the bend, thelonger the cable life.

2) Reeling and Pendant Applicationsa) Cable Preparation

i) As in the case with rolling up a garden hose, reelingcable is best done with the natural set of the cable.The natural set occurs during the manufacturing ofthe cable. The cable is curved in one direction witha definite tendency to be reeled one way as opposedto another. The cable must be put on the reel usingits natural set with care exercised not to have thereel oppose the natural set.

ii) Ideally the cable should be pre-cut and hung suspended for 24 hours to develop its most naturalset prior to installation.

iii) Measure off the cable and cut to the desired length.The length should allow for the Cat-Track length plusextra for routing and termination.

Robotic ApplicationsThese types of applications expose thecable to both bending and twisting motions. This is one of thetougher applications for a cable since the cable is moving inmultiple axes. This type of motion requires a cable design similar to the cat-track cable but with a modified lay length toaccommodate the twisting motion.

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Application

Roboticwhere there is a constantbending and twistingof the cable.

No direct pulling ofthe cable.

Cable DesignCharacteristics

Typically these cables have the following design characteristics: Smaller Overall cable OD

is preferred. Reinforcement of the jacket

is not necessary. Often has a softer jacket with a

lower Durometer.Allows the cableto bend more freely.

Constructed on a Planetary Cablerto eliminate conductor stress.

Conductor insulation has a verylow coefficient of frictionallowingthe conductors to slide freely within the conductor jacket.

The construction cannot have a single center conductor or drain wire.

A medium lay lengthA shorter laylength is preferred for bendingapplications, A longer lay length ispreferred for twisting applications.

These cables typically fail because: The cable bend exceeds the cable

designthis is typically an equipment design flaw.

The cable was tied down with wireties. If applied too tightly, wire tiescan constrict the movement of theconductors within the jacket causing work hardening of the conductors and failure.

Installation Keys

Allow the cableto hang freelyfor 24 hours sothat any tensions frombeing stored on a reel arereleased.

Use a cable with a smalloverall OD.

Do not exceedthe cables bendradius.

Use a MeshStrain relief atboth ends of the cable. Thiswill help spreadthe load on thejacket, helpingto prevent jacket stretch.

Continual research and development

Pendant ApplicationsThese applications appear to be a verylight duty application for a cable but in reality can be one of themost abusive. The cables are typically hanging from a junctionbox 15-20 up. They have a pendant box on the end that mayweight 5-10lbs. They have an operator pulling on the pendantbox adding another 20-30lbs of force to cable. This applicationplaces tremendous stresses on the jacket and conductors. If thecorrect cable is not used and installed properly, the cable willquickly begin to cork screw and ultimately fail.

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All configurations

Application

Any type of reeling applicationwhere the cable isbeing pulled.

Pendant applicationswhere the weight of the cable and orthe pendant box can cause the cable jacket topotentially stretch

Cable DesignCharacteristics

Typically these cables have the following design characteristics:

Reinforced jacket or Strength member

Hard Durometer jacketConstructed on a Planetary

Cabler to eliminate conductor stress.

Conductor insulation has avery low coefficient of frictionallowing the conductors to slide freely within the conductor jacket.

A short lay lengthA shorter lay length is preferred for bending applications.

These cables typically fail when the jacketbegins to stretch because of the pulling ten-sion. When the jacket begins to stretch, theconductors are pulled out of their lay withinthe cable, and the cable begins to corkscrew.When the jacket has stretched enough, theconductors begin bearing the weight of thepull tension. At this point the individual conductors begin to work harden and fail.

Installation Keys

Use a cablewith a reinforcedjacket orstrength member.

Do not exceedthe cablesrated pull tension.

Do not exceedthe cablesbend radius

Use a MeshStrain relief atboth ends ofthe cable. Thiswill help spreadthe load on thejacket, helpingto prevent jacket stretch.

INSTALLATION GUIDE

1) Cat-Track Applicationsa) Cable Preparation

i) Before installing cables in a Cat-Track, allow thecable to relax from the memory induced by beingtightly wound onto the shipping reel. To relax thecable, we recommend that it be hung for a period of24 hours prior to installation.

ii) Measure off the cable and cut to the desired length.The length should allow for the Cat-Track length plusextra for routing and termination.

b) Tensioning And Spacingi) Cables are not to be pulled taught nor should any

slack be present in the cable. The ideal installationshould be stress free where the track and cablemove, as one.

ii) Lay out the carrier with the bending direction facingupward. Do not weave the cables between andaround other cables, using separators between them.Spacing between cables should be 5 10% of thecable diameter.

iii) The cable must lay loosely side by side and must beable to move freely in the cable carrier. Cableweight must beevenly distributedwith the heaviercables placedtowards the out-side of the carrier.

iv) Do not attachcables to eachother or to thecable carrier.

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TPC-313 (REV. 10/00) PRINTED IN U.S.A. All rights reserved. No portion of this publication, whether in whole or in part, can be

reproduced without the express written consent of Premier Farnell, LLC.Copyright 2000 by Premier Farnell, LLC

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