Conduit and Trunking System

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Trade of Electrician

Standards Based Apprenticeship

Conduit and Trunking Systems

Phase 2

Module No. 2.

!nit No. 2..".

C#!$SE N#TES



Revision 1 April 2000

Created by Charlie Walsh - Athlone TC

Revised by:Charlie Walsh - Athlone TCEugene Trindles - Cork TC

Christy Ludlo - !undalk TC

Revision 2" #eb 200$ byChristy Ludlo % !undalk TC

Revision &" 'uly 200( byChristy Ludlo % !undalk TC

Revision )* +ove,ber 201&.LA

Co,plied by Lia, Carroll % Certi/iation tandards

Published by

27-33 Upper Baggot StreetDublin 4Ireland

© SOLS - 2!"3

All rights reserved" +o part o/ this publiation ,ay be reprodued* stored in a retrieval syste, or trans,itted in any /or, or by any ,eans* eletroni* ,ehanial* photoopying* reording or

otherise* ithout the prior per,ission o/ the opyright oner"



SOLS #le$tri$al %ourse &otes - Unit 2'3'"

Ta%le of Contents

STEEL TRUNKING.......................................................................................................................................4

T3E A+! 45E .# TEEL TR6+74+8""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""")AREA .# A33L4CAT4.+"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""(T3E .# 633.RT"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" """"""""""""""" """""""""""""""" """"""""""""""" """""""""""""""" (3AC4+8 .# 633.RT"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""10CA9LE CA3AC4T A+! 3ACE #ACT.R """""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""10#A9R4CAT4.+ A+! 4 +TALLAT4.+ .# TEE A+! 9E+!""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""10#.R4+8 A TEE '.4+T"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""11#.R4+8 A+ 4 +TER+AL 9E+!""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""12#.R4+8 A+ E;TER+AL 9E+!"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""1&#.R4+8 A #LAT 9E+!""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""1)EART<4+8 .# TEEL TR6+74+8"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""1=

OVERVIEW OF CONDUIT TYPES.........................................................................................................16

STEEL CONDUIT SYSTEM......................................................................................................................16

T3E A+! 45E .# TEEL C.+!64T"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""1>E!! C6RRE+T 4+ TEEL C.+!64T""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""1>

.E A!?A+TA8E .# TEEL C.+!64T""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""1>.E !4A!?A+TA8E .# TEEL C.+!64T """""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""1@CA9LE CA3AC4T .# TEEL C.+!64T 3ACE #ACT.R B """""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""1@C6TT4+8 TEEL C.+!64T""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""1@T<REA!4+8 TEEL C.+!64T""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""1$#4TT4+8 A+! #4;4+8 TEEL C.+!64T"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""1$3AC4+8 .# 633.RT #.R C.+!64T""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""1$A!!LE""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" """"""""""""""" """""""""""""""" """"""""""""""" """"""""" 1(!4TA+CE A!!LE """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""206LT43LE A!!LE """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""20TER4+AT4.+ .# TEEL C.+!64T T. E +CL.6RE """""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""21C.63L4+8 A+! ALE 96< ET<.!"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""21L.C7+6T A+! #EALE 9RA 96< ET<.!"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""21

8AL?A+4E! TEEL C.+!64T ACCE.R4E"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""22'.4+T4+8 TEEL C.+!64T""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""2&ETT4+8 63 E6E+CE .# A 9E+!4+8 AC<4+E """""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""2)9E+! <.6L! 9E #.RE! T. A+ 4+TER+AL RA!46 .# +.T LE T<A+ 2"= T4E T<E C.+!64T !4AETER 2=A74+8 A (0. 9E+! 4+ TEEL C.+!64T"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""2=A74+8 A !.69LE ET .R .##ET 4+ TEEL C.+!64T""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""2@#.R4+8 .# A &0D .##ET"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""2@#.R4+8 A )=D .##ET"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""2(A74+8 A A!!LE ET '63B 4+ TEEL C.+!64T """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""&0A74+8 A !.69LE (0. 9E+! 4+ TEEL C.+!64T""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""&&

PVC CONDUIT ............................................................................................................................................34

C.3.4T4.+ .# 3?C C.+!64T""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""&)C<.4CE .# 3?C C.+!64T """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""&)'.4+T4+8 3?C C.+!64T """""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""&)3RECA6T4.+ W<E+ 64+8 A!<E4?E """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""&)E;3A+4.+ .# 3?C C.+!64T""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""&)#4TT4+8 A+! #4;4+8 .# 3?C C.+!64T""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""&=A!?A+TA8E .# 3?C C.+!64T""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""&=!4A!?A+TA8E .# 3?C C.+!64T """""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""&=W.R74+8 W4T< 3?C C.+!64T """""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""&><.T 9E+!4+8 .# 3?C C.+!64T"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""&@

UNIT RELATED ETCI RULES................................................................................................................38

(e)ision 4* &o)e+ber 2!"3&




Steel Trunking

A trunking is an enlosure that provides /or the protetion o/ ables" 4t is nor,ally suare orretangular in ross setion* and has a re,ovable lid"

A trunking syste, o//ers great /leFibility hen used in onGuntion ith onduit syste,s"Trunking /or,s the bakbone or /ra,eork o/ an installation" Conduits run /ro, the trunking toaessory outlet boFes"

When an alteration or eFtension is reuired to an installation it is easy to drill a hole in the side o/the trunking and run a onduit to the ne aessory point" +e iring an then be dranthrough the ne onduit and the eFisting trunking to the supply point"

Types and Sizes of Steel Trunking

There are a nu,ber o/ types o/ steel trunking suh as:-

• Lighting Trunking

• Cable trunking

• ulti-Co,part,ent trunking

• 9us-bar Trunking

Typial sur/ae /inishes"

• <ot dipped galvanised oating• 8rey ena,el on Hin oating

• ilver ena,el on Hin oating

• tainless steel

Standad S!"#$ %& T'n(!n)

• =0,, F =0,, 1=0,, F @=,,

• @=,, F =0,, 1=0,, F 100,,• @=,, F @=,, 1=0,, F 1=0,,

• 100,, F =0,, 200,, F 100,,

• 100,, F @=,, 22=,, F 1=0,,

• 100,, F =0,, 2=0,, F 1=0,,

• 100,, F 100,, &00,, F 2=0,,

Trunking is generally supplied in & ,etre lengths" Lighting trunking is o/ten supplied in = ,etrelengths" .ther lengths are available on reuest"

(e)ision 4* &o)e+ber 2!"3)




L!)*t!n) T'n(!n)

teel trunking ,ay be used to install lu,inaires" This type has uik /it drive-in ouplings* hihallo /or /ast* easy installation o/ long runs" The trunking is installed ith the openingdonards as shon in #igure 1"

"

Trunking !rive-in oupling

&igure "

A range o/ /ittings is available to ao,,odate hanges in diretion* tees and intersetions"These are bolted in position using at least to bolts depending on trunking siHe"ee #igure 2

#lat 9end Tee

&igure 2

(e)ision 4* &o)e+ber 2!"3=




Cable retainers are used to prevent the ables /alling out o/ the trunking" peial attah,ents areused to /iF the lu,inaires to the trunking and also to allo the ables enter /or onnetion"ee #igure &

Cable Retainer Attah,ent

&igure

uspension brakets are used to suspend the trunking at the reuired height belo the eiling"

End aps and either steel or plasti lids are installed to o,plete the enlosure" The lid is si,plylipped into position"ee #igure )

uspension 9raket End Cap&igure '

(e)ision 4* &o)e+ber 2!"3>




Ca+,# T'n(!n)

tandard able trunking is si,ilar in design to lighting trunking" The lid in this ase is held in plae ith turnbukles" A uarter turn o/ a large /lat sredriver ill either /asten or loosen theturnbukle"ee #igure =

&igure (

A range o/ /ittings is available to ao,,odate hanges in diretion* tees* intersetions and toouple lengths together" These are bolted in position using at least to bolts depending ontrunking siHe"ee #igures >

#lat 9end 4nternal 9end EFternal 9end

Tee )=D 9end Coupling

&igure )

(e)ision 4* &o)e+ber 2!"3@




Changes in trunking siHe are si,ply ,ade by using reduers" Cables are easily kept in plae in thetrunking ith able retainers" End aps are used to o,plete the enlosure"ee #igure @

Reduer Cable Retainer End Cap

&igure *

M',t!-C%/at#nt t'n(!n)

The inreasing use o/ eletronis and di//ering voltage levels in industrial installations hasneessitated the use o/ ,ulti-o,part,ent trunking* hih is designed to segregate separate Bthe various voltages and servies"

egregation o/ this nature is a reuire,ent o/ the ETC4 Rules" #or eFa,ple* it prevents an eFtralo voltage syste,* o,ing into ontat ith a lo voltage syste, even in the event o/ a /ault"

#igure $ shos a typial setion o/ ,ulti-o,part,ent trunking"

&igure +

(e)ision 4* &o)e+ber 2!"3

23!-4!! ,%ables

%o+puter

%ables

Up to ! ,%ables

$




Areas of Application

teel trunking syste,s are used in o,,erial and industrial pre,ises" Lighting trunking isgenerally used to supply and support /luoresent /ittings* hih illu,inate large /loor areas"Cable trunking is installed at a suitable height around the alls o/ the building" Conduit drops are

then used to supply outlet points" ulti-o,part,ent trunking is used here di//erent eletrialservies are reuired in lose proFi,ity to eah other" 4t is ideal in large o//ies and lassroo,s"<ere it ,ay be used to ao,,odate ables /or supplying euip,ent at 2&0 ?olts* plus dataables /or o,puters* printers et" These supplies ,ust be segregated /ro, eah other"

Types of Support

Trunking should be seured by round-headed sres or bolts" This prevents da,age to ablesduring installations" 4n industrial installations* trunking ,ay be run overhead* supported atintervals by the loer ,e,bers o/ the roo/ trusses" 4t ,ay be suspended /ro, or /astened diretly

to right angle brakets" 4t ,ay also be /iFed diretly to a all sur/ae" #igure ( shos a nu,bero/ /iFings* hih ,ay be used to support trunking"

9ea, Cla,p ?ertial #lange <angers Channel spring +ut

&igure ,

#igure 10 shos a run o/ trunking supported by suspension brakets" The threaded rod alsoallos /or /inal height adGust,ent"

&igure "-

(e)ision 4* &o)e+ber 2!"3(




Spacing of Supports

The spaing o/ trunking supports is not a si,ple topi as there are so ,any variables suh as: -siHe o/ trunking* siHe and nu,ber o/ ables to be installed* type and strength o/ support available"<oever the /olloing table lists the a0!' distanes beteen supports /or steel trunking"

Maximum Support Spacing for Steel Trunking

Trunking Sie /oriontal 0ertical

! . ! "'7 2'!

7 . ! 3'! 3'!

Larger Si/es 3'! 3'!

Cable Capacity and Space Factor

Trunking is pri,arily intended /or the installation o/ 3?C insulated ables" The ,aFi,u,nu,ber o/ ables that an be installed in a trunking syste, is based on only )=I o/ the availablespae being oupied" This does n%t ,ean that the trunking should appear to be less than hal//ull o/ able" Re,e,ber that all the unoupied spae in beteen the ables is inluded in thealulation"The ,ain reason /or li,iting the nu,ber o/ ables to this level is to eli,inate proble,sassoiated ith an eFessive build up o/ heat inside the trunking" 4/ too ,any ables are installed

the able insulation ill su//er da,age due to overheating" There is also the possibility o/ /irerisk"The ETC4 Rules provides a handy guide to aid the alulation o/ the able apaity o/ trunking"4t allos /or a ,iFture o/ all the o,,on able siHes up to 10 ,,2" .ther able siHes have to beaounted /or on an individual basis" Re,e,ber that the overall able CA ,ust be used in thealulation not the CA o/ the ondutor alone B"4/ ,ulti-ore ables are to be installed in trunking the )=I spae /ator still applies* eFept in thease o/ %n# ,ulti-ore able %n,"

Fabrication and Installation of Tees and Bends

Tee and bends ,ay be /abriated here reuired in lengths o/ trunking" This ,ay be neessary orsi,ply ,ore onvenient* partiularly i/ the reuired bend or set is non-standard" 4t takes ,oreti,e to /abriate tees or bends than to bolt on ,anu/atured aessories"

N%t#-2 It !$ #%#nd#d t*at a 3 TPI *a($a5 +,ad# +# '$#d &% 'tt!n) $t##, t'n(!n).





Forming a Tee Joint

&igure ""





Forming an Internal Bend

&igure "2





Forming an xternal Bend

&igure "





Forming a Flat Bend

&igure "'





art!ing of Steel Trunking

A trunking installation ,ust be earthed" Earth ontinuity is ensured by the proper tightening o/all bolts used throughout the syste," o,e ,anu/atures reo,,end that earth ontinuity beo,pleted by /iFing a opper or alu,iniu, strap aross all Goints" 4t is ,ore i,portant that all the

bolts involved in the syste, are tightened" 4t is not unusual to /ind that opper or alu,iniu,straps are used* but are le/t loose* resulting in poor earth ontinuity" ee #igure 1="

Copper Earth trap

F!)'# 1.





#1er1ie of Conduit Types

A onduit is a tube* hannel or pipe in hih insulated ondutors are ontained" The onduit ine//et replaes the 3?C outer sheath o/ a able* providing ,ehanial protetion /or the

insulated ondutors" A onduit installation an be reired easily or altered at any ti,e and this/leFibility* oupled ith ,ehanial protetion* ,akes onduit installations popular /oro,,erial and industrial appliations"

EFa,ples o/ types o/ onduit used in eletrial installation ork are as /ollos :

• 3?C

• teel

• #leFible

• tainless teel

Steel Conduit System

Types and Sies of Steel Conduit

teel onduits are ,anu/atured to spei/iations de/ined by the 9ritish tandards 4nstitute 9B"

Class 4 conduit has a hot dip galvanized finish. It is of heavy gaugewith a welded seam. This conduit is suitable for use in external ordamp installations.This is the conduit most widely used in this country.

+ote: The galvaniHed /inish on onduit is to prevent the steel /ro, orroding innor,al use"

Also ,anu/atured is a solid dran sea,less onduit hih is ,ore eFpensive and only used /orspeial gas tight* eFplosion proo/ or /la,e proo/ installations"

Conduit is nor,ally supplied in & or &"@= ,etre lengths and typial onduit eFternal dia,etersare 1>* 20* 2= and &2,,"

Eddy Currents in Steel Conduit

etal onduits in hih a"" iruit iring is installed 6T ontain all the urrent arryingondutors o/ eah iruit in the sa,e onduit* to eli,inate the possibility o/ indued eddyurrents" Eddy urrents ould result in the ,etal onduit and ables beo,ing hot"

Some Ad1antages of Steel Conduit

• A//ords ables good ,ehanial protetion

• 3er,its easy reiring

• ini,ises /ire risks"

• Can be utiliHed as the Ciruit Protetive Condutor . CPC B





Some 3isad1antages of Steel Conduit

• 6nder ertain onditions ,oisture is liable to /or, on the inside all o/ the onduit"

• EFpensive o,pared ith so,e other iring syste,s"

• Liable to orrosion here subGet to aids* alkalis and orrosive /u,es"

Ca%le Capacity of Steel Conduit 4 Space &actor 5

<aving deter,ined the orret nu,ber and ross-setional area o/ ables /or a given load it isneessary to selet the siHe o/ onduit that ill ao,odate the,"

4/ a greater nu,ber o/ ables are installed in the onduit* over-heating* insulation da,age and/ire ,ay result" As a general rule the nu,ber o/ ables dran into a onduit should n%t be suhas to ause da,age to either the ables or the onduit during the installation"

The ,aFi,u, nu,ber o/ ables hih ,ay be dran into a onduit an be alulated by usingthe /ator syste, desribed in the ETC4 Rules"

Cutting Steel Conduit

Conduit should be ut ith a haksa* using a blade having &2 teeth J inh"

The ut should be ,ade at !)*t an),#$ to avoid di//iulty in threading the onduit"

#igure 1" illustrates this proess"

• <old onduit to be ut seurely in a pipe vie" Avoid da,age to the galvanised oating"

• tand suare to the Gob and ,ake sure your ,ove,ent is unobstruted"

•8rip the haksa lightly and apply light pressure on the /orard utting stroke" 6se the /ulllength o/ the blade"

F!)'# 1.





Threading Steel Conduit

4t is neessary to ut threads on the onduit ends in order to sre the, into onduit ouplingsand aessory boFes" The onduit ends are threaded using stoks and dies" A/ter threading theends* a,, !nt#na, +'$ '$t +# #%7#d to ensure that ables are not da,aged as they are

being dran into the onduits"

A,, t*#ad#d #nd$ '$t +# $#5#d '/ t!)*t, !nt% a#$$%!#$ t% #n$'# #at* %nt!n'!t.

• <old the onduit seurely in a pipe vie ensure that pipe vie Ga bolts are tight B"

• While threading keep the die well lubricated preferably with amanufacturer’s paste or tallow.

• Thread to reuired length and remove any burrs with a file or reamer!

this will prevent sharp edges causing damage to cables while beingdrawn into the conduit.

• To ensure a lean* unbroken thread the die should be rotated ounter-lokise /reuently

and /inally run up and don the threads to re,ove any sar/ ,etal /rag,ents B"

&itting and &i6ing Steel Conduit

Conduit ,ust be seurely /iFed and here it is liable to ,ehanial da,age* it should be suitably proteted"

!rainage outlets ,ust be provided at points here ondensation is likely to ollet"

Spacing of Supports for Conduits

The table belo shos a suggested spaing o/ supports /or steel onduits up to 2=,, in

dia,eter" upports should be positioned ithin &00,, o/ bends and /ittings" The table assu,esthat the onduit is not subGet to other eFternal ,ehanial stresses"

C%nd'!t S!"# +ot eFeeding 1>,,20-2=,,

%!"%nta, R'n$@=0,,1@=0,,

V#t!a, R'n$1000,,2000,,

(e)ision 4* &o)e+ber 2!"31$




Saddles

A range o/ lips and saddles are available /or onduit installations" The spaer bar saddle* is thedevie ,ost o,,only used /or /iFing onduit* see #igure 2" They provide a very seure ,ethodo/ /iFing and )#n#a,, should be spaed as per the table on the previous page"

F!)'# .

paer bar saddles inorporate a spaing plate" These spaing plates are approFi,ately =,,thik" This spaing plate tends to align the onduit ith the knokouts in sith and soketoutlet boFes" .n vertial runs ensure that saddles are /itted the orret ay round" An i,portant/untion o/ the spaer bar saddle is to keep the onduit out o/ ontat ith plaster and e,entsur/aes" Contat beteen onduit and these sur/aes ould result in orrosion o/ the onduitand disolour,ent o/ the sur/aes"

When a onduit is /iFed to onrete* ,uh installation ti,e is spent in plugging the onrete /or/iFings" paer bar saddles have the advantage o/ a entral* single-hole /iFing" The additionalost o/ spaer bar saddles over the plain saddle see #igure &"B an be o//set against the saving inti,e and e//ort reuired in /iFing"

F!)'# 3.





3istance Saddles

!istane saddles are designed to spae the onduit approFi,ately 10,, /ro, the all or eiling"These saddles are generally ,ade o/ ,alleable ast iron" They are ,uh ,ore substantial thanspaer bar saddles and the additional spaing provides greater protetion against orrosion" Theuse o/ distane saddles eli,inates the possibility o/ dust and dirt olleting behind the onduit"

9y adeuate spaing it is possible to keep the onduits /ree o/ dust and it is /or this reasondistane saddles #igure )AB and hospital saddles #igure )9B are generally spei/ied"

F!)'# 4A F!)'# 49

Multiple Saddles

Where to or ,ore onduits /ollo the sa,e route it is generally an advantage to use ,ultiplesaddles* see #igure =" 3roper spaing o/ the onduits ensures that there is no need to set theonduits here they enter onduit aessories

F!)'#





Termination of Steel Conduit to Enclosures

To ,ethods o/ ter,inating steel onduit are o,,only used"

• The oupling and ,ale bush ,ethod* see #igure >A 6sually used and pre/erredB

• The loknut and /e,ale bush ,ethod* see #igure >9 6sed here spae is tightB

Coupling and Male %ush Method

The oupling and ,ale bush ,ethod is slightly ,ore eFpensive than the loknut and /e,ale bush,ethod but it allos ,ore iring spae and is a stronger /or, o/ ter,ination" 6sing this ,ethoda oupling is sreed seurely on to a standard threaded onduit end and then butted against theaessory boF" A ,ale bush is passed through the boF entry and sreed tightly into theoupling using an open-ended spanner or a bushing spanner"

Male Brass Bush Conduit Coupling

Conduit Surface &inish $emo1ed

F!)'# 6A

7ocknut and &emale Brass Bush Method

6sing this ,ethod a loknut is sreed tightly onto a standard threaded onduit end and thethread passed through the hole in the aessory boF" A seond loknut is sreed onto theonduit e//etively sandihing the all o/ the boF" To prevent da,age to ables* /ro, theeFposed end o/ the onduit* a /e,ale bush is then sreed onto the onduit thread" .nedisadvantage in using this ,ethod o/ ter,inating a onduit to a sith or soket boF is that theonduit protrudes into the boF and ,ay inhibit the /iFing o/ the sith or soket"

&emale Brass Bush

7ocknut

7ocknut or lockring

Conduit

F!)'# 69

+ote: - These are earth ter,inations





8al1anised Steel Conduit Accessories

#igure @A illustrates a range o/ galvanised steel onduit boFes* reduers and adaptors"

# n d B o . 0 h r o u g h B o . n g l e B o . 0 e e B o . % r o s s B o .

0 a n g e n t 0 h r o u g h 0 a n g e n t n g l e 0 a n g e n t 0 e e 0 a n g e n t 1

U B o . B o .

B a $ # n t r y L o o p I n B o . e s

# . t e n s i o n 0 h r o u g h B o . ( e d u $ e r d a p t o r

F!)'# :A





9ointing Steel Conduit

Where to lengths o/ onduit are to be Goined a plain oupling is used" To ensure good eletrialontinuity and ,aFi,u, ,ehanial strength the tube ends ,ust tighten inside the ouplingaF gap 2 ,,B* see #igure @9" Care ,ust be eFerised to do this ithout leaving threadsoutside the oupling"

F!)'# :9

Where neither tube an be turned it is neessary to resort to the tehniue knon as the Krunningoupling * see #igure @C" A/ter tightening up the lokring the eFposed thread ,ust be painted

to prevent orrosion"

A 9

F!)'# :C





Setting up Se:uence of a Bending Machine

• 3lae the se,i-irular /or,er M9N to suit the siHe o/ onduit to be bentB in position and

seure the entre-pin* see #igure $"

B

#or,er

F!)'# 8.

• 3osition the stop MCN in the orret position /or siHe o/ onduit* see #igure ("

C

-top

F!)'# ;.

• 4nsert the grooved roller in the orret position /or siHe o/ onduit* see #igure 10"

A

F!)'# 1<.





9#nd!n) St##, C%nd'!t

The ,ost o,,on ,ethod o/ bending steel onduit is to use a bending ,ahine" <oever* /or bending &2,, dia,eter or larger onduits it is reo,,ended to use a portable rathet bender"The /olloing are the ,ain steps to be taken hen using a bending ,ahine"

• 4nsert the onduit under the stop and into the groove in the /or,er"

• 3ull don the handle* alloing the roller to bend the onduit around the /or,er"

• 6se a te,plate to o,pare the angle o/ the bend /or,ed ith the desired angle"

Bends should %e formed to an internal radius of not less than 2' ti+es theconduit diameter

Making a ,-o Bend in Steel Conduit

#igure 11 illustrates a right angle bend in steel onduit* hih ,ust be /or,ed to a di,ension o/200,,"

2--mm

F!)'# 11.

The /irst step is to ,ark o// 200,, /ro, the end o/ the onduit as illustrated in #igure 12"

Mark 2--mm from &i6ed Point

&i6ed Point Marked Point

F!)'# 1.





The neFt step is to plae the onduit in the /or,er ith the ,ark to the rear" 3osition the onduitso that a try-suare* held against the ,ark touhes and /or,s a tangent to the edge o/ the /or,eras illustrated in #igure 1&"

Stop

4i.edPoint

5ared Point

Bend do6n to 7! !

F!)'# 13.

+eFt pull the lever don until the (0D angle* is ahieved"





Making a 3ou%le Set or #ffset in Steel Conduit

+or,ally o//sets should be /or,ed at either &0D or )=D"

A &0D o//set is pre/erred /or to reasons:

• Ease o/ ,easure,ent"• Ease o/ draing-in ables"

&orming of a -; #ffset

#igure 1) illustrates a &0D o//set to be /or,ed in steel onduit" #ro, the illustration it an beseen that the &0D angle is one o/ three angles /or,ing a right angled triangle"

8! !

7! ! 3! ! "!!++

F!)'# 14.

A rule o/ thu,b /or a right angle triangle &0D* >0D* (0DB states that the relationship beteen the

three sides is in the ratio o/ 1:2:√&* see #igure 1="

2"

√ 3

F!)'# 1.

With this in/or,ation* one e kno the di,ension o/ the o//set 100,, in this aseB e an

no alulate and ,ark o// the distane beteen the to bends" At this point take the straight piee o/ onduit and ,ark on it here you ant the /irst bend to start /ro,* then ,easure200,, /ro, that point to here the seond bend starts* see #igure 1>"

" s t 2 n d

2 ! ! + +

F!)'# 16.





+o go to the bending ,ahine" ark a point on the /or,er as shon in #igure 1@" 3lae theonduit in the /or,er ,athing the /irst ,ark on the onduit ith the ,ark on the /or,er and

bend to &0D as shon in #igure 1$" +o re,ove the onduit and hek the o//set angle against a&0D te,plate"

9 : i n l i n e 6 i t h $ e n t r e o ; ; o r + e r <

F!)'# 1:.

" s t 2 n d

i r s t S e t

F!)'# 18.

3lae the onduit bak in the ,ahine pointing in the sa,e diretion as be/ore but inverted and,ath the seond ,ark on the onduit ith the ,ark on the /or,er* see #igure 1(" The seondo//set is no /or,ed until it is in parallel ith the /irst o//set"

S e $ o n d 5 a r

(e)ision 4* &o)e+ber 2!"32$




&orming a '(; #ffset

A )=D degree o//set is /or,ed in eFatly the sa,e ,anner as the &0D version eFept that the,easure,ents beteen the /irst and seond bends are alulated using the /olloing /or,ula

1:1:√2" #igure 20 illustrates the use o/ this /or,ula* in this ase √2 O1)1,, or 100 F √2 O

1)1,,"

"

"√ 2" ! ! + + "

4 "

+ +

F!)'# <.





Making a Saddle Set 49ump5 in Steel Conduit

Assu,e you are reuired to /or, a saddle set ith a learane o/ &0,, as illustrated in #igure21"

3!++

F!)'# 1.

The /irst step is to bend the onduit to an angle o/ )=D as shon in #igure 22"

4 - !

F!)'# .

The /olloing /or,ula ill help you alulate the position o/ the neFt to bends hih ,ust be /or,ed in order to ahieve the &0,, learane reuired"

ine o/ the Angle O .ppositeJ<ypotenuse

ine 22"= O &0J<ypothenuse<ypothenuse O &0Jine 22"=<ypothenuse O &0J"&$2@ ,,<ypothenuse O @$,,"

#igure 2& illustrates the appliation o/ the /or,ula"

2 2 ' - !

2 2 ' - !

1 y p o t e n

u s e

3 ! + +

F!)'# 3.

(e)ision 4* &o)e+ber 2!"3&0




ark the onduit as shon in #igure 2)"

5 a r 2 a t 7 = + +; r o + 5 a r "3 ! + +

3 2

"

5 a r " 0 h e $ e n t r e o ;

t h e e . i s t i n g 4 - ! b e n d

5 a r 3 a t 7 = + +; r o + 5 a r "

F!)'# 4.

arks 2 and & ,ay also be loated using a straight edge or other ,ethod"

3lae the onduit in the ,ahine so that ,ark 2 is opposite the eFisting ,ark on the /or,er* and bend donards as shon in #igure 2="

5 a r 2 o n $ o n d u i t

o r + e r 5 a r

5 a r 3

5 a r "

S e $ o n dS e t

F!)'#.





Reverse the onduit in the /or,er and ,ath ,ark & ith the eFisting /or,er ,ark" 9end donuntil the edges o/ the onduit are in line* see #igure 2>"

5 a r 3 o n $ o n d u i t

o r + e r 5 a r

F!)'# 6.





Making a 3ou%le ,-o Bend in Steel Conduit

easure,ents /or a double (0D bend in steel onduit an be taken using any o/ the three,ethods shon in #igure 2@"

C e n t r e t o C e n t r e

# u t s i d e t o <n s i d e

< n s i d e t o # u t s i d e

A l l a r e 2 - - m m

F!)'# :.

4/ you add the outside dia,eter o/ the onduit 20,,B to the entre to entre ,easur,ents200,,B e an no ,ark the position o/ the seond bend 220,,B* see #igure 2$" 9enddon until the (00 angle is ahieved"

2 2 ! + +

2 ! ! + + % e n t r e t o % e n t r e

F!)'# 8.

+ote: - The above ,ethods ,ay reuire adGust,ents due to ,anu/aturerNs toleranes and earin di//erent bending ,ahines

(e)ision 4* &o)e+ber 2!"3&&




P0C Conduit

Composition of P0C Conduit

The basi ,aterial is poly-vinyl-hloride 3?C B hih is produed in both /leFible and rigid/or,s" 4t is i,pervious to aids* alkalis* oil* aggressive soils* /ungi and bateria and is una//eted

by sea* and air" 4t ithstands all pests and does not attrat rodents"

3?C onduit ,ay be buried in li,e* onrete or plaster ithout har,/ul e//ets"

Choice of P0C Conduit

The hoie is dependant on the type o/ ork being undertaken and the Gob spei/iation"

• <eavy gauge round onduit is nor,ally used in sur/ae ork and /or /or,ing on-site"

• Light gauge round onduit is suitable /or onealed ork"

• .val onduit is nor,ally hosen /or use in plaster alls and an be used /or drops in sur/ae

ork"

Typial eletrial installations use a heavy guage standard i,pat tube ,anu/atured to 9 )>0@"The onduit siHes and range o/ /ittings are the sa,e as those available /or ,etal onduit"

9ointing P0C Conduit

3?C onduit is ,ost o/ten Gointed by plaing the end o/ the onduit into the appropriate /itting"'oints into aessories an be easily ,ade dry or by the use o/ silione grease or a per,anentsolvent* dependant on the installation onditions" The silione grease should be used /oreFpansion ouplings and here an installation ,ay be subGet to /uture alteration"

Precautions =hen !sing Adhesi1es

Care should be taken hen using adhesives* hih are pro-he,ial based* and as suh are uite/la,,able and volatile"

• Replae the lid on the tin i,,ediately a/ter use"

• 6se in a ventilated area aay /ro, naked /la,e"

• Und# n% !'$tan# $*%',d %' $%(# 5*!,# 5%(!n) 5!t* t*!$ ad*#$!7#.

• 4/ adhesive should get into your eyes* seek /irst-aid i,,ediately"

E6pansion of P0C Conduit

EFpansion ouplings should be used /or sur/ae installations at a reo,,ended ,aFi,u, o/ 4#t# intervals"

Where /reuent variations in a,bient te,perature are likely to our this distane ,ust begreatly redued"

N%t#2 3?C onduit is n%t suitable /or installations subGet to te,peratures belo -%C or above

6%C

(e)ision 4* &o)e+ber 2!"3&)




&itting and &i6ing of P0C Conduit

A range o/ /iFings /or 3?C onduit is available as shon in #igure 2("

# p e n S a d d l e S p a c e r B a r S a d d l e # 1 a l S t r a p S a d d l e

# 1 a l C l i p $ o u n d > ! > C l i p

F!)'# ;.

3?C onduit is /iFed in the sa,e ay as ,etal onduit" All horiHontal runs should be saddled atnot ,ore than ;<< intervals unless high a,bient te,peratures or rapid hanges inte,perature are likely to be enountered* hen the intervals should be redued"

?ertial runs should be saddled at not ,ore than 1<< intervals eFept here diretionalhanges are ,ade" addles should be installed approFi,ately 1< either side o/ a bend"Conduit should be able to ,ove /reely in the saddle"

Ad1antages of P0C Conduit

• Lighteight and easy to handle

• Easy to ut and deburr

• i,ple to /or, and bend

• !oes not reuire painting

• ini,al ondensation due to lo ther,al ondutivity in all o/ onduit"

• peed o/ installation

• EFellent eletrial and /ire resistant properties

3isad1antages of P0C Conduit

• Care ,ust be taken hen glueing Goints to avoid /or,ing a barrier aross the inside o/ the

onduit"

• 4/ insu//ient adhesive is used the Goints ,ay not be aterproo/"

• 3?C eFpands about = ti,es as ,uh as steel and this eFpansion ,ust be alloed /or"

• 3?C does not o//er the sa,e level o/ ,ehanial protetion as steel"

• A separate Ciruit 3rotetive Condutor ,ust be run inside the onduit"

(e)ision 4* &o)e+ber 2!"3&=




=orking ith P0C Conduit

3?C onduit is easily ut using a Gunior hak sa" Any roughness o/ ut and burrs should bere,oved ith the aid o/ kni/e blade or si,ply by iping ith a loth" There are proprietary toolsavailable /or utting 3?C onduit"

Cold bending o/ 3?C onduit ,ay be arried out on onduit siHes up to 2=,, dia,eter using a bending spring* see #igure &0" 4t is essential to use the orret siHe bending spring and it should be noted that springs /or heavy guage onduit are olour oded green and those /or light gaugeonduit are olour oded hite" T*# a# n%t !nt#*an)a+,#"4t is i,portant that the spring is not da,aged or kinked" A /aulty spring an ause the onduit tokink and /rature" The spring an also Ga, inside the bend"

The radius o/ the bends should be as near as possible to that o/ a si,ilar bend /or,ed in steelonduit o/ a si,ilar siHe"

F!)'# 3<.

<aving inserted the spring into the onduit* grip the onduit on either side o/ the proposed bendand bend the onduit $,%5,* as illustrated in #igure &1"

F!)'# 31.

(e)ision 4* &o)e+ber 2!"3&>




The onduit should be bent to a ,ore aute angle than the angle /inally desired beause o/ thetendeny o/ 3?C to Kreover a/ter bending" This tendeny lessens as the te,peraturedereases"

4n very old eather it is reo,,ended that the onduit is ar,ed slightly by rubbing ith aloth held in the hand" 4/ the onduit is bent too uikly there is a risk o/ kinking and J or

/raturing o/ the onduit and possible da,age to the bending spring"4/ the onduit is intended /or sur/ae ork it should be saddled and /iFed as soon as possiblea/ter bending" .ne a bend has been /or,ed it should not be /ored bakards as this anda,age both the onduit and the spring"

To re,ove the spring* tist it in an anti-lokise diretion" This ill redue the dia,eter o/ thespring and ,ake it possible to pull the onduit and spring apart" 4/ the spring Ga,s during thisoperation do not pull hard on it* otherise the spring ill be da,aged"

/ot Bending of P0C Conduit

<ot bending o/ onduit should be arried out on siHes over 2=,, dia,eter" A bending spring o/

the orret siHe should be used" Apply a gentle heat pre/errably ith a hot air torh* eletriheating ele,ent or hot ater" 9end the onduit in aordane ith above instrutions and #ig"&1"

Care should be taken to avoid the diret appliation o/ /la,e to the onduit" When the onduit isin a pliable state it should be sloly bent around a suitable /or,er and held in position /or aboutone ,inute until set" A/ter setting* the bending spring ,ay be tisted anti-lokise andre,oved"

(e)ision 4* &o)e+ber 2!"3&@




!nit $elated ETC< $ules

T/#$ %& W!!n) S$t# 1=21"=* =21"="1* =21"="2

=21">* =21">"1* =21">"2* =21">"& =21">")* =21">"==21"10

S#,#t!%n and E#t!%n !n R#,at!%n t%E0t#na, In&,'#n#$

=22"&"2=22"$"2* =22"$"=* =22"$">* =22"$"11

E,#t!a, C%nn#t!%n$ 6=2>"2"&=2>"&"&

S#,#t!%n and E#t!%n %& W!!n)S$t#$ t% !n!!$# t*# $/#ad %& F!#

:=2@"1"2* =2@"1"& ite, 2 B

=2@"2* =2@"2"1* =2@"2"2* =2@"2"&P#a't!%n$ a)a!n$t D#t!#nta, E&&#t$&% Ad=a#nt S#7!#$

8=2$"1* =2$"1"1 ite,s a* * and e

P%t#t!7# C%nd't%$ 43=)&"2"1 ite,s 2 and > B* =)&"2")

Ann#0 A9- ite, & B

Ta+,#$ UVW

>Y?

Documents

Conduit and Trunking System