Kewtech KTD40 User Manual

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Operation overview
TheKTD40willtestforNo-triploop,HighcurrentTrueLoopImpedance,No-tripPFC/
PSC(ProspectiveFaultCurrent),HighcurrentPSCusingTrueLoopImpedance,mains
voltage(L-N,L-EandN-E)andcorrectsocketwiring,inadditiontotheincomingsupply
polaritycheckdescribedonthepreviouspage.
AnotheruniquefeatureofyourKTD40testeristhehighcurrent2-wiremeasurementof
theTLI(TrueLoopImpedance).Regulationsandguidancebooksrefertoloopimpedance
measurementsbutupuntilnowlooptestersmeasuredloopresistancewhichisdifferent
fromloopimpedance,particularlywhentestingclosetothemainsupplytransformer.
Thisfunctionisthereforerecommendedwhentestingforexternalearthfaultloop
impedance(Ze)atdistributionboardsonnonTTsystemsandsimilarpointsonthe
supplysideofanySwitch/RCDgearandwhentestingtheLine/Neutrallooptodetermine
prospectiveshortcircuitcurrent.
ItisthevariationinpowerfactorthatmakestheTLImeasurementofyourKTD40so
muchmoreaccuratethanolderlooptestingtechniques.(Becauseofthistheremaywell
bevariationsinreadingscomparedtoordinarylooptestersortheno-tripfunctionofthis
tester,particularlywhenthemeasurementismadeneartothemainsupplytransformer).
TheKTD40alsohasaNo-triptestmodethatisguaranteednottotripa30mAorhigher
ratedRCDprovidingthatthecircuitisotherwisehealthy.
No-trip vs High current testing
AlthoughtheKTD40HighcurrentTLImeasurementmodeisinherentlymoreaccurate
thanconventionaltechniqueswhenmeasuringclosetothemainsupplytransformer,the
differencebetweenresistanceandtrueimpedancereducesthefurtherawayfromthe
transformer the measurement is made.
ThisiswhyusingtheNo-tripmodeissuitableformeasurementonnalcircuitsand
similarlyremotepoints.ItshouldbenotedhoweverthatwhilstNo-triptestingatthese
locationswillnormallyfunctionatasimilarhighlevelofaccuracy,thelowcurrent
measurementtechniqueusedismorelikelytobeadverselyaffectedbyexternalfactors
suchascontactresistance(e.g.whentestingatseldomusedsocketoutlets)andcircuit
noise(e.g.switchedmodepowersupplyonthesamecircuit).Thiscanresultinthe
occasional erroneous reading.
Forthisreasonitisrecommendedthatmultiplemeasurementsaremadewhenusingthe
No-tripmodeandanyisolatedoddresultsareignored.Whentakingmultiplereadingsthe
testerorthesupplyshouldbepoweredoffbetweenconsecutivetests.Wherepractical
otherequipmentpoweredbythesamesocketshouldbeturnedoff.
ForsafetyreasonsNo-tripmodeisrecommendedforallmeasurementsmadeonTT
systems.
Test lead configuration
Important
TheKTD40canbeusedwith2differenttypesofconnectinglead.Itisimportantto
understandandusethecorrectleadcongurationforeachtestmodeoryoumaynot
obtainthecorrectresults.
Leadoptions
1 Ref:KAMP13 Themainslead(IECC13to13Aplug)typeconnectorthatis
supplied with the tester.
2 Ref:ACC016E The3-Polefuseddistributionboardtestleadsetwhichterminates
infusedprods/crocodileclips.Thisissuppliedasaseparateaccessorytothe
KTD40.
Theleadisanintegralpartofthetesterset-upandshouldaccompanythetesterwhen
beingreturnedforre-calibrationorservice.Donotuseanyothertypeofmainsleador
fusedtestleadsetasitwouldbelikelytogiveincorrectresults.
Lead configuration for No-trip testing
This is the default mode that the KTD40 will start in when turned on. This mode is most
usefulfortestingatsocketoutlets,luminaires,wiringterminals,etc.ininstallations
wherethecircuitundertestmaybeprotectedbyanRCD.
InNo-tripmodethetestercanbeusedwiththemainsleadwhentestingat13Asocket
outlets,orthedistributionboardleadsetfortestingatotherpointsinthecircuit.
WhentestingwiththeKTD40inNo-tripmodethe3colourcodedprods/crocodileclips
ofthetestleadshouldbeconnectedtothecorrespondingLine,NeutralandEarth
terminals.
Thismodecanbere-selectedatanytimebypressingbutton5labelled‘No-trip’.

Kewtech KTD40 Specifications

General

Brand	Kewtech
Model	KTD40
Category	Measuring Instruments
Language	English