Kyoritsu Electrical Instruments Works, Ltd. KEW 4140 User manual

INSTRUCTION MANUAL
DIGITAL LOOP/PFC/PSC TESTER
ＫＥＷ 4140

CONTENTS
1.SafeTesting ･･･････････････････････････････････････････ 1
2.InstrumentsLayout･･････････････････････････････････････ 4
3.Accessories････････････････････････････････････････････ 7
4.Features･･･････････････････････････････････････････････ 8
5.Specification･･･････････････････････････････････････････ 9
5.1MeasurementSpecification･･････････････････････････ 9
5.2OperatingError････････････････････････････････････10
5.3GeneralSpecification･･････････････････････････････11
5.4AppliedStandards･････････････････････････････････11
6.PreparationforMeasurement････････････････････････････12
7.LOOP/PSC/PFCTest ･････････････････････････････････13
7.1
PrinciplesofMeasurementofFaultLoopImpedanceandPFC ･13
7.2
PrinciplesofMeasurementofLineImpedanceandPSC ･17
7.3OperatingInstructionsforLOOPandPSC/PFC･･･････18
7.3.1InitialChecks････････････････････････････････････18
7.3.2MeasurementOfLOOPAndPSC/PFC･････････････19
7.3.3ContentsonSubDisplay･･････････････････････････20
8.PhaseRotationTest･･･････････････････････････････････23
9.Volts･････････････････････････････････････････････････24
10.BackLight･･･････････････････････････････････････････24
11.Auto-Test････････････････････････････････････････････24
12.BatteryReplacement･･････････････････････････････････25
13.Servicing････････････････････････････････････････････26
14.CaseandStrapAssembly･････････････････････････････27
The KEW4140 incorporates Anti Trip Technology (ATT) which
electronically bypasses RCDs when performing loop impedance
tests.ThissavestimeandmoneybynothavingtotaketheRCD
outofthecircuitduringtestingandisasaferproceduretofollow.
WiththeATTfunctionenabled,atestof15mAorlessisapplied
betweenline&earth.
ItenablesloopimpedancemeasurementswithouttrippingRCDs
ratedat30mAandabove.
Please read this instruction manual carefully before using this
equipment.

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1. Safe Testing
#WARNING
●Read through and understand instructions contained in this
manualbeforestartingusingtheinstrument.
●Save and keep the manual handy to enable quick reference
whenevernecessary.
●Theinstrumentistobeusedonlyinitsintendedapplications.
●Understandandfollowallthesafetyinstructionscontainedinthe
manual.
Failure to follow the instructions may cause injury, instrument
damage and/or damage to equipment under test. Kyoritsu is by
nomeansliableforany damage resulting from the instrument in
contradictiontothiscautionarynote.
The symbol # indicated on the instrument means that the user
mustrefertotherelatedsectionsinthemanualforsafeoperationof
theinstrument.Besuretocarefullyreadinstructionsfollowingeach
symbol#inthismanual.
#DANGERisreservedforconditionsandactionsthatarelikely
tocauseseriousorfatalinjury.
#WARNINGisreservedforconditionsandactionsthatcan
causeseriousorfatalinjury.
#CAUTIONisreservedforconditionsandactionsthatcan
causeaminorinjuryorinstrumentdamage.
#DANGER
●This instrument is designed to work in distribution systems
wherethelinetoearthhasamaximumvoltageof300V50/60Hz
andforsomerangeswherelinetolinehasamaximumvoltage
of500V50/60Hz.
Besuretouseitwithinthisratedvoltage.
●When conducting tests do not touch any exposed metalwork
associated with the installation. Such metalwork may become
liveforthedurationofthetest.

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● For safety reasons only use accessories (test leads, probes,
cases, etc) designed to be used with this instrument and
recommended by KYORITSU. The use of other accessories is
prohibitedastheyareunlikelytohavethecorrectsafetyfeatures.
●Never open the battery compartment cover when making
measurement.
●Theinstrumentshouldbeused only initsintendedapplications
or conditions. Otherwise, safety functions equipped with the
instrument do not work, and instrument damage or serious
personalinjurymaybecaused.
●Keep your fingers and hands behind the protective fingerguard
duringmeasurement.
#WARNING
●
Never attempt to make any measurement, if the instrument has
any structural abnormality such as cracked case and exposed
metalpart.
●Iftheoverheat symbol appearsin thedisplaydisconnectthe
instrumentfromthemainssupplyandallowtocooldown.
●
Donotinstallsubstitutepartsormake anymodificationtothe
instrument. Return the instrument to Kyoritsu or your distributor
forrepairorre-calibration.
●Stopusing the test lead if the outer jacket is damaged and the
innermetalorcolorjacketisexposed.
●
Donottrytoreplacethebatteryifthesurfaceoftheinstrumentiswet.
●EnsurethattheTestLeadisdisconnectedfromtheobjectunder
test, and that the instrument is powered off when opening the
batterycompartmentcoverforbatteryorfusereplacement.
#CAUTION
●Donotexposetheinstrumenttothedirectsun,extreme
temperaturesordewfall.
●Besuretosetthefunctionselectorswitchtothe“OFF"position
afteruse.Whentheinstrumentwillnotbeinuseforalong
periodoftime,placeitinstorageafterremovingthebattery.
●Alwaysmakesuretoinserteachplugofthetestleadsfullyinto
theappropriateterminalontheinstrument.

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Measurementcategories(Over-voltagecategories)
To ensure safe operation of measuring instruments, IEC 61010
establishes safety standards for various electrical environments,
categorizedasOtoCATIV,andcalledmeasurementcategories.
Higher-numbered categories correspond to electrical environments
with greater momentary energy, so a measuring instrument
designed for CAT III environments can endure greater momentary
energythanonedesignedforCATII.
O :Circuits which are not directly connected to the mains
powersupply.
CATII :Primary electrical circuits of equipment connected to an
ACelectricaloutletbyapowercord.
CATIII :Primary electrical circuits of the equipment connected
directly to the distribution panel, and feeders from the
distributionpaneltooutlets.
CATIV :Thecircuitfromtheservicedroptotheserviceentrance,
and to the power meter and primary overcurrent
protectiondevice(distributionpanel).
O: Device which is
not directly
connected to the
mains power supply
●Duringtestingitispossiblethattheremaybeamomentary
degradationofthereading dueto thepresenceofexcessive
transientsordischargesontheelectricalsystemundertest.
Shouldthisbeobserved, the test must be repeated toobtaina
correctreading.Ifindoubt,contactyourdistributor.
●Useadampclothanddetergentforcleaningtheinstrument.Do
notuseabrasivesorsolvents.

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2. Instrument Layout
1.FrontView
Fig.2-1
Name Operation
①Display(LCD) --
②TestSwitch Startmeasurements.
③BackLightSwitch Switches on/off the Back light of
theDisplay(LCD)
④L-PEATTONSwitch Select“L-PEATTON”function
⑤L-PEATTOFFSwitch
Select“L-PEATTOFF”function
⑥L-N/L-LSwitch Select“L-N/L-L”Function
⑦DISPSwitch Change thecontentsonSub
Display
⑧
VOLTS/FREQUENCYSwitch Select"VOLTS/FREQUENCY" function
⑨PHASEROTATIONSwitch
Select"PHASEROTATION"function
⑩PowerSwitch PowerSwitch
(Pressdownforatleast1sec.)
④ ⑥ ⑤
①
②
③
⑦
⑧
⑨
⑩

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2.InputTerminal
Fig.2-2
①TerminalNamesfor:
LOOP,VOLTS
L:Line
PE:ProtectiveEarth
N:Neutral(forLOOP)
②TerminalNamefor L1:Line1
PHASEROTATION L2:Line2
L3:Line3
3.LCD
Fig.2-3
②
①
Sub Display
Main Display

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List of Display Message
Batterysymbol
Displayedwhenthemeasuredvaluesexceedthe
displayablerange.
(over-range)
e.g.Thedisplayshows“>1999Ω”ataLOOPtestwhen
atestresultexceeds1999Ω.
Displayedwhen “L-PEATTON” function is selected to
indicateATTison.
TheLCDindicates“L-PE”when“L-PEATTON”or
“ATT OFF” is selected and “L-N/L-L” when “L-N/L-L” is
selected.
IndicatingwhatthevaluesdisplayedontheSubDisplay.
Temperature monitor for internal resistance, available
atLoop,PSC/PFCfunction.Furthermeasurementsare
suspendeduntilthe“ ”symboldisappears.
Measuringsymbol(LOOPfunction)
L-N>20Ω Alert:Presenceof20ΩormorebetweenLine
‐
Neutralat
ATTONmeasurement
Caution:Presenceofnoiseinthecircuitundertest
duringATTmeasurement.ATTfunctionshouldbe
disabledtocontinuemeasurements.
nEHv
Caution:PresenceofhighvoltagebetweenNEUTRAL-
EARTHduringATTmeasurement.ATT function should
bedisabledtocontinuemeasurements.
WiringcheckforLOOPfunction
DisplayedatPHASEROTATIONcheck
Correctphasesequence:displayed mark.
Reversedphasesequence:displayed mark.
no
PHASE
ROTATION
Appears to indicate wrong connection
atPhaseRotationcheck.
LOOP WhenontheLOOPfunction,supply
mayhavebeeninterrupted.

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3. Accessories
1.MainTestLead(Model7218)
Fig.3-1
2.DistributionBoardTestLead(Model7246)
Fig.3-2
Protectivefingerguard
Itisapartprovidingprotectionagainstelectricalshockand
ensuringtheminimumrequiredairandcreepagedistances.
Whentheinstrumentandthetestleadarecombinedandusedtogether,
whicheverlowercategoryeitherofthembelongstowillbeapplied.
3.SoftCaseModel9156A…x1
4.StrapBeltModel9155……x1
5.Battery…x6

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4. Features
The KEW4140 LOOP/PFC/PSC tester performs three function in
oneinstrument.
1Loopimpedancetester
2Voltagetester
3Phaserotationtester
TheKEW4140havethefollowingfeatures:
ATT(AntiTripTechnology) ATTenables a measurement without
trippingtheRCDswiththerated
residualcurrentof30mAormore.
Wiringcheck ThreeWiringsymbolsindicateif
the wiring of the circuit under test is
correct.
Overtemperatureprotection Detectsoverheatingoftheinternal
resistor displaying a warning symbol
() and automatically halting further
measurements.
Autopoweroff Automaticallyswitchestheinstrument
offafteraperiodofapproximately10
minutes.
TheAutopoweroffmodecanonlybe
cancelledbyswitchingtheinstrument
onagain.
BackLight Poweredoffautomaticallywhen2
minpassafterthelastoperation.
SUBDisplay PFC,PSCandL-NLOOPresistance
values are also measured at LOOP
L-PE test and displayed on the Sub
Display.

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5. Specification
5.1 Measurement Specification
LoopImpedance
Function
(OperatingVoltage)
RatedVoltage
Range
(Auto-Ranging)
NominalTestCurrent
at0ΩExternalLoop:
Magnitude/Duration
(＊1)
Accuracy
GuaranteedVoltage
Range
L-PE
ATTOFF
(100〜280Ｖ)
(45〜65Hz)
230V(50／60Hz) L-PELOOP:
20Ω:0.00-19.99Ω
200Ω:20.0-199.9Ω
2000Ω:200-1999Ω
PFC/PSC:
2000A
：
0-1999A
20kA
：
2.00-19.99kA
L-PE:
20Ω
:
6A/20ms
200Ω
:
2.3A/20ms
2000Ω
:
15mA/250ms
L-N:
6A/20ms
±(3%rdg+4dgt)
(＊2)
230V(+10%/-15%)
(50/60Hz)±1%
ATTON
(100〜280Ｖ)
(45〜65Hz)
230V(50／60Hz) L-PELOOP:
20Ω:0.00-19.99Ω
200Ω:20.0-199.9Ω
2000Ω:200-1999Ω
PFC/PSC:
2000A
：
0-1999A
20kA
：
2.00-19.99kA
(L-N<20Ω)
L-N:6A/60ms
N-PE:10mA
/approx.5s
±(3%rdg+6dgt)
(＊2)
230V(+10%/-15%)
(50/60Hz)±1%
L-N/L-L
(100〜500Ｖ)
(45〜65Hz)
L-N
：
230V(50/60Hz)
L-L
：
400V(50/60Hz) L-N/L-LLOOP:
20Ω:0.00-19.99Ω
PSC:
2000A
：
0-1999A
20kA
：
2.00-19.99kA
20Ω:6A/20ms
L-N
：
±(3%rdg+4dgt)
L-L
：
±(3%rdg+8dgt)
(＊3)
L-N
：
230V(+10%／-15%)
L-L
：
400V(+10%／-15%)
(50／60Hz)±1%
＊1:at230V
＊2:AccuracyofL-NLOOPdisplayedontheSubDisplayis
synchronizedwiththeoneatL-N/L-Lfunction.
PSC/PFCAccuracyisderivedfrommeasuredloopimpedance
specificationandmeasuredvoltagespecification.
＊3:PSCAccuracyisderivedfrommeasuredloopimpedance
specificationandmeasuredvoltagespecification.

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PHASEROTATION
Rated
Voltage Remarks
50〜500V
45~65Hz
Correctphasesequence:displayed“1.2.3”and mark
Reversedphasesequence:displayed“3.2.1”and mark
Volts
Range DisplayRange Guaranteed
VoltageRange Accuracy
500V Volt：0 〜 525V
Frequency：40.0 〜 70.0Hz 25 〜 500Vrms 45 〜 65Hz Volt：±(2%rdg+4dgt) Frequency：±(0.5%rdg+2dgt)
Possiblenumberoftestswithfreshalkalinebatteries.
LOOP/PFC/PSC  :Approx.3000timesmin(ATT)
VOLT/PHASEROTATION :Approx.100H.
5.2 Operating error
LoopImpedance(EN61557-3)
FUNCTION Operatingrangecompliant
withEN61557-3operatingerror
Maximumpercentage
operatingerror
L-PE 0.40~1999Ω ±30%
L-N/L-L 0.40~19.99Ω
The influencing variations used for calculating the operating error
aredenotedasfollows;
Temperature :0℃and35℃
Phaseangle :Ataphaseangle0°to18°
Systemfrequency :49.5Hzto50.5Hz
Systemvoltage :230V+10%-15%
Supplyvoltage :6.8Vto10.35V
Harmonics :5%of3rdharmonicat0°phaseangle
5%of5thharmonicat180°phaseangle
5%of7thharmonicat0°phaseangle
D.Cquantity :0.5%ofthenominalvoltage

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5.3 General specification
Instrument dimensions 84X184X133mm
Instrument weight:- 860g(includingbatteries.)
Reference conditions Specificationsarebasedonthefollowing
conditionsexceptwhereotherwisestated:-
1.Ambienttemperature:23±5°C:
2.Relativehumidity45%to75%
3.Position:horizontal
4.ACpowersource230V,50Hz
5.DCpowersource:9.0V
6.Altitudeupto2000m,Indooruse
Battery type Six1.5VAAbatteries
Useofalkalinebatteries(LR6)is
recommended.
Operating temperature
and humidity.
-10to+50°C,relativehumidity85%orless,
nocondensation
Storage temperature
and humidity
-20to+60°C,relativehumidity75%orless,
nocondensation
5.4 Applied standards
Instrumentoperating IEC/EN61557-1,3,7,10
Standard
Safetystandard IEC/EN61010-1,61010-2-030
CATIII(300V)-Instrument
IEC/EN61010-031
CATII(250V)-TestLeadModel7218
CATIII(600V)-TestLead7246
Protectiondegree IEC60529IP54
EMC EN61326-1
RoHS EN50581
This manual and product may use the following symbols adopted
fromInternationalSafetyStandards;
EquipmentprotectedthroughoutbyDOUBLE
INSULATIONorREINFORCEDINSULATION;
#Caution(refertoaccompanyingdocuments)
EarthGround
Thisinstrumentsatisfiesthemarkingrequirement
definedintheWEEEDirective(2002/96/EC).This
symbol indicates separate collection for electrical and
electronicequipment.

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6. Preparation for Measurement
CheckofBatteryvoltage
(1)See“12.Batteryreplacement”andinstallbatteriesinKEW4140.
(2)PressthePowerswitchonKEW4140foratleast1sectopower
ontheinstrument.
*Powerswitchisactivatedonlywhentheswitchispressedfor1
secormore.
Presstheswitchforatleast1sectopowerofftheinstrument.
(3)Power on KEW4140 and check the Battery symbol displayed
at the upper left on the LCD. When the displayed battery level
is lowest ( ), the installed batteries will be exhausted soon.
Replacethebatterieswithreferenceto“12.Batteryreplacement”
tocontinuefurthertests.
WhentheBatterysymbolisempty( ),batterylevelis
lower than the lower limit of the working voltage. In this case,
accuraciesofthemeasuredvaluesaren’t assured. Replace the
batterieswithnewones.
TheemptyBatterysymbol( )isdisplayedandwarning
buzzer sounds for 2 sec when powering on the instrument with
exhaustedbatteries.
Batteriestobeused
Use of alkaline batteries is recommended. Battery level may not
berecognizedproperlywhenalkalinebatteriesaren’tused.

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7. LOOP/ PSC/PFC Test
7.1 Principles of measurement of fault loop impedance and PFC
If an electrical installation is protected by over-current protective
devicesincludingcircuitbreakersorfuses,theearthloop
impedanceshouldbemeasured.
In the event of a fault the earth fault loop impedance should be
lowenough(andtheprospectivefaultcurrenthighenough)to
allowautomaticdisconnectionoftheelectricalsupplybythecircuit
protectiondevicewithina prescribedtime interval.Everycircuit
mustbetestedtoensurethattheearthfaultloopimpedancevalue
does not exceed that specified or appropriate for the over-current
protectivedeviceinstalledinthecircuit.TheKEW4140takesa
current from the supply and measures the difference between the
unloadedandloadedsupplyvoltages. Fromthisdifferenceitis
possibletocalculatetheloopresistance.
TT System
ForaTTsystemtheearthfaultloopimpedanceisthesumofthe
followingimpedances;
●Impedanceofthepowertransformersecondarywinding.
●Impedanceofthephaseconductorresistancefromthepower
transformertothelocationofthefault.
●Theimpedanceoftheprotectiveconductorfromthefaultlocation
totheearthsystem.
●Resistanceofthelocalearthsystem(R).
●Resistanceofthepowertransformerearthsystem(Ro).
Thefigure belowshows(dottedline) theFaultloopimpedance for
TTsystems.
Fig.7-1

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AccordingtotheInternationalStandardIEC60364,forTTsystems
thecharacteristicsoftheprotectivedeviceandthecircuitresistance
shallfulfillthefollowingrequirements:
Ra x Ia ≤ 50V Where:
RaisthesumoftheresistancesinΩofthelocalearthsystemand
theprotectiveconductorfortheexposedconductiveparts.
50isthemaximumsafetytouchvoltagelimit(itcanbe25Vin
particularcaseslikeconstructionsites,agriculturalpremises,etc.).
Iaisthecurrentcausingtheautomaticdisconnectionofthe
protectivedevicewithinthemaximumdisconnectingtimesrequired
byIEC60364-41:
-200msforfinalcircuitsnotexceeding32A(at230/400VAC)
-1000 ms for distribution circuits and circuits over 32A (at 230 /
400VAC)
Thecompliancewiththeaboverulesshallbeverifiedby:
1)Measurement of the resistance Ra of the local earth system by
LooptesterorEarthtester.
2)Verificationof the characteristics and/or theeffectivenessof the
RCDassociatedprotectivedevice.
Generally in TT systems, RCDs shall be used as protective device
andinthiscase, Ia is the rated residual operating currentI△n.For
instanceinaTTsystemprotectedbyaRCDthemaxRavaluesare:
RatedresidualoperatingcurrentI△n 30 100 300 500 1000 (mA)
RA(withtouchvoltageof50V) 1667 500 167 100 50 (Ω)
RA(withtouchvoltageof25V) 833 250 83 50 25 (Ω)
Shown below is a practical example of verification of the protection by
RCDinaTTsystemaccordingtotheinternationalStandardIEC60364.
Fig7-2

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Forthisexamplethemaxpermissiblevalueis1667Ω(RCD=30mA
and contact voltage limit of 50 V). The instruments reads 12.74Ω,
thus the condition RA ≤ 50/Ia is respected. However, considering
that the RCD is essential for protection, it must be tested (Please
refertoRCDTESTSsection).
TN System
For TN systems the earth fault loop impedance is the sum of the
followingimpedances.
●Impedanceofthepowertransformersecondarywinding.
●Impedanceofthephaseconductorfromthepowertransformerto
thelocationofthefault.
●Impedance of the protective conductor from the fault location to
thepowertransformer.
Thefigure belowshows(dottedline) theFaultloopimpedance for
TNsystems.
Fig.7-3
AccordingtotheInternationalStandardIEC60364,forTN
system the characteristics of the protective device and the circuit
impedanceshallfulfillthefollowingrequirement:
Zs x Ia ≤ Uo Where:
ZsistheFaultloopimpedanceinohm.
Uo is the nominal voltage between phase to earth (typically 230V
ACforbothsinglephaseandthreephasecircuits).
Iaisthecurrentcausingtheautomaticdisconnectionofthe
protectivedevicewithinThemaximumdisconnectingtimesrequired
byIEC60364-41thatare:

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-400msforfinalcircuitsnotexceeding32A(at230/400VAC)
-5sfordistributioncircuitsandcircuitsover32A(at230/400VAC)
Thecompliancewiththeaboverulesshallbeverifiedby:
1)MeasurementofthefaultloopimpedanceZsbyLooptester.
2)Verificationof the characteristics and/or theeffectivenessof the
associatedprotectivedevice.Thisverificationshallbemade:
-forcircuit-breakersandfuses,byvisualinspection(i.e.shorttime
orinstantaneoustrippingsettingforcircuit-breakers,currentrating
andtypeforfuses);
-forRCDs,byvisualinspectionandtestusingRCDtesters
recommendingthatthedisconnectingtimesmentionedaboveare
met(PleaseseeRCDTESTsection).
ForinstanceinaTNsystemwithnominalmainsvoltageUo=230
VprotectedbyGeneralpurposegGfusesorMCBs(Miniature
CurrentBreakers)requiredbyIEC898/EN60898,theIaandmax
Zsvaluescouldbe:
ProtectionbygGfuses
withUoof230V
ProtectionbyMCBswithUoof230V
(Disconnectiontime0.4and5s)
Rating
(A)
Disconnection
time5s
Disconnection
time0.4s
Characteristic
B
Characteristic
C
Characteristic
D
la(A) Zs(Ω) la(A) Zs(Ω) la(A) Zs(Ω) la(A) Zs(Ω) la(A) Zs(Ω)
6 17 13.5 38 8.52 30 7.67 60 3.83 120 1.92
10 31 7.42 45 5.11 50 4.6 100 2.3 200 1.15
16 55 4.18 85 2.7 80 2.87 160 1.44 320 0.72
20 79 2.91 130 1.77 100 2.3 200 1.15 400 0.57
25 100 2.3 160 1.44 125 1.84 250 0.92 500 0.46
32 125 1.84 221 1.04 160 1.44 320 0.72 640 0.36
40 170 1.35 -- -- 200 1.15 400 0.57 800 0.29
50 221 1.04 -- -- 250 0.92 500 0.46 1000 0.23
63 280 0.82 -- -- 315 0.73 630 0.36 1260 0.18
80 403 0.57 -- --
100 548 0.42 -- --
ThemostcompletelooptestersorMultifunctiontestersalso
havetheProspectiveFaultcurrentmeasurement.Inthiscase,
ProspectiveFaultcurrentmeasuredwithInstrumentsmustbe
higherthanthetabulatedIaoftheprotectivedeviceconcerned.
BelowisapracticalexampleofverificationoftheprotectionbyMCB
inaTNsystemaccordingtotheinternationalStandardIEC60364.

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17
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Fig.7-4
MaxvalueofZsforthisexampleis1.44Ω(MCB16A,characteristic
C),theInstrumentreads1.14Ω(or202AonFaultcurrentrange)it
meansthattheConditionZsxIa≤Uoisrespected.
InfacttheZsof1.14Ωislessthan1.44Ω(ortheFaultcurrentof
202AismorethanIaof160A).
Inother words,incase offaultbetween phaseandearth, thewall
socket tested in This example is protected because the MCB will
tripwithinthedisconnectiontimerequired.
7.2 Principles of the measurement of line impedance and PSC
The method for measuring Line – neutral impedance and line-line
impedance is exactly the same as for earth fault loop impedance
measurement with the exception that the measurement is carried
outbetweenlineandneutralorlineandline.
Prospectiveshortcircuitorfaultcurrentatanypointwithinan
electricalinstallationisthecurrentthatwouldflowinthecircuitifno
circuit protection operated and a complete (very low impedance)
shortcircuit occurred.Thevalue of thisfaultcurrentis determined
bythesupplyvoltageandtheimpedanceof thepath takenbythe
faultcurrent.Measurementofprospective short circuit current can
beusedtocheckthattheprotectivedeviceswithinthesystemwill
operatewithinsafetylimitsandinaccordancewiththesafedesign
of the installation. The breaking current capacity of any installed
protectivedeviceshouldbealwayshigherthanthe prospective
shortcircuitcurrent.

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18
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Fig.7-5
7.3. Operating instructions for LOOP and PSC/PFC
7.3.1 Initial Checks: to be carried out before any testing
1. Preparation
Alwaysinspectyourtestinstrumentandleadaccessoriesfor
abnormalityordamage:IfabnormalconditionsexistDONOT
PROCEEDWITHTESTING.Havetheinstrumentcheckedby
yourdistributor.
(1)OperatethePowerswitchandturnontheinstrument.(Pressthe
Powerswitchforatleast1sec.)
Pressanyofthefollowingswitchestoselectafunction.
・
L-PEATTON:forLine–Earthloopimpedancetests(withATTon)
・L-PEATTOFF:forLine–Earthloopimpedancetests
・L-N/L-L:forline-neutralorline–lineloopimpedancetests
●ATT enables a measurement without tripping the RCDs with the
ratedresidualcurrentof30mAormore.
(2)InserttheTestLeadintotheinstrument.(Fig.7-6)
Fig.7-6
2. Wiring Check
Aftertheconnection,ensurethatthesymbolsforWiringcheckon
theLCDareinthestatusindicatedinFig.7-6beforepressingthe
testswitch.
If the status of the symbols for Wiring check differ from Fig.7-6