Instruction Manual
POWERED BY
Appliance
KT71 / Portable
Tester
Tel:01494 792212
Instruction Manual
92-1890A
07-01
CONTENTS
1. Safe testing ………………………………………………………………… 1
2. Procedure of removing cover …………………………………………….. 3
2.1 Method of removing the cover ………………………………………... 3
2.2 Method of storing the cover …………………………………………... 3
3. Product summary and explanation ……………………………………… 4
3.1 Product summary …………………………………………………….... 4
3.2 Test function ……………………………………………………………. 5
3.3 Features ………………………………………………………………... 6
3.4 Instrument layout …………………………………………………….... 6
3.5 Explanation for indications ………………………………………….... 9
3.6 Applicable standards …………………………………………..…….. 10
4. Specification ………………………………………………………………. 11
4.1 General specification, measuring range and accuracy ………………… 11
4.2 Threshold and display ……………………………………………….. 12
4.3 Reference test condition …………………………………………….. 12
5. Preparation before a measurement …………………………………….. 13
5.1 Visual inspection ……………………………………………………… 13
5.2 Connection to main power supply ………………………………….. 13
5.2.1 Connection of mains cord ………………………………………. 13
5.2.2 Check the warning display of mains power voltage ………………… 14
5.2.3 Null setting (Protective conductor resistance function) ………………... 14
5.2.4 Voltage setting for insulation resistance measurement ………………... 16
6. Measuring method ……………………………………………………….. 17
6.1 Class I Test (Common function for both IT200mA and 20A) ……………..… 17
6.2 Class I Test (Select the leakage current test) …………………….. 19
6.3 Class Ⅱ Test ………………………………...……………………….. 21
6.4 Class Ⅱ Test (Select the leakage current test) …………………... 23
6.5 Extension Leads Test ………………………………………………... 25
6.6 Leakage Current Test ………………………………………………... 27
7. Fuse replacement ………………………………………………………… 29
8. Case and strap assembly ………………………………………………... 30
9. Maintenance …………………………………………………..…………... 30
Kewtech Corporation Ltd.
Midas House, Unit 2b
Stones Courtyard
High Street, Chesham
Buckinghamshire HP5 IDE
www.kewtechcorp.com
31
Electricity is dangerous and can cause injury and death. Always treat it
with the greatest of respect and care. If you are not quite sure how to
proceed, then stop, take advice from a qualified person.
This instruction manual contains warning and safety rules which must
be observed by the user to ensure safe operation of the instrument
and retain it in safe condition. Therefore, read through these operating
instructions before using the instrument.
IMPORTANT:
This instrument must only be used by a competent and trained person
and operated in strict accordance with these instructions.
KEWTECH will not accept liability for any damage or injury caused
by misuse or non-compliance with the instructions or with the safety
procedures.
It is essential to read and to understand the safety rules contained in
these instructions and with the safety procedures.
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
minor injury or instrument damage.
 DANGER
● This instrument can be connected only to the commercial
power of 230V+10%-10%, 50Hz.
● For safety reasons, only use the Test Leads designed to be
used with this instrument and recommended by KEWTECH.
● Use only grounded mains outlets to supply the instrument.
Do not touch the device under test whilst testing is in
progress.
1
1 Safe Testing
Safe Testing
 DANGER
● Since a high voltage of 500V is being output continuously,
when measuring insulation resistance, the user may get
an electrical shock. Any capacitors in the appliance under
test may become charged during testing and may contain
hazardous voltages do not touch them.
● When testing, always be sure to keep your fingers behind the
safety barriers on the test leads.
● Disconnect the instrument from the power supply when
measurement is finished.
● Do not leave the instrument with connected to the power
supply.
 WARNING
● Never open the instrument case – because dangerous voltages
are present. Only fully trained and competent electrical engineers
should open the case.
● If abnormal conditions of any sort are noted (such as a faulty
display, unexpected readings, broken case, cracked test leads,
etc) do not use the instrument and return it to your distributor
for inspection and repair.
● Never attempt to use the instrument if the instrument or your
hands are wet.
 CAUTION
● When using Test Leads with the crocodile clip, be sure to
check the crocodile clip is firmly connected to the metal part of
the device under test. Otherwise, inaccurate measurements or
arcing at the contacts may occur.
● The rated measuring voltage for the insulation test is 500V. DC.
If this voltage seems too high for the appliance under test
contact the appliance manufacturer for advice. The IEE Code
of Practice allows for a touch current test where an insulation
test cannot be carried out.
● When testing a faulty appliance, it may trip the circuit breaker
of main power supply during test and may cause interruption
of service. Be careful when the same main power supply is
used for PCs.
● We are not liable for loss of data on PC during testing with this
instrument. The appliance under test is powered on during
most tests, but please turn it to the OFF position after testing.
● Use a very slightly damp cloth for cleaning the instrument. Do
not use abrasives or solvents.
2
The KT71 has a dedicated cover to protect against an impact from the
outside and to prevent the fascia, the LCD, and the connector socket from
becoming dirty. The cover can be detached and put on the back side of
the main body during measurement.
2.1 Method of removing the cover
Fig.1
2.2 Method of storing the cover
Fig.2
3
2 Procedure
of removing
cover
3 Product
summary and
explanation
3.1 Product summary
The KT71 is a hand-held portable appliance tester, performing four
functions to ensure the Safety of Class I and Class II appliances.
Readings are displayed on a large liquid crystal display (LCD) below
which are four bicolour LEDs, which unambiguously display a pass or fail
indication for results dictated by the IEE Code of Practice.
This instrument is suitable for performing tests as required by the
following standard.
The IEE Code of Practice for In-service Inspection and Testing of
Electrical Equipment : 2003
This instrument is designed to check the electrical safety of appliances of
Class I and Class II categories.
As a guide the IEC standard define these two categories as follows:
Class I : Appliances which have a functional insulation throughout and
an earth connected case. These are often described as earthed
appliances.
Class II: Appliances which have both functional and additional insulation
where any metal parts cannot become“Live”under fault
conditions.
4
3.2 Test Function
KT71 has the following features.
Function
Tests of contents
Extension Lead Test
● Protective conductor resistance (Test
current 20A AC nominal)
● Insulation P/N-PE (Test voltage 250V DC
or 500V DC)
● Polarity (Test current 200mA DC nominal)
Class I Test IT200mA
● Protective conductor resistance (Test
current 200mA DC nominal)
● Insulation (Test voltage 250V DC or 500V
DC)
Select Switch
+ Class I Test IT200mA
● Protective conductor resistance (Test
current 200mA DC nominal)
● Load current and leakage current test
Class I Test 20A
● Protective conductor resistance (Test
current 20A AC nominal)
● Insulation (Test voltage 250V DC or 500V
DC)
Select Switch
+ Class I Test 20A
● Protective conductor resistance (Test
current 20A AC nominal)
● Load current and leakage current test
Class ll Test
● Insulation (Test voltage 250V DC or 500V
DC)
Select Switch
+ Class II Test
Leakage Current Test
● Load current and leakage current test
● Load current measurement (Maximum
appliance current 13A) and leakage
current test
5
Product
summary and
explanation
Product
summary and
explanation
3.3 Features
● Check for whether the appliance is switched ON.
● Selection for 250V or 500V on the insulation resistance test.
● Null function for the earth bond test lead.
● Warning for the over range value by the LCD.
● Capable of judging pass/fail of tests by LEDs on the panel and by a
buzzer.
3.4 Instrument layout
Fig.3
⑴ Test socket
Insert the mains plug of the appliance to be tested to this socket for
the protective conductor resistance, insulation resistance, leakage
current test and extension lead test.
⑵ Terminal block
Connect the supplied mains cord and Test Leads to this terminal block.
⑶ Terminal for mains lead
This terminal is connected to a mains supply via M-7209.
6
⑷ Terminal for Extension lead adaptor
For use with the KAMP S (UK) extension lead adaptor.
⑸ PE / Class II insulation probe
Connect the Test Lead with crocodile clip (M-7208) (fig 5) to this
terminal for the measurement of protective conductor resistance and
Class II insulation, and clip the metal parts of the appliance under test
with the crocodile clip.
⑹ LCD
Measured value is displayed
⑺ LED for test result
When the value of protective conductor resistance and insulation
resistance exceeds the limit dictated by applicable standards, LED
lights up in red. When it is within the limit, LED lights up in green.
⑻ Start/Stop switch
A measurement starts by pressing this switch.
Pressing the Start/Stop switch again during a Leakage Current Test
stops the measurements.
⑼ NULL/250V-500V switch
● The rotary dial has to be set to a Class l test for this button to be
used to zero out the test lead resistance.
● The rotary dial has to be set to Class ll for this button to be used to
select either 250 V or 500V test voltage.
⑽ Function switch
Select a function with this switch.
⑾ Select switch (Applicable for Class I and Class II function)
When the function is set at the same time as the Select switch is
being pressed, the leakage test will be conducted the insulation test.
⑿ Fuse
Protected by a 600V/10A ceramic fuse (F type Φ6.3x32mm).
User can replace this fuse.
7
Product
summary and
explanation
Product
summary and
explanation
⒀ Mains cord (UK) M-7209
This mains cord can be connected to the mains supply so that the
instrument can derive power from it. To measure contact current, the
socket of the mains power supply has to have an earth terminal.
Fig.4
⒁ Test Lead with safety crocodile clip(M-7208) and Probe with Blade type
Prod(M-7163). The probe and crocodile clip are interchangeable.
Please use it according to a measurement use.
Probe with Blade Type Prod
Fig.5
Crocodile Clip
⒂ Extension leads adaptor KAMP S (UK)
This is for connecting the instrument and an extension lead (cord
reel).
IEC Connector
Fig.6
8
3.5 Explanation for indications
LCD Display
Insulation measurement voltage
Product
summary and
explanation
Leakage current indication
Power supply voltage
(Live-Neutral) indication
Load current indication
Null indication
Unit indication
Over range display:“ >”is displayed on the LCD.
Fig.7
9
Product
summary and
explanation
List of display message
Displayed when appliance under test is
switched off.

=>
=>Value
Displayed when the protective conductor
resistance exceeds the threshold value. (*1)
=>
=>Value
Displayed when the insulation resistance
between LN-E is less than the threshold
value.
=>
=>Value
Displayed when the leakage current
exceeds the threshold value.
=>
=>Value
Displayed when the resistance between L-L
exceeds 10Ω at extension lead test.
=>
=>Value
Displayed when the resistance between
N-N exceeds 10Ω at extension lead test.
Displayed when the appliance under test is
undergoing the leakage current test.

or
Displayed when emergency stop is
operated at leakage current test.
Displayed when the mains voltage exceeds
the range of specifications (207V to 260V).
Testing will be diasabled.
(*1) Please note that the IEE Code of Practice states that the maximum
resistance should be no greater than 0.1 Ohms + the resistance of
the mains cable
3.6 Applicable standards
Instrument operation
The IEE Code of Practice for In-service Inspection and Testing of
Electrical Equipment : 2003
Safety
IEC/EN61010-1 CAT.III 300V-instrument
IEC/EN61010-031 CAT.III 300V(600V)-test lead
EMC
EN61326 (EN55022/EN61000-3,4)
10
4.1 General specification, measuring range and accuracy
Measurement of protective conductor resistance - RPE
Test function
IT 200mA continuity
20A continuity test
Measuring range
0 ~ 15.00Ω
Resolution
10mΩ
Open-circuit voltage
4 ~ 24V
Measuring current
200mA DC (nominal)
Accuracy
20A AC (nominal)
± (3%rdg+5dgt)
Measurement of insulation resistance - RINS
Output voltage
250V
500V
Measuring range
0.1~19.99MΩ
Resolution
10kΩ
Open-circuit voltage
250V (+30%/-0%)
500V (+30%/-0%)
Nominal current
1mA DC min. @250kΩ
1mA DC min. @500kΩ
Short-circuit current
2.5mA DC or less
Accuracy
± (2%rdg+3dgt)
Measurement of leakage current test (With load current test) –LEAK
Test function
Measuring range
Resolution
Accuracy
Examination time
Load current test
Leakage current test
AC0.1~ 13.00Arms
AC0.1~ 19.99mArms
10mA
10μA
±(10%rdg ± 5dgt)
±(3%rdg ± 5dgt)
Max 5 seconds
Max 10 seconds
Note: For MOV appliances use leakage current test.
11
4. Specification
Specification
4.2 Threshold and display
Function
Protective
conductor
resistance
Insulation
resistance
Leakage
current
Polarity
Extension Lead
RPE ≦ 0.1Ω
RINS ≧ 1MΩ
−
Cont ≦ 10Ω
Class I IT200mA
RPE ≦ 0.1Ω
RINS ≧ 1MΩ
LEAK ≦ 3.5mA
−
Class I 20A
RPE ≦ 0.1Ω
RINS ≧ 1MΩ
LEAK ≦ 3.5mA
−
Class ll
−
RINS ≧ 2MΩ
LEAK ≦ 0.25mA
−
Leakage Current
−
−
LEAK ≦ 0.75mA
−
4.3 Reference test condition
Unless otherwise specified, this specification is dependent on the
following conditions.
(1) Ambient temperature: 23±5˚C
(2) Relative humidity: 45 ~ 75%
(3) Attitude: Horizontal
(4) AC power supply: 230V, 50Hz
(5) Altitude up to 2000m, Indoor use
Operating temperature and humidity range
0℃ ~ +40℃ Relative humidity: 85% or less (no condensation)
Storage temperature and humidity range
-20℃ ~ +60℃ Relative humidity: 85% or less (no condensation)
Rate voltage and frequency
Rated voltage: 230V ±10%
Rated frequency: 50Hz ±1%
Maximum rated power
Load current at test socket: 3kVA(15sec.)
Other test function: Approx.9VA
Outer dimension and weight
Outer dimension: 185(L) × 167(W) × 89(D)mm
Weight: Approx. 1.3kg (Only the instrument body)
12
Specification
Symbols used on the instrument:
 Eq uipment protected throughout by DOUBLE INSULATION or
REINFORCED INSULATION
 Caution (Refer to the accompanying instruction manual)
5.1 Visual inspection
Before starting a measurement, the user should undertake visual
checks on the mains cord, case and that the correct type and rated fuse
is fitted to the appliance under test. There should also be no evidence
of damage of a nature that may impair the electrical safety of the
appliance.
5.2 Connection to main power supply
5.2.1 Connection of mains cord
Connect the mains supply and the instrument with M-7209 mains cord.
M-7209
Fig.8
 CAUTION
● Always be sure to check there are no abnormal conditions or
damage to the instrument and leads.
If any evidence of abnormality is found, measurement must be
stopped immediately.
● The outlet of the mains power supply must have an earth
terminal and be earthed.
● This instrument can be only connected to the commercial
power of 230V+10%-10%, 50Hz.
13
5. Preparation
before a
measurement
Preparation
before a
measurement
5.2.2 Check the warning display of mains power voltage
The warning device can work in any position of the function switch
of the instrument. When“Lo v”or“Hi v”is displayed on the LCD at
the time of the instrument connected with the mains power source, it
means the measurement can not proceed because the mains voltage
value of the instrument is out of the specific range. Do not connect the
instrument with the mains power until the cause is identified.
 WARNING
● When the voltage of mains power supply is 260V or more, “Hi
v”is displayed on the LCD.
● In that case, disconnect the mains cord of the instrument from
main power supply.
5.2.3 Null setting
The IEE Code of Practice pass level for protective conductor resistance
is 0.1Ω, which is a low value. So even the resistance of Test Leads will
affect the measurement result.
The KT71 can cancel the resistance of test lead by pressing
NULL|250V/500V . The procedure of Null setting is shown below.
The Null function is held in memory even when the instrument is turned
off, so there’s no need to Null the lead resistance every time.
However, when replacing fuses or test leads, it is recommended to do a
Null setting again.
Procedure:
(1) Set the function switch to Class I Test function. (Setting is possible
at both IT200mA and 20A.)
(2) Connect the mains supply and the instrument with the M-7209
mains cord.
14
Preparation
before a
measurement
Fig.9
(3) Insert Test Lead with probe (M-7208) in to the E terminal of the
instrument, and contact the tip of the Test Lead with the earth contacts
of the socket on the instrument.
Press the NULL|250V/500V switch whilst maintaining contact
between the Test Lead and the earth contacts of the socket, the
resistance of the Test Lead will be displayed on the LCD as shown in
fig.10 for 2sec.
Then, the instrument cancels the resistance value of Test Lead and
adjusts the displayed value to“0.00”as shown in fig.10.
The NULL icon is then displayed in the LCD.
Null setting cannot be done when the resistance is 3Ω or more.
A message“no”appears to indicate a resistance is exceeding the
Null setting range.
Display at Null setting
Fig.10
15
Preparation
before a
measurement
(4) Null setting can be released by pressing NULL|250V/500V switch
for 2sec. The NULL icon on the LCD will disappear when Null
setting is released.
The Null setting and release can only be done in a Class I Test
function.
 CAUTION
● Null setting can be set only with either Class I Test IT200mA or
Class I Test 20A selected.
● It is possible that there is a different setting value between
Class I Test IT200mA and Class I Test 20A.
5.2.4 Voltage setting for insulation resistance measurement
(How to change between 250V and 500V)
(1) Set the function switch to Class II Test function, and press the
NULL|250V/500V switch. The LCD display will change to indicate
the voltage selected. By pressing the NULL|250V/500V switch,
250V and 500V can be changed over.
Fig.11
16
6.1 Class l Test (Common function for both IT200mA and 20A)
The purpose of the test carried out for Class I appliances is to check
the resistance of earth continuity from exposed metal parts and the
plug is below a certain level and the insulation resistance between live
and neutral connected together and earth is below 1MΩ. To conduct
protective conductor resistance and insulation resistance tests on an
appliance, connect the mains plug of the appliance to the test socket (1)
described in clause 3.4 Instrument layout and the PE probe to terminal
(5).
Use the following setups, depending upon the type of appliance.

Connect to exposed metal parts but not
rotating parts or heating elements.

Switch ON the power.
Fig.12
17
6. Measuring
method
Measuring
method
Class I Test Flowchart
Start
(1). Protective conductor resistance.
No
RPE ≦ 0.1Ω ?
Lights up in red
”no” →“Con”→”value”
will be repeated on
the LCD.
(See note 1 below)
Yes
Lights up in green
Re-start
Can proceed to the next
step by pressing the Start
switch again even if the
result was a fail
(2).Appliance switch test
No ”oFF” →“ ? ” is displayed
alternately on the LCD.
Is the appliance
switched on?
Yes
Re-start
(3). Insulation resistance between L/N and PE.
No
LnE ≧ 1MΩ ?
”no” →“LnE”→”value”
will be repeated on the
LCD.
Yes
Lights up in green
Lights up in red
PASS
Value (1). and (3). will be alternately displayed on LCD
Note 1: The IEE Code of Practice states that the maximum resistance
should be no greater than 0.1 Ohms + the resistance of the mains cable.
Therefore if the appliance has a long mains lead then the allowable
resistance can be higher than the pre-programmed 0.1Ω.
18
 CAUTION
● If the Appliance switch test fails, displayed by“OFF”and“?”
appearing alternately on the LCD, and the appliance is actually
switched on there may be a direct short between L and N.
Suspend testing immediately.
● Follow the procedure described in 5.2.3 and undertake the Null
setting before a measurement.
● The crocodile clip must make good contact with the enclosure
of the appliance.
● When the terminal is open or the resistance value exceeds
measuring range,“>”mark (over range display) appears on the
LCD.
● Do not touch the appliance under test whilst testing is in
progress. Since a high voltage of 500V will be present and the
user may get an electrical shock.
6.2 Class I Test (Select the leakage current test) – common to both
IT200mA and 20A function
Turning the rotary dial to either“Class I Test”whilst the Select switch
is being pressed down initiates a leakage current test instead of the
Insulation resistance test.
When selecting the leakage current test, exposed metal parts other than
the heating or movable parts must be clipped with Test Lead M-7208
since the appliance will switch on and activate. Pressing the Start/Stop
switch during the leakage current test stops the test immediately. To
restart the test, press the Start/Stop switch again 2 sec after the test
has been stopped. Then (1) Protective conductor resistance will be
restarted. Fig 12 indicates how to connect the devices.
Refer to item 6.6 on details of Leakage Current Test
19
Measuring
method
Measuring
method
Class I Test (Select the Leakage Current Test) Flowchart
Start
(1). Protective conductor resistance.
No
RPE ≦ 0.1Ω ?
Lights up in red
”no” →“Con”→”value”
will be repeated on
the LCD.
(See note 1 below)
Yes
Lights up in green
Re-start
(2). Wait
Standby until Start switch is pressed
again whilst indicating
on the LCD.
(3). Appliance load current test.
5sec
Measures load current of the instrument.
(4). Power-on leakage current test.
10sec
Measures leakage current of the appliance.
LCD indicates
during the measurement.
No
LEA ≦ 3.5mA ?
Lights up in red
Stop the test and
”no” →“LEA”→”value”
will be repeated on the
LCD.
Yes
Lights up in green
PASS
Value of (1),(3) and (4) will be alternately displayed on the LCD.
Note 1: The IEE Code of Practice states that the maximum resistance
should be no greater than 0.1 Ohms + the resistance of the mains cable.
Therefore if the appliance has a long mains lead then the allowable
resistance can be higher than the pre-programmed 0.1Ω.
20
 CAUTION
● When the terminal is open or the resistance value, load current
and leakage current exceeds the measuring range,“ > ”(over
range display) appears on the LCD.
● If the test is stopped, a message“StP”appears on the LCD and
values of leakage current are not displayed.
 WARNING
● When conducting a leakage test the appliance will
automatically power on and will operate in its normal manner.
It is imperative that the appliance is secured safely before the
test is carried out. Extra care needs to taken with appliances
which have heating elements and rotating parts.
● Firmly insert the plug of the appliance to the socket of the
KT71. Plugs may get hot if leakage current test is performed
with improper connection.
● Do not connect/remove the plugs during leakage current test.
It may cause a reading error. Do not use the instrument on the
device which has a power consumption of 3kVA or more.
6.3 Class ll Test
The Class ll appliances have the indication of“DOUBLE INSULATION”
or the  symbol. The Class ll insulation test is to check the insulation
resistance of the appliances is within the range defined in the
standards.
21
Measuring
method
Measuring
method

Switch ON the power.

Connect to exposed
metal parts but not
rotating parts or
heating elements.
Fig.13
Class ll Test Flowchart
Start
(1). Appliance switch test
When the resistance
between L-N is about
No 100kΩ or more ”oFF” →
“ ? ” is displayed alternately on the LCD.
Re-start
Is the appliance
switched on?
Yes
(2). Insulation resistance between L/N and PE.
No
LnE ≧ 2MΩ ?
Lights up in red
”no” →“LnE”→ ”value”
will be repeated on the
LCD.
Yes
Lights up in green
PASS
Value of (2). will be displayed on the LCD.
22
 CAUTION
● If the Appliance switch test fails, displayed by“OFF”and“?”
appearing alternately on the LCD, and the appliance is actually
switched on there may be a direct short between L and N.
Suspend testing immediately.
● When the terminal is open or the resistance value exceeds the
measuring range,“ > ”mark (over range display) appears on
the LCD.
● Do not touch the appliance under test whilst testing is in
progress. Since a high voltage of 500V will be present and the
user may get an electrical shock.
6.4 Class ll Test (Select the leakage current test)
When turning the rotary dial to the Class II Test whilst pressing the
Select switch, power-on leakage current test will be carried out instead
of Insulation resistance test. When leakage current test is chosen,
the appliance will switch on and operate in its normal manner. When
connecting the test lead do not clip a metal a rotating part or heating
element with the Test Lead M-7208.
Refer to item 6.6 on details of Leakage Current Test
23
Measuring
method
Measuring
method
Class II Test (Select the Leakage Current Test) Flowchart
Start
(1). Wait
Standby until the Start switch is
pressed again whilst the flashing
icon is indicated.
(2). Appliance load current test.
5sec
Measures load current of the instrument.
(3). Power-on leakage current test.
10sec
Measures leakage current of the
appliance. LCD indicates
during the measurement.
No
LEA ≦ 0.25mA ?
Lights up in red
Stop the test and
”no” → “LEA” → ”value”
will be repeated on the
LCD.
Yes
Lights up in green
PASS
Value of (2) and (3) will be displayed on the LCD.
 CAUTION
● When load current exceeds 15A or leakage current exceeds
20mA,“ > ”(over range display) appears on the LCD.
● If the test is stopped, a message“StP”appears on the LCD and
values of leakage current are not displayed.
 WARNING
● When conducting a leakage test the appliance will
automatically power on and will operate in its normal manner.
It is imperative that the appliance is secured safely before the
test is carried out. Extra care needs to taken with appliances
which have heating elements and rotating parts.
● Firmly insert the plug of the appliance to the socket of the
KT71. Plugs may get hot if leakage current test is performed
with improper connection.
● Do not connect/remove the plugs during leakage current test.
It may cause a reading error. Do not use the instrument on the
device which has a power consumption of 3kVA or more.
24
6.5 Extension Leads Test
This test is for extension leads, and checks for;
● Protective conductor resistance between accessible conductive
parts and connection of protective earth.
● Insulation resistance between L/N and PE.
● Polarity check of the Live and Neutral terminal of plug and socket.
Test procedure and the connection are as follows.
Extension
leads adapter
KAMP S (UK)
M-7209
Fig.14
25
Measuring
method
Measuring
method
Extension Leads Test Flowchart
Start
(1). Protective conductor resistance test.
No
RPE ≦ 0.1Ω ?
Lights up in red
”no” → “Con” → ”value”
will be repeated on the
LCD.
(See note 1 below)
Re-start
Yes
Lights up in green
(2). Insulation resistance test between L/N and PE.
No
LnE ≧ 1MΩ?
Lights up in red
”no” →“LnE”→”value”
will be repeated on the
LCD.
Yes
Lights up in green
Re-start
(3). Polarity test between L-L and N-N.
No
L-L & N-N ≦ 10Ω?
Lights up in red
”no” → “L-L” → ”value”
or ”no” → ”n-n” → ”value”
will be repeated on the
PASS
LCD.
Value of (1) and (2) will be alternately displayed on LCD.
Yes
Note 1: The IEE Code of Practice states that the maximum resistance
should be no greater than 0.1 Ohms + the resistance of the mains cable.
Therefore if the appliance has a long mains lead then the allowable
resistance can be higher than the pre-programmed 0.1Ω.
26
 CAUTION
● Follow the procedure described in 5.2.3 and do Null setting
before a measurement, but use the short KAMP S lead instead
of the M-7208 test lead, by plugging the KAMP S. Into the
Extension Lead Adaptor terminal and the UK socket on the
front of the unit.
● When the terminal is open or the resistance value exceeds the
measuring range,“ > ”(over range display) appears on the
LCD.
● Do not touch the device under test whilst testing is in
progress. Since a high voltage of 500V will be present, the user
may get an electrical shock.
6.6 Leakage Current Test
This function is to conduct the leakage current test separately at mains
voltage, the appliance will be automatically switched on and power up in
its normal manner.
The leakage current test, measures load current of the instrument for
about 5 seconds, then measures leakage current for about 10 seconds
and both measured results are displayed. The KT71 can measure up to
20mA although the threshold value is 0.75mA in this function.
● Set the function switch to Leakage Current Test position.
● Refer to the Fig12 or Fig13 for connection of an appliance.
● After set up is done, press the Start/Stop switch. (Indicated by the
flashing
icon on the LCD at standby mode.)
● Check the switch of the appliance is ON.
● Press Start/Stop switch again.
● The appliance will operate for 15 seconds and indicate the final
values (value after 15 sec.) of load current and the maximum value
of leakage current.
27
Measuring
method
Measuring
method
Leakage Current Measurement Flowchart
Start
(1). Wait
Standby until Start switch is pressed
again whilst the flashing
icon is
indicated.
(2). Appliance load current test.
5sec
Measures load current of the instrument.
(3). Power-on leakage current test.
10sec
Measures leakage current of the
appliance. LCD indicates
during the measurement.
No
LEA ≦ 0.75mA ?
Lights up in red
Stop the test and
”no” → “LEA” → ”value”
will be repeated on the
LCD.
Yes
Lights up in green
PASS
Value of (2) and (3) will be displayed on the LCD.
- Remarks Stopping the Test
1) Emergency stop and restart manually for power-on leakage current
test:
In order to stop testing the leakage current whilst measuring, press
Start/Stop . To start a test again, press Start/Stop again after about
2 seconds or more from when the test has been stopped. The test will
restart.
2) Auto stop of power-on leakage current test:
The instrument stops measuring immediately when load current
exceeds 15A or leakage current exceeds 20mA (but more than 3.5mA
in Class I test function and more than 0.25mA in Class II test function).
28
 WARNING
● When conducting a leakage test the appliance will
automatically power on and will operate in its normal manner.
It is imperative that the appliance is secured safely before the
test is carried out. Extra care needs to taken with appliances
which have heating elements and rotating parts.
● Firmly insert the plug of the appliance to the socket of the
KT71. Plugs may get hot if leakage current test is performed
with improper connection.
● Do not connect/remove the plugs during leakage current test.
It may cause a reading error. Do not use the instrument on the
device which has a power consumption of 3kVA or more.
When the fuse blows during use, please replace with a new one
according to below procedure.
Fig.15
(1) Use a flat head screwdriver and turn about 45º to the left and remove
the fuse cap and fuse.
(2) Remove the fuse from the fuse cap and replace it with new one.
(3) Refitting is the reverse procedure.
29
Measuring
method
7. Fuse
replacement
Fuse
replacement
 WARNING
● Remove mains cord from the instrument before replacing the
fuse.
● This is the only user replaceable fuse. Never attempt to
perform any other repairs.
 CAUTION
● Please use the specified fuse (Fast acting type ceramic fuse:
600V/10A - Φ6.3x32mm).
8. Case and
strap
assembly
The strap and test lead case can be attached to the instrument as below.
Pass the strap belt down through the side panel of the main body from the
top, and up through the slots of the test lead case from the bottom. (Fig.
16).
Pass the strap through the buckle, adjust the strap for length and secure.
Fig.16
9. Maintenance
Use a very slightly damp cloth for cleaning the instrument. Do not use
abrasives or solvents.
30
CONTENTS
1. Safe testing ………………………………………………………………… 1
2. Procedure of removing cover …………………………………………….. 3
2.1 Method of removing the cover ………………………………………... 3
2.2 Method of storing the cover …………………………………………... 3
3. Product summary and explanation ……………………………………… 4
3.1 Product summary …………………………………………………….... 4
3.2 Test function ……………………………………………………………. 5
3.3 Features ………………………………………………………………... 6
3.4 Instrument layout …………………………………………………….... 6
3.5 Explanation for indications ………………………………………….... 9
3.6 Applicable standards …………………………………………..…….. 10
4. Specification ………………………………………………………………. 11
4.1 General specification, measuring range and accuracy ………………… 11
4.2 Threshold and display ……………………………………………….. 12
4.3 Reference test condition …………………………………………….. 12
5. Preparation before a measurement …………………………………….. 13
5.1 Visual inspection ……………………………………………………… 13
5.2 Connection to main power supply ………………………………….. 13
5.2.1 Connection of mains cord ………………………………………. 13
5.2.2 Check the warning display of mains power voltage ………………… 14
5.2.3 Null setting (Protective conductor resistance function) ………………... 14
5.2.4 Voltage setting for insulation resistance measurement ………………... 16
6. Measuring method ……………………………………………………….. 17
6.1 Class I Test (Common function for both IT200mA and 20A) ……………..… 17
6.2 Class I Test (Select the leakage current test) …………………….. 19
6.3 Class Ⅱ Test ………………………………...……………………….. 21
6.4 Class Ⅱ Test (Select the leakage current test) …………………... 23
6.5 Extension Leads Test ………………………………………………... 25
6.6 Leakage Current Test ………………………………………………... 27
7. Fuse replacement ………………………………………………………… 29
8. Case and strap assembly ………………………………………………... 30
9. Maintenance …………………………………………………..…………... 30
Kewtech Corporation Ltd.
Midas House, Unit 2b
Stones Courtyard
High Street, Chesham
Buckinghamshire HP5 IDE
www.kewtechcorp.com
31
POWERED BY
Appliance
KT71 / Portable
Tester
Tel:01494 792212
Instruction Manual
92-1890A
07-01
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