Kewtech KT72 User manual

KT72
PAT TESTER WITH AUTO
TEST SEQUENCES
•Performs Earth bond at 200mA at both +ve and -ve
polarities (IT appliance safe)
•250V / 500V insulation test voltages
•Substitute leakage tests
•Single rotary dial position initiates test sequence
•Class I IT 200mA Earth Bond
•Class II
•Extension lead test – including polarity
•LED indication of pass / fail as well as a result display
•Automatic check if appliance is switched on or not
•Test 110V appliances for earth bond and insulation
(with appropriate test adaptor).
•Tests in accordance with the IEE Code of Practice
•Powered by batteries
•Earth lead
•Instruction Manual
•Calibration Certificate
•Extension Lead Adaptor
•Pass & Fail labels
•PATLOG1 PAT record log book for multiple sites
•PATLOG2 for single sites, including pass labels
MEASUREMENT OF INSULATION RESISTANCE - R INS
Rating 250V / 20M Ωand 500V / 20M Ω
Measuring range 0.1~19.99M Ω
Resolution 10kΩ
Rated voltage 250V/500V DC(-0%/+30%) @250k Ω/500kΩ
Short-circuit current 2.5mA DC or less
Accuracy ± (2%rdg+3dgt)
Protective conductor Insulation Substitute Polarity
resistance resistance Leakage
current
LED Colour Green Amber Green Green Green
Extension Lead Rpe < 0.1 Ω Ppe < 0.1 Ω Rins > 1M Ω Cont < 10 Ω
< 0.3 Ω
Class I Rpe < 0.1 Ω Ppe < 0.1 Ω Rins > 1M Ω Leak < 0.75mA
< 0.3 Ω
Class II Rins > 2M Ω Leak < 0.25mA
THRESHOLD AND DISPLAY
Test function Leakage current test
Measuring range 0.1-12.00A rms
Resolution 0.01mA
Accuracy ±(3%rdg ± 5dgt)
SUSTITUTE LEAKAGE CURRENT
Test function IT 200mA continuity test
Measuring range 0 - 19.99 Ω
Resolution 10mΩ
Open-circuit voltage 5V
Measuring current 200mA DC (nominal)
Accuracy ±(3%rdg ± 5dgt)
MEASUREMENT OF PROTECTIVE CONDUCTOR RESISTANCE - RPE
ACCESSORIES
PRODUCT DATA SHEET
SPECIFICATIONS
OPTIONAL
KT72
PAT Tester with
Auto Test Sequence
t: 01494 792 212 kewtechcorp.com e: [email protected]

1
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
maintain it in a 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 could
cause serious or fatal injury.
#CAUTION is reserved for conditions and actions that could
cause minor injury or instrument damage.
Note: This indicates information that is essential for handling the
instruments or should be noted in order to familiarise yourself
with the instruments operating procedures and/or functions.
#DANGER
●Do not apply any voltage to the test socket and test lead of this
instrument.
●For safety reasons, only use the Test Leads designed to be
used with this instrument and recommended by KEWTECH.
●Do not touch the device under test whilst testing is in
progress.
1.Safe testing

2
#DANGER
●Sin ce a high v oltage of 250V or 500V is being out put
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.
●Do not touch the metal part of the Test Lead with crocodile clip
(M-7242) whilst testing is in progress.
●Do not touch or disconnect the appliance under test until
testing is completed.
#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 recomended 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 (substitute leakage) or
a 250V insulation test where a 500V insulation test cannot be
carried out.
●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.
●When the measurement function is completed, turn the
function switch back to the OFF position to turn off.
●This instrument will automatically be powered off after
approximately 10 minutes if no key operation is carried out.
●If the instrument will not be used for a prolonged period,
remove the batteries.
Safe testing

3
The KT72 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 backside of
the main body during measurement.
2.1 Method of removing the cover
2.2 Method of storing the cover
Fig.1
Fig.2
2.Procedure
of removing
cover

4
3.1 Product summary
The KT72 is a hand-held battery powered portable appliance tester,
performing three 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: 2007
This instrument is designed to check the electrical safety of appliances
of Class I and Class II categories.
As a guide the two categories are defined as follows:
Class I : Appliances which have 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, often referred to as double insulated.
3.Product
summary and
explanation

5
3.2 Test Functions
KT72 has the following features.
Function Tests of contents
Class I Test 200mA
●Protective conductor resistance (Test current
200mA DC nominal)
●Insulation (Test voltage 250V DC or 500V
DC)
●Substitute leakage current test
Class ll Test
●Insulation (Test voltage 250V DC or 500V
DC)
●Substitute leakage current test
Extension Lead test
●Protective conductor resistance (Test current
200mA DC nominal)
●Insulation L/N-PE (Test voltage 250V DC or
500V DC)
●L-N Short
●Polarity
3.3 Features
●Auto-testing
●Checks for whether the appliance is correctly switched ON or not
●Selection for 250V or 500V for the insulation resistance test.
●Null function for the earth bond test lead.
●Over range indication on the LCD.
●Pass / fail indication of tests by LEDS and by a buzzer.
●Auto-power-off function
Product
summary and
explanation

6
3.4 Instrument layout
Front View
End View
⑴Test socket
Insert the mains plug of the appliance to be tested in to this socket for
the protective conductor resistance, insulation resistance, substitute
leakage current test and extension lead test.
⑵LCD
Measured value is displayed
⑶LED for test result
When the value of protective conductor resistance, insulation
resistance and substitute leakage current exceeds the limit dictated by
applicable standards, LEDs light up in red. When it is within the limit,
the LEDs light up in green. (For protective conductor resistance, the
LED can light orange, for details please refer to the note in section 6.1:
Class I Test.)
⑷Start switch
A measurement starts by pressing this switch.
(1) Test socket (2) LCD
(3) LEDs for test result
(4) Start switch
(5) NULL /250V-500V
switch
(6) Function switch
(7) Terminal for Extension lead adaptor
(8) Terminal for RPE – Test lead
Fig.3
Product
summary and
explanation

7
⑸NULL/250V-500V switch
●The rotary dial has to be set to a Class l or Extension Lead 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 insulation test voltage
⑹Function switch
Select a function with this switch.
⑺Terminal for Extension lead adaptor
For use with the KAMP S (UK) extension lead adaptor.
⑻PE / Class II insulation probe
Connect the Test Lead with crocodile clip (M-7242) (fig 4) 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.
⑼Test Lead with crocodile clip M-7242
⑽Extension leads adaptor KAMP S (UK)
This is for connecting the instrument and a mains extension lead.
⑾Earth pin adapter M-8251
Product
summary and
explanation
Fig.4
IEC Connector
Fig.5
Fig.6

8
3.5 Explanation for indications
LCD Display
Product
summary and
explanation
RPE Continuity indication
(with both polarities)
Appears when the batteries are
becoming low
Leakage current indication
Null indication
Unit indication
Over range display: “ >” is displayed on the LCD.
Insulation measurement voltage
Fig.7

9
List of display message
Displayed when the value at preliminary
measurement for the protective conductor
resistance exceeds 20Ω, a n d t h e
measurement cannot be carried out.
Displayed when the protective conductor
resistance exceeds the threshold value. (*1)
Displayed when appliance under test is
switched off.
Displayed when the insulation resistance
between LN-E is less than the threshold value.
Displayed when the leakage current exceeds
the threshold value.
Displayed when L-N is close to short during an
Extension lead test.
Displayed when the resistance between L-L
exceeds 10Ωduring an Extension lead test.
Displayed when the resistance between N-N
exceeds 10Ωduring an Extension lead test.
(*1): Extension leads and appliances with long mains leads have a
greater resistance allowance for earth continuity. Please refer to the
table.1 on page 11.
3.6 Applicable standards
Instrument operation
The IEE Code of Practice for In-service Inspection and Testing of
Electrical Equipment: 2007
Safety
IEC/EN61010-1 CAT.III 300V-instrument
IEC/EN61010-031 CAT.III 300V-test lead
EMC
EN61326 (EN55022/EN61000-4-2, 4-3)
Product
summary and
explanation

10
4.1 General specification, measuring range and accuracy
Measurement of earth continuity (protective conductor resistance) - RPE
Test function 200mA continuity
Measuring range 0 ~ 19.99Ω
(including pre-set Null values) (*2)
Resolution 10mΩ
Open-circuit voltage 5V DC
Measuring current 200mA DC (nominal)
Accuracy ± (3%rdg+5dgt)
(*2): Test lead resistance of 3Ωor less can be cancelled by NULL
function.
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.
@250kΩ1mA DC min. @500kΩ
Short-circuit current 2.5mA DC or less
Accuracy ± (2%rdg+3dgt)
Measurement of substitute leakage current test - LEAK
Test function Leakage current test
Measuring range 0.1~12.00mA rms, 50Hz AC
Resolution 0.01mA
Accuracy ± (3%rdg+5dgt)
4.2 Threshold and display
Function Earth
Continuity
Insulation
Resistance Polarity Leakage Current
Class I 200mA RPE ≦0.1Ω(*3) RINS ≧1MΩ − LEAK ≦ 0.75mA
Class ll − RINS ≧2MΩ − LEAK ≦ 0.25mA
Extension Lead RPE ≦0.1Ω(*3) RINS ≧1MΩ Cont ≦10Ω −
(*3): Extension leads and appliances with long mains leads have a
greater resistance allowance for earth continuity. Please refer to the
table 1 on next page.
¤Green (RPE ≦0.1Ω) = Pass for all appliances
¤Orange (0.1Ω＜ RPE ＜0.3Ω) = Pass for appliances with extended
mains leads
¤Red (RPE ≧0.3Ω) = Fail
4.Specification

11
table.1: Summary of flexible table resistance rounded to two decimal places*
Nominal Conductor csa
– should be marked on
flexible cable
(mm2)
Length
(m)
Resistance
(at 20° )
(Ω)
Max. carrying
current
(A)
0.5
1 0.04
3
2 0.08
3 0.12
4 0.16
0.75
1 0.025
6
2 0.05
3 0.08
4 0.10
5 0.13
1.0
1 0.02
10
2 0.04
3 0.06
4 0.08
5 0.10
1.25
1 0.015
13
2 0.03
3 0.05
4 0.06
5 0.08
1.5
1 0.01
15
2 0.03
3 0.04
4 0.05
5 0.06
2.5
1 0.01
20
2 0.01
3 0.02
4 0.03
5 0.04
4
1 0.00
25
2 0.01
3 0.01
4 0.01
5 0.02
*For flexible cables to BS 6500 or BS 6360
Note. For further information on protective conductor resistance and
testing of portable appliances can be found in the Code of Practice
for In-service Inspection and Testing of Electrical Equipment
published by the IEE.
Specification

12
4.3 Reference test condition
Unless otherwise specified, this specification is dependent on the
following conditions.
⑴ Ambient temperature: 23±5˚C
⑵ Relative humidity: 45 ~ 75%
⑶ Attitude: Horizontal
⑷ Altitude: 2000m or less
Operating temperature and humidity range
0ºC ~ +40ºC Relative humidity: 85% or less (no condensation)
Storage temperature and humidity range
-20ºC ~ +60ºC Relative humidity: 85% or less (no condensation)
Power supply
AA-size R6 / LR6 (HR6) 1.5V (1.2V) batteries x 8
Use of alkaline batteries is recommended. (AA-size nickel hydride
rechargeable batteries are also usable.)
Maximum rated power
Approx. 4.5VA
Outer dimension and weight
Outer dimension: 185(L) × 167(W) × 89(D)mm
Weight: Approx. 1.1kg (instrument with batteries)
Symbols used on the instrument:
Equipment protected throughout by DOUBLE INSULATION or
REINFORCED INSULATION
#Caution (Refer to the accompanying instruction manual)
Fuse
This symbol indicates a fuse.
Battery
This symbol indicates a battery.
Ground
This symbol indicates ground (earth).
Specification

13
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 Battery Voltage Check
If the batteries fall below the normal operating voltage, the " "
icon turns on. If the Low battery icon is indicated (Fig.7), replace the
batteries according to7. for Battery and Fuse Replacement.
5.3 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 KT72 can cancel the resistance of the test lead by pressing the
NULL|250V/500V switch. 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.
Note
●Null setting is possible at both Class l Test and Extension Lead
Test. However, only one Null value can be held in memory. For
example, when the Null setting is carried out at Class l Test, the set
value will also be used for Extension Lead Test (unless it is reset).
●After the function switch is turned to the OFF position, the set Null
value is still held in the internal memory.
5. Preparation
before a
measurement

14
5.3.1 Null setting for Class I Test
⑴Set the function switch to Class l Test 200mA function.
⑵Insert the Earth pin adapter (M-8251) in to the end of the Earth
terminal of the Test socket.
⑶Connect the Test lead with the crocodile clip (M-7242) to the
Terminal for RPE-Test Lead of the instrument, and attach the
crocodile clip on to the earth pin. (Fig.8)
⑷Press the NULL|250V/500V switch whilst maintaining contact
between the Test Lead and the earth pin adapter, the resistance of
the Test Lead will be displayed on the LCD as shown in Fig.9 for
2sec.
Then, the instrument cancels the resistance value of the Test Lead
and adjusts the displayed value to0.00as shown in Fig.9.
At this point the NULL icon is displayed in the LCD.
The Null setting cannot be done when the test lead resistance is 3Ω
or more.
A messagenoappears to indicate that the resistance is exceeding
the Null setting range.
Display at Null setting
⑸Null setting can be released by pressing NULL|250V/500V switch
for 2sec. The NULL mark on the LCD will disappear when Null
setting is released.
Preparation
before a
measurement
M-7242
M-8251
Earth pin
Set the Function switch to
“Class I Test 200mA”
Fig.8
Fig.9

15
5.3.2 Null setting for Extension Lead Test
⑴Set the function switch to Extension Lead Test function.
⑵Connect the Extension lead adaptor KAMP S (UK) as indicated in
Fig.10, and then follow the procedure described at clause 5.3.1 (4).
⑶Follow the procedure described at clause 5.3.1 (5) to cancel the Null
setting.
5.4 Voltage setting for insulation resistance measurement
(How to change between 250V and 500V)
⑴Set the function switch to the 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.
Note
●The Insulation test voltage setting is saved and kept in the internal
memory of the instrument and is maintained even after switching
the instrument off.
Set the Function switch to
“Extension Lead Test”
Fig.10
Preparation
before a
measurement
Fig.11

16
Connect to exposed metal parts but not rotating
parts or heating elements.
Switch ON the power.
Set the function switch to
Class 1 test 200mA
6.1 Class I Test (200mA earth bond test)
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 above 1MΩ. This test sequence
also conducts a substitute leakage current test on an appliance. To
conduct a test, connect the mains plug of the appliance to the test
socket (1) described in clause 3.4. INSTRUMENTS LAYOUT and the
PE probe to terminal (8).
Use the following setups, depending upon the type of appliance.
6. Measuring
method
Fig.12

17
Measuring
method
Check earth connections
and press start again.
(*5)
(*4)
Lights up in red
No
Yes
Yes
Yes
(1). Preliminary measurement
No
(4). Insulation resistance between L/N and PE.
Lights up
in green
Value of (2),(4) and (5) will be alternately displayed on the LCD.
No
Re-start
Can proceed to the next step
by pressing the Start switch
again even if the result was
a fail
Start
Class I Test Flowchart
Lights up in red
Lights up
in green
No
Re-start
(2). Protective conductor resistance.
Lights up in red
Re-start (*6)
(5). Leakage current between L/N and PE.
No
RPE≦20Ω?
“no”→“Con” is displayed
alternately on the LCD.
RPE≦0.1Ω?
(0.1Ω<RPE<0.3Ω?)
Lights up in green or
if the resistance
is:between >0.1 and
< 0.3Ω it lights orange
“no” →“Con”→“value” will
be repeated on the LCD.
(*7)
(3). Appliance switch test
Is the appliances
switched on? “oFF”→“ ? ” is displayed
alternately on the LCD.
Yes
Leakage
Current
Leakage
Current
PASS
LEAK≦0.75mA?
Stop the test and
“no”→“LEA”→“value” will be
repeated on the LCD.
LnE
≧ 1MΩ ? Lights up in red
“no”→“LnE”→“value” will be
repeated on the LCD.

18
Note
●(*4) This instrument conducts a Preliminary measurement before
conducting Protective conductor resistance measurement. In
case that the resistance value exceeds 20Ω,noandConare
alternately displayed on the LCD, and the next measurement in the
sequence will not be conducted.
●Extension leads and appliances with long mains leads have a
greater resistance allowance for earth continuity. Please refer to the
table.1 on page 11.
●(*5)This instrument displays the test results of protective conductor
resistance as follows.
Green (RPE≦0.1Ω) = Pass for all appliances
Orange (0.1Ω<RPE<0.3Ω) = Pass for appliances with extended
mains leads
Red (RPE≧0.3Ω) = Fail
●(*6)This instrument has a Re-Start function.
It can proceed to the next step by pressing the Start switch again
even if the result was a fail.
●(*7) When conducting Insulation resistance test and Leakage
current test, the appliance under test must be being switched ON.
This instrument automatically detects the condition of power switch
ON. In case that the condition of power switchONcannot be
detected,oFFand?are alternately displayed on the LCD, and
the test will be stopped. In this case, please make sure the power
switch of the appliance isON.
●This instrument will automatically be powered off after
approximately 10 minutes if no key operation is carried out.
#CAUTION
●Follow the procedure described in 5.3, 5.4 and undertake the
NULL and Voltage setting before taking 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 the
measuring range, or the leakage current exceeds the measuring
range the> 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 250V or 500V will be present
and the user may get an electrical shock.
●When the measurement function is completed, turn the
function switch back to the OFF position to turn off.
Measuring
method

19
6.2 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 and leakage current of the appliances is within the range
defined in the standards.
Measuring
method
Switch ON the power.
Set the function switch to
the Class II position.
Fig.13