Kewtech KT64 User manual

92-1885A 06-11

Kewtech Corporation Ltd.
Midas House, Unit 2b
Stones Courtyard
High Street, Chesham
Buckinghamshire HP5 IDE
www.kewtechcorp.com
40
1. Safe Testing ...…………………………………………………….….……. 1
2. Instruments Layout ..………………………………………………..…….. 3
3. Accessories ……………………………………………………………….. 4
4. Features .…………………………………………………………………… 4
5. Specification .………………………………………………………………. 6
5.1 Measurement Specification ..………………………………………… 6
5.2 Operating error ..……………………………………………….……. 9
5.3 General Specification ..….………………………………………….. 10
5.4 Applied standards .………………………………………………….. 11
5.5 List of Display Message .…………………………………………… 12
6. Configuration ..…………………………………………………………… 13
7. Continuity(resistance) tests ……………………………………………... 14
7.1 Test procedure ……………………………………………………... 14
7.2 2Ω Buzzer ....……………………………………………………… 16
8. Insulation tests ..…………………………………………………………. 16
8.1.1 The nature of insulation resistance .…………………………….. 16
8.1.2 Capacitive current ..……………………………………………… 17
8.1.3 Conduction current ………………………………………………. 17
8.1.4 Surface leakage current ……………………………………….... 18
8.1.5 Total leakage current .………………………………………….... 18
8.2 Damage to voltage sensitive equipment .……………………….... 19
8.3 Preparation for measurement .…………………………………….. 19
8.4 Insulation resistance measurement ...…………………………...… 20
9. LOOP/PSC/PFC test ………………………………………...………...… 22
9.1 Principles of Measurement of fault loop impedance and PFC …... 22
9.2 Principles of measurement of line impedance and PSC ………….. 26
9.3 Operating instructions for LOOP and PSC/PFC ……………...…… 28
9.3.1 Initial Checks …………………………………………………...... 28
9.3.2 Measurement of LOOP and PSC/PFC …………………………… 30
10. RCD tests ..……………………………………………………………..... 31
10.1 Principles of RCD Measurement ………………………………..... 31
10.2 Operating Instructions for RCD .……………………………...…. 33
10.2.1 Initial Checks ………………………………………………...…. 33
10.2.2 RCD Measurement ...………………………………………..….. 34
11. Volts ..………………………………………………………………...…... 36
12. Touch Pad ………………………………………………………………. 36
13. Back Light ………………………………………………………….……. 36
14. General ...…………………………………………………………...……. 36
15. Battery replacement ..…………………………………………………… 37
16. Fuse replacement …………………………………………………...…… 37
17. Servicing and Calibration …………………………………………...…… 38
18. Case and strap assembly ....…………………………………………….. 39
Contents

The KT 64 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.

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, stop and take advice from a qualified person.
1 This instrument must only be used by a competent and trained person
and operated in strict accordance with the 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.
2 It is essential to read and to understand the safety rules contained
in these instructions. They must always be observed when using the
instrument.
3 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.
For use in the continuity testing and insulation testing modes this
instrument must be used ONLY on circuits which are de-energized.
4 When conducting tests do not touch any exposed metalwork associated
with the installation. Such metalwork may become live for the duration of
the test.
5 Never open the instrument case (except for fuse and battery
replacement and in this case disconnect all leads first) because
dangerous voltages are present. Only fully trained and competent
electrical engineers should open the case. If a fault develops, return the
instrument to Kewtech for inspection and repair.
6 If the overheat symbol appears in the display disconnect the instrument
from the mains supply and allow to cool down.
7 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 tester and return it to Kewtech for repair.
8 For safety reasons only use accessories (test leads, probes, fuses,
cases, etc) designed to be used with this instrument and recommended
by Kewtech. The use of other accessories is prohibited as they are
unlikely to have the correct safety features.
9 When testing, always be sure to keep your fingers behind the finger
guards on the test leads.
10 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
Kewtech.
1 Safe Testing

2
11 Kewtech recommends the use of fused test leads particularly when
measuring voltages in high energy circuits. Where assessments show
that the risk is significant, then the use of fuse test leads constructed in
accordance with the HSE Guidance Note GS38 should be used. The test
accessories supplied with this instrument for loop impedance and RCD
tests are all fused.
12 Do not operate the function selector whilst the instrument is connected to
a circuit. If, for example, the instrument has just completed a continuity
test and an insulation test is to follow, disconnect the test leads from the
circuit before moving the selector switch.
13 Do not rotate rotary switch when test button is depressed. If the function
switch is inadvertently moved to a new function when the test button is
depressed or in lock-down position the test in progress will be halted.
14 Always check the test lead resistance before carrying out tests. This
ensures the leads are ok before taking measurements. The resistance
of leads and/or crocodile clips may be significant when measuring
low resistances. If crocodile clips can be avoided for low resistance
measurements, this will reduce the error due to lead accessories.
15 When carrying out Insulation Resistance tests, always release the test
button and wait for charged capacitances to totally discharge before
removing the test leads from the test circuit.
Safe Testing

3
Input Terminal
Name Operation
(1) Back Light Button Switches on/off the Backlight of the
Display(LCD)
(2) Test Button Starts measurements. (press and rotate for
lock down feature)
(3) Touch Pad Checks the electrical potential at the PE
terminal
(4) Power Switch Power Switch
(5) Function Switch Function setting (F1 ~ F4)
(6) Display (LCD) Dot Matrix LCD 160(W)X240(H)
(7) Insulation resistance LED Alerts that the test voltage is being output
(8) Rotary Switch Selects measurement functions.
2 Instrument
layout
Fig. 1
Fig. 2

4
Main Test Lead (KAMP12)
Remote Test Lead (ACC064SP)
Distribution Board fused test lead (ACC064)
(Fuse: 10A/600V fast acting ceramic)
Test Lead Carry pouch
Carrying Bag
The KT64 Multi-Function tester performs six functions in one instrument.
1 Continuity tester
2 Insulation resistance tester
3 Loop impedance tester
4 Prospective short circuit current tester
5 RCD tester
6 Voltage tester
Fig. 3
Fig. 4
Fig. 5
3 Accessories
4 Features

5
Continuity and insulation resistance functions have the following features:
Live circuit warning Live Circuit warning on the display.
Continuity Null Allows automatic subtraction of test lead
resistance from continuity measurements.
Continuity 2Ω Buzzer Buzzer sounds at 2Ω or less at Continuity
function. (Switchable on or off)
Auto discharge Electric charges stored in capacitive circuits
are discharged automatically after testing by
releasing the test button.
Insulation Resistance LED LED lights up while making measurements at
Insulation function and alerts that test voltage
is being output.
Loop impedance, PSC/PFC and RCD testing functions have the following
features:
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
(used for LOOP and PSC/PFC tests) and of the
current control MOS FET (used for RCD tests)
displaying a warning symbol and automatically
halting further measurements.
Phase angle selector The test can be selected from either the
positive (0°) or from the negative (180°)
halfcycle of voltage. This selector is used in
the RCD mode to obtain the maximum trip time
of an RCD for the test selected.
UL value selector Select UL (limit of contact voltage) 25V or 50V.
Where Uc (contact voltage) exceeds UL value
at RCD testing, Uc > UL will be displayed
without starting the measurement.
Features

6
ALL testing functions have the following
Touch Pad Gives an alert, when touching the Touch Pad, while the PE
terminal is connected to Line by mistake.
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.
5.1 Measurement Specification
Continuity
Open Circuit
Voltage (DC)
Short Circuit
Current Range Accuracy
5V ± 20%Greater than
200mA
20/200/2000Ω
Auto - Ranging
0~0.19Ω±0.1Ω
0.2~2000Ω±(2%rdg+8dgt)
2Ω Buzzer : Buzzer sounds when measured resistance is 2Ω or less.
2Ω Buzzer Accuracy : 2Ω±0.4Ω
Insulation Resistance
Open Circuit
Voltage (DC) Rated Current Range Accuracy
250V+40% - 0%1mA or greater
@ 250kΩ
20/200MΩ
Auto - Ranging
0~19.99MΩ:
±(2%rdg+6dgt)
20~200MΩ:
±(5%rdg+6dgt)
500V+30% - 0%1mA or greater
@ 500kΩ
20/200/2000MΩ
Auto - Ranging
0~199.9MΩ:
±(2%rdg+6dgt)
200~2000MΩ:
±(5%rdg+6dgt)
1000V+20% - 0%1mA or greater
@ 1MΩ
20/200/2000MΩ
Auto - Ranging
5 Specification

7
Loop Impedance
Function
Rated
Voltage
Nominal Test Current at
0Ω External Loop:
Magnitude/Duration(*1)
Range Accuracy
L-PE 100~260V
50/60Hz
20Ω: 6A/20ms
200Ω: 2A/20ms
2000Ω: 15mA/360ms
20/200/2000Ω
Auto-Ranging
±(3%rdg+4dgt) *2
±(3%rdg+8dgt) *3
L-PE
(ATT)
100~260V
50/60Hz
L-N: 6A/40ms
N-PE: 10mA/approx. 4s
20/200/2000Ω
Auto-Ranging
L-N < 20Ω
±(3%rdg+6dgt) *2
±(3%rdg+8dgt) *3
L-N / L-L
50/60Hz
L-N:100~300V
L-L:300~500V
20Ω: 6A/20ms 20Ω
±(3%rdg+4dgt) *2
±(3%rdg+8dgt) *3
*1: at 230V
*2: 230V+10%-15%
*3: voltages except for *2
PSC (L-N/L-L) / PFC (L-PE)
Function
Rated
Voltage
Nominal Test Current
at 0Ω External Loop:
Magnitude/
Duration(*4)
Range Accuracy
PSC 100~500V
50/60Hz 6A/20ms
2000A/20kA
Auto-Ranging
PSC/PFC
accuracy is
derived from
measured loop
impedance
specification
and measured
voltage
specification
PFC 100~260V
50/60Hz
6A/20ms
2A/20ms
15mA/360ms
PFC
(ATT)
100~260V
50/60Hz
L-N: 6A/40ms
N-PE: 10mA/approx. 4s
*4: at 230V
Specification

8
RCD
Function Rated Voltage
Accuracy
Trip Current Trip Time
AC Type A Type
X1/2
230V+10%-15%
50/60Hz
-8%~-2% -10%~0%
±(1%rdg+3dgt)
X1+2%~+8%0%~+10%
X5+2%~+8%0%~+10%
Ramp ( ) ±4%± 10%
Auto
Depending on the accuracy at each function.
Measurement sequence:
X1/2 0°→X1/2 180°→X1 0°→X1 180°→X5 0°→X5 180°
Measurements with x5 are not carried out for RCDs with nominal
current of 100mA or more.
RCD Trip Current Duration
Function Type RCD Trip Current Duration
10 30 100 300 500 1000
Trip
Current
Duration
(ms)
X1/2
GAC 2000 2000 2000 2000 2000 2000
A2000 2000 2000 2000 2000 n.a
SAC 2000 2000 2000 2000 2000 n.a
A2000 2000 2000 2000 2000 n.a
X1
GAC 550 550 550 550 550 550
A550 550 550 550 550 n.a
SAC 1000 1000 1000 1000 1000 n.a
A1000 1000 1000 1000 1000 n.a
X5
GAC 410 410 410 n.a n.a n.a
A410 410 410 n.a n.a n.a
SAC 410 410 410 n.a n.a n.a
A410 410 410 n.a n.a n.a
Ramp
( )
GAC Goes up by 10% from 20% to 110%
300ms×10 times
n.a
A n.a
SAC Goes up by 10% from 20% to 110%
500ms×10 times
n.a
A n.a
Volts
Function Rated voltage Measuring
Range Accuracy
Volts 25~500V
45~65Hz 25~500V±(2%rdg+4dgt)
Frequency 25~500V
45~65Hz 45~65Hz ±(0.5%rdg+2dgt)
Specification

9
Possible number of tests with fresh batteries.
Continuity :Approx. 2000 times min. at load 1Ω
Insulation Resistance :Approx. 1000 times min. at load 1MΩ (1000V)
LOOP/PFC/PSC :Approx. 1000 times min. (ATT)
RCD :Approx. 2000 times min. (G-AC X1 30mA)
Reference Conditions
Ambient temperature 23±5℃
Relative humidity 45% to 75%
Nominal system voltage and
frequency 230V, 50Hz
Altitude Less than 2000m
5.2 Operating error
Continuity (EN61557-4)
Operating range compliant with
EN61557-4 operating error
Maximum percentage
operating error
0.20~1999MΩ±30%
The influencing variations used for calculating the operating error are denoted as follows;
Temperature : 0℃ and 35℃
Supply voltage : 8V to 13.8V
Insulation Resistance(EN61557-2)
Volt Operating range compliant with
EN61557-2 operating error
Maximum percentage
operating error
250V0.25~199.9MΩ
±30%500V0.50~1999MΩ
1000V1.00~1999MΩ
The influencing variations used for calculating the operating error are denoted as follows;
Temperature : 0℃ and 35 ℃
Supply voltage : 8V to 13.8V
Loop Impedance(EN61557-3)
Volt Operating range compliant with
EN61557-3 operating error
Maximum percentage
operating error
L-PE 0.40~1999Ω±30%
L-N 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 : 8V to 13.8V
Specification

10
RCD(EN61557-6)
Function Operating error of trip current
X1/2-10%~0%
X1, X5 0%~+10%
Ramp -10%~+10%
The influencing variations used for calculating the operating error are denoted as follows;
Temperature : 0 ℃ and 35 ℃
Earth electrode Resistance (shall not exceed below) :
IΔn (mA) Earth electrode resistance (Ω max.)
UL50V UL25V
10 2000 2000
30 600 600
100 200 200
300 130 65
500 80 40
1000 40 20
Table.1
System voltage: 230V+10%-15%
Supply voltage : 8V to 13.8V
5.3 General specification
Instrument dimensions 235 X 136 X 114mm
Instrument weight:- 1300g (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: 12.0 V, ripple content 1%
or less
6. Altitude up to 2000m, Indoor use
Battery type Eight LR6 or R6 batteries.
Operating temperature 0 to +40℃, relative humidity 80% or less, no
and humidity. condensation
Storage temperature -20 to +60℃, relative humidity 75% or less,
and humidity no condensation.
Specification

11
Display Dot Matrix LCD 160(W) X 240(H) pixels.
Overload protection The continuity test circuit is protected by a
0.5A/600V fast acting (HRC) ceramic fuse
mounted in the battery compartment, where a
spare fuse is also stored.
The insulation resistance test circuit is
protected by a resistor against 1000 V AC for
10 seconds.
5.4 Applied standards
Instrument operating IEC/EN61557-1,2,3,4,6,10 (1997)
Standard
Safety standard IEC/EN 61010-1(2001),
CATIII (300V) -Instrument
IEC/EN 61010-031(2001),
CATII (250V)-Test Lead KAMP12
CATIII (600V)-Test Lead ACC064
CATIII (1000V)-Test Lead ACC064SP
Protection degree IEC 60529 (1989 + A1) IP40
EMC EN 61326
 ・EN 55022
 ・EN 61000-4-2 (performance criterion C)
 ・EN 61000-4-3 (performance criterion B)
This manual and product may use the following symbols adopted from
International Safety Standards;
CAT.III Designed to protect against transient overvoltages in a building
wiring installation (low-voltage distribution level)
 Equipment protected throughout by DOUBLE INSULATION
or REINFORCED INSULATION;
Caution (refer to accompanying documents)
Caution, risk of electric shock
Protection against wrong connection is up to 500V
Earth Ground
Specification

12
5.5 List of Display Message
Low battery warning
Temperature monitor for internal resistance,
available at Loop, PSC/PFC & RCD function. Further
measurements are suspended until the  symbol
disappears.
Measuring Measurements in progress
Live Circuit Live circuit warning (Continuity / Insulation Function)
PE Hi V Caution : Presence of 100V or more at PE terminal,
appears when touching the Touch Pad
L-N >20ΩAlert : Presence of 20Ω or more between Line -
Neutral at ATT measurement
Noise Caution : Presence of noise in the circuit under test
during ATT measurement. ATT function should be
disabled to continue measurements.
N - PE Hi V Caution: Presence of high voltage between NEUTRAL
- EARTH during ATT measurement. ATT function
should be disabled to continue measurements.
Uc > UL Caution : Uc at RCD measurement is exceeding the
preset UL value (25 or 50V).
no Error message : When on the RCD function, RCD
tripped before measuring RCD trip time. Selected
IΔn value may not be correct.
When on the LOOP, PSC/PFC function, supply may
have been interupted.
L-PE● L-N● ○Wiring check for LOOP, PSC/PFC function
OK Appears when all results passed during the RCD Auto
Test function.
× NO Appears when any results failed during the RCD Auto
Test function.
---- V Appears when the test lead connection is not correct.
Specification

13
Setting for following three parameters
▲ UL value ･･･････Selects a UL value for RCD function
▲ Touch Pad･･････Enables / disables Touch Pad function
▲ Back Light･･････ Selects Backlight ON / OFF. When ON is selected, the
Backlight automatically turns on at powering on the
instrument.
Setting method
1. Press the Config Button (F4) when powering on KT64. (Fig.6)
2. Then, Configuration Screen (Fig.7) is displayed.
3. Press either F1 or F2 or F3 for setting change on UL value or Touch Pad or
Back Light.
Parameter Selection Initial value
F1UL value 25 or 50V50V
F2Touch Pad ON or OFF ON
F3Back Light ON or OFF OFF
4. Press the F4 Button when setting change is completed, and return to the
normal screen.
Fig. 6
Fig. 7
6 Configuration

14
Warning: Ensure that circuits to be tested are not live.
Disconnect the instrument from the circuit under test before operating
the function switch.
To select the low resistance range select CONTINUITY.
7.1 Test Procedure
The object of continuity testing is to measure only the resistance of the parts
of the wiring system under test. This measurement should not include the
resistance of any test leads used. The resistance of the test leads needs to
be subtracted from any continuity measurement. The KT64 is provided with a
continuity null feature which allows automatic compensation for any test lead
resistance.
You should only use the test leads supplied with the instrument.
Operation of Function Switch
F1Switches on / off NULL function
F2Switches on / off 2Ω buzzer
F3N/A
F4N/A
Proceed as follows:-
1 Select the continuity test by rotating the Rotary switch.
2 Insert the Test Leads to the L and PE terminal on KT64 respectively as
shown in Fig.9.
L terminal
Brown cord of ACC064, or
ACC064SP Remote Test Lead
PE terminal
Green cord of ACC064
3 Connect the ends of the test leads firmly together (see Fig.10) and press
and lock down the test button. The value of the lead resistance will be
displayed.
Fig. 8
Fig. 9
7 Continuity

15
4 Operate the Continuity Null (F1) button, this will null out the lead resistance
and the indicated reading should go to zero.
5 Release the test button. Press the test button and ensure the display reads
zero before proceeding. While using the Continuity null function, NULL 
is displayed on the LCD as indicated in Fig.10. The null value will be stored
even if the instrument is powered off. This memorized null value can be
cancelled by disconnecting the test leads and pushing the Continuity Null
button (F1) with the test button pressed or locked. When this is cancelled
you will know because NULL OFF is displayed on the LCD.
CAUTION - before taking any measurements always check the leads have
been zeroed.
6 Connect the test leads to the circuit whose resistance is required (see
Fig.11 for a typical connection arrangement), having first made sure that
the circuit is not live. Note that Live Circuit warning will be displayed
on the LCD if the circuit is live - but check first anyway!
7 Press the test button and read the circuit resistance from the display.
The reading will have the test lead resistance already subtracted if the
Continuity null function has been used.
8 Note that if the circuit resistance is greater than 20Ω the instrument will
autorange to the 200Ω, if it is greater than 200Ω it will autorange to the
2000Ω range.
Note: If the reading is greater than 2000Ω the overange symbol >
will remain displayed.
The results of measurements can be adversely affected by impedances of
additional operating circuits connected in parallel or by transient currents.
Fig. 10
Continuity

16
7.2 2Ω Buzzer ( ) function
Use F2 Button to enable / disable 2Ω Buzzer. Buzzer sounds when measured
resistance is 2Ω or less while this function is enabled. Buzzer does not sound
if it is disabled.
Warning: Ensure that circuits to be tested are not live.
Disconnect the instrument from the circuit under test before operating
the function switch.
To select the insulation resistance range select INSULATION.
8.1.1 The nature of insulation resistance
Live conductors are separated from each other and from earth metal by
insulation, which has a resistance which is high enough to ensure that the
current between conductors and to earth is kept at an acceptably low level.
Ideally insulation resistance is infinite and no current should be able to flow
through it. In practice, there will normally be a current between live conductors
and to earth, and this is known as leakage current. This current is made up of
three components, which are:-
1. capacitive current
2. conduction current, and
3. surface leakage current.
Fig. 11
Continuity
8 Insulation

17
8.1.2 Capacitive Current
The insulation between conductors which have a potential difference between
them behaves as the dielectric of a capacitor, the conductors acting as
the capacitor plates. When a direct voltage is applied to the conductors, a
charging current will flow to the system which will die away to zero (usually
in less than a second) when the effective capacitor becomes charged. This
charge must be removed from the system at the end of the test, a function
which is automatically performed by the KT64. If an alternating voltage
is applied between the conductors, the system continuously charges and
discharges as the applied voltage alternates, so that there is a continuous
alternating leakage current flowing to the system.
8.1.3 Conduction Current
Since the insulation resistance is not infinite, a small leakage current flows
through the insulation between conductors. Since Ohm's Law applies, the
leakage current can be calculated from
applied voltage (V)
Leakage current (μA) ＝
insulation resistance (MΩ)
Fig. 12
Fig. 13
Insulation