Kewtech KT72 User Manual

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 t
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 con
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 re

#

cause serious or fatal injury.

CAUTION is reserved for conditions and actions that could

#

cause minor injury or instrument damage.

served for conditions and actions that could

hese operating

tained in

1.Safe testing

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 vol

instrument.

● For safety reasons, only use the Test Leads designed to be

used with this instrument and recommended by KEWTECH.

● Do not to uch the d ev ice un de r test wh ilst t es ting i s in

progress.

tage to the test socket and test lead of this

1

2

Safe testing

DANGER

#

● Sin c e a hi gh vo lta g e of 250V o r 500V is be ing o utp u t

continuously, when measuring insulation resistance, the user
may get an electrical shock. Any capacitors in the appliance
un der test may be come charged during te sting an d 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

testing is completed.

● Never open the instrument case – because dangerous voltages

ar e present. Only fu ll y trained and co mp et en t 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 re
for inspection and repair.

● Never attempt to use the instrument if the instrument or your

hands are wet.

● 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 vol

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
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.

● Wh en th e mea surement function is complet ed , t ur n t he

function switch back to the OFF position to turn off.

● Th is instrument will aut om at ically be powered off aft er

approximately 10 minutes if no key oper

● If the instrument will not be us ed for a prolonged period,

remove the batteries.

touch or disconnect the appliance un der test until

WARNING

#

turn it to your distributor

CAUTION

#

tage for the insulation

under test is powered on during

ation is carried out.

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

Fig.1

2.2 Method of storing the cover

2. Procedure
of removing
cover

Fig.2

4

3. Product
summary and
explanation

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 s

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:

uitable for performing tests as required by the

Class I : Appliances which have functional insulation throughout

earth connected case. These are often described as earthed
appliances.

Class II: Appliances which have both functional and additional insulation

where any metal parts cann ot become Live under fault
conditions, often referred to as double insulated.

and an

5

3.2 Test Functions

KT72 has the following features.

Function Tests of contents

● Protective conductor resistance (Test current

200mA DC nominal)

Class I Test 200mA

Class ll Test

Extension Lead test

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

● Insulation (Test voltage 250V DC or 500V

DC)

● Substitute leakage current test

● Insulation (Test voltage 250V DC or 500V

DC)

● Substitute leakage current test

● Protective conductor resistance (Test current

200mA DC nominal)

● Insulation L/N-PE (Test voltag

500V DC)

● L-N Short

● Polarity

e 250V DC or

Product
summary an
explanation

d

6

(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

Product
summary and
explanation

3.4 Instrument layout

Front View

End View

Fig.3

⑴ Test 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.

⑵ LCD
  Measured value is displayed

⑶ LED for test result
  Wh en th e value of protective con du ct or re si st an ce , i ns ul at io n

resistance and substitu
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.)

⑷ Start switch
  A measurement starts by pressing this switch.

te leakage current exceeds the limit dictated by

7

⑸ NULL/250V-500V switch

IEC Connector

  ● 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

⑹ Function switch
  Select a function with this switch.

⑺ Terminal for Extension lead adaptor
  For use with the KAM

⑻ PE / 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.

⑼ Test Lead with crocodile clip M-7242

P S (UK) extension lead adaptor.

Product
summary and
explanation

⑽ Extension leads adaptor KAMP S (UK)
  This is for connectin

⑾ Earth pin adapter M-8251

g the instrument and a mains extension lead.

Fig.4

Fig.5

Fig.6

8

Product

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

summary and
explanation

3.5 Explanation for indications
LCD Display

Fig.7

9

List of display message

Displayed wh en the value at pre li minary
measuremen t for the prote ctive conduc tor
r e s i s t a n c e e x c e e d s 20Ω , a n d t h e
measurement cannot be carried out.

Di sp la ye d when the pro te ct iv e conductor
resistance exceeds the threshold value. (*1)

Dis pl aye d wh en app lia nce un der tes t is
switched off.

Di sp layed when the insu la tion resis ta nce
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 10Ω during an Extension lead test.

Displayed when the resistance between N-N
exceeds 10Ω during 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.

Product
summary and
explanation

3.6 Applicable standards
Instrument operation

The IEE Code of Practice for In-service Inspection and Testing of

Electrical Equipment: 2007

Safet

IEC/EN61010-1 CAT.III 300V-instrument
IEC/EN61010-031 CAT.III 300V-test lead

EMC

EN61326 (EN55022/EN61000-4-2, 4-3)

y

10

4.Specification

4.1 General specification, measuring range and accuracy
Measurement of earth continuity (protective conductor resistance) - RPE

Test function 200mA continuity

Measuring range

Resolution 10mΩ

Open-circuit voltage 5V DC

Measuring current 200mA DC (nominal)

Accuracy ± (3%rdg+5dgt)

(*2): Test lead resistance of 3Ω or 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

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)

(including pre-set Null values) (*2)

1mA DC min.

@250kΩ

0 ~ 19.99Ω

1mA DC min.

@500kΩ

4.2 Threshold and display

Function

Class I 200mA

Class ll

Extension Lead

(*3): Ext ension leads and applian ces with long mains lea ds have a

greater resistance allowance for earth continuity. Please refer to the
table 1 on next page.

¤ Green (RPE ≦ 0.1Ω) = Pass for all ap
¤ Orange (0.1Ω＜ RPE ＜0.3Ω) = Pass for appliances with extended

mains leads

¤ Red (RPE ≧ 0.3Ω) = Fail

Earth

Continuity

RPE ≦ 0.1Ω(*3)

−

RPE ≦ 0.1Ω(*3)

Insulation

Resistance

RINS ≧ 1MΩ
RINS ≧ 2MΩ
RINS ≧ 1MΩ

pliances

Polarity

−

−

Cont ≦ 10Ω

Leakage

Current

LEAK ≦ 0.75mA

LEAK ≦ 0.25mA

−

11

table.1: Summary of flexible table resistance rounded to two decimal places*

Nominal Conductor csa

– should be marked on

flexible cable

(mm2)

0.5

0.75

1.0

1.25

1.5

2.5

4

*For flexible cables to BS 6500 or BS 6360

Length

(m)

1 0.04
2 0.08
3 0.12
4 0.16
1 0.025
2 0.05
3 0.08
4 0.10
5 0.13
1 0.02
2 0.04
3 0.06
4 0.08
5 0.10
1 0.015
2 0.03
3 0.05
4 0.06
5 0.08
1 0.01
2 0.03
3 0.04
4 0.05
5 0.06
1 0.01
2 0.01
3 0.02
4 0.03
5 0.04
1 0.00
2 0.01
3 0.01
4 0.01
5 0.02

Resistance

(at 20° )

(Ω)

Max. carrying

current

(A)

3

6

10

13

15

20

25

Specification

Note. For further information on p

testing of portable appliances can be found in the Code of Practice
for In-service In spection and Testing of Electrical Equipme nt
published by the IEE.

rotective conductor resistance and

12

Specification

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 ~

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

+60ºC Relative humidity: 85% or less (no condensation)

Outer dimension and weight
  Outer dimension: 185(L) × 167(W) × 89(D)mm
  Weight: Approx. 1.1kg (instrument with batter

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).

ies)

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 bel ow the normal oper ating volt age, 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 t

NULL|250V/500V

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.

switch. The pr ocedure of Null set ting is shown

" "

he

5. Preparation
before a
measurement

Note

● Null setting is possible at both Class l Test and Extension Lead

Test. However, only one Null value can be
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.

held in memory. For

14

Preparation

M-7242

M-8251
Earth pin

Set the Function switch to
“Class I Test 200mA”

before a
measurement

5.3.1 Null setting for Class I Test

⑴ Set the function switch to Class l Test 200mA function.
⑵ Insert the Earth pin adapter (M-8251) in to the end of the Earth

terminal of the Test socket.

⑶ Co nnect the Te st lea d with the crocodile clip (M-7242) to the

Termi nal for RPE -Test Lead of the instrument, and at tach the
crocodile clip on to the earth pin. (Fig.8)

⑷ Press the

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
  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.

NULL|250V/500V

NULL

switch whilst maint aining contact

icon is displayed in the LCD.

Display at Null setting

⑸ Null setting can be released by pressing

for 2sec. The

setting is released.

mark on the LCD will disappear when Null

NULL

NULL|250V/500V

Fig.8

Fig.9

switch

15

5.3.2 Null setting for Extension Lead Test

Set the Function switch to
“Extension Lead Test”

⑴ Set the function switch to Extension Lead Test function.
⑵ Connect the Extension lead adaptor KAMP S (UK) as indicated in

Fig.10, and then follow the procedure described at clause 5.3.1 (4).

⑶ Follow the procedure described at clause 5.3.1 (5) to cancel the Null

setting.

Fig.10

5.4 Voltage setting for insulation resistance measurement
(How to chang

⑴ Set the function switch to the Class II Test function, and press the

NULL|250V/500V
the voltage selected. By pressing the
250V and 500V can be changed over.

e between 250V and 500V)

switch. The LCD display will change to indicate

NULL|250V/500V

switch,

Preparation
before a
measurement

Fig.11

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.

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. Measuring
method

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
co

nduct 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.

Fig.12

17

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.

Measuring
method

18

Measuring
method

Note

● (*4) This instrument conducts a Preliminary measurement before

conducting Pro tecti ve c onductor resistance measur ement . 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 lead s and appl iances with long mains leads have a

greater resistance allowance for earth continui

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

en if the result was a fail.

ev

● (*7) When conducti ng Insu lation resistan ce 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, pleas

switch of the appliance is ON.

● This i n s trum e nt wil l a u toma t ical l y b e powe r e d off af t er

approximately 10 minutes if no key operation is carried out.

ty. Please refer to the

e make sure the power

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 unde r 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.

● Wh en th e mea surement function is complet ed , t ur n t he

function s

witch back to the OFF position to turn off.

19

6.2 Class ll Test

Switch ON the power.

Set the function switch to
the Class II position.

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

Fig.13

20

Class Il Test Flowchart

No

Value (2) and (3) will be alternately displayed on the LCD.

Yes

(2). Insulation resistance between L/N and PE.

(1). Appliance switch test

(*7)

Yes

Yes

No

Start

(*6)

Lights up in red

Lights up
in green

No

(3). Leakage current between L/N and PE.

When the resistance
between L-N is about
100kΩ or more
“ oFF”→“ ? ” is displayed
alternately on the LCD.

Is the appliance
switched on?

Re-start

Re-start

LnE ≧2MΩ?

Lights up
in green

Lights up in red

“no”→“LnE”→“value” will
be repeated on the LCD.

PASS

LEAK≦0.25mA?

Stop the test and
“no”→“LEA”→“value” will be
repeated on the LCD.

Leakage
Current

Leakage
Current

Measuring
method

21

Note

● (*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 conducti ng Insu lation resistan ce 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 O

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 i n s trum e nt wil l a u toma t ical l y b e powe r e d off af t er

approximately 10 minutes if no key operation is carried out.

CAUTION

#

● Follow the proc edure des cribed in 5.4 and unde rtake the

Voltage setting before taking a m

● The crocodile clip must make good contact with the enclosure

of the appliance.

● When the terminal is open or the resistance value exceeds

th e measuri ng range, or th e leakage current exceeds the
measuring range the  >  mark (over range display) appears
on the LCD.

● Do not touch the appliance unde r test whils t testing is in

progress. Since a high voltage of 250V or 500V will be pre
and the user may get an electrical shock.

● Wh en th e mea surement function is complet ed , t ur n t he

function switch back to the OFF position to turn off.

easurement.

N cannot be

sent

Measuring
method

22

Extension leads adaptor
KAMP S (UK)

Set the function switch to
the extension lead test position

Measuring
method

6.3 Extension Leads Test

This test is for extension leads, and checks for;

● Protective conductor resistance.

● Insulation resistance between L/N and PE.

● Short test between L and N.

● Polarity check of the Line and Neutral terminals of the plug and

socket.

Test procedure and the connection are as follows.

Fig.14

23

Check earth connections
and press start again

(*5)

(*4)

Lights up in red

No

Yes

Yes

Yes

(1). Preliminary measurement

No

(4). Short test between L and N.

Lights up
in green

Value of (2) and (3) will be alternately displayed on LCD.

No

Re-start

Start

Extension Leads Test Flowchart

Lights up in red

Lights up
in green

No

Re-start

(2). Protective conductor resistance test.

Re-start

(*6)

(5). Polarity test between L-L and N-N.

No

RPE≦20Ω?

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

(3). Insulation resistance test between L/N and PE.

Yes

PASS

Lights up in red

Lights up in red

“no”→“Con” is displayed
alternately on the LCD.

Lights up in red

“no” →“Con”→“value” will
be repeated on the LCD.

“no”→“LnE”→“value”will
be repeated on the LCD.

“no”→“Sht” is displayed
alternately on the LCD.

“no”→“L-L”→“value”
or “no” →“n-n” →“value”
will be repeated on the LCD

.

LnE

≧

1MΩ?

L-N

≧

100kΩ?

L-L & N-N≦10Ω?

Polarity

Polarity

Measuring
method

24

Measuring
method

Note

● (*4) This instrument conducts a Preliminary measurement before

conducting the Protective conductor resistance measurement. In

the 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 lead s and appl iances with long mains leads have a

greater resistance allowance for earth

table.1 on page 11.

● (*5) This instrument displays the test results of t he 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 switc

even if the result was a fail.

● This i n s trum e nt wil l a u toma t ical l y b e powe r e d off af t er

approximately 10 minutes if no key operation is carried out.

WARNING

#

● Do not connect the M-7242 to main power supply. And do not

apply any voltage to the test socket.

continuity. Please refer to the

h again

CAUTION

#

● Follow the procedure described in 5.3 and undertake the Null

setting before taking a measurement, but use the short KAMP

S

lead instead of the M-7242 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 to uch the d ev ice un de r test wh ilst t es ting i s in
progress. Since a high voltage of 250V or 500V will be present,
the

user may get an electrical shock.

● Wh en th e mea surement function is complet ed , t ur n t he
function switch back to the OFF position to turn off.

25

DANGER

#

● N e v e r a t tem p t to rep l a c e b a t t eri e s w h i l e m a k i ng

measurements. When replacing the Fuse, use one with the
same specification.

WARNING

#

● To avoid electrical shock hazard, disconnect the Test Leads

from the instrument before opening the Battery Compartment.

  Screw and fasten the cover before using the instrument again.

CAUTION

#

● Do not mix new and old batter ies. Inst all batte ries in the

o

rient ation as sho wn insid e the B at ter y C ompar tment ,

observing correct polarity.

● If the instrument is not to be used for a prolonged period,

remove the batteries.

● When disposing of the old batteries, please follow your local

regulations.

7.1 Battery Replacement

⑴ Set the Range Switch to the OFF position, and disconnect the Test

Leads from the instrument.

⑵ Unscrew the Battery-Compartment

the Cover and replace the batteries with new ones. Replace all 8

batteries.

⑶Fix the Cover after replacing batteries and screw up the Cover.

-fixing screws, and remove

7. Battery
and Fuse
Replacement

7.2 Fuse Replacement

⑴ Set the Range Switch to the OFF position, and disconnect the Test
Leads from the instrument.
⑵ Unscrew the Battery-Compartment-fixing screws, and remove the

Cover.

Replace the fuse with a new one
  Fuse Spec : T 3.15A / 500V, dia. 6.35 x 32mm.
⑶ Fix the Cover after replacing a fuse and screw up the Cover.

. (Fig.15)

26

Battery

Spare Fuse

Screw

Fuse

Battery

and Fuse
Replacement

Fig.15

27

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

8. Case and

strap
assembly

Use a very slightly damp cloth for cleaning the instrument. Do not use

abrasives or

solvents.

9. Maintenance