Megger MFT1500/2 series, MFT1552, MFT1553, MFT1552 series, MFT1553 series user Manual

M

MFT1500/2, MFT1552 and MFT1553 Series
Multifunction Tester

USER MANUAL

GSAFETY WARNINGS

■ Safety Warnings and Precautions must be read and understood before the instrument is used. They must be observed during use.

■ The circuit under test must be switched off, de-energised and isolated before test connections are made when carrying out insulation and continuity

tests.

■ Continuity of protective conductors and earthed equipotential bonding of new or modified installations must be verified before carrying out an earth

fault loop impedance test, or RCD test.

■ Circuit connections and exposed metalwork of an installation or equipment under test must not be touched.

■ The live circuit warning and Automatic discharge are additional safety features and should not be regarded as a substitute for normal safe working

practices.

■ Do not change the rotary switch positions while a test is in progress.

■ The LCD ‘neon’ voltage indicators cannot reveal a Neutral - Earth reversal. They cannot be relied upon to identify circuit correctness and are for

guidance only.

■ After insulation tests, capacitive circuits must be allowed to discharge before disconnecting test leads.

■ The instrument should not be used if any part of it is damaged.

■ Test leads, probes and crocodile clips must be in good order, clean and with no broken or cracked insulation.

■ Ensure that hands remain behind guards of probes/clips when testing.

■ UK Safety Authorities recommend the use of fused test leads when measuring voltage on high energy systems.

■ Replacement fuses must be of the correct type and rating.

Failure to fit the correctly rated fuse will result in damage to the instrument in the event of an overload.

■ The battery cover must be in place whilst conducting tests.

NOTE

THE INSTRUMENT MUST ONLY BE USED BY SUITABLY TRAINED AND COMPETENT PERSONS.

Users of this equipment and/or their employers are reminded that Health and Safety Legislation requires them to carry out valid risk assessments of all
electrical work so as to identify potential sources of electrical danger and risk of electrical injury such as inadvertent short circuits. Where the assessments
show that the risk is significant then the use of fused test leads constructed in accordance with the HSE guidance note GS38 'Electrical Test Equipment for
use by Electricians' should be used.

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CONTENTS

Safety Warnings 2
Description 4

Overview of MFT1500 Series 4

Instrument layout 4
Display 4
Control panel 4
Front switch panel 4
Connection panel 4

Test leads 4
Battery /fuse warning, fitting and replacement 5
Setup 5
Operation 6

General operation 6

Live circuit warning 6

Test button lock 6

Backlight (MFT1502/1552 and 1553 only) 6

Auto shut-off 6

Polarity indication 6

Illuminated switched probe 6

Operation 6

Voltage measurement (V) 7
Continuity 7

Continuity measurement 7

Lead null 8

Continuity buzzer 8

Buzzer threshold 8
Insulation 8

Insulation resistance 8

Insulation voltage ranges 8

Test lock 9
Loop impedance 9

NO TRIP (15 mA) loop test 10

High Current loop test 10

P-N and P-P loop test 11
PFC 12
Residual current device (RCD testing) 14

1/2I, I, 5I, 0 & 180° 14
RCD auto test sequence (MFT1552 only) 15

Ramp testing 15
DC Sensitive RCDs 16
Bluetooth downloading (MFT1553 only) 17
Technical specification 21
Accessories 24
Repair and warranty 25

Appendix - Additional Bluetooth information
(Attaching a Dongle) 26

Symbols used on the instrument are:

F Caution: risk of electric shock
G Caution: refer to accompanying notes
t Equipment protected throughout by Double

Insulation (Class II)

c Equipment complies with current EU directives.

>500V

G

Max 300 V
CAT III

Maximum nominal system voltage of 500 V

Maximum 300 V a.c. CAT III to Earth

g

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DESCRIPTION

Thank you for purchasing the MFT1500 Multifunction Tester. The
MFT1500 series of tester is compact and designed to perform all of the
functions required by the electrical contractor to fully test domestic,
commercial and industrial wiring. Specially designed to comply with UK,
European and other International wiring regulations and standards, the
MFT may be used on all single and three phase systems with rated voltages
up to 300 Volts a.c. rms to earth/ground.

All test leads supplied with the MFT form part of the measuring circuit of
the instrument and must not be modified or changed in any way, or be
used with any other electrical instrument or appliance.

A plug severed from the power cord

MUST be destroyed, as a plug

with bare conductors is hazardous in a live socket outlet.

OVERVIEW OF MFT SERIES

BLUE (RCD)

ORANGE (BUZZER THRESHOLD)

BLACK (BACKLIGHT)
(1502/1552/1553 ONLY)

YELLOW (TEST BUTTON)

RED (TEST LOCK)
(BLUETOOTH)

Connection

indicators

Ohms

Null

Warning

Continuity and
insulation
connections

Switched probe

Test selection

Display

Contact Noise warning

Battery cover (side panel)

RCD range

selection

Fuse warning

Battery status

Temperature

warning

LOOP & RCD
connections

Mains plug test
lead

4

REPLACING FUSES AND BATTERIES

Battery and Fuse fitting/Replacement

Battery type: 8 x 1.5 V alkaline LR6 (AA). Rechargeable batteries must not
be used.
Fuse type: 500 mA (F) HBC 10 kA 500 V
Low battery warning symbol
Fuse blown symbol

Battery charge indication

The battery charge level is automatically indicated when the MFT is turned
on.

To replace batteries

Switch off the instrument and disconnect (the instrument) from any
electrical circuits.

Remove the battery cover.

Slide out the battery clip and remove the dead cells.

Refit new batteries following correct polarity as marked on the battery
holder.

Replace the battery holder and cover.

Note:- Incorrect battery cell polarity can cause electrolyte leakage,
resulting in damage to the instrument.

To replace the fuse

Should the main fuse fail, the symbol fwill be displayed.

Disconnect the instrument from any circuits.

Remove the battery cover as above.

The blown fuse should be replaced with a 500 mA (F) HBC 10 kA 500 V
fuse (Megger part no.25950-039)

f

b

Replace the battery cover.

Setup
RCD Touch voltage selection (to select either 25 V or 50 V)

1. With the instrument turned OFF, hold down the YELLOW test button

and turn the left hand rotary switch to any ON position.

2. Keep the button held down until the instrument displays the ‘SET’

warning.

3. Now release the TEST button.

4. Press the TEST button again to view the current setting for the touch

voltage.

The display shows the touch voltage limit, either ‘25 V’ or ‘50 V’.

Note: The MFT can also display the measured Touch Voltage on a bar­graph display.

If the touch voltage display is active, a bar-graph display will also
appear.

5. Press the ORANGE (buzzer) button to change the touch voltage limit

setting.

6. Press the BLUE (RCD) button to turn the bar-graph display ON or

OFF.

7. Press the TEST button to exit from the set-up menu.

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OPERATION

GENERAL OPERATION

Note: These functions are generally applied and not limited to an
individual test function.

Live circuit warning - Test inhibit

Testing is automatically inhibited if:

During insulation testing - an external voltage >55 V is
present on the terminals

During continuity testing - a voltage >10 V is present on the
terminals

During RCD or No-Trip loop testing - a voltage >270 V is
present

During Loop testing - a voltage >480 V is present

Test button lock

To lock the test button hold down the RED L test lock button whilst

holding down the YELLOW TEST button.

Intelligent backlight (MFT1502/1552/1553 only)

Both the display and range knobs have a backlight. To activate, press the
BLACK Jbutton.

To disable the Intelligent backlight function, press the BLACK
and the RED Llock button together.

Repeat to enable the intelligent backlight.

Instrument auto shut-off

Automatically activated after 5 minutes of instrument inactivity.

To restore operation press the RED lock button or switch the instrument
off and on.

J

button

Polarity indication

If connected to a single-phase power supply by a plug or by the 3-wire lead
set, three LCD ‘neons‘ marked L-PE, N-PE and L-N respectively will indicate
supply polarity.

If a voltage is detected between their respective two wires, the ‘neon’(s)
will activate.

L-PE N-PE L-N

Correct supply indication

Live –neutral swapped

Any other combinations should be investigated further. However the LCD
'NEONS' cannot be relied upon to identify circuit correctness and are for
guidance only.

Note:- The presence of a voltage between phase and earth does not prove
earth continuity, as the earth could have a high resistance and a voltage
would still be measured. To test earth continuity refer to the sections on
loop resistance or RCD testing.

Warning: The LCD 'Neons' are invalid when using the two wire lead-set
and should be ignored.

ILLUMINATED SWITCHED PROBE SPL1000 (MFT1502/1552/1553 ONLY)

The Illuminated switched probe accessory replaces the RED 4 mm test
lead. It can be used anywhere that the 4 mm lead set is specified in this
user guide, and it will also add extra resistance to a loop test measurement.

Operation (SPL1000)

The YELLOW button duplicates the function of the TEST key on the
instrument, allowing quick and easy testing.

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The BLACK switch operates a white LED, which illuminates the probe tip
for use when testing under low light levels.

There is also a visual indication via a red/green LED to notify the user of
the display status, the meanings are as follows:

Green : A valid result is present on the display or the

continuity buzzer is buzzing.

Red: A warning is being shown on the display, testing

will be inhibited.

VOLTAGE MEASUREMENT [V]
TEST LEAD CONNECTION

OPTION 1

2 wire lead
set

BLACK

RED

BLACK

PROBE

OPTION 2

Switched
probe

OPTION 3

Mains plug
test lead L-E

PLUG

OR Using the mains plug lead set (OPTION3)

Voltage between the L and E pins is displayed

Note:- When connected to the circuit under test the instrument will
automatically display AC or DC voltage measurement up to 500 V.

Warning: The voltage measurement range should not be used for
verifying power has been removed (isolated) from a circuit for testing of
documentation, a test lamp should be used.

This function will continue to work if the fuse is blown.

CONTINUITY

Z

Warning: Prior to any continuity testing, ensure the circuits under test are
isolated and not live

TEST LEAD CONNECTION

OPTION 1

2 wire lead
set

BLACK

RED

OPTION 2

Switched
probe

BLACK

Set the Rotary range knob to the [V] range

(The position of the right hand ‘mA’ rotary range knob does not matter)

Two wire lead set or Switched Probe connection

Using the 2-wire lead set OPTION 1 or OPTION 2

1. Connect the test leads as shown.

2. DC Voltage (V) or AC Voltage (V~) is automatically displayed.

PROBE

Set the left hand rotary range knob to the range required.
(The position of the right hand rotary range knob does not matter).

Continuity measurement can be made using one of the 2 options shown
above.

A continuity measurement is made automatically when the test leads

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are connected to the circuit under test. The contact symbol on the
display closes when a resistance of approximately 200 kΩ or less is
detected.

Lead null (up to 9.99 Ω)

Short test probes or clips together and press the YELLOW TEST button on
the instrument (or on the switched probe if fitted). The
displayed to indicate lead null is active.

This null value is stored until the YELLOW TEST button is pressed
again.

To cancel the LEAD NULL, press the YELLOW TEST button.

Continuity Buzzer

Test leads OPTIONS 1 or 2 above

The MFT buzzer will sound continuously if the resistance between the
leads is less than a set limit (Default value 2 Ω).

If being used with the illuminated switched probe (OPTION 2) continuity
is also indicated by a GREEN LED on the probe.

To turn off the buzzer press the TEST button whilst in BUZZER mode. The
display will indicate ON or OFF status.

Buzzer threshold

The resistance at which the buzzer stops sounding can be changed to
meet individual test requirements. Press the ORANGE Zbutton to select
the resistance limit.

Selectable limits of 2 Ω, 5 Ω, 10 Ω, 20 Ω, 50 Ω and 100 Ω.

This setting is stored even when the instrument is switched off.

Z

z

will be

Notes:­Method of measurement

The 2-wire lead set must be used for this measurement. The instrument
produces a d.c. voltage of nominally 4,5 V with a current limit of at least
200 mA when measuring 2 Ω.

Possible sources of error

Measurement results can be affected by the following:

■ The impedance of operating circuits connected in parallel.

■ Impedance such as inductors that vary during the measurement.

■ A poor connection to the circuit under test, which can give readings as

much as 100 mΩ (0,10 Ω) high. The best way to avoid this error is to
use sharp prods and press these firmly into the conductors being
measured.

INSULATION RESISTANCE [MΩ] [250 V] [500 V] [1000 V]

Warning: Prior to any insulation testing, ensure the circuits under test are
isolated and not live.

TEST LEAD CONNECTION

OPTION 1

2 wire lead
set

BLACK

RED

OPTION 2

Switched
probe

BLACK

PROBE

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Set the left hand rotary range knob to the required INSULATION Range.

250 V Insulation measurement to 99.9 MΩ

500 V Insulation measurement to 299 MΩ

1000 V Insulation measurement to 499 MΩ

(The position of the right hand rotary range knob does not matter.)

To initiate insulation testing press and hold the YELLOW TEST button on
the instrument or the switched probe if connected.

Release the test button after the displayed reading has settled.

TEST LOCK

To lock down the test button press the YELLOW TEST button followed by
the RED LOCK L button.

A warning triangle

Press the YELLOW TEST button to stop the test.

Note:- A 1000 V warning is displayed whenever the 1000 V range is selected
and the test button pressed

Warning: The test voltage will be permanently present on the test probes
or crocodile clips when in the locked modes.

Notes:- Auto discharge - Auto discharge facility automatically and safely
discharges connected circuit after test via 250 kΩ resistor.

Live circuit warning - operates when connected to Live circuits > 25 V.

Test Inhibited - an audible alarm operates at >55 V. The instrument
will not perform a test until the voltage source has been removed.

G will appear in the display while the test lock is active.

Method of measurement

A current limited (2 mA) d.c source is used, and the resistance is calculated
from measurements of the voltage and current.

The voltage is only present when the test button is pressed or the test lock
is active. A measurement of the terminal voltage is made before the test and
if this exceeds 55 V the test is disabled. The reading is stable with a circuit
capacitance up to 5 µF.

LOOP IMPEDANCE [LOOP] TESTING

Loop impedance measurement can be made via installation sockets using
the plug terminated test lead at any other convenient point on the
installation, using a two/three wire lead set.

The MFT will measure the loop resistance from the supply end of the
standard test leads, allowing for their resistance.

NON TRIPPING LOOP TESTS [NO TRIP]

Set the LEFT rotary range knob to the required LOOP range as
described below:

OPTION 1

3 wire
measurement

BLACK
GREEN

RED

(The position of the right hand rotary range knob does not matter.)

OPTION 2

Mains plug
test lead

PLUG

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[NO TRIP] LOOP-TESTING - SINGLE PHASE TESTING ONLY

The NO TRIP loop test is a high resolution low current earth loop resistance
measurement (Loop L-PE 0.01 Ω) range which does not trip RCDs with a
rated current 30 mA or higher.

[NO TRIP] PHASE TO EARTH LOOP IMPEDANCE MEASUREMENT
(AT A POWER SOCKET)

Test Lead set: OPTION 2

1. Select

NO TRIP Loop test range.

2. Insert the plug into an installation socket.

3. Supply voltage and polarity are displayed.

4. The test will ‘beep’ and automatically start when voltage is
detected.

5. Measured loop value is displayed

If desired the test can be repeated by pressing the YELLOW TEST button.

[NO TRIP] EARTH LOOP IMPEDANCE MEASUREMENT (NOT AT A
POWER SOCKET)

Test Lead set: OPTION 1

1. Firmly connect the GREEN lead to EARTH, the BLACK lead to
NEUTRAL and the RED lead to PHASE.

2. Perform the loop test, as above for power socket.

If desired the test can be repeated by pressing the YELLOW TEST
button.

PFC MEASUREMENT [NO TRIP PFC]

Use Test Lead set OPTION 1 or OPTION 2

1. Select NO TRIP PFC test range.

2. Connect the leads as shown.

3. Supply voltage and polarity are displayed.

4. The test will ‘beep’ and automatically start when sufficient
voltage is detected.

5. The measured PFC result is displayed.

HIGH CURRENT LOOP-TESTING [HI]

Single Phase and Phase to Phase loop testing on circuits that are NOT
protected by RCD

OPTION 1

2 wire lead
set

GREEN

RED

OPTION 2

Mains plug
test lead

PLUG

Set the instrument to the [HI] Loop test range

High current Phase to Earth loop impedance measurement (at a
power socket):

Test Lead set: OPTION 2

1. Insert the plug into an installation socket.

2. Supply voltage and polarity are displayed.

3. The test will ‘beep’ and automatically start when voltage is
detected.

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