Megger MFT1800 series User manual

MFT1800 series
Multifunction testers
User Guide

This document is copyright of:
Megger Limited, Archcliffe Road, Dover, Kent CT17 9EN. ENGLAND
T+44 (0)1304 502101 F+44 (0)1304 207342 www.megger.com
Megger Limited reserves the right to alter the specification of its products from time to time without
notice. Although every effort is made to ensure the accuracy of the information contained within this
document it is not warranted or represented by Megger Limited to be a complete and up-to-date
description.
For Patent information about this instrument refer to the following web site:
megger.com/patents
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MFT1800 series
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Declaration of Conformity
Hereby, Megger Instruments Limited declares that radio equipment manufactured by Megger Instruments Limited
described in this user guide is in compliance with Directive 2014/53/EU. Other equipment manufactured by Megger
Instruments Limited described in this user guide is in compliance with Directives 2014/30/EU and 2014/35/EU where they
apply.
The full text of Megger Instruments EU declarations of conformity are available at the following internet address:
megger.com/eu-dofc
This manual supersedes all previous issues of this manual. Please ensure that you are using the most recent issue of this
document. Destroy any copies that are of an older issue.
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Contents
1. Safety ............................................................................................................................................8
1.1. Safety Warnings.......................................................................................................................................8
1.2. Live earth safety precautions..................................................................................................................9
1.3. Symbols used on the instrument ............................................................................................................10
2. Introduction ..................................................................................................................................11
2.1. Overview ..................................................................................................................................................11
2.1.1. Front panel and controls........................................................................................................................11
2.1.2. Display ..................................................................................................................................................12
2.1.3. Display symbols.....................................................................................................................................12
2.1.4. Waste electrical and electronic equipment.............................................................................................13
2.1.5. Battery and fuse location, fitting and replacement.................................................................................13
3. Operation......................................................................................................................................15
3.1. General operation – all models ..............................................................................................................15
3.1.1. Switching on.........................................................................................................................................15
3.1.2. Switching off.........................................................................................................................................15
3.1.3. Backlight...............................................................................................................................................15
3.1.4. Test buttons ..........................................................................................................................................15
3.1.5. Test button lock ....................................................................................................................................15
3.2. Mode button functions .....................................................................................................................16
3.3. Test inhibit ...............................................................................................................................................17
3.3.1. Insulation ..............................................................................................................................................17
3.3.2. Continuity.............................................................................................................................................17
3.3.3. Earth loop impedance ...........................................................................................................................17
3.3.4. RCD/GFCI testing ..................................................................................................................................17
3.3.5. Earth testing .........................................................................................................................................17
3.3.6. Battery exhausted .................................................................................................................................17
4. Voltage, frequency, current and temperature measurement ................................................... 18
4.1. Making a voltage measurement.............................................................................................................18
4.2. Frequency measurement.........................................................................................................................19
4.3. Phase rotation .........................................................................................................................................19
4.4. Leakage current measurement...............................................................................................................19
4.5. Temperature measurement ....................................................................................................................19
4.6. Switch probe............................................................................................................................................20
5. Continuity / resistance measurement.........................................................................................21
5.1. Nulling test lead resistance (up to 9.99 ohms) W................................................................................21
5.2. Making a CONTINUITY measurement....................................................................................................22
5.3. Storing / downloading results.................................................................................................................22
5.4. Continuity Buzzer ON/OFF ......................................................................................................................22
5.5. Switch probe (SP5)...................................................................................................................................23
5.6. Buzzer threshold .....................................................................................................................................23
5.7. Measurement methods and sources of error.........................................................................................23
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6. Insulation resistance 500
V..............................................................................................................24
6.1. Making an INSULATION measurement ..................................................................................................24
6.2. Insulation test lock ..................................................................................................................................25
6.3. Measurement methods and sources of error.........................................................................................25
7. Loop impedance testing ..............................................................................................................26
7.1. Range selection and test leads ...............................................................................................................26
7.1.1. Phase to earth L-E circuits......................................................................................................................26
7.1.2. L-N or L-L circuits...................................................................................................................................28
7.1.3. Z, Zmax, Zref and R1+R2.......................................................................................................................28
7.2. Making a loop impedance measurement ..............................................................................................28
7.2.1. Ze measurements at the origin (Phase to Earth) .....................................................................................28
7.2.2. Zs and Zdb loop measurements without RCD - eg Zs, Zdb etc................................................................29
7.2.3. Earth Loop measurements with an RCD in circuit................................................................................... 30
7.3. Phase to Neutral (all models) or Phase to Phase testing.......................................................................32
7.4. Prospective Fault Current and Short Circuit calculation (PFC & PSCC) .................................................33
7.5. Confidence MeterTM for non-trip (3Lo) loop impedance tests ...........................................................34
7.5.1. Display information ...........................................................................................................................34
7.5.2. 3Lo Loop Impedance Measurement..................................................................................................34
7.6. Measurement methods and sources of error.........................................................................................36
8. Residual Current Device (RCD) or Ground Fault Current Interrupt (GFCI) testing ................... 37
8.1. Making an RCD measurement................................................................................................................38
8.2. Selecting RCD type ..................................................................................................................................38
8.3. ½ x I RCD current rating (No-trip test) ........................................................................................39
8.4. 1 x I RCD current rating (Tripping test on 30 mA RCD) .......................................................................40
8.5. 2 x I RCD Current Rating (Tripping test on 30mA RCD) (Not MFT1815) ............................................41
8.6. 5 x I RCD current rating (Tripping test on 30 mA RCD) .......................................................................41
8.7. Ramp test ..........................................................................................................................................42
8.8. Fast Ramp Test.........................................................................................................................................42
8.9. Type A (DC Sensitive) RCD test ...................................................................................................42
8.10. Type B (Pure DC) RCD test (Not MFT1815) ...........................................................................................43
8.11. Variable RCDs......................................................................................................................................... 44
8.12. AUTO RCD testing .................................................................................................................................44
8.13. 3 Phase RCD testing...............................................................................................................................45
8.14. Touch voltage display............................................................................................................................45
8.15. Measurement methods and sources of error.......................................................................................46
8.16. Useful information ................................................................................................................................46
9. Testing of Electric Vehicle Charge Point RCD’s ........................................................................... 47
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10. Earth resistance measurement ..................................................................................................49
10.1. Connection terminals ............................................................................................................................49
10.2. Touch voltage limit................................................................................................................................ 49
10.3. Making a measurement – Two pole resistance measurement............................................................ 49
10.4. Making a measurement – Three terminal resistance measurement ..................................................50
10.5. Making a measurement – Three terminal resistance measurement using ART ................................51
10.6. Two-clamp stake-less measurement (MFT1835 and MFT1845+ Only)................................................52
11. Setup options .............................................................................................................................53
12. Warning messages ..................................................................................................................... 54
12.1. Startup warnings ...................................................................................................................................54
12.2. Battery....................................................................................................................................................54
12.3. Battery charger......................................................................................................................................54
12.4. Fuse warning .........................................................................................................................................54
12.5. Invalid rotary switch setting .................................................................................................................54
12.6. Continuity test .......................................................................................................................................54
12.7. Insulation test ........................................................................................................................................54
12.8. RCD test (or GFCI) .................................................................................................................................. 54
12.9. RCD range selection errors....................................................................................................................55
12.10. Loop test ..............................................................................................................................................55
12.11. Earth test .............................................................................................................................................55
12.12. Test will not start .................................................................................................................................55
13. Appendix A – Sending, Storing, Deleting and Recalling Test Results
(MFT1835 and MFT1845+) .......................................................................................................... 56
14. Appedix B – Downloading data via Bluetooth®
(MFT1835 and MFT1845+) .......................................................................................................... 60
15. Appendix C – Installation category definitions........................................................................61
16. Appendix D – Safe working practice ........................................................................................61
17. Appendix E – Cleaning and maintenance.................................................................................61
18. Appendix F – Earth resistance testing – Basic principles ......................................................... 62
18.1. F.1 Principle of operation (three-terminal resistance measurement)................................................62
18.2. F.2 Principle of operation (three-terminal resistance measurement using ART) ..............................63
18.3. F.3 Principle of operation (two-clamp stake-less resistance measurement)......................................63
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19. Specifications..............................................................................................................................64
19.1. Accuracy .................................................................................................................................................64
19.1.1. Insulation test .....................................................................................................................................64
19.1.2. Continuity / Resistance ........................................................................................................................64
19.1.3. Loop test 2Hi (L-PE, L-N, L-L) ...............................................................................................................64
19.1.4. Loop test 3Lo, 2Lo (L-E).......................................................................................................................64
19.1.5. RCD test ............................................................................................................................................. 65
19.1.6. Voltage ...............................................................................................................................................65
19.1.7. Frequency ...........................................................................................................................................65
19.1.8. Earth test ranges .................................................................................................................................65
19.1.9. Current (via Clamp meter)...................................................................................................................65
19.1.10. mV Sensor input ..............................................................................................................................66
19.1.11. Internal memory................................................................................................................................66
19.1.12. Power consumption ..........................................................................................................................66
19.1.13. Temperature (via 3rd Party Module) ...................................................................................................66
19.2. Environmental Specification.................................................................................................................66
20. Accessories..................................................................................................................................67
21. Repair and Warranty..................................................................................................................68
21.1. Calibration, repair and spare parts.......................................................................................................68
21.2. Approved Service Centres ..................................................................................................................... 68
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1. Safety
1.1 Safety 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, RCD or earth testing
Do not touch circuit connections and exposed metalwork of an installation or equipment under test. Under fault
conditions the system earth could become hazardous live.
Do not touch the earth stakes, test leads and their terminations (including connections to the earthing system
under test) if an installation earth fault can arise, unless adequate precautions are taken.
The ‘live circuit warning’ and ‘automatic discharge’ functions are additional safety features and should not be
regarded as a substitute for normal safe working practices.
Do not move the rotary switch positions while a test is in progress.
Do not operate the instrument or connect it to any external system if it shows any visible signs of damage or if it
has been stored for prolonged periods in unfavourable conditions.
Do not operate the instrument or connect it to any external system if the battery compartment or casing is open
or any parts of the case (including keypad, selector switch, display window, etc.) are missing.
Always disconnect the instrument from all systems while batteries are being changed or the fuse replaced.
Do not replace rechargeable cells in the instrument with non-rechargeable “dry” cells and attempt to charge the
cells. This can cause explosion or fire.
Do not operate charging equipment supplied with the instrument in damp or wet environments or outdoors. All
test leads must be removed from the instrument while charging.
After insulation tests, capacitive circuits must be allowed to discharge before disconnecting test leads. Locking
the insulation test ON should only be used where there is no risk of a circuit holding a charge.
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.
All test leads supplied with the instrument form part of the measuring circuit of the instrument. They 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.
Ensure that hands remain behind guards of probes/clips when testing.
U.K. 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.
Special precautions are necessary when operating in situations where “live” earths may be encountered:
isolation switches and fuses (not supplied with this instrument) must be used.
Special precautions are necessary when working near high tension systems (MV and HV): rubber gloves and
shoes (not supplied with this instrument) should be worn.
Special precautions are necessary when working in wet conditions or in agricultural areas: observe the local
safety standards and take all necessary special precautions applicable to the particular location and do not touch
the test leads with bare hands.
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Safety

1.2 Live earth safety precautions
A ‘Live’ earth is one that carries current from the mains supply, or could do so under fault conditions. The following
warnings apply in addition to those listed previously:
All persons involved must be trained and competent in isolation and safety procedures for the system to be
worked on. They must be clearly instructed not to touch the earth electrode, test stakes, test leads, or their
terminations if any ‘Live’ earths may be encountered. It is recommended that they wear appropriate rubber
gloves, rubber soled shoes, and stand on a rubber mat.
The earth electrode under test should be isolated from the circuit it is protecting before testing commences. If
this is not possible, ART (attached Rod Technique) may be used to measure electrode resistance.
The instrument terminals should be connected to the system under test through isolation switches that are rated
to handle the likely maximum fault voltages and currents that could be encountered at the installation. The
isolation switch must be open whilst any personal contact is made with the remote test stakes, or the connecting
leads, e.g. when changing their position.
The instrument terminals should be connected to the system under test through fuses that are rated to handle
the likely maximum fault voltages and currents that could be encountered at the installation.
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 not GS38 ‘Electrical Test Equipment for use by
Electricians’ should be used .
This instrument is internally protected against electrical damage when used for the purposes of testing low voltage
electrical installations as defined herein. If used in a manor other than those defined in this user guide, the protection
capabilities could be impaired with potential risk to the operator and the instrument.
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Safety

1.3 Symbols used on the instrument
This section details the various safety and hazard icons on the instruments outer case.
Icon Description
GCaution: Refer to accompanying notes

Maximum 300 V AC CAT IV to earth
> 600 V Maximum nominal system voltage of 600 V
fInstrument protected by 2 x F2 1000 V 30 kA fuses
cEquipment complies with current EU directives
Equipment complies with current UK legislation
Do not dispose of to landfill, sewage systems or by fire.
Equipment complies with current ‘C tick’ requirements
12 V DC charger socket
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MFT1800 series
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Safety

2. Introduction
Congratulations on your purchase of a genuine Megger Multifunction tester. The MFT1800 series Multi-function
tester is a compact instrument 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 U.K., European and other
International wiring regulations and standards, the MFT1800 may be used on all single and three phase systems with
rated voltages up to 300 V AC. rms to earth (ground).
2.1 Overview
2.1.1. Front panel and controls
EV
45+
1
6
2
7
3 4
8
5 1
9
Item Description Item Description
1Test button
Lead Null
6Test lock
Setup selector
Results store
2Mode 7Display backlight
3Display 8Touch voltage contact point
4Primary functions 9Test lock
Setup selector
5Secondary functions
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Introduction

2.1.2. Display
NOTE : Some features detailed within this user
guide are model dependent.
Not all features appear on all models
2.1.3. Display symbols
Symbol Description Symbol Description
Test function locked on (also used to
indicate a change is saved in setup) GWarning triangle – instruction to refer to this user guide
zTest lead null active fFuse blown
UL= 50V Touch voltage limit (and Earth test voltage)
set to 50 V (change setup) Battery indicator
Buzzer enabled NiMH Battery type set to rechargeable NiMH -
Change in setup section 10
AUTO RCD test in AUTO mode >100 V
Indicates that the ground noise voltage
exceeds the instrument measurement
capability (test is inhibited)
Type AC RCD selected Rp (Rs)
Potential stake (P stake)
resistance exceeds range for accurate
measurement
Type A RCD selected Rc (RH)
Current stake (C Stake)
resistance exceeds range for accurate
measurement
SType S RCD (Type AC) V
Ground noise voltage exceeds range for
accurate measurement of resistance
SType S RCD (Type A) V MVC1010 error
Type B RCD selected I MCC1010 error
Fast or Full RAMP test selected Bluetooth®enabled
TEST Instrument is running a test TInstrument is too hot, allow to cool
Earth loop noise detected. N<->L Live and neutral connections reversed
Zref Reference loop measurement R1+R2 Loop measurement with Zref value
automatically deducted
ZMAX Loop maximum measurement
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Introduction

2.1.4. Waste electrical and electronic equipment
WEEE
The crossed out wheeled bin placed on Megger products is a reminder not to dispose of the product at the end
of its life with general waste.
Megger is registered in the UK as a producer of electrical and electronic equipment. The Registration No is WEE/
HE0146QT
2.1.5. Battery and fuse location, fitting and replacement
Battery type: 6 x 1.5 V Alkaline LR6 (AA) or NiMH HR6 rechargeable
Fuse type: 2 x F2 1000 V 30 kA fuses
Battery condition is shown by the following display symbols:
Where NiMH rechargeable batteries are fitted, the battery condition display can be adjusted accordingly. Refer to
section 10 Setup options to change between alkaline and rechargeable batteries.
When set to NiMH batteries, the battery indicator in the display wil show NiMH under the battery status symbol as
below: (Feature available on all models).
NiMH
To replace batteries or fuse:
Switch off the instrument.
Disconnect the instrument from any electrical circuits.
Remove the battery cover from the base.
For battery replacement:
Remove old cells and refit new batteries following correct polarity as marked on the battery holder.
Replace the battery cover.
Incorrect battery cell polarity can cause electrolyte leakage, resulting in damage to the instrument.
For fuse replacement
Withdraw each fuse in turn and check for failure. The blown fuse must be replaced with a F2 1000 V 30 kA fuse.
Rechargeable batteries and battery charging
Some models are supplied with rechargeable NiMH cells. These batteries can be charged in the instrument, using the
supplied Megger charger.
To charge the batteries:
Ensure fitted batteries are of the rechargeable NiMH type.
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Introduction

Connect the 12 V DC plug of the charger to the socket on the front of the MFT marked
WARNING : Whenever battery cells are being recharged, there should be no connections to the instrument
terminals and the instrument should be switched off.
WARNING : Do not attempt to recharge non-rechargeable (Primary) cells. Doing so may result in
instrument damage and may cause personal injury.
Ensure ambient temperatures are between 4 ºC and 40 ºC while charging the MFT.
NOTE : The crossed out wheeled bin placed on the batteries is a reminder not to dispose of them with
general waste at the end of their life.
Spent Alkaline and NiMH batteries are classified as portable batteries and should be disposed of in the UK in
accordance with Local Authority requirements. For disposal of batteries in other parts of the EU contact your local
distributor.
Megger is registered in the UK as a producer of batteries.
The Registration number is BPRN00142
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Introduction

3. Operation
3.1 General operation – all models
3.1.1. Switching on
Turn the rotary knob away from the off position.
The instrument will perform internal self tests then display the appropriate test screen, depending on the position of
the function knobs.
3.1.2. Switching off
Turn the primary function knob to the OFF position.
The instrument will automatically turn itself off after 20 minutes* of inactivity. Press any button or turn either of the
rotary knobs to turn back on.
* 2 minute option in Setup, refer to section 10.
3.1.3. Backlight
Press the backlight button. The backlight will operate for 20 seconds.
3.1.4. Test buttons
Test buttons are duplicated on the left and right. Both buttons perform the same function except, when the is
displayed, in this case the right hand buttons perform a scrolling function. The left RED button also performs storage
and lock functions on the MFT1731.
3.1.5. Test button lock
To lock the test button, hold down either of the RED test lock buttons with the symbol, whilst holding down the
test button. If is displayed, the right hand buttons perform a scrolling function.
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Operation

3.2 Mode button functions
The function of the mode button is dependent on the test function selected:
Test selected Function Options Comments
V / mV ºC Volts (mv model specific) Temperature requires suitable
transducer
Continuity
RLO
Buzzer
ENABLE/DISABLE
Buzzer ON
Buzzer OFF
Buzzes on <2 Ω
May be changed in SETUP.
Refer to “11. Setup options” on
page 53.
Insulation
RSIO Buzzer
ENABLE/DISABLE
Buzzer ON
Buzzer OFF
Buzzes on <1 MΩ
May be changed in SETUP.
Refer to “11. Setup options” on
page 53.
Loop impedance (Z)
L-PE
3Lo - 3 wire no trip
2Hi – 2 wire high current
2Lo – 2 wire no trip
3Lo
2Hi
2Lo
3Lo default measurement
2Lo not available if 3 wire
connection is detected
RCD/GFCI
0º /180º selection 0º
180º (Press and release)
RCD Type
AC
A
AC(s)
A(s)
B
(Press and HOLD)
Type B available on MFT1835 and
MFT1845+ only
EARTH (RE) Touch voltage limit 50 V/ 25 V (Press and release)
SETUP
Refer to “11. Setup
options” on page
53.
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Operation

3.3 Test inhibit
Each test mode has conditions under which testing will be inhibited, as below:
3.3.1. Insulation
Detection of a circuit voltage above 50 V (a warning is displayed at 25 V)
3.3.2. Continuity
Detection of a circuit voltage above that used by the instrument will inhibit testing
3.3.3. Earth loop impedance
Touch voltage exceeds 50 V (or 25 V depending on instrument configuration)
Supply voltage over range or under range
Supply frequency out of specification
3.3.4. RCD/GFCI testing
Touch voltage detected or predicted to exceed 50 V (or 25 V depending on instrument configuration)
Supply voltage over range or under range
Supply Frequency out of specification
3.3.5. Earth testing
External voltage greater than 25 V present
Leads not connected as per the test requirements
Potential stake not within range (Rp)
Current stake not within range (Rc)
Other conditions that will inhibit testing include:
3.3.6. Battery exhausted
All testing will be inhibited in the event of a flat battery, refer to “2.1.5. Battery and fuse location, fitting and
replacement” on page 13.
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Operation

4. Voltage, frequency, current and temperature measurement
4.1 Making a voltage measurement
1. Set the Main rotary range knob to volts

(The position of the right hand rotary range knob does not matter)
2. Using two test leads, connect test leads to the L1 (+ve) and L2 (-ve) terminals
L1
L2
L3
N
E
L1
L2
L3
N
E
OR if Using the Mains plug Lead SAI10:
1. Connection (a)
For Live to Neutral measurements, connect the Red connector to the L1 terminal and the Blue connector to the
L2 terminal
2. Connection (b)
For Live to Earth measurements connect the Red test to the L1 terminal and the Green connector to the L2
terminal
L1
N
E
L1
N
E
Connection (a) Connection (b)
NOTE : When connecting all three test leads (eg Phase, Neutral and Earth) or the mains plug test lead, the
voltage displayed is the highest of the three possible voltages.
Pressing either TEST button scrolls through L-E, N-E and L-N individual voltages. When the frequency of supply is
shown, the voltage displayed reverts to the maximum voltage across all 3 terminals.
On models with a dedicated mV range this is selected using the Mode button to select mV mode.
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Voltage, frequency, current and temperature measurement

4.2 Frequency measurement
1. Automatically displayed when connecting to a live circuit as per 4.1
4.3 Phase rotation
Display of Phase rotation is Automatic when all three test leads are connected to the 3 phase supply as below:
1. Set the main rotary range knob to volts

(The position of the right hand rotary range knob does not matter)
2. Using three test leads, connect test leads to the L1 to Phase1, L2 to Phase 2 and L3 to Phase 3. The MFT will
display L1 L2 L3 or L1 L3 L2 depending on the direction of phase rotation.
L1
L2
L3
Normal rotation Reverse rotation
4.4 Leakage current measurement
Leakage current measurement uses the optional accessory current clamp (MCC1010).
1. On the MFT1825 and 1835 set the primary (left hand) knob to RE and the secondary (right hand) knob to A
2. Connect to MCC1010 (part No. MCC1010) to the MCC1010 socket on the MFT
3. Connect the clamp to the circuit conductor. The instrument will display the ac current flowing in the conductor.
4.5 Temperature measurement (not on MFT1815)
1. Connect the thermocouple transducer to the L1 (+ve) and L2 (-ve) terminals. The transducer should have a 1 mV
DC output per °C.
2. Press the Mode button to select ºC. (Pressing the mode button will cycle round the V, mV and ºC
measurement modes). The display will show the temperature at the tip of the temperature probe.
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Voltage, frequency, current and temperature measurement

4.6 Switch probe
In the V/mV/ºC mode all measurements except temperature can be made with the
remote switch probe. Tests are automatic and do not require the test button to be
pressed.
L1
L2
L3
N
E
1. Connect the switch probe to the switch probe socket. The probe replaces the
standard RED test lead and can now be used as a normal test probe.
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Voltage, frequency, current and temperature measurement