METREL MI 3288 User manual

EI Tester
MI 3288
Instruction manual
Version 1.2.2, Code No. 20 753 190

2
Distributor:
Manufacturer:
METREL d.d.
Ljubljanska cesta 77
1354 Horjul
Slovenia
web site: http://www.metrel.si
e-mail: [e-mail]
Mark on your equipment certifies that it meets requirements of all subjected EU regulations
© 2021 METREL
The trade names Metrel®, Smartec®, Eurotest®, Auto Sequence®are trademarks registered in Europe and
other countries.
No part of this publication may be reproduced or utilized in any form or by any means without
permission in writing from METREL.

3
i. About the Instruction manual
➢This Instruction manual contains detailed information on the MI 3288, its key
features, functionalities and use.
➢It is intended for technically qualified personnel responsible for the product
and its use.
➢Please note that LCD screenshots in this document may differ from the actual
instrument screens in details due to firmware variations and modifications.
➢Metrel reserve the right to make technical modifications without notice as part of
the further development of the product.
➢MI 3288 instrument is available in multiple sets with a combination of different
accessories and measurement functions. The functionality of an existing set can
be expanded by ordering additional accessory and license keys.
See Appendix B–Profiles Selection Table for more information.

MI 3288 EI Tester Table of contents
4
Table of contents
1General description.................................................................................................8
1.1 Features............................................................................................................8
2Safety and operational considerations..................................................................9
2.1 Warnings and notes ..........................................................................................9
2.2 Battery and charging of Li-ion battery pack.....................................................11
2.2.1 Precharge.................................................................................................12
2.2.2 Li –ion battery pack guidelines................................................................14
2.3 Standards applied ...........................................................................................15
3Terms and definitions ...........................................................................................16
4Instrument description..........................................................................................17
4.1 Operator’s panel..............................................................................................17
4.2 Connector panel..............................................................................................18
4.2.1 Designation of the Test connector terminals............................................18
4.3 Back side.........................................................................................................19
4.3.1 Secure attachment of the strap ................................................................21
5Accessories............................................................................................................22
5.1 Standard set....................................................................................................22
5.2 Optional accessories.......................................................................................22
6Instrument operation.............................................................................................23
6.1 General meaning of keys.................................................................................23
6.2 General meaning of touch gestures ................................................................23
6.3 Virtual keyboard ..............................................................................................24
6.4 Display and sound...........................................................................................25
6.4.1 Battery and time indication.......................................................................25
6.4.2 Messages.................................................................................................25
6.4.3 Sound indication.......................................................................................27
6.4.4 Terminal voltage monitor..........................................................................27
6.4.5 Bluetooth..................................................................................................28
6.4.6 Help screens............................................................................................28
7Main menu..............................................................................................................29
7.1 Instruments main menu...................................................................................29
8General Settings....................................................................................................30
8.1 Language ........................................................................................................31
8.2 Power Save.....................................................................................................31
8.3 Date and time..................................................................................................32
8.4 Instrument profiles...........................................................................................32
8.5 Settings ...........................................................................................................33
8.6 Initial Settings..................................................................................................34
8.7 About...............................................................................................................34
8.8 Auto Sequence® groups .................................................................................35
8.8.1 Auto Sequence® groups menu ................................................................35
8.8.2 Operations in Auto Sequence® groups menu: .........................................35
8.8.3 Selecting a list of Auto Sequences® ........................................................36
8.8.4 Deleting a list of Auto Sequences®..........................................................36
8.9 Workspace manager .......................................................................................37
8.9.1 Workspaces and Exports .........................................................................37

MI 3288 EI Tester Table of contents
5
8.9.2 Workspace Manager main menu .............................................................37
8.9.3 Operations with Workspaces....................................................................38
8.9.4 Operations with Exports...........................................................................38
8.9.5 Adding a new Workspace.........................................................................39
8.9.6 Opening a Workspace..............................................................................40
8.9.7 Deleting a Workspace / Export.................................................................40
8.9.8 Importing a Workspace ............................................................................41
8.9.9 Exporting a Workspace............................................................................41
8.10 User accounts .................................................................................................43
8.10.1 Signing in .................................................................................................43
8.10.2 Changing user password, signing out ......................................................44
8.10.3 Managing accounts..................................................................................45
8.10.4 Setting Black-box password.....................................................................47
9Memory Organizer.................................................................................................48
9.1 Memory Organizer menu.................................................................................48
9.1.1 Measurement statuses.............................................................................48
9.1.2 Structure items.........................................................................................49
9.1.3 Measurement status indication under the Structure item .........................49
9.1.4 Operations in Tree menu..........................................................................50
10 Single tests.............................................................................................................64
10.1 Selection modes..............................................................................................64
10.1.1 Single test screens...................................................................................65
10.1.2 Setting parameters and limits of single tests............................................66
10.1.3 Single test result screen...........................................................................67
10.1.4 Recall single test result screen.................................................................68
10.1.5 Single test (Visual Test) screens..............................................................68
10.1.6 Single test (Visual Test) start screen........................................................69
10.1.7 Single test (Visual Test) screen during test..............................................70
10.1.8 Single test (Visual Test) result screen......................................................71
10.1.9 Single test (Visual Test) memory screen..................................................72
11 Tests and Measurements......................................................................................73
11.1 Visual tests......................................................................................................73
11.2 Voltage and Frequency Measurements [U/f]...................................................75
11.2.1 Voltage Meter...........................................................................................75
11.3 Earth Measurements [Ze and Re] ...................................................................77
11.3.1 2 –pole measurement..............................................................................77
11.3.2 3 –pole measurement..............................................................................79
11.3.3 4 –pole measurement..............................................................................81
11.3.4 Selective (Iron Clamp) measurement.......................................................82
11.3.5 2 Clamps measurement...........................................................................84
11.4 Specific Earth Resistance Measurements[ρ] ...................................................87
11.4.1 General on specific earth .........................................................................87
11.4.2 Wenner method measurement.................................................................88
11.4.3 Schlumberger method measurement.......................................................90
11.5 Earth Potential [Us] .........................................................................................92
11.5.1 Step and Touch Measurement.................................................................93
11.6 DC Resistance [R]...........................................................................................95
11.6.1 Ω - Meter (200 mA) Measurement............................................................96
11.6.2 Ω - Meter (7 mA) Measurement................................................................97

MI 3288 EI Tester Table of contents
6
11.7 Insulation Resistance Measurement [Riso] .....................................................99
11.7.1 Insulation Resistance measurement ......................................................100
11.7.2 Diagnostic Test ......................................................................................101
11.7.3 Varistor Test...........................................................................................105
11.8 Current [I] ......................................................................................................106
11.8.1 Current Clamp Meter..............................................................................107
12 Auto Sequences®................................................................................................108
12.1 Selection of Auto Sequence®........................................................................108
12.1.1 Selecting an active Auto Sequence® group in Auto Sequences® menu108
12.1.2 Searching in Auto Sequences® menu ...................................................109
12.1.3 Organization of Auto Sequences® in Auto Sequences® menu .............110
12.2 Organization of Auto Sequence® ..................................................................112
12.2.1 Auto Sequence® view menu ..................................................................112
12.2.2 Step by step executions of Auto Sequence® .........................................113
12.2.3 Auto Sequence® result screen...............................................................114
12.2.4 Auto sequence memory screen..............................................................117
13 Communication....................................................................................................118
14 Maintenance.........................................................................................................119
14.1 Fuse replacement..........................................................................................119
14.2 Battery pack insertion / replacement .............................................................120
14.3 Cleaning........................................................................................................121
14.4 Periodic calibration........................................................................................121
14.5 Service ..........................................................................................................121
14.6 Upgrading the instrument..............................................................................121
15 Technical specifications .....................................................................................122
15.1 Voltage and frequency [U/f]...........................................................................122
15.1.1 Voltage Meter RMS................................................................................122
15.1.2 Frequency..............................................................................................122
15.2 Current [I] ......................................................................................................123
15.2.1 Iron (A 1281) and Flex (A 1227, A 1609) current clamp.........................123
15.3 Earth [Ze].......................................................................................................124
15.3.1 2, 3, 4 - pole...........................................................................................124
15.3.2 Selective (Iron Clamp)............................................................................125
15.3.3 2 Clamps................................................................................................126
15.4 Specific Earth Resistance Measurements [ρ] ................................................127
15.4.1 Wenner and Schlumberger method........................................................127
15.5 Earth Potential [Us] .......................................................................................128
15.5.1 Step and Touch......................................................................................128
15.6 DC Resistance [R].........................................................................................129
15.6.1 Ω - Meter (200mA) .................................................................................129
15.6.2 Ω - Meter (7mA) .....................................................................................130
15.7 Insulation Resistance Measurement [Riso] ...................................................131
15.7.1 Insulation Resistance - (IR, DD, - Test)..................................................131
15.7.2 Varistor test............................................................................................133
15.8 Influence of the auxiliary electrodes..............................................................134
15.9 Influence of low test current through clamps.................................................134
15.10 Influence of noise ..........................................................................................135
15.10.1 Digital filtering technique........................................................................136
15.11 Sub-results in measurement functions ..........................................................136

MI 3288 EI Tester Table of contents
7
15.12 General data..................................................................................................137
Appendix A –Structure objects...........................................................................139
Appendix B –Profiles Selection Table ................................................................140
Appendix C –Functionality and placing of test probes.....................................141
Appendix D –Programming of Auto Sequences® on Metrel ES Manager .......145
D.1 Auto Sequence® Editor workspace...............................................................145
D.2 Managing groups of Auto Sequences®.........................................................146
D.2.1 Auto Sequences® Name, Description and Image editing ......................148
D.2.2 Search within selected Auto sequence® group......................................149
D.3 Elements of an Auto Sequence® ..................................................................149
D.3.1 Auto Sequence® steps...........................................................................149
D.3.2 Single tests.............................................................................................149
D.3.3 Flow commands.....................................................................................150
D.3.4 Number of measurement steps..............................................................150
D.4 Creating / modifying an Auto Sequence® .....................................................150
D.5 Description of flow commands.......................................................................151
D.6 Custom Inspection programming...................................................................152
D.6.1 Creating and editing Custom Inspections...............................................152
D.6.2 Applying Custom Inspections.................................................................154

MI 3288 EI Tester General description
8
1 General description
1.1 Features
EI (Earth –Insulation) Tester (MI 3288) is a Multi-function, portable battery (Li-ion) test
instrument with excellent IP protection IP54, intended for: Voltage and frequency measurement
(TRMS), Insulation resistance measurement up to 2,5 kV, Earth resistance and impedance,
Specific earth resistance, Earth potential and continuity (7 mA, 200 mA) measurement. It is
designed and produced with the extensive knowledge and experience acquired through many
years of working in this field.
Available functions and features offered by the MI 3288 Tester:
➢Voltage and frequency measurement up to 1 kV TRMS;
➢Earth Impedance or Resistance 2, 3, 4 –pole;
➢Selective Earth Impedance (Iron Clamp);
➢2 Clamps measurement;
➢Specific Earth Resistance ρ (Wenner, Schlumberger method);
➢Earth Potential;
➢Insulation measurement from 50 to 2500 V;
➢Polarization Index (PI) and Dielectric Absorption ratio (DAR);
➢Dielectric Discharge ratio (DD);
➢Capacitance measurement;
➢Varistor test (Over-voltage Protection Devices);
➢Ω - Meter (7 mA and 200 mA);
➢Current RMS Measurement;
➢Auto Sequence®;
➢Visual Test;
➢Memory Organizer.
A 4.3'' (10.9 cm) colour LCD display with touch screen offers easy-to-read results and all
associated parameters. The operation is straightforward and clear to enable the user to operate
the instrument without the need for special training (except reading and understanding this
Instruction Manual).
Test results can be stored on the instrument. PC software that is supplied as a part of standard
set enables transfer of measured results to PC where can be analysed or printed.
MI 3288 EI Tester
according to:
2 –pole
3 –pole
4 –pole
EN 61557 –5 [Resistance to earth]
IEEE Std 81 –2012 [Two-point method, Three-point method,
Fall-of-potential method]
2 Clamps
IEEE Std 81 –2012 [Resistance measurements by clamp-on stakeless method]
Selective (Iron Clamp)
IEEE Std 81 –2012 [Resistance measurements by FOP/clamp-on method]
Wenner Method
Schlumberger Method
IEEE Std 81 –2012 [Four-point method (Equally Spaced or Wenner
Arrangement); (Unequally Spaced or Schlumberger-Palmer Arrangement)]
Ω - Meter (200mA)
EN 61557 –4 [Resistance of earth connection and equipotential bonding]
Insulation Resistance
EN 61557 –2 [Insulation resistance]

MI 3288 EI Tester Safety and operational considerations
9
2 Safety and operational considerations
2.1 Warnings and notes
In order to maintain the highest level of operator safety while carrying out various tests and
measurements Metrel recommends keeping your MI 3288 instruments in good condition and
undamaged. When using the instrument, consider the following general warnings:
▪The symbol on the test equipment means »Read the Instruction manual with
special care for safe operation«. The symbol requires an action!
▪If the test equipment is used in a manner not specified in this Instruction manual,
the protection provided by the equipment could be impaired!
▪Read this Instruction manual carefully, otherwise the use of the test equipment
may be dangerous for the operator, the test equipment itself or for the tested
object!
▪A lethal voltage can exist between the ground electrode under test and a remote
ground!
▪Do not use the test equipment or any of the accessories if any damage is noticed!
▪Consider all generally known precautions in order to avoid risk of electric shock
while dealing with hazardous voltages!
▪Do not connect the test equipment to a mains voltage different from the one
defined on the label adjacent to the mains connector, otherwise it may be
damaged.
▪Service intervention or adjustment is only allowed to be carried out by competent
authorized personnel!
▪All normal safety precautions must be taken in order to avoid risk of electric
shock while working on electrical installations!
▪Do not use the equipment in a wet environment, around explosive gas, vapour.
▪Only adequately trained and competent persons may operate the equipment.
▪Do not connect any voltage source on GUARD (C1) terminal. It is intended only for
connection of GUARD lead.
2 wire test accessory:
▪Maximum allowed input voltage between HV+ and HV- test terminals on test
connector is 1000 V! (CAT II 1000 V)
4 wire test accessories:
▪Maximum allowed input voltage between C1 and C2 or H and E test terminals on
test connector is 1000 V! (CAT II 1000 V)
▪Maximum allowed input voltage between any other combination of test terminals
on test connector is 300 V! (CAT IV 300 V)
Markings on the instrument:
Read the Instruction manual with special care to safety operation«. The
symbol requires an action!
Mark on your equipment certifies that it meets requirements of all
subjected EU regulations.

MI 3288 EI Tester Safety and operational considerations
10
This equipment should be recycled as electronic waste.
Warnings related to measurement functions:
Working with the instrument
❑Use only standard or optional test accessories supplied by your distributor!
❑Always connect accessories to the test equipment and to the test object before starting
measurement. Do not touch test leads or crocodile clips during measurement.
❑Do not touch any conductive parts of equipment under test during the test, risk of electric
shock!
❑Make sure that the tested object is disconnected (mains voltage disconnected) and
de-energized, before connecting the test leads and starting the measurement!
❑Do not use a current measurement as an indication that a circuit is safe to touch. A
voltage measurement is necessary to know if a circuit is hazardous.
❑The instrument automatically discharges tested object after finished measurement.
❑It is recommended to use the GUARD connection when high insulation resistance
(>10 GΩ) is measured.
❑Insulation resistance measurements shall be performed on de-energized objects, i.e.,
voltage between test terminals should be lower than 300 Vac and 50 Vdc!
❑Earth resistance measurements shall be performed on de-energized objects, i.e.,
voltage between test terminals should be lower than 30 Vac or dc!
❑Ohm resistance R7 measurements shall be performed on de-energized objects, i.e.,
voltage between test terminals should be lower than 10 Vac or dc!
❑Ohm resistance R200 measurements shall be performed on de-energized objects, i.e.
voltage between test terminals should be lower than 5 Vac or dc!
❑PASS / FAIL indication is enabled when limit is set to ON. Apply appropriate limit value
for evaluation of measurement results.
Warnings related to Batteries:
❑Use only batteries provided by the manufacturer.
❑Never dispose of the batteries in a fire as it may cause them to explode or
generate a toxic gas.
❑Do not attempt to disassemble, crush or puncture the batteries in any way.
❑Do not short circuit or reverse polarity the external contacts on a battery.
❑Keep the battery away from children.
❑Avoid exposing the battery to excessive shock/impacts or vibration.
❑Do not use a damaged battery.
❑The Li –ion battery contains safety and protection circuit, which if damaged, may
cause the battery to generate heat, rupture or ignite.
❑Do not leave a battery on prolonged charge when not in use.
❑If a battery has leaking fluids, do not touch any fluids.
❑In case of eye contact with fluid, do not rub eyes. Immediately flush eyes
thoroughly with water for at least 15 minutes, lifting upper and lower lids, until no
evidence of the fluid remains. Seek medical attention.

MI 3288 EI Tester Safety and operational considerations
11
2.2 Battery and charging of Li-ion battery pack
The instrument is designed to be powered by rechargeable Li-ion battery pack or with mains
supply. The LCD contains an indication of battery condition and the power source (upper left
section of LCD). In case the battery is too weak the instrument indicates this as shown in
Figure 2.1.
Symbol:
Indication of low battery.
Figure 2.1: Battery test
The battery is charged whenever the power supply is connected to the instrument. The power
supply socket is shown in Figure 2.2. Internal circuit controls (CC, CV) charging and assures
maximum battery lifetime. Nominal operating time is declared for battery with nominal capacity
of 4.4 Ah.
Figure 2.2: Charger socket polarity
The instrument automatically recognizes the connected power supply and begins charging.
Symbol:
Indication of battery charging
Figure 2.3: Charging indication
(animation)
Battery and charging characteristic
Typical
Battery type
18650T22A2S2P
18650T22A2S4P (optional)
Charging mode
CC / CV
Nominal voltage
7.2 V
Rated capacity
4400 mAh (type: 18650T22A2S2P)
8800 mAh (type: 18650T22A2S4P)
Max charging voltage
8.0 V
Max charging current
2.2 A (type: 18650T22A2S2P)
3.0 A (type: 18650T22A2S4P)
Max discharge current
2.5 A
Typical charging time
3 hours (type: 18650T22A2S2P)
4.5 hours (type: 18650T22A2S4P)

MI 3288 EI Tester Safety and operational considerations
12
Typical charging profile which is also used in this instrument is shown in Figure 2.4.
ICH/8
Fastcharge Safety Time
Precharge
Time
Current Regulation Voltage Regulation
ICH
VREG
VLOWV
Charge
Current
Charge
Voltage
Figure 2.4: Typical charging profile
where:
VREG...................................Battery charging voltage
VLOWV .................................Precharge threshold voltage
ICH......................................Battery charging current
ICH/8....................................1/8 of the charging current
2.2.1 Precharge
On power up, if the battery voltage is below the VLOWV threshold, the charger applies 1/8 of the
charging current to the battery. The precharge feature is intended to revive deeply discharged
battery. If the VLOWV threshold is not reached within 30 minutes of initiating precharge, the
charger turns off and a FAULT is indicated.
Figure 2.5: Battery fault indication
(charging suspended, timer fault, battery
absent)
Figure 2.6: Battery full indication
(charging completed)
Note:
❑As a safety backup, the charger also provides an internal 5-hour charge timer for fast
charge.

MI 3288 EI Tester Safety and operational considerations
13
Typical charging time is 3 hours (Battery type: 18650T22A2S2P) in the temperature range of
5°C to 60°C.
Ich/8
Ich
TLTF
TCOOL
TWARM
THTF
Charge
Suspended
Charge
Suspended
Temperature
Current
Charge
Figure 2.7: Typical charging current vs temperature profile
where:
TLTF....................................Cold temperature threshold (typ. -15°C)
TCOOL..................................Cool temperature threshold (typ. 0°C)
TWARM.................................Warm temperature threshold (typ. +60°C)
THTF....................................Hot temperature threshold (typ. +75°C)
The charger continuously monitors battery temperature. To initiate a charge cycle, the battery
temperature must be within the TLTF to THTF thresholds. If battery temperature is outside of this
range, the controller suspends charge and waits until the battery temperature is within the TLTF
to THTF range.
If the battery temperature is between the TLTF and TCOOL thresholds or between the TWARM and
THTW thresholds, charge is automatically reduced to ICH/8 (1/8 of the charging current).

MI 3288 EI Tester Safety and operational considerations
14
2.2.2 Li –ion battery pack guidelines
Li –ion rechargeable battery pack requires routine maintenance and care in their use and
handling. Read and follow the guidelines in this Instruction manual to safely use Li –ion battery
pack and achieve the maximum battery life cycles.
Do not leave batteries unused for extended periods of time –more than 6 months (self –
discharge).
When a battery has been unused for 6 months, check the charge status see chapter 6.4.1
Battery and time indication. Rechargeable Li –ion battery pack has a limited life and will
gradually lose their capacity to hold a charge. As the battery loses capacity, the length of time it
will power the product decreases.
Storage:
❑Charge or discharge the instruments battery pack to approximately 50% of capacity
before storage.
❑Charge the instrument battery pack to approximately 50% of capacity at least once every
6 months.
Transportation:
❑Always check all applicable local, national, and international regulations before
transporting a Li –ion battery pack.
Handling Warnings:
❑Do not disassemble, crush, or puncture a battery in any way.
❑Do not short circuit or reverse polarity the external contacts on a battery.
❑Do not dispose of a battery in fire or water.
❑Keep the battery away from children.
❑Avoid exposing the battery to excessive shock/impacts or vibration.
❑Do not use a damaged battery.
❑The Li –ion battery contains safety and protection circuit, which if damaged, may
cause the battery to generate heat, rupture or ignite.
❑Do not leave a battery on prolonged charge when not in use.
❑If a battery has leaking fluids, do not touch any fluids.
❑In case of eye contact with fluid, do not rub eyes. Immediately flush eyes
thoroughly with water for at least 15 minutes, lifting upper and lower lids, until no
evidence of the fluid remains. Seek medical attention.

MI 3288 EI Tester Safety and operational considerations
15
2.3 Standards applied
The MI 3288 instrument is manufactured and tested in accordance with the following
regulations:
Electromagnetic compatibility (EMC)
EN 61326 - 1
Electrical equipment for measurement, control and laboratory
use –EMC requirements –Part 1: General requirements
EN 61326 - 2 - 2
Electrical equipment for measurement, control and laboratory
use –EMC requirements –Part 2-2: Particular requirements - Test
configurations, operational conditions and performance criteria for
portable test, measuring and monitoring equipment used in low-
voltage distribution systems
Safety (LVD)
EN 61010 - 1
Safety requirements for electrical equipment for measurement, control
and laboratory use –Part 1: General requirements
EN 61010 - 2 - 030
Safety requirements for electrical equipment for measurement, control
and laboratory use –Part 2-030: Particular requirements for testing and
measuring circuits
EN 61010 - 2 - 032
Safety requirements for electrical equipment for measurement, control
and laboratory use –Part 2-032: Particular requirements for hand-held
and hand-manipulated current sensors for electrical test and
measurement.
EN 61010 - 031
Safety requirements for hand-held probe assemblies for electrical
measurement and test.
Some further recommendations
EN 61557
Electrical safety in low voltage distribution systems up to 1000 V a.c.
and 1500 V d.c. - Equipment for testing, measuring or monitoring of
protective measures.
Part 1: General requirements
Part 2: Insulation resistance
Part 4: Resistance of earth connection and equipotential bonding
Part 5: Resistance to earth
Part 10: Combined measuring equipment
IEEE 81 –2012
IEEE Guide for Measuring Earth Resistivity, Ground Impedance, and
Earth Surface Potentials of a Grounding System.
EN 50522 –2010
Earthing of power installations exceeding 1 000 V a.c.
IEEE 142 –2007
IEEE Recommended Practice for Grounding of Industrial and
Commercial Power Systems (US).
IEEE 367 –2012
IEEE Recommended Practice for Determining the Electric Power
Station Ground Potential Rise and Induced Voltage from a Power Fault.
Li –ion battery pack
IEC 62133 - 2
Secondary cells and batteries containing alkaline or other non-acid
electrolytes - Safety requirements for portable sealed secondary cells,
and for batteries made from them, for use in portable applications –
Part 2: Lithium systems protection for household and similar uses
Note about EN and IEC standards:
❑Text of this manual contains references to European standards. All standards of EN
6XXXX (e.g. EN 61010) series are equivalent to IEC standards with the same number
(e.g. IEC 61010) and differ only in amended parts required by European harmonization
procedure.

MI 3288 EI Tester Terms and definitions
16
3 Terms and definitions
For the purposes of this document and instrument MI 3288, the following definitions apply.
Index:
Unit:
Description:
Re
[Ω]
Earth resistance of complete system.
Ze
[Ω]
Earth impedance of complete system.
Rp
[Ω]
Auxiliary potential probe impedance.
Rc
[Ω]
Auxiliary current probe impedance.
Ie
[A]
System current or generator current.
f
[Hz]
Test frequency.
Ic
[A]
Iron clamp current.
Zsel
[Ω]
Earth impedance of measured branch.
ρ
[Ωm / Ωft]
Specific earth resistance [resistivity].
R
[Ω]
Resistance [DC current].
Idc
[A]
DC current.
R+
[Ω]
Low Ohm resistance [positive current direction].
R-
[Ω]
Low Ohm resistance [negative current direction].
Riso
[Ω]
Insulation resistance
Um
[V]
Measured test voltage.
I
[A]
Measured leaking current or clamp current
C
[F]
Measured capacitance.
R1-5
[Ω]
Insulation resistance 1 to 5 [different time of measurement].
U1-5
[V]
Measured test voltage 1 to 5 [different time of measurement].
DAR
[ ]
Dielectric Absorption Ratio.
PI
[ ]
Polarization Index.
DD
[ ]
Dielectric Discharge index.
Udc
[V]
Breakdown voltage DC in varistor test measurement
Uac
[V]
Calculated breakdown AC voltage in varistor test measurement
U
[V]
Measured voltage.
Freq
[Hz]
Measured frequency.
f
[Hz]
Measured frequency.
R
[m/ft]
Distance between E and auxiliary earth rod H.
r
[m/ft]
Distance between E and S probe.
Igen
[A]
Generator current.
Us
[V]
Calculated step, touch voltage.
Ifault
[A]
Maximum expected fault current.
Notes (acc.to EN 50522-2010):
❑Resistance to earth, RE- real part of the impedance to earth.
❑Impedance to earth, ZE- impedance at a given frequency between a specified point in
a system or in an installation or in equipment and reference earth.
The impedance to earth is determined by the directly connected earth electrodes and also by connected
overhead earth wires and wires buried in earth of overhead lines, by connected cables with earth electrode
effect and by other earthing systems which are conductively connected to the relevant earthing system by
conductive cable sheaths, shields, PEN conductors or in another way.

MI 3288 EI Tester Instrument description
17
4 Instrument description
4.1 Operator’s panel
The operator’s panel is shown in Figure 4.1 below.
Figure 4.1: The operator’s panel
1
Colour TFT display with touch screen
2
SAVE
Stores actual measurement result(s)
3
CURSOR
Navigate in menus
4
RUN
Start / stop selected measurement.
Enter selected menu or option.
View available values for selected parameter / limit.
5
ON / OFF
Switch instrument on / off.
The instrument automatically switches off after 10 minutes of
idle state (no key pressed or any touchscreen activity)
Press and hold the key for 5 s to switch off the instrument.
6
GENERAL
SETTINGS
Enter General settings menu.
7
OPTIONS
Show detailed view of options.
8
MEMORY
ORGANIZER
shortcut
Shortcut key to enter Memory organizer menu.
9
SINGLE TESTS
shortcut
Shortcut key to enter Single Tests menu.
10
AUTO
SEQUENCES
shortcut
Shortcut key to enter Auto Sequencesmenu.
11
ESC
Back to previous menu.

MI 3288 EI Tester Instrument description
18
4.2 Connector panel
Figure 4.2: Connector panel
1
Test connector
2
Protection cover
3
Protection cover –PS/2 communication port
4
Charger socket
5
USB communication port
Communication with PC USB port
6
PS/2 communication port
Communication with PC RS232 serial port
7
P/S input
Active current clamps measuring terminal
8
GUARD (C1)
Guard input terminal.
Warnings!
❑Do not connect any voltage source on GUARD (C1) terminal. It is intended only for
connection of GUARD lead.
❑Use original test accessories only!
❑Maximum short-term voltage of external power supply adapter is 14 V!
4.2.1 Designation of the Test connector terminals
2-wire test accessory (Insulation resistance, Voltage measurement, DC Resistance (2-wire)):
❑HV+ (red)
- positive high voltage output terminal
- positive voltage input terminal
- DC resistance terminal
❑HV- (black)
- negative high voltage output terminal
- negative voltage input terminal
- DC resistance terminal

MI 3288 EI Tester Instrument description
19
4-wire test accessory (Earth measurements, Step and Touch voltage):
❑E(blue)
- terminal for the earth electrode
❑ES (red)
- terminal for the probe placed nearest to the earth electrode
- potential terminal (A 1597 and metal plates)
❑S(green)
- terminal for a probe
- potential terminal (A 1597 and metal plates)
❑H(black)
- terminal for the auxiliary earth electrode
4-wire test accessory (DC Resistance 4-wire):
❑C1 (red)
- current terminal
❑P1 (black)
- potential terminal
❑P2 (black)
- potential terminal
❑C2 (red)
- current terminal
Warnings!
2 wire test accessory:
❑Maximum allowed input voltage between HV+ and HV- test terminals on test
connector is 1000 V! (CAT II 1000 V)
4 wire test accessories:
❑Maximum allowed input voltage between C1 and C2 or H and E test terminals on
test connector is 1000 V! (CAT II 1000V)
❑Maximum allowed input voltage between any other combination of test terminals
on test connector is 300 V! (CAT IV 300 V)
4.3 Back side
Figure 4.3: Back view
1
Battery / fuse compartment cover
2
Fixing screws for battery / fuse compartment cover
3
Back panel information label

MI 3288 EI Tester Instrument description
20
Figure 4.4: Battery and fuse compartment
1
Li-ion battery pack
Type: 4400 mAh (18650T22A2S2P)
Type: 8800 mAh (18650T22A2S4P)
2
Fuse F2
FF 2 A / 1000 V (breaking capacity 50 kA)
3
SD card slot
Figure 4.5: Bottom view
1
Neck belt openings
2
Stand for desktop use
3
Bottom information label
4
Serial number label