METREL Euro Z 800 V User manual

Euro Z 800 V
MI 3144
Instruction manual
Version 1.3.4, Code No. 20 752 881

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.
© 2019 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.

MI 3144 Euro Z 800 V Table of contents
3
Table of contents
1General Description............................................................................................5
1.1 Features........................................................................................................5
2Safety and operational considerations .............................................................6
2.1 Warnings and notes......................................................................................6
2.2 Battery and charging of Li-ion battery pack...................................................8
2.2.1 Battery indication...................................................................................8
2.2.2 Charger state.........................................................................................8
2.2.3 Precharge..............................................................................................9
2.2.4 Li –ion battery pack guidelines ...........................................................10
2.3 Standards applied.......................................................................................11
3Instrument description .....................................................................................12
3.1 Instrument casing .......................................................................................12
3.2 Operator’s panel .........................................................................................12
4Accessories.......................................................................................................13
4.1 Standard set ...............................................................................................13
4.2 Optional accessories...................................................................................13
5Instrument operation ........................................................................................14
5.1 General meaning of keys............................................................................14
5.2 LED indicators ............................................................................................14
5.2.1 Measurement indication.......................................................................14
5.2.1 Temperature indication........................................................................14
5.2.2 Battery indication.................................................................................14
5.3 Messages on the master instrument...........................................................15
5.3.1 Terminal voltage monitor.....................................................................15
5.4 Operation with the master instrument.........................................................16
5.5 Operation with the aMESM.........................................................................17
6Tests and Measurements .................................................................................18
6.1 Impedance Measurements [Z]....................................................................18
6.1.1 Z line mΩ Measurement ......................................................................18
6.1.2 Z loop mΩ Measurement .....................................................................19
6.1.3 High Current Measurement .................................................................20
6.2 DC Source & Line Resistance Measurements [R]......................................22
6.2.1 R line mΩ Measurement......................................................................22
6.3 Earth Potential [U].......................................................................................24
6.3.1 U touch Measurement .........................................................................24
6.4 ELR Test [I and t]........................................................................................25
6.4.1 ELR Current Injection Test ..................................................................26
6.4.2 ELR Combination Time Test................................................................27
6.5 Current [I]....................................................................................................28
6.5.1 Current Clamp Measurement ..............................................................28
7Communication.................................................................................................29
8Maintenance ......................................................................................................30
8.1 Cleaning......................................................................................................30
8.2 Periodic calibration .....................................................................................30
8.3 Service........................................................................................................30

MI 3144 Euro Z 800 V Table of contents
4
8.4 Upgrading the instrument............................................................................30
9Technical specifications...................................................................................31
9.1 Impedance [Z].............................................................................................31
9.1.1 Z line mΩ, Z loop mΩ ..........................................................................31
9.1.2 High Current ........................................................................................32
9.1.3 Averaging options................................................................................32
9.2 DC Source & Line Resistance [R]...............................................................33
9.2.1 R line mΩ.............................................................................................33
9.3 Earth Potential [U].......................................................................................34
9.3.1 U touch................................................................................................34
9.4 Sub-results in measurement functions........................................................34
9.5 ELR Test [I and t]........................................................................................35
9.5.1 ELR Current Injection Test and ELR Combination Time Test..............35
9.6 Current [I]....................................................................................................36
9.6.1 Iron (A 1281) and Flex (A 1227, A 1609) current clamp ......................36
9.7 Test Current................................................................................................37
9.8 General data...............................................................................................38
Appendix A –Supported Instruments Selection Table........................................39
Appendix B –MRCD Test (acc.to IEC 60947-2 Annex M) ....................................40
Appendix C –Short-circuit currents in 3p a.c. systems......................................44

MI 3144 Euro Z 800 V General description
5
1 General Description
1.1 Features
Euro Z 800 V (MI 3144) is a Multi-function, portable battery (Li-ion) or mains powered test
instrument with excellent IP protection: IP65 (case closed), IP54 (case opened), intended for:
high current line and loop impedance, DC source and line resistance testing, ELR testing and
current 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 Euro Z 800 V:
Impedance measurement up to 800 V;
Maximum nominal voltage is 720 V;
CAT IV 600 V measuring category (altitude up to 3000 m);
Frequency range from 16 Hz up to 420 Hz;
Selectable test load (16.6 % to 100 %);
DC source and line resistance measurement up to 260 V;
Selective loop measurement;
Current Clamp Measurement (Iron or Flex Clamps);
ELR Current injection test;
ELR Combination time test;
Improved thermal performance;
Bluetooth communication;
Black box design (Can be remotely controlled from an Android device)
Two LED bar graph indicators offer easy-to-read battery and thermal condition of the instrument.
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).
MI 3144 Euro Z 800 V
according to
Z line mΩ
Z loop mΩ
EN 61557 –3 [loop impedance]
High Current
IEEE Std 81 –2012 [Integrity of ground systems]
U touch
IEEE Std 81 –2012 [Testing earth potentials and step and touch voltages]
ELR Current Injection Test
ELR Combination Time Test
IEC 60947-2 Annex M [Modular residual current devices]

MI 3144 Euro Z 800 V Safety and operational considerations
6
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 Euro Z 800 V 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!
Do not use the test equipment or any of the accessories if any damage is noticed!
Regularly check the instrument and accessories for correct functioning to avoid
hazard that could occur from misleading results.
Consider all generally known precautions in order to avoid risk of electric shock
while dealing with hazardous voltages! Note that Euro Z 800 V high current
impedance adapter is intended for use in environments where dangerous voltages
are easy accessible (e.g. switchgears, power stations)!
Use only standard or optional test accessories supplied by your distributor!
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, calibration 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!
Consider that protection category of some accessories is lower than of the
instrument. Test tips have removable caps. If they are removed, the protection falls
to CAT II. Check markings on accessories!
cap off, 18 mm tip: CAT II up to 1000 V
cap on, 4 mm tip: CAT II 1000 V / CAT III 600 V / CAT IV 300 V
Do not use the equipment in a wet environment, around explosive gas, vapour.
Only adequately trained and competent persons may operate the equipment.

MI 3144 Euro Z 800 V Safety and operational considerations
7
Markings on the instrument:
Read the Instruction manual with special care to safety operation«. The
symbol requires an action!
Front panel can overheat when performing the rapid sequence of high
precision line-to-line impedance measurements.
Mark on your equipment certifies that it meets requirements of all
subjected EU regulations.
This equipment should be recycled as electronic waste.
This equipment is protected by reinforced insulation.
Warnings related to measurement functions:
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!
Do not connect test terminals (C1, P1, P2, C2 and S) to an external voltage higher than
800 V AC (CAT IV environment) and 260 DC to prevent any damage to the test
equipment!
Do not connect live voltage to A 1597 Human body probe.
Z loop mΩ
The Z loop mΩimpedance function will trip-out the RCD in RCD protected installation
that is tested. To prevent the RCD trip-out, make measurements on entry side of the
RCD or bypass the RCD but only for test purpose.
Specified accuracy of tested parameters is valid only if mains voltage is stable during the
measurement.
Z line mΩ
Specified accuracy of tested parameters is valid only if mains voltage is stable during the
measurement.
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 3144 Euro Z 800 V Safety and operational considerations
8
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.
2.2.1 Battery indication
The battery indication indicates the charge condition of battery. Press LED bar graph key for
test.
Battery capacity indication (LED bar graph indicator).
2.2.2Charger state
The battery is charged whenever the power supply is connected to the instrument. The power
supply socket is shown in Figure 2.1. 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 2.1: Power supply socket (C7)
The instrument automatically recognizes the connected power supply and begins charging.
Description
Yellow LED
Green LED
Charging in progress (if power supply
adapter is connected and battery
inserted).
On
Undefined
Charger complete (battery is full).
Off
On
Charger disconnected. (Battery operating
instrument)
Sleep mode.
Off
Off
Charger suspend. Battery fault indication
(timer fault, battery absent, temperature).
Blinking
Undefined
Battery and charging characteristic
Typical
Battery type
VB 18650
Charging mode
CC / CV
Nominal voltage
7,2 V
Rated capacity
4,4 Ah
Max charging voltage
8,0 V
Max charging current
2,2 A
Max discharge current
2,5 A
Typical charging time
3 hours

MI 3144 Euro Z 800 V Safety and operational considerations
9
Typical charging profile which is also used in this instrument is shown in Figure 2.2.
ICH/8
Fastcharge Safety Time
Precharge
Time
Current Regulation Voltage Regulation
ICH
VREG
VLOWV
Charge
Current
Charge
Voltage
Figure 2.2: Typical charging profile
where:
VREG ...................................Battery charging voltage
VLOWV..................................Precharge threshold voltage
ICH ......................................Battery charging current
ICH/8 ....................................1/8 of the charging current
2.2.3 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.
Note:
As a safety backup, the charger also provides an internal 5-hour charge timer for fast
charge.
Typical charging time is 3 hours 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 2.3: Typical charging current vs temperature profile

MI 3144 Euro Z 800 V Safety and operational considerations
10
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).
2.2.4 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 5.2.2
Battery 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 3144 Euro Z 800 V Safety and operational considerations
11
2.3 Standards applied
The Euro Z 800 V instrument is manufactured and tested in accordance with the following
regulations:
Electromagnetic compatibility (EMC)
EN 61326
Electrical equipment for measurement, control and laboratory
use –EMC requirements Class A
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 - 031
Safety requirements for hand-held probe assemblies for electrical
measurement and test.
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
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 3: Loop resistance
IEEE 81 –2012
IEEE Guide for Measuring Earth Resistivity, Ground Impedance, and
Earth Surface Potentials of a Grounding System.
EN 60947-2
Low-voltage switchgear and controlgear –Part 2: Circuit-breakers –
Annex M Modular residual current devices (without integral current
breaking device)
EN 60909 - 0
Short-circuit currents in three-phase a.c.systems –Part 0: Calculation
of currents
Li –ion battery pack
EN 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
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 3144 Euro Z 800 V Instrument description
12
3 Instrument description
3.1 Instrument casing
The instrument is housed in a plastic box that maintains the protection class defined in the
general specifications.
3.2 Operator’s panel
The operator’s panel is shown in Figure 3.1 below.
Figure 3.1: The operator’s panel
1
Input power supply (charger) socket (type C7).
2
Charger status (green and yellow LED indicators).
3
Battery status (LED bar graph).
4
Temperature status (LED bar graph).
5
LED bar graph key (active if pressed).
6
On/Off
Switch the instrument power on or off.
Instrument hard reset (if hold for 10 s or more).
7
Clamp
Clamp input terminal (Only for connection of Metrel Smart
clamps).
8
RS232
RS232 communication port.
9
HOT
Instrument overheated.
10
TEST
Measurement status.
11
ON
Power indication.
12 - 16
S, C1, P1, P2, C2
Measuring terminals.
Warnings!
Do not connect test terminals (C1, P1, P2, C2) to an external voltage higher than
800 V AC (CAT IV environment) or 260 V DC to prevent any damage to the test
equipment!
Use original test accessories only!

MI 3144 Euro Z 800 V Accessories
13
4 Accessories
The accessories consist of standard and optional accessories. Optional accessories can be
delivered upon request. See attached list for standard configuration and options or contact your
distributor or see the METREL home page: http://www.metrel.si.
4.1 Standard set
Instrument MI 3144 Euro Z 800 V
Large Kelvin test clips (A 1593), 2 pcs
Test lead 5 m, 2 pcs (black/red)
Test tip, 2 pcs (red)
Test tip, 2 pcs (black)
Test lead 5 m, 2 pcs (green)
G clamp, 1 pc
Crocodile clips, 2 pcs (black)
RS232 cable (9 pin - PS2)
Mains cable
Bag for accessories
Instruction manual
Calibration certificate
4.2 Optional accessories
See the attached sheet for a list of optional accessories and licence keys that are available on
request from your distributor.

MI 3144 Euro Z 800 V Instrument operation
14
5 Instrument operation
According to principle, the instrument offers remote control from METREL instruments whose
test functions are implemented by application of the Euro Z.
5.1 General meaning of keys
LED bar graph key is used to:
Power up the temperature and battery bar graph indication;
ON / OFF key:
Switches the instrument power on or off;
Instrument hard reset (hold key for 10 s or more).
The instrument automatically turns off 10 minutes after the last key was
pressed and no communication with the master instrument or app.
5.2 LED indicators
5.2.1 Measurement indication
LED
Status
Description
ON
ON
Power indication.
Blinking
Low battery.
TEST
ON
Measurement status.
LED is activated while measurement is running.
HOT
Blinking
Overheated.
Temperature of internal components in the Euro Z
instrument reached top limit. The measurement is
prohibited until temperature drops below the limit.
ON TEST HOT
Blinking
Hardware error. (Input relay failure detected.)
Measurements are prohibited!
Service intervention is required!
5.2.1Temperature indication
The temperature indicates the condition of the loading resistor.
Temperature indication (LED bar graph indicator).
Cool, Mild, Warm, Hot
5.2.2 Battery indication
The battery indication indicates the charge condition of battery.
Battery capacity indication (LED bar graph indicator).
Low, Middle, Good, Full

MI 3144 Euro Z 800 V Instrument operation
15
5.3 Messages on the master instrument
Warning!
Low battery on the Euro Z adapter.
Select OK for acknowledgement; connect power supply to the Euro Z instrument and
recharge the batteries.
Warning!
Euro Z adapter is overheated. The measurement is prohibited until
the temperature decreases under the allowed limit.
Select OK for acknowledgement; cool down the Euro Z instrument.
Warning!
Wrong voltage system or nominal mains voltage out of range!
Select OK for acknowledgement; limit [40 V ≤ Uac ≤ 800 V].
Warning!
Wrong frequency system!
Select OK for acknowledgement; limit [16 Hz ≤ f ≤ 420 Hz].
Warning!
Wrong voltage system, voltage out of range or wrong polarity +, - !
Select OK for acknowledgement; limit [3 V ≤ Udc ≤ 260 V].
Error!
Connection! Check the correct terminals connection (C1, P1, P2, C2)!
See help for more information.
Select OK for acknowledgement.
Error!
Hardware Error!
The measurement is prohibited.
Select OK for acknowledgement; Input relay failure detected. Service intervention is
required.
5.3.1 Terminal voltage monitor
The terminal voltage monitor displays on-line voltages and frequency on the test terminals.
Up1p2
RMS voltage across P1 –P2 measuring terminals.
Uc1c2
RMS voltage across C1 –C2 measuring terminals.
Freq
RMS frequency across C1 –C2 measuring terminals.

MI 3144 Euro Z 800 V Instrument operation
16
5.4 Operation with the master instrument
(e.g. MI 3155 EurotestXD, MI 3152 EurotestXC)
Applied functions
See Appendix A –Supported Instruments Selection Table for more information.
Connection with the master instrument (RS232 or Bluetooth)
For RS 232 communication, connect serial communication interface cable RS
232_9pin_female / PS 2 to the master instrument and the Euro Z instrument. See
Figure 5.1.
Figure 5.1: Connection of the Euro Z 800 V to the master instrument using RS 232 or
Bluetooth (Example of MI 3152 and MI 3155)
Power on the master instrument and the Euro Z instrument.
Select the communication port RS 232 or Bluetooth on the master instrument.
Figure 5.2: Master instrument Setting menu
Set (pair) the appropriate Bluetooth device from a list of detected Bluetooth devices.
The correct name consists of the instrument type plus serial number, e.g.
MI 3144-12345678I.
Select measurement function on the master instrument from the EURO Z group.
The master instrument recognizes the Euro Z instrument in the measurement window
by activating terminal voltage monitor and with Bluetooth indication (if Bluetooth
communication is set).
Figure 5.3: Terminal voltage monitor –activated and not activated
Figure 5.4: Bluetooth indication - connected and disconnected
Select the proper parameters and limits of the selected measurement on the master
instrument.
Connect the Euro Z instrument to the test object. (Check terminal voltage monitor for
proper connection. Use help screens on master instrument if necessary.)
Press TEST/ RUN/ ENTER key on the master instrument to measure.
Result of measurement is displayed on the master instrument.

MI 3144 Euro Z 800 V Instrument operation
17
5.5 Operation with the aMESM
Applied functions
See Appendix A –Supported Instruments Selection Table for more information.
Connection with aMESM (Bluetooth)
Power on the Euro Z instrument and the tablet or smart phone.
Enable the Bluetooth hardware on the tablet or smart phone device.
Run aMESM application on the tablet or smart phone device.
Figure 5.5: Connection of the Euro Z 800 V to the aMESM
Search for the appropriate device (your Euro Z instrument) in the Bluetooth menu and
connect to it. The correct name consists of the instrument type plus serial number,
e.g. MI 3144-12345678I.
Bluetooth communication device pairing code is 1234.
Select measurement function on the aMESM.
Select the proper parameters and limits.
Connect the Euro Z instrument to the test object.
Press the START key on the aMESM application to measure.
Result of a measurement is displayed on the aMESM application.

MI 3144 Euro Z 800 V Tests and Measurements
18
6 Tests and Measurements
The MI 3144 Euro Z 800 V instrument is able to carry out different measurement methods.
The operator can select the appropriate one.
6.1 Impedance Measurements [Z]
When performing measurements close to the power transformer or inductance is present,
inductive part of impedance has a significant influence to prospective fault/short-circuit
current. Therefore, impedance has to be measured (instead of resistance) for correct
calculation of prospective fault/short-circuit current.
AC
Impedance
Measurement
Test
Mode
Test
Method
Limit
Z
Z line mΩ
single
4-wire
yes
Z loop mΩ
single
4-wire
yes
High Current
single
4-wire + clamp
yes
High precision line and fault loop impedance measurements are performed using high
current impulses to assure adequate voltage drop during the test.
Warnings:
The Euro Z instrument applies very high loading current into tested installation and it
is recommended to make rare measurements, typically one per 15 s to reduce
problems caused by such current.
Flickers can be observed due to high test current pulses.
6.1.1 Z line mΩ Measurement
Line impedance is the impedance within the current loop when a short-circuit occurs:
Conductive connection between phase conductor and neutral conductor in single-phase
system,
Between two line conductors in three-phase system.
C1
P1
P2
C2
MI 3144 Euro Z 800 V
E a r t h
L1
L2
L3
N
Pe
R1
4 wire (Kelvin)
V
A
Supply
R
Pe
Itest
ΔU
Z
R2
Figure 6.1: Z line mΩ measurement example
During the measurement, an internal resistance is connected between C1 and C2 for a
period of a half cycle. The instrument internal shunt resistor measures the current (Itest). A
voltmeter measures the open circuit voltage with no load (UUNLOADED), followed by the second
reading with a load (ULOADED). The impedance Z is determined from the voltage dip / current
ratio. In the example, following impedance is measured:

MI 3144 Euro Z 800 V Tests and Measurements
19
   
  
where:
Z........................................ Impedance
UUNLOADED........................... Measured voltage [no load]
ULOADED .............................. Measured voltage [with load]
ΔU..................................... Voltage dip
Itest ..................................... Test current
[A]
[s]
[V] U unloaded
[s]
U loaded
Itest
ΔU
Figure 6.2: Z line mΩ measurement voltage and current waveforms examples
6.1.2 Z loop mΩ Measurement
Loop impedance is the impedance within the fault loop when a short-circuit to exposed
conductive parts occurs (conductive connection between phase conductor and protective
earth conductor).
C1
P1
P2
C2
MI 3144 Euro Z 800 V
E a r t h
L1
L2
L3
N
Pe
R1
4 wire (Kelvin)
V
A
Supply
R
Pe
Itest
ΔU
Z
R2
Figure 6.3: Z loop mΩ measurement example
During the measurement, an internal resistance is connected between C1 and C2 for a
period of a half cycle. The instrument internal shunt resistor measures the current (Itest). A
voltmeter measures the open circuit voltage with no load (UUNLOADED), followed by the second
reading with a load (ULOADED). The impedance Z is determined from the voltage dip / current
ratio. In the example, following impedance is measured:

MI 3144 Euro Z 800 V Tests and Measurements
20
  
  
where:
Z........................................ Impedance
UUNLOADED........................... Measured voltage [no load]
ULOADED .............................. Measured voltage [with load]
ΔU..................................... Voltage dip
Itest ..................................... Test current
6.1.3 High Current Measurement
The measurement can be applied for measuring contact resistance (bad contacts) in a live
distribution board or fuse box. With test currents from 10 A and all the way to the 100 A,
depending on the mains voltage and test load parameter. For more information, see chapter
9.7 Test Current.
C1
P1
P2
C2
MI 3144 Euro Z 800 V
E a r t h
L1
L2
L3
N
Pe
R1
4 wire (Kelvin)
V
A
Supply
R4
R
Itest UR1
R3R2
Itest
UAC
UR1+R2
UR1+R2+R3
Figure 6.4: High Current Measurement example 1 (distribution board)
Proposed measurement can be referenced to standard IEEE-81 par. 10.2 and 10.3.
C1
P1
P2
C2
MI 3144 Euro Z 800 V
E a r t h
4 wire (Kelvin)
V
A
R
Itest
Ic
Remote Power
Source
tower
Ground Grid
Mesh
UP1-P2
Itower
Igrid
Igrid
Itest
A 1281
Itest=Itower + Igrid
Itest
Figure 6.5: High Current Measurement example 2 (IEEE-81)