METREL MI 3144 Euro Z 800 V User manual

Page 1 Measuring and Regulation Equipment Manufacturer
MI 3144
Euro Z 800 V
MI 3143
Euro Z 440 V
Measuring
instruments
and testers
www.metrel.si

Page 2
Most powerful Industrial Safety & Quality bundles
MI 3144 Euro Z 800 V and MI 3143 Euro Z 440 V
MAIN FEATURES MI 3144 MI 3143
High Precision 4-wire 300A Z Line and Z Loop Impedance Tester • •
High Range 800 V / 16 ... 420 Hz AC Networks •
High Range 440 V / 16 ... 420 Hz AC Networks • •
DC Source & Line Resistance 3 ... 260 V DC •
High Current dR 300A 4-wire Partial Voltage drops • •
High Current dR 300A 4-wire Current's Path Resistances •
Earth Leakage Relay (ELR) Trip-out Testing Time and Current •
ELR current injection test; •
ELR supported types AC, A, B; •
Ground Fault Analysis with Contact, Touch and Step Voltage • •
Floating Voltmeter for partial contact results • •
One-Clamp High Current Ground Integrity method with clamps (Flex & Iron) •
MI 3144 Euro Z 800 V or
MI 3143 Euro Z 440 V both
are fully operated test
instruments that could be
driven through Android
Application aMESM or one of
supported instrument like
MI 3155 EurotestXD or
MI 3325 MultiservicerXD.
Powerful features for
industrial environment are
implemented where hi test
current is crucial demand to
evaluate results.

Page 3 Measuring and Regulation Equipment Manufacturer
Eurotest XD/XC, Multiservicer XD or Android App
APPLICATIONS
• Live Power Transformer High Precision 4-wire 300 A Z Line / Loop Impedance Testing
• Partial Voltage Drops and Partial Clamp Current’s Path* Resistances
• Airports High Frequency Band 16 ... 420 Hz Installation Impedances testing
• DC Networks’ and Power Sources’ Line and Loop Resistances
• Flex & Iron One-Clamp High Current dR 300 A Grounding method for Lightning systems
• High Current dR 300 A Integrity of Grounding system with Flex and Iron One-Clamp method
• ELR (MRCD) trip-out Current and trip-out Time testing
• Earth Potentials by method of measuring Step, Touch and Transfer voltages
GENERAL DATA
• CAT IV 600 V (3000 m) safety category;
• Portable battery (Li-ion) or mains
powered test instrument;
• IP protection: IP65 (case closed),
IP54 (case opened);
• Improved thermal performance;
• Bluetooth communication;
• Black box design (Can be remote-
controlled via an Android device).
STANDARDS
Electromagnetic compatibility:
• EN 61326
Safety:
• EN 61010 - 1
• EN 61010 - 2 - 030
• EN 61010 - 031
Functionality:
• EN 61557
• IEEE 81 – 2012
• IEC 60947 - 2 Annex M
• IEC 60609 - 0
Li–ion battery pack:
• EN 62133 - 2

Page 4
Most powerful Industrial Safety & Quality bundle
MI 3144 Euro Z 800 V and MI 3143 Euro Z 440 V

Page 5
Measuring and Regulation Equipment Manufacturer
Automatic trip out protection ability test in
case of faults in transformers, generators,
turbines, contactors, distribution boards
and switchyards whenever energetic
loads and sources of protection exceed
200A need precise, robust and accurate
measuring method to evaluate results for
first inspection and periodical predictive
maintenance or fast troubleshooting on any
industrial platform.
High precision line and loop impedances
on AC and DC circuits is on the top of the
importance list for high test current, 4-wire
connectivity, temperature management
with selectable test loads, calculations and
algorithms that offer robustness and stable
high-resolution results.
High Current dR 300A loop and line
measurements with completely insulated
voltmeter with supported current clamps
enable testing of partial currents and partial
voltage drops. This innovation made several
applications possible, from measuring
partial resistance of separate contacts to
controlled fault with high current injecting
method to partial ground paths. No
more cable screens removal for accurate
evaluation.
Contact voltages can be measured during
generated fault to ground. With insulated
voltmeter and parallel 1 kOhm resistor
connected as body resistance simulator,
realistic touch and step voltages can be
MI 3144 MI 3143 Instrument
High Current Impedance
4-wire
Zline Zloop Impedance ••Supported by following testers and applications
over bluetooth or cable communication:
• MI 3155 EurotestXD
• MI 3152 EurotestXC
• MI 3152HEurotestXC 2.5 KV
• MI 3325 MultiserviserXD
• aMESM Android APP
ΔR High Current • •
R Selective •
DC Source & Line Resistance DC Source •
DC Line Resistance •
Earth Potential [U] Utouch • •
Ustep • •
Ucontact • •
ELR Test [I and t] Residual operating current •
Combination time •
Current [I] A 1609 flex clamp •
A 1227 flex clamp Optional
A 1281 iron clamp Optional
scaled to faults like phase to ground or even
a lightning strike.
ELR feature supports AC, A and B types
of electrical leakage relay testing with
fault current injection and trip-out time
measurement. Testing relays to proper
reaction in case of faults or leakages, high
neutral current, missing phase situations or
asymmetry will protect people and livestock
as well as electrical loads and sources.
DC Sources, accumulators and batteries,
DC lines and circuits, fuses, switches and
contacts can be evaluated on live circuits in
range from 3 V DC up to 260 V DC. Quality
of the batteries can be estimated by voltage
drop reading and evaluated as drop in
quality through years of usage.
MI 3144 Euro Z 800 V and MI 3143 Euro Z
440 V are multi-function, battery (Li-ion)
or mains powered test instrument with
excellent IP protection: IP65 (case closed),
IP54 (case opened).
Professional kelvin crocodiles and full set of
accessories complete the package prepared
for field testing. Several types of current
clamps including long flex clamp make
industrial testing possible.
Bundle set could be packed into
professional high IP protected portable case
on wheels. Several solutions are prepared;
from easy field transportation to simple
ready to test procedure.
FIELD TEST EVALUATION
After months of evaluation on real field
industrial applications we are capable to
make some real conclusions. The bundle
in the portable case with MI 3144 Euro Z
800 and MI3155 Eurotest XD is the most
remarkable powerful industrial safety and
quality test set package. Recommended
with no hesitation.
Make your competency highly professional.
MEASUREMENT FUNCTIONS

Page 6
Most powerful Industrial Safety & Quality bundle
Technical specifications
MI 3144 and MI 3143*
High Current Impedance [Z], ΔR, R Selective
Z line mΩ, Z loop mΩ
Measuring range according to EN61557-3: 12.0 mΩ ... 19.99 Ω
Measurement principle Voltage / Current measurement (synchronous sampling)
Loop/Line Impedance Measuring range Resolution Uncertainty (* See note)
Zline Zloop Impedance 0,1 mΩ … 199,9 mΩ 0,1 mΩ ±(5 % of reading + 3 mΩ)
ΔR High Current 200 mΩ … 1999 mΩ 1 mΩ
R Selective (only MI 3144) 2,00 Ω … 19,99 Ω 10 mΩ ±(5 % of reading + 3digits)
16 Hz Nominal frequency 400 Hz
40 Vac Nominal voltage range 800 Vac
470 Vac*
Test load parameter 16.6 %, 33.3%, 50 %, 66.6%, 83.3%, 100%
Test method 4-wire / Ipsc - Imax, Imin, Imax2p, Imin2p, Imax3p, Imin3p /R and XLvalues / Averaging option /
Automatic range selection
MI 3144
DC Sources & Line Resistance [R]
R line mΩ
Measurement principle: Voltage (dc) / Current (dc) measurement
Resistance Measuring range Resolution Uncertainty
R 0 mΩ … 1999 mΩ 1 mΩ ±(5 % of reading + 3 digits)
2,00 Ω … 19,99 Ω 10 mΩ
3 Vdc Nominal voltage range 260 Vdc
Max test current (Itest) ~10 A / Duration 20 ms / 4-wire / Automatic range
MI 3144 and MI 3143*
Earth Potential [U]
Utouch, Ustep, Ucontact
Voltage Measuring range Resolution Uncertainty (* See note)
Utouch 0,0 V … 199,9 V 0,1 V calculated value
200 V … 999 V 1 V
Sub-result in measurement function Utouch
Voltage Measuring range Resolution Uncertainty (* See note)
Um1 mV … 1999 mV 1 mV ±(2 % of reading + 2 digits)
2,00 V … 19,99 V 10 mV
20,0 V … 199,9 V 0,1 V
16 Hz Nominal frequency 400 Hz
40 Vac Nominal voltage range 800 Vac
470 Vac*
Utouch = Umx (Ifault/Itest) Ifault range (selectable) 10 A … 200 kA
A 1597 Human body probe with an internal resistance of 1 kΩ ±1 %.

Page 7 Measuring and Regulation Equipment Manufacturer
Most powerful Industrial Safety & Quality bundle
Technical specifications
MI 3144
ELR Test [I and t]
ELR Current Injection Test and ELR Combination Time Test
Residual operating current Measuring range Resolution Uncertainty (* See note)
I 0,1 mA … 199,9 mA 0,1 mA ±(5 % of reading + 3 digits)
200 mA … 1999 mA 1 mA
2,00 A … 19,99 A 10 mA
Combination time Measuring range Resolution Uncertainty
t 0,1 ms … 199,9 ms 0,1 ms ±(2 % of reading + 3 digits)
200 ms … 1999 ms 1 ms
2,00 s … 19,99 s 10 ms
Nominal voltage range (P1 - P2) 40 ... 800 V
40 V Nominal voltage range 800 V
Nominal frequency range (P1 - P2) 16,7 ... 400 Hz 16 Hz Nominal frequency range 420 Hz
Current Waveform
t [ms]
If[A]
t [ms]
If[A]
t [ms]
If[A]
Alternating Pulsed DC
-
+++
Alternating, Pulsating, DC
Test current selectable 3 mA, 5 mA, 6 mA, 10 mA, 15 mA, 30 mA, 50 mA, 0,1 A, 0,15 A, 0,25 A, 0,3 A, 0,5 A
Number of turns - up to 10
MI 3144
Current [I]
Iron current clamps A 1281 and Flex current clamp A 1227 and A 1609
Current Type Range Measuring range Display range Resolution Overall Uncertainty
(* See note)
I A 1281 0,5 A 10 mA … 749 mA 0 … 749 mA 1 mA ±0,5 % * Irms
5 A 0,1 A … 7,49 A 0,00 … 7,49 A 0,01 A
100 A 2 A … 149 A 0,0 … 99,9 A 0,1 A
1000 A 20 A … 999 A 100 … 149 A 1 A
0 … 999 A 1 A
A 1227
A 1609
30 A 0,6 A … 59,9 A 0,0 … 59,9 A 0,1 A ±1,5 % * Irms
300 A 6 A … 599 A 0 … 599 A 1 A
3 kA 0,06 kA … 5,99 kA 0,00 … 5,99 kA 0,01 kA
* only MI 3144 Euro Z 800 V
Battery power supply 7,2 V DC (4,4 Ah Li-ion)
Battery charging time typical 3,0 h (deep discharge)
Mains power supply 90 ... 260 V AC, 45 ...65 Hz, 80 VA
Over-voltage category 300 V CAT II
Battery operation time:
Idle state > 24 h
Measurements > 12 h continuous testing for line, loop, high current
Auto - off timer 10 min (idle state)
Protection classification reinforced insulation
Measuring category 600 V CAT IV
Pollution degree 2
Degree of protection IP 65 (case closed), IP 54 (case open)
Dimensions (w x h x d) 36 cm x 16 cm x 33 cm
Weight 7 kg, (without accessories)
Sound / Visual warnings yes
Reference conditions:
Reference temperature range 25 °C ± 5 °C
Reference humidity range 40 % RH … 60 % RH
Operation conditions:
Working temperature range -10 °C … 50 °C
Maximum relative humidity 90 % RH (0 °C … 40 °C), non-condensing
Working nominal altitude up to 3000 m
Storage conditions:
Temperature range -10 °C … 70 °C
Maximum relative humidity 90 %RH (-10 °C … 40 °C)
80 %RH (40 °C … 60 °C)
RS 232 communication:
RS 232 serial communication galvanic separated
Baud rate 115200 baud rate, 1 stop bit, no parity
Connector standard RS232 9-pin D female
Bluetooth communication:
Device pairing code 1234
Baud rate 115200 bit/s
Bluetooth module class 2
GENERAL DATA

Page 8
ORDERING INFORMATION (MI 3144)
Standard set (MI 3144)
• Instrument MI 3144 Euro Z 800 V
• Mains cable
• RS232-PS/2 cable
• Test lead 5 m, black, 2 pcs
• Test lead 5 m, red, 2.5 mm2, 2 pcs
• Test lead 50 m, red, 2.5 mm2*
• Test lead 20 m, black
• Test lead 50 m, green*
• Large Kelvin test clip, 2 pcs
• Crocodile clip, black, 2 pcs
• Crocodile clip, red, 2 pcs
• Crocodile clip, green
• Test probe, black, 2 pcs
• Test probe, red , 2 pcs
• G clamp
• Human body resistance probe
• Test rod, 2 pcs
• Step voltage plates, 2 pcs
• Metrel ES Manager BASIC license**
• Metrel aMESM Android app with P 1102 PRO
license key
• Short instruction manual
• Calibration certificate
• Protective bag for accessories
• Soft carrying bag*
* Replaced by test leads on a cable reel in MI 3144 EU set.
Euro set MI 3144 (EU)
• MI 3144 ST
• Test lead 5m, green
• Test lead on a cable reel, 75 m, red, 2.5 mm2
• Test lead on a cable reel, 75 m, green
• Professional current earth spike, 42 cm
• 1-phase flexible current clamp 3000 / 300 / 30 A
/ 1 V (A 1609) with 5m current clamp extension
cable (A 1648)
• Current clamp A 1281 extension cable, 5 m
• Metrel ES Manager PRO license**
• Jumbo case
• Extension cable reel
• Jumbo case mount
** Metrel ES Manager can be downloaded free of charge from
Metrel Web server.
Most powerful Industrial Safety & Quality bundle
Standard set MI 3144 / MI 3143
A 1658 JUMBO CASEORDERING INFORMATION (MI 3143)
Standard set (MI 3143)
• Instrument MI 3143 Euro Z 440 V
• Mains cable
• RS232-PS/2 cable
• Test lead, 2-wire, 2 pcs*
• Crocodile clip, black, 2 pcs
• Crocodile clip, red, 2 pcs
• Test probe, black, 2 pcs
• Test probe, red, 2 pcs
• Metrel ES Manager BASIC license**
• Metrel aMESM Android app with P 1102 PRO
license key
• Short instruction manual
• Calibration certificate
• Protective bag for accessories
* Replaced by 5 m and 20 m test leads in MI 3143 EU set.
Euro set MI 3143 (EU)
• MI 3143 ST
• Test lead 5 m, black, 2 pcs
• Test lead 5 m, red, 2.5mm2, 2 pcs
• Test lead 20 m, red, 2.5mm2
• Test lead 20 m, black
• Test lead 20 m, green
• Large Kelvin test clip, 2 pcs
• G clamp
• Human body resistance probe
• Test rod, 2 pcs
• Step voltage plates, 2 pcs
• Metrel ES Manager PRO license**
• Soft carrying bag
** Metrel ES Manager can be downloaded free of charge from
Metrel Web server.

Page 9
Measuring and Regulation Equipment Manufacturer
Most powerful Industrial Safety & Quality bundle
Optional accessories
OPTIONAL ACCESSORIES
RECOMMENDED ACCESSORIES
Photo Part No. Description
MI 3144 MI 3143
A 1620 Test lead 5 m, black • •
A 1621 Test lead 20 m, black • •
A 1527 Test lead 5 m, red,
1.5 mm2
• •
A 1640 Test lead 20 m, red,
1.5 mm2
• •
A 1608 Test lead 20 m, green • •
A 1654 Test lead on a cable
reel, 50 m, red, 2.5
mm2, extendable
• •
A 1509 Test lead on a cable
reel, 50 m, black,
extendable
• •
A 1510 Test lead on a cable
reel, 50 m, green,
extendable
• •
A 1619 Test lead, 2-wire,
2 pcs
• •
A 1660 Extension test leads
on reel, 75 m, red,
green, 2.5 mm2
• •
Photo Part No. Description
MI 3144 MI 3143
A 1661 Jumbo case mount
for A 1660
• •
A 1593 Large Kelvin test clip,
2 pcs
• •
A 1595 Large test
crocodile, black
• •
A 1596 Large test
crocodile, red
• •
A 1013 Crocodile clip, black,
2 pcs
• •
A 1064 Crocodile clip, red,
2 pcs
• •
A 1014 Test probe, black,
2 pcs
• •
A 1016 Test probe, red, 2 pcs • •
A 1530 G clamp • •
A 1597 Human body
resistance probe
• •
Photo Part No. Description
MI 3144 MI 3143
A 1022 Test rod, 2 pcs • •
A 1528 Professional current
earth spike, 50 cm
• •
S 2053 Step voltage plates,
2 pcs
• •
A 1609 1-phase flexible
current clamp
•
A 1227 1-phase flecible
current clamp
3000/300/30 A / 1 V
•
A 1281 Current clamp
0,5/5/100/1000 A
/ 1 V
•
A 1648 Current clamp A 1281
extension cable, 5 m
•
A 1658 Jumbo case for MI
3144
• •
P 1101 BASIC to PRO license
key upgrade for
Metrel ES Manager
• •
A 1660 Extension test leads on reel, 75 m, red, green,
2.5 mm2
A 1661 Jumbo case mount for A 1660 A 1597 Human body resistance probe

Page 10
Power Electrical Installation's Automatic trip-out ability is the majority evaluation during
maintenance process to protect power transformer in case of overloading, overheating
and shorting. Heavy Industrial solution supports live testing without disconnection of the
transformer from power network.
Periodical inspections of Z line and Z loop
impedances can show bad contacts on busbars,
condition of power switches, contactors or fuse
holders. However, it needs to be working in
high resolution mili-Ohm range. The accuracy
of the result depends on 4-wire connection and
high enough test current.
The switchyards with fuses over 100A need
at least 10A test current, the more the
better. Insufficient test current results in an
instability of calculated short circuit current.
MI 3144 impedance testing with 300 A can
offer robust repeatable results with high
noise immunity and reliability.
Results of L to N or L to L need to be
compared between phases at the source
and at the load. There should be only the
calculated differences based on length and
cross section of the conductors.
Performing measurements close to the
power transformer’s inductive impedance
has a significant influence. Resistance,
inductance and voltage drops need to be
evaluated accordingly.
Short-circuit currents in three-phase
a.c. systems calculation accordingly to
international standard IEC 60909-0
Calculated HOT Factor with the measured
of Ipsc min and Ipfc min represents unique
solution for predicting the factor of reserve in
case of an error on overheated transformers.
Systems with neutral conductor L-N:
Fault Loop Impedance live testing with test current of 300 A in CAT IV environment with
voltages up to 440 V (MI 3143) / 800 V (MI 3144) and frequencies in range 16 ... 420 Hz.
Four-wire type of connection with Kelvin
crocodiles for high precision and stable results
eliminates problems of bad connectivity and
test leads compensation.
Automatic trip out ability evaluation with
high accuracy and stability of result even on
powerful systems with fuses above 1000 A
where classic methods became useless.
Impedance with Resolution of 1mOhm
detailed evaluation of transformer’s Isc min,
Isc max and Z HOT based on overheating
reserve.
Application Note - 1 (MI 3144 and MI 3143)
Live Power Transformer High Precision 4-wire 300A Z Line /
Loop Impedance Testing
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
Z(L-N) HOT =(1.5 x RL-N)2 + X2L-N
Z(L-L) HOT =(1.5 x RL-L)2 + X2L-L
IKMIN 3ph =
IKMIN 2ph =
IKMIN (L-N) =
3x
Z(L-L) HOT
Z(L-N) HOT
Z(L-L) HOT
CMIN x U N(L-L)
CMIN x U N(L-L)
CMIN x U N(L-N)
2
Systems without neutral conductor L-L:

Page 11 Measuring and Regulation Equipment Manufacturer
Industrial electrical installation components, fuse holders, cables, contacts, busbars and
powerful switches are crucial for operability, automatic trip-out ability, and functional safety.
Industrial solution supports live testing without power network disconnection.
[V]
[s]
[V]
[s]
U P1-P2
[A] Itest
U C1-C2
Ic
The maintenance procedure project can be
designed in advance and all replacements
and repairs can become predictable.
Periodical inspections of Z line and Z loop
impedances can show bad contacts on busbars,
condition of power switches, contactors or fuse
holders. However, it needs to be working in
high resolution mili-Ohm range. The accuracy
of the result depends on 4-wire connection and
high enough test current.
MI 3144 impedance testing with 300 A can
offer robust repeatable results with high
noise immunity and reliability.
Floating synchronized voltmeter can be
connected parallel to any contact in the
tested circuit. Series resistances do not
influence the tested result.
External iron or flex clamps will give exact
value of testing current through the connected
path of measured contact. Circuits, connected
in parallel, fuses, switches and powerful loads
do not influence the tested result.
Four-wire type of connection with separated
test crocodiles to eliminate serial resistances
and bad connections. Test leads compensation
is not needed.
Iron Clamps connected to an external output
to eliminate parallel resistances and current
paths where several circuits are connected to
live network.
Flex Clamps connected to an external output
for use on high current busbars and powerful
conductors with large cross-section.
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 U
R1
R3R2
Itest
U AC
U
R1+R2
U R1+R2+R3
Application Note - 2 (MI 3144 and MI 3143*)
Partial Voltage Drops and Partial Clamp Current’s Path*
Resistances

Page 12
Application Note - 3 (MI 3144)
Airports High Frequency Band 16 ... 420 Hz Installation
Impedances testing
Mobile Ground Power Supply or Central Supply Systems with generators, motors,
converters, connection systems, sub-distribution units, cables, connectors and plugs need
robust and reliable predictive maintenance. The rationality behind this is to provide safety
and quality of electrical power supply and connected electrical circuits and subsystems for
the aircraft in the flight preparation phase.
Using our solution in parallel to existing
test procedures with load banks allows us
to provide comprehensive evaluation of
potential faults and errors on live electrical
circuits supplied by various sources ranging
from 28 V DC to 420 Hz 800 V AC.
The quality of the motor, generator or
transformer windings can be evaluated
with the four wire method, enabling
accurate evaluation on power sources as
powerful as 500 kVA.
The results measured first at the source
and later at the sub distribution boards
are compared to find potential faults and
errors. The (instrument’s) resolution in the
range of milliohms is sufficient to show
deviations in case of bad joints on cables
or bus bars, failures inside contactors
or switches and within fuse holders and
similar.
Live testing of loop Impedance of a 400 Hz AC 110 V Ground Power Supply Unit. High Power Load is connected to the GPU circuit during
testing period. The measured voltage drop and loading current will give the result of possible bad contacts and short circuit current
calculation to evaluate appropriate fuse protection.
GPU quality and safety can be completely
evaluated with the use of MI 3155
EurotestXD in cases where IT protection
circuits and insulation should be evaluated.
The comparison of results at the source with
the results at sub distribution board shows
potential faults and errors within the system.
Testing must be predicted periodically.
Loading live circuits on a 90 kVA generator
and testing with the 4-wire Kelvin method
will bring stable results of 50 mΩ and 2,2
kA prospective short circuit ability same to
all three phases in case of error free GPU.
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 U
R1
R3R2
Itest
U AC
U R1+R2
U R1+R2+R3

Page 13 Measuring and Regulation Equipment Manufacturer
Centralised rotary generators and
converters need to be monitored, measured
and evaluated for quality and safety in
reasonable time periods.
Portability of the test system with good
protection for all weather situation.
Fast and efficient transport to the field.
[A]
[s]
[V]
U unloaded
[s]
U loaded
Itest
ΔU
Udc
The MI 3144 Euro Z 800 V portable test unit is capable of loading and testing live circuit
impedance without disconnection from the power source.
Memorization and periodic comparison of test results can predict the maintenance
procedure, servicing and fast troubleshooting in case of malfunction.
Live testing of loop resistance of DC 28 V Ground Power Supply Unit. High Power Load is connected to the GPU circuit during testing
period. The measured voltage drop and loading current will give the result of possible bad contacts and short circuit current calculation to
evaluate appropriate fuse protection.
Loading live circuits on a 28 V DC generator
and testing with 4-wire Kelvin method
will bring stable result of 50 mΩ on a good
system between DC+ to DC- plug.
Udc
R
4 wire (Kelvin)
Itest
+
-
C1
P1
P2
C2
MI 3144 Euro Z 800 V
V
A
R
+
-

Page 14
Application Note - 4 (MI 3144)
DC Networks’ and Power Sources’ Line and Loop Resistances
Substations DC control circuits, supplying DC sources, DC charging stations and batteries
with electrical installation’s circuit protection is based on internal resistance of the source,
power lines and grounded loops. Automatic trip-out protection with fuses will regularly
operate in case of faults, errors or shorts where resistances in the circuit are low enough.
[A]
[s]
[V]
U unloaded
[s]
U loaded
Itest
ΔU
Udc
Industrial solution supports live testing
without disconnection of the DC batteries or
DC power sources during testing.
The purpose of periodical inspections of DC
circuits is to show bad contacts on bus bars,
condition of batteries, conditions of power
switches, contactors or fuse holders. The
resistance result at the power source need
to be compared with the result at the outer
edge of the circuit where voltage drops shall
not exceed evaluated border limit.
Internal resistance of the batteries
shows their quality and condition. It can
be measured in either parallel or series
connection, either whole system or partially.
MI 3144 compares loaded and unloaded
battery’s voltage. Measured and calculated
values are compared to the reference. The
batteries from DC 3 V up to DC 260 V can be
evaluated.
Live testing Loop Resistance of DC Networks and DC Power Sources for wide range of applications. Quality of the battery banks and
separate cells could be evaluated and measured in percentage of the voltage drop during loading. Cells shell be compared one to another
to eliminate possible power failures.
Four-wire type of connection with Kelvin
crocodiles for high precision and sta¬ble
results elimi¬nates connection problems even
in an aggressive environment.
Internal resistance of the Power Source with
Automatic trip-out ability evaluation with high
accuracy on DC circuits.
Measured result of live loop resistance on DC
control circuits at the field end to be compared
with battery source for evaluation of the
conductors, relays and contacts quality.
Udc
R
4 wire (Kelvin)
Itest
+
-
C1
P1
P2
C2
MI 3144 Euro Z 800 V
V
A
R
+
-

Page 15
Measuring and Regulation Equipment Manufacturer
Application Note - 5 (MI 3144)
Flex & Iron One-Clamp High Current dR 300A Grounding
method for Lightning systems
Lightning protection on buildings with faraday cages and metal shields connected to
conductive construction of the building must be tested periodically to check the connections
from the lightning rods to the grounding nets.
High Current testing with controlled power management of the source pulsing current. Safety
mannered procedure where partial current Ic measured in synchronization with voltage drop U
P1-P2 gives result of separate earthing leg resistance.
Flex Clamps measure selective currents to the
ground during generated pulse.
Robust G-clamp connects the test leads
through colored or rusted surfaces to conduct
hi test current to grounded paths.
Portable protected travel case to transport all
the necessary equipment to the test site.
Body resistance simulation with 1 kOhm
adapter A1597 for correct Touch Voltage
calculation.
Conductive paths through the building must
evenly dissipate power of the lightning
strike all the way down to the ground. The
voltage drops during lightning discharge
throughout the building will then be low
enough to protect living beings and inbuilt
equipment.
High current dR 300A testing with MI 3144
Euro Z provides enough power while still
being small and portable enough to be easily
brought to any roof or part of industrial
platform.
External flex clamps can be wrapped around
any metal leg or construction with high
cross-section. Partial currents through
building’s construction, metal straps or cable
screens can be evaluated.
Synchronized testing of voltage drops in the
building’s surroundings during high current
pulse shows potential risks in case of a bad
connection to the ground net due to aging,
corrosion or mechanical damage.

Page 16
Application Note - 6 (MI 3144 and MI 3143*)
High Current dR 300A Integrity of Grounding system with Flex
and Iron One-Clamp method*
Ground impedance and ground bonding measurements have to be performed, after
installation and periodically to verify the continuity of buried ground conductors and
connectors to the ground.
[V]
[s]
[V]
[s]
UP1-P2
[A] Itest
UC1-C2
Ic
Measurement is performed within a half-period and therefore the safety condition is fulfilled even during high current pulse with up to several
hundred volts. Synchronized measuring method and a higher current amplitude improves the immunity against voltage noise.
Flex or iron Clamps measures selective current
from riser to grid.
Kelvin Crocodiles ensure robust 4-wire
connection for reliable results.
G-clamp reference point on the grid connection
improving the result stability.
Properly designed, installed, and maintained
grounding grid eliminates the shock hazard
and disturbances to the installation that can
arise due to fault currents.
The ground integrity test should be
performed before any other tests for safety
reasons and for quality control for large
ground grid systems such as power plants,
substations, switchyards, railways or any
industrial platform.
Lightning or fault-related surge protection
prevents damage to sensitive electronic
circuits in the buildings,
control gears, antenna towers, remote
control stations and similar.
Ground grid integrity measurements may be
referenced to standard IEEE-81.2012 parts
10.2 and 10.3 by injecting a high test current.

Page 17
Measuring and Regulation Equipment Manufacturer
Application Note - 7 (MI 3144)
ELR (MRCD) trip-out Current and trip-out Time testing
The MI 3144 Euro Z 800 V instrument supports testing of ELRs (MRCDs) without integral
current breaking devices and with separate sensing means.
C1
1 - turn
C2
C1
C2
C1
C2
2 - turns 3 - turns
Earth potentials, step and touch voltages may be referenced to standard IEEE-81.2012 part 9. The
measured values should be compared to referenced body withstanding values.
Always count the inner number of turns!
ELR Current Injection Test
Verifying the operation in case of a steady
increase of the residual current.
Igen
C1
P1
P2
C2
MI 3144 Euro Z 800 V
G
A
R load
Trip current adjustment
Time delay adjustment
E a r t h
R load
R load
MRCD or ELR
L1
L2
L3
Pe
Igen
V
Toroid
Circuit Breaker
Supply
N
Off Load Test !
Number of turns
1 - 10
Note (acc.to IEC 60947-2 Annex M)
The Earth Leakage Relay (ELR) or Modular
Residual Current Devices (MRCD) shall be
installed, mounted and wired according to
the manufacturer's instructions. Unless
otherwise specified, it is connected to
a test equipment, as specified by the
manufacturer, representing normal service
conditions for the output circuit in order
to verify the change in the status of the
output. For the measurement of the
combination time, the ELR is connected
[A]
combination time
IΔset
[s]
ON
[s]
OFF
Circuit Breaker
The instrument measures the combination
time (ELR + Circuit Breaker) from
establishing the current (Iset) to the change
detected in the circuit braker OFF state.
Multiple turns supported through the
MRCD's remote sensor can generate high
fault current for adjustment of industrial
platform protection.
Following IEC 60947-2 Annex M standard
brings multiple solution to fulfil industrial
demands.

Page 18
Application Note - 8 (MI 3144 and MI 3143)
Earth Potentials by method of measuring Step, Touch and
Transfer voltages
Measuring step and touch voltages caused by injecting a known amount of current into the
ground system offers better assurance that the grid meets its design objectives.
Earth potentials, step and touch voltages may be referenced to standard IEEE-81.2012 part 9. The
measured values should be compared to referenced body withstanding values.
Actual magnitude of step, touch and
transfer voltages can then be determined
by scaling the measured values up to the
prospective fault current. Such current
can occur during phase to ground error or
lightning strike.
Following the IEEE 81 rules or any other
local regulation or standard like IEC 62305
the step and contact or touch and transfer
voltages shell be tested in a safe manner
periodically.
The most critical situations need to be
observed in surrounding of any metal
construction, building with LPS or in
surrounding of any kind of production,
generation, distribution or transmission of
the energy.
Exposed parts where the dangerous
voltages could be transfered to longer
distances are meshes, fences, pipes, pylons,
bridges, rails, cable's shields, metal stripes
or similar.
Well conducted probes - weights of 25 kg /
200 cm2 or two step-on plates used for proper
connection to grounding material.
Due to short 0.01s duration of the test, the
operation is safe for people in surrounding
even for public places measurements.
Copper probes - weights of 5 kg to be
combined with 25 kg weight in addition for
proper connection to wet concrete material.

Page 19
Measuring and Regulation Equipment Manufacturer
Touch Voltage calculation on the instrument screen can be selected from the list of parameters. Fault current in the equation is a manually inserted
value of the predicted power of a lightning strike, e.g. 50 kA. Combined with the body simulator A 1597, the measurement will be scaled to the
potential risk around lightning systems.
Example of permissible body current IB and calculated values of the permissible touch voltage UTp depending on the fault duration tf
Fault duration (s) Permissible body current IB
(mA)
Permissible touch voltage
UTp (V)
0,05 900 716
0,10 750 654
0,20 600 537
0,50 200 220
1,00 80 117
2,00 60 96
5,00 51 86
10,00 50 85
Body resistance simulation with 1 kOhm
adapter A1597 for correct Touch Voltage
calculation.
Bundle set with all the accessories in a portable
IP67 protected case for field transport.
Extremely portable and easy to handle.
Equipped with robust wheels and extended
arm with added holders for backside mounted
extension cable reel.

Page 20
METREL d.d.
Measuring and Regulation Equipment Manufacturer
Ljubljanska 77, SI-1354 Horjul, Slovenia
T [phone], F [phone]
[email protected], www.metrel.si
Note! Photographs in this catalogue may slightly dier from the instruments at the time of delivery.
Subject to technical change without notice.
BROCHURE_MI 3144 Euro Z 800 V & MI 3143 Euro Z 440 V_2020_Ang_December