Sonel WMGBMZC304F User manual

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USER MANUAL
FAULT LOOP IMPEDANCE METER
MZC-304F
SONEL S.A.
Wokulskiego 11
58-100 Świdnica
Poland
Version 1.0112.05.2023

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The MZC-304F is a modern, state-of-the art measuring instrument, easy to operate and safe. Read
this manual to avoid mistakes during the measurements and prevent operational problems.

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CONTENTS
1General information.........................................................................................5
1.1 Safety symbols.........................................................................................................5
1.2 Safety....................................................................................................................... 6
2Quick start ........................................................................................................7
2.1 Switching on and off, display backlight ....................................................................7
2.2 Selecting general measurement parameters ...........................................................7
2.3 Remembering the last measurement result ............................................................. 7
3Measurements................................................................................................10
3.1 AC voltage measurement....................................................................................... 10
3.2 Voltage and frequency measurement....................................................................10
3.3 Checking the correctness of PE (protective earth) connections ............................11
3.4 Fault loop parameters............................................................................................12
3.4.1 Selecting the lead length................................................................................................12
3.4.2 Prospective short-circuit current ....................................................................................13
3.4.3 Fault loop parameters in the L-N and L-L circuits...........................................................14
3.4.4 Fault loop parameters in the L-PE circuit.......................................................................17
3.4.5 Fault loop impedance in L-PE circuit protected with a residual current device (RCD) ....19
3.5 Low-voltage resistance measurement ...................................................................21
3.5.1 Test leads resistance compensation –auto-zeroing.......................................................21
3.5.2 Low-current resistance measurement............................................................................22
3.5.3 Measurement of resistance of protective conductors and equipotential bonding with
±200 mA current............................................................................................................24
4Memory of measurement results..................................................................26
4.1 Entering the measurement results to the memory .................................................26
4.2 Changing the cell and bank number ......................................................................28
4.3 Browsing the memory ............................................................................................28
4.4 Clearing the memory..............................................................................................30
4.4.1 Clearing the bank...........................................................................................................30
4.4.2 Clearing the whole memory ...........................................................................................31
4.5 Communication with computer............................................................................... 32
4.5.1 Package for cooperation with computer.........................................................................32
4.5.2 Data transmission with Bluetooth 4.2 module ................................................................32
5Troubleshooting.............................................................................................33
6Power supply..................................................................................................34
6.1 Monitoring the power supply voltage...................................................................... 34
6.2 Replacing the batteries ..........................................................................................34
6.3 General rules of using the Nickel Metal Hydride (Ni-MH) batteries...........................35
7Cleaning and maintenance ...........................................................................35
8Storage............................................................................................................36
9Dismantling and disposal .............................................................................36
10 Technical data................................................................................................37
10.1 Basic information ................................................................................................... 37
10.1.1 Voltage measurement....................................................................................................37

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10.1.2 Frequency measurement...............................................................................................37
10.1.3 ZL-PE, ZL-N, ZL-L fault loop impedance measurement.......................................................37
10.1.4 ZL-PE fault loopimpedance measurement RCD (without trippingtheRCD)...............................38
10.1.5 Low-voltage continuity and resistance measurement.....................................................39
10.2 Other technical specifications ................................................................................ 39
10.3 Additional information ............................................................................................40
10.3.1 Additional uncertainty according to IEC 61557-3 (Z)......................................................40
10.3.2 Additional uncertainty according to IEC 61557-4 (R ±200 mA).......................................40
11 Accessories....................................................................................................41
11.1 Standard accessories ............................................................................................ 41
11.2 Optional accessories..............................................................................................42
12 Manufacturer ..................................................................................................44
13 Laboratory services.......................................................................................45

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1 General information
1.1 Safety symbols
The following international symbols are used in the device and/or in this manual:
Warning;
See explanation in
the manual
Ground
AC current/voltage
DC current/voltage
Dual insulation
(Protection class)
Declaration of Conform-
ity with EU directives
(Conformité
Européenne)
Do not dispose of
with other house-
hold waste
Recycling information
Confirmed compliance
with Australian Stand-
ards
Measurement categories according to IEC 61010-2-030:
CAT II –concerns measurements performed in circuits directly connected to low voltage in-
stallations,
CAT III –concerns measurements performed in buildings installations,
CAT IV –concerns measurements performed at the source of low voltage installation.

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1.2 Safety
The meter is designed for testing the protection against electric shock in the mains systems. The
meter is used to make measurements which results determine the electrical installation safety level.
Consequently, in order to ensure safe operation and correct measurement results, observe the follow-
ing recommendations:
Before you proceed to operate the meter, acquaint yourself thoroughly with the present manual
and observe the safety regulations and recommendations of the manufacturer.
Any application that differs from those specified in the present manual may cause damage of the
instrument and a serious hazard to its user.
The meters must be operated solely by appropriately qualified personnel with relevant certificates
to perform measurements of electric installation. Operation of the instrument by unauthorized per-
sonnel may result in damage to the device and constitute a hazard to the user.
Using this manual does not exclude the need to comply with occupational health and safety regu-
lations and with other relevant fire regulations required during the performance of a particular type
of work. Before starting the work with the device in special environments, e.g. potentially fire-
risk/explosive environment, it is necessary to consult it with the person responsible for health and
safety.
It is unacceptable to operate the following:
a damaged meter which is completely or partially out of order,
leads with damaged insulation,
a meter which ahs been stored to long in unsuitable conditions (for example is wet). When the
meter is transferred from cold environment to warm and humid one, do not make measure-
ments until the meter warms up to the ambient temperature (about 30 minutes).
Remember that the message on the display means that the power supply voltage is too low and
indicates the need to replace/ charge the batteries. The measurements performed with the meter with
insufficient supply voltage have additional measuring errors which are impossible to be evaluated by
the user and cannot be the basis to determine the correct protection of the tested installation.
Do not leave the discharged batteries in the meter as they can leak and damage the instrument.
Before starting the measurement, check if the leads are connected to correct measuring terminals.
Never use the meters with open or only partially closed battery compartment cover and use only
the power supplies specified in this manual.
Repairs may be performed solely by an authorized service outlet.
NOTE!
Only accessories for a given device should be used, as listed in section 11. Using
other accessories may cause damage to measuring terminals, introduce additional
measurement error and create a risk for the user.
An attempt to install drivers in 64-bit Windows 8 and Windows 10 may result in dis-
playing "Installation failed" message.
o Cause: Windows 8 and Windows 10 by default blocks drivers without a digi-
tal signature.
o Solution: Disable the driver signature enforcement in Windows.
Due to continuous development of the meter’s software, the actual appearance of
the display, in case of some of the functions, may slightly differ from the display
presented in this operating manual.

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2 Quick start
2.1 Switching on and off, display backlight
To switch on the meter, briefly press the button. To switch off, press the same button
longer (the message appears).
To switch on/off the display and keypad backlight during the meter operation, briefly press the
button.
2.2 Selecting general measurement parameters
+
Keeping the SET/SEL button depressed, switch on the meter and wait
for the parameter selection screen to appear.
Use the ◄► buttons to go to next parameter.
Use the ▲▼ buttons to change the parameter value. The value or
symbol to be changed is flashing.
Set the parameters according to the algorithm.
Press and hold ENTER (until a signal sounds –ca. 3 s) to save the
changes and go to the measurement function or press ESC to go the
measurement function without saving the changes.
At first start-up or after replacing batteries, select the type of power supply: re-
chargeable batteries (ACCU) or batteries (BATT). General measurement parameters
can be selected in the same menu.
Before the first measurements, set the mains rated voltage Un(220/380 V, 230/400 V
or 240/415 V) which is applicable in the test location. The voltage is used to calculate
the prospective short-circuit current, if this option was chosen from the main menu.
The symbol in the time to auto-off settings, indicates disabling this function.
PIN settings –see Meter settings schematic.
Software upgrade –see Meter settings schematic and section 4.5.
2.3 Remembering the last measurement result
The result of the last measurement is remembered until the next measurement is activated, the
measurement parameters are changed or the measuring function is changed with the rotary switch.
Use the ESC button to go to the starting screen of a given function and press ENTER to display the
last measurement result.

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Meter settings –algorithm
Mains voltage
Mains frequency
Result of impedance measurement: short- circuit current / impedance
Voltage for calculating Ik: rated / measured
Auto-OFF ▪ disabled ▪ time to automatic shutdown
Bluetooth communication: enabled / disa- bled
UN
►
◄
fN
►
◄
LOOP
DISP
►
◄
Ik
►
◄
OFF
►
◄
BT
►
◄
▲
▼
▪ 220 V
▪ 230 V
▪ 240 V
▪ 50 Hz
▪ 60 Hz
▪ Ik
▪ Z
▪ U
▪ UN
▪ - - -
▪ 300 s
▪ 600 s
▪ 900 s
▪ on
▪ off

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Change PIN
Power supply selection: rechargeable batteries / batteries
Beeper: enabled / disabled
Firmware update
Factory reset: yes / no
PIN
conf
►
◄
SUPP
►
◄
BEEP
►
◄
UPDT
►
◄
FACT
SETT
►
◄
3 s
▪ ACCU
▪ BATT
▪ on
▪ off
▲
▼
▪ yes
▪ no
3 s
▲
▼
0
…
9
◄
►
0
…
9
◄
►
0
…
9
◄
►
0
…
9
3 s

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3 Measurements
WARNING
During the measurements (fault loop impedance) never touch the earthed and
accessible parts in the tested electrical installation.
During the measurement do not switch the rotary switch as this may cause dam-
age of the meter and hazard for the user.
Message indicates, that an incompatibile measurement adapter is connected
to the meter.
3.1 AC voltage measurement
The meter measures and displays the mains alternating voltage in all measurement functions
with the exception of R. The voltage is measured for the 45…65 Hz frequency range. The test leads
should be connected as for a given measuring function.
3.2 Voltage and frequency measurement
Set the rotary switch to the U,f position.
Read the measurement result: frequency in the
main display field, voltage in the auxiliary field.

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3.3 Checking the correctness of PE (protective earth) connections
Connect the meters as shown in the figure, touch the contact electrode with your finger and wait about
1 second. When the voltage on the PE conductor is detected, the instrument displays the mes-
sage (error in the installation, the PE conductor is connected to the phase conductor) and generates a
continuous audio signal. This option is available for all measurement functions related to the fault
loop, except for ZL-N,L-L.
WARNING
When dangerous voltage on the protective conductor PE is detected, discon-
tinue the measurements immediately and repair the electrical installation.
Make sure that during the measurements you are not standing on an uninsulated
floor as this may cause erroneous results.
The threshold value, which triggers the signal of exceeded allowable voltage on PE
conduit, is approximately 50 V.

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3.4 Fault loop parameters
NOTE!
If the tested mains includes residual current devices, for the duration of measure-
ment they should be omitted by bypassing. Remember however that bypassing
changes the tested circuit and the results may very slightly differ from the actual
values.
After the measurement, restore the mains to its original state and check operation
of the residual current device. This note does not apply to the earth loop impedance
measurements with the ZL-PE RCD function.
Measurements of fault loop impedance performed downstream of inverters are inef-
fective and their results are unreliable. This is due to the instability of internal im-
pedance in inverter circuits during its operation. The measurements of fault loop
impedance should not be performed directly downstream of inverters.
3.4.1 Selecting the lead length
Switch on the meter.
Set the rotary switch to one of the fault loop im-
pedance measurement types.
SET L
▲
▼
▪ 1.2 m
▪ 5 m
▪ 10 m
▪ 20 m
Set the parameters according to the following algo-
rithm and the rules for setting the general parame-
ters.
Using original leads and selecting correct length is a guarantee of keeping the de-
clared measuring accuracy.
The WS leads are detected by the meter and you cannot select their length (the
symbol is displayed). When you are using the leads with banana plugs, before you
start the measurements set the correct phase conductor length complying with the
test leads length.

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3.4.2 Prospective short-circuit current
The meter always measures the impedance, and the displayed short-circuit current is calculat-
ed according to the following formula:
S
n
kZ
U
I
where:
Un–rated voltage of the tested mains,
ZS–measured impedance.
Based on the rated voltage Unselected in the general settings (section 2.2), the meter auto-
matically detects the measurement with phase-to-neutral or phase-to-phase voltage and includes this
in the calculations.
If the tested mains voltage is out of tolerance range, the meter will not be able to determine the
correct rated voltage for calculation of short-circuit current. In such case, horizontal lines will be dis-
played instead of the short-circuit current. The figure below shows the voltage ranges for which the
short-circuit current is calculated.
230 400 440 U [V]
U voltage ranges for which the
short-circuit current is calculated
L-N
Voltage range for which the impedance is measured
207 253 360
220 380 418
198 242 342
373 415 440 216 240 264
440 U [V]
U [V]
U =220V
n
U =230V
n
U =240V
n
U voltage ranges for which the
short-circuit current is calculated
L-L

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3.4.3 Fault loop parameters in the L-N and L-L circuits
Switch on the meter.
Set the rotary switch to the ZL-L ZL-N position.
Select the leads length as described in
sec. 3.4.1 according to the needs.
Connect the test leads as shown in the figure:
for measurement in the L-N circuit,
measurement in the L-L circuit
The meter is ready for measurement.
Phase conductor length or the symbol.
UL-N or UL-L voltage
Press START to perform the measurement.

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Read the main result: the fault loop impedance ZS
and the mains voltage during the measurement.
Press ►to display additional results.
Short-circuit current IK
Fault loop resistance R
Fault loop reactance XL

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Save the result in the memory (see sections 4.1, 4.2) or press ESC to return to the
voltage measurement.
Making a large number of tests over a short time causes the meter to emit a lot of
heat. As a result the casing may become warm. This is normal. The meter has an
overheat protection.
The minimum time between successive measurements is 5 seconds. This value is
controlled by the meter which displays the message when you can make
the next measurement.
Additional information displayed by the meter
Meter ready for measurement
Voltage on the meter Land Nterminals is out of range for
which the measurement can be made.
Voltage on the meter Land PE terminals is out of range
for which the measurement can be made.
Measurement error
Incorrect or unstable power grid frequency.
Measurement error –loss of voltage after the measure-
ment.
Short-circuit loop of the meter is faulty.
N conductor not connected.
Message (displayed after the measurement) indicates sig-
nificant disturbances in the mains during measurement.
The measurement result may include a large, unspecified
error.
Temperature inside the meter has exceeded the allowed
limit. The measurement is blocked.
The L and N conductors are switched (voltage between the
PE and N conductors).

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3.4.4 Fault loop parameters in the L-PE circuit
Switch on the meter.
Set the rotary switch to the ZL-PE position.
Select the leads length as described in
sec. 3.4.1 according to the needs.
Connect the test leads as shown in one of the figures.
Measurement in L-PE circuit
Checking effectiveness of protection against electric shock
of the meter housing in case of:
TN network or TT network

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The meter is ready for measurement.
Phase conductor length or the symbol.
UL-PE voltage
Press START to perform the measurement.
The remaining measurement issues are analogous to the ones described for the measurements
in the L-N or L-L systems.
A double-lead measurement is possible when selecting the test lead other than with
the socket adapter.
Additional information displayed by the meter
Meter ready for measurement
Voltage on the meter Land Nterminals is out of range for
which the measurement can be made.
Voltage on the meter Land PE terminals is out of range
for which the measurement can be made.
Measurement error
Incorrect or unstable power grid frequency.
Measurement error –loss of voltage after the measure-
ment.
Short-circuit loop of the meter is faulty.
N conductor not connected.
Message (displayed after the measurement) indicates sig-
nificant disturbances in the mains during measurement.
The measurement result may include a large, unspecified
error.
Temperature inside the meter has exceeded the allowed
limit. The measurement is blocked.
The L and N conductors are switched (voltage between the
PE and N conductors).