Sonel MZC-305 User manual

OPERATING MANUAL
FAULT LOOP IMPEDANCE METER
MZC-305
SONEL SA
ul. Wokulskiego 11
58-100 Świdnica, Poland
Version 1.08 25.01.2016

OPERATING MANUAL MZC-305 version 1.08
2
The MZC-305 meter is a modern, easy in use and safe measuring device. Please acquaint yourself
with the present manual in order to avoid measuring errors and prevent possible problems related to
operation of the meter.

OPERATING MANUAL MZC-305 version 1.08
3
CONTENTS
1SAFETY....................................................................................................................5
2MEASUREMENTS..................................................................................................6
2.1 SELECTION OF GENERAL MEASUREMENT PARAMETERS.........................................6
2.2 REMEMBERING THE LAST MEASUREMENT RESULT ................................................7
2.3 MEASUREMENT OF ALTERNATING VOLTAGE .........................................................8
2.4 CHECKING CORRECTNESS OF PE (PROTECTIVE EARTH)CONNECTIONS..................8
2.5 MEASUREMENT OF FAULT LOOP PARAMETERS ......................................................8
2.5.1 Selection of measurement parameters ...........................................................9
2.5.2 Prospective short-circuit current.................................................................10
2.5.3 Measurement of fault loop parameters in the L-N and L-L circuits ............11
2.5.4 Measurement of fault loop parameters in the L-PE circuit .........................13
2.5.5 Measurement of short circuit loop impedance in L-PE circuit protected with
a residual current device (RCD)..................................................................15
3MEMORY OF MEASUREMENT RESULTS.....................................................17
3.1 STORING THE MEASUREMENT RESULT DATA IN THE MEMORY .............................17
3.2 CHANGING THE CELL AND BANK NUMBER...........................................................19
3.3 VIEWING MEMORY DATA.....................................................................................20
3.4 DELETING MEMORY DATA...................................................................................21
3.4.1 Deleting bank data.......................................................................................21
3.4.2 Deleting the whole memory .........................................................................22
3.5 COMMUNICATION WITH A COMPUTER .................................................................23
3.5.1 Computer connection accessories ...............................................................23
3.5.2 Data transmission........................................................................................23
3.5.3 Software update...........................................................................................24
4TROUBLESHOOTING.........................................................................................25
5METER POWER SUPPLY...................................................................................26
5.1 MONITORING OF THE POWER SUPPLY VOLTAGE...................................................26
5.2 REPLACEMENT OF BATTERIES .............................................................................26
5.3 GENERAL RULES OF USING THE NICKEL METAL HYDRIDE (NI-MH) BATTERIES..28
6CLEANING AND MAINTENANCE....................................................................29
7STORAGE ..............................................................................................................29
8DISMANTLING AND DISPOSAL.......................................................................29
9TECHNICAL SPECIFICATIONS .......................................................................30
9.1 BASIC DATA ........................................................................................................30

OPERATING MANUAL MZC-305 version 1.08
4
9.2 ADDITIONAL DATA..............................................................................................32
9.2.1 Additional uncertainties according to IEC 61557-3 (Z)..............................32
10 EQUIPMENT .........................................................................................................33
10.1 STANDARD EQUIPMENT.......................................................................................33
10.2 OPTIONAL ACCESSORIES .....................................................................................33
11 MANUFACTURER ...............................................................................................35

OPERATING MANUAL MZC-305 version 1.08
5
1 Safety
The MZC-305 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 following 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 MZC-305 meters must be operated solely by appropriately qualified personnel with relevant
certificates to perform measurements of electric installation. Operation of the instrument by
unauthorized personnel 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
regulations 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
measurements 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
Use only standard and optional accessories intended for a given instrument which are
listed in the “Equipment” section. Using other accessories may cause damage of the
measuring terminal and additional measuring errors.
Note:
An attempt to install drivers in 64-bit Windows 8 may result in displaying "Installation
failed" message.
Cause: Windows 8 by default blocks drivers without a digital signature.
Solution: Disable the driver signature enforcement in Windows.

OPERATING MANUAL MZC-305 version 1.08
6
Note:
Due to continuous development of the meter software, the display view for some
functions may be a bit different from the view shown in this manual.
2 Measurements
WARNING:
During measurements, the earthed parts and parts accessible in the electrical
installation being tested must not be touched.
WARNING:
During a measurement, switching of the range switch is forbidden because it
may damage the meter and pose a threat to the user.
2.1 Selection of general measurement parameters
Keeping the SETUP button
depressed, turn on the meter and wait
for the parameter selection screen.
SEL
The SEL button is used to go to the next
parameter and to confirm the changes in the
currently displayed parameter.
Use the and buttons to change the
parameter value. The value or symbol to be
changed is flashing.
The symbol indicates an active parameter,
the symbol indicates an inactive one.
Set the parameters according to the following algorithm:

OPERATING MANUAL MZC-305 version 1.08
7
Parameter
Mains
voltage
Auto-
OFF
Main result of
fault loop
impedance
measurement
Symbol(s)
Press ENTER to validate the last change and go
to the measurement function.
or
ESC
Press ESC to go the measurement function without
validating the last change.
Note:
- Before the first measurements, select the mains rated voltage Un(110/190V, 115/200V, 127/220V,
220/380V, 230/400V, 240/415V, 290/500V or 400/690V) used in the area where measurements are
made. This voltage value is used for calculating the values of prospective short-circuit current.
- After switching the gauge on and displaying a software version, a current nominal voltage of the
network is shown: in the main field –the phase voltage, in the auxiliary field –the inter-phase voltage.
2.2 Remembering the last measurement result
Result of the latest measurement is remembered by the meter until a next measurement is
started or measurement settings are changed or the measuring function is changed by means of the
rotary switch or the meter is switched off. When you go to the voltage measurement screen with the
ESC button, you can recall this result by pressing ENTER. Use the same button to recall the last
result after powering the meter off and on (if the position of function selector has not been changed)

OPERATING MANUAL MZC-305 version 1.08
8
2.3 Measurement of alternating voltage
The meter measures and displays alternating mains voltage before the measurement. This
voltage is measured for the frequencies within the range of 45...65 Hz. The test leads should be
connected as for a given measuring function.
2.4 Checking correctness of PE (protective earth) connections
or
PE
Note:
WARNING:
When a dangerous voltage is detected on PE conductor, measurements must
be immediately stopped and a fault in the installation must be removed.
- The person making a measurement must ensure that he/she is standing on a non-insulated floor
during the measurement; otherwise the result of the measurement may be incorrect.
- The threshold value, which triggers the signal of exceeded allowable voltage on PE conduit, is
approximately 50 V.
- In the ZL-PE andL-PE RCD functions, when only the phase conductor is connected to one of the
measuring terminals of the meter (L,N,PE), the "PE" alarm will be generated when the contact
electrode is touched.
When in the ZL-PE and ZL-PE RCD functions only L and N conductors are connected (respectively to
the meter's L and N terminals), the "PE" alarm may be triggered when the contact electrode is
touched, but sometimes this does not happen (this depends, among other things, on the floor
resistance, mains voltage, footwear, etc.).
2.5 Measurement of fault loop parameters
If there are residual current devices in the tested network, they should be bypassed by
bridging for the period of impedance measurement. However, it should be remembered
that the tested circuit is modified in this way and the obtained results may slightly differ
from the actual results.
Each time after completion of measurements, modifications introduced to the installation
for the period of measurements should be removed and operation of the residual current
device should be checked.
The above remark does not apply to measurements of short circuit loop impedance with
the use of the ZL-PE RCD function.
When the meter is connected as in the the
drawing, touch the contact electrode with your
finger and wait for about 1 second. When
voltage if found on PE, the meter displays the
symbol (error in the installation; PE connected to
the phase conductor) and generates a
continuous audio signal. This option is available
for the ZL-PE measurements.

OPERATING MANUAL MZC-305 version 1.08
9
Measurements of fault loop impedance performed downstream of inverters are
ineffective and their results are unreliable. This is due to the instability of internal
impedance in inverter circuits during its operation. The measurements of fault
loop impedance should not be performed directly downstream of inverters.
2.5.1 Selection of measurement parameters
Turn the rotary switch to one of
the loop impedance
measurement ranges.
Set the phase conductor length according to the following
algorithm, and according to the rules described in general
parameters setting.
NOTE: The Uni-Schuko lead is detected by the meter and it
is then impossible to select the cable length (the symbol
is displayed). Using cables terminated with banana plugs,
before starting to measure, select the appropriate length of
the phase conductor, compatible with the length of cable
used for measurement.
Parameter
Phase
conductor
length
Note:
Using cables from known manufacturers and selecting the correct length
guarantees the declared measurement accuracy.

OPERATING MANUAL MZC-305 version 1.08
10
The leads with Uni-Schuko plugs can be used only in mains below 250V.
2.5.2 Prospective short-circuit current
The meter always measures impedance. The short-circuit current is calculated according to the
following formula:
S
n
kZ
U
I
where: Un- mains rated voltage, ZS- measured impedance.
On the basis of Unrated voltage selected (section 2.1), the meter automatically recognizes the
measurement at phase-to-neutral or phase-to-phase voltage and takes it into account in the
calculations.
If the voltage of the network being tested is outside the tolerance range, the meter will not be
able to determine a proper rated voltage for the short-circuit current calculation. In such a case,
horizontal dashes will be displayed instead a short-circuit current value. The following diagram shows
voltage ranges for which short-circuit current value is calculated.
230 400 440 U [V]
Zakresy napięć U , dla których
liczony jest prąd zwarciowy
L-N
Zakres napięcia, dla którego wykonywany
jest pomiar impedancji
207 253 360
115 127 180 200 220
220 380 418
198 242 342
373 415 457 216 240 264
103 U [V]
U [V]
U [V]
U =115V
n
U =220V
n
U =230V
n
U =240V
n
Zakresy napięć U , dla których
liczony jest prąd zwarciowy
L-L
110 121 171 190 209
100 U [V]
U =110V
n
127 140 198 220 242
114 U [V]
U =127V
n
100
100
100
100
100
290 500 550 U [V]
261 319 450
621 690 750 360 400 440 U [V]
U =290V
n
U =400V
n
Zakres napięcia, dla którego wykonywany
jest pomiar impedancji
750
voltage range for which the
impedance is measured
voltage range for which the
impedance is measured
voltage ranges UL-N for which the
short-circuit current is calculated
voltage ranges UL-l for which the
short-circuit current is calculated

OPERATING MANUAL MZC-305 version 1.08
11
2.5.3 Measurement of fault loop parameters in the L-N and L-L circuits
Turn on the meter.
Turn the rotary switch
to the Z/UL-N,L-L position.
Depending on the needs, select the measurement parameters
according to section 2.5.1.
or
N L N L
a) b)
Connect test
leads according
to the drawing
a) for
measurement in
the L-N circuit
or
b) for
measurement in
the L-L circuit
The meter is ready for
measurement.
Phase conductor
length or the
symbol.
UL-N voltage
Make the measurement by pressing the
START button.

OPERATING MANUAL MZC-305 version 1.08
12
Read the main
measurement result:
fault loop impedance
ZSor short-circuit
current IK.
To read additional results, press the
and buttons.
IK
short-circuit
current or
ZS
fault loop
impedance
R
fault loop
resistance
XL
fault loop
reactance

OPERATING MANUAL MZC-305 version 1.08
13
Mains voltage
at the time of
measurement
Note:
- Enter the result into memory (see section 3.2) or press ESC to return to the voltage measurement.
- When many measurements are made in short time intervals, the meter may emit a large amount of
heat. As a result of this, the enclosure of the device may become hot. This is normal and the meter is
equipped with the protection against excessive temperature.
- Minimum interval between successive measurements is 5 seconds. This is controlled by the meter
which displays the message informing that the measurement can be made.
Additional information displayed by the meter
The meter is ready for measurement.
L-N!
Voltage on terminals L and N is within the measurable
range.
Error during the measurement.
Error during the measurement –voltage dip after the
measurement
Short circuit malfunction!
2.5.4 Measurement of fault loop parameters in the L-PE circuit
Turn on the meter.
Turn the rotary switch
to the Z/UL-PE position.
Depending on the needs, select the measurement parameters
according to section 2.5.1.

OPERATING MANUAL MZC-305 version 1.08
14
or
N LPE
Connect test leads
according to one
of the drawings.
PE L
0
a)
b)
Checking effectiveness of protection against electric shock
of the enclosure in case of: a) TN b) TT.
The meter is ready
for measurement.
Phase conductor
length or the
symbol.
UL-PE voltage
Make measurement by pressing START push-
button.
Remaining issues connected with the measurements are the same as those described for
measurements in L-N circuit or L-L circuit.

OPERATING MANUAL MZC-305 version 1.08
15
Note:
- Double lead measurement is possible when a test lead other that the lead with a mains socket is
selected.
Additional information displayed by the meter
The meter is ready for measurement.
L-N!
For The lead with the plug - voltage on terminals L and N
is within the measurable range.
L-PE!
Voltage on terminals L and PE is not within the
measurable range.
Error messages - as for the L-N and L-L measurement.
2.5.5 Measurement of short circuit loop impedance in L-PE circuit protected
with a residual current device (RCD)
The MZC-305 enables the fault loop impedance measurements without altering the mains with
RCD's with the rated current of at least 30mA.
Turn on the meter.
Turn the rotary switch
to the
ZL-PE
RCD
position.
Depending on the needs, select the measurement parameters
according to section 2.5.1.
Connect test leads according to one of the drawings.

OPERATING MANUAL MZC-305 version 1.08
16
Remaining issues connected with the measurements are the same as those described for
measurements of the L-PE circuit.
Note:
- Maximum measurement time is about 32 seconds. The measurement can be interrupted by
pressing the ESC button.
- In the electrical installations with 30 mA RCD's the sum of leakage currents of the installation and
the test current may trigger the RCD. If this happens, try to reduce the leakage current in the tested
mains (for example by disconnecting loads).
Additional informations displayed by the meter
The meter is ready for measurement.
L-N!
Voltage on terminals L and N is within the measurable
range.
L-PE!
Voltage on terminals L and PE is not within the
measurable range.
Conductor N is not connected.
Huge noise in the system during the measurement. The
measurement result may be affected by a large,
unspecified error.
Error messages - as for the L-N and L-L measurement.