HT 400 Series User manual

Copyright HT ITALIA 2014 Release EN 2.02 - 24/09/2014
400 Series
User manual

400 Series
EN - 1
Table of contents:
1.SAFETY PRECAUTIONS AND PROCEDURES ..........................................................4
1.1.Preliminary instructions ..................................................................................................... 4
1.2.During use ......................................................................................................................... 4
1.3.After use ............................................................................................................................ 5
1.4.Overvoltage categories - definitions .................................................................................. 5
2.GENERAL DESCRIPTION ...........................................................................................6
2.1.Introduction........................................................................................................................ 6
2.2.Instrument operation ......................................................................................................... 6
3.PREPARATION FOR USE ...........................................................................................7
3.1.Initial checks...................................................................................................................... 7
3.2.Instrument power supply ................................................................................................... 7
3.3.Calibration ......................................................................................................................... 7
3.4.Storage.............................................................................................................................. 7
4.NOMENCLATURE........................................................................................................8
4.1.Instrument description ....................................................................................................... 8
4.2.Backlighting....................................................................................................................... 8
4.3.Keyboard description......................................................................................................... 9
4.4.Display description ............................................................................................................ 9
4.5.Initial screen ...................................................................................................................... 9
5.MAIN MENU ...............................................................................................................10
5.1.AUTO ÷ PWR .................................................................................................................. 10
5.2.SET – Instrument settings ............................................................................................... 10
5.2.1.Language ............................................................................................................................... 10
5.2.2.Auto Power OFF .................................................................................................................... 11
5.2.3.Nominal voltage ..................................................................................................................... 11
5.2.4.Frequency .............................................................................................................................. 11
5.2.5.System ................................................................................................................................... 11
5.3.MEM ................................................................................................................................ 11
5.4.RS232 ............................................................................................................................. 11
6.OPERATING INSTRUCTIONS...................................................................................12
6.1.AUTO .............................................................................................................................. 12
6.1.1.Description of anomalous results........................................................................................... 14
6.2.LOWOHM: Continuity test of earth leads with 200mA .................................................... 17
6.2.1.CAL mode .............................................................................................................................. 19
6.2.2.Description of anomalous results........................................................................................... 20
6.3.M: Measurement of the insulation resistance ............................................................... 22
6.3.1.Description of anomalous results........................................................................................... 24
6.4.RCD: Test on A-type and AC-type RCDs........................................................................ 26
6.4.1.AUTO mode ........................................................................................................................... 28
6.4.2.x½ mode ................................................................................................................................ 29
6.4.3.x1, x2, x5 mode...................................................................................................................... 30
6.4.4.mode ................................................................................................................................. 31
6.4.5.RA mode ................................................................................................................................ 32
6.4.6.Description of anomalous results........................................................................................... 32
6.5.LOOP: Measurement of Line/Loop impedance ............................................................... 36
6.5.1.P-N mode............................................................................................................................... 38
6.5.2.P-P mode ............................................................................................................................... 39
6.5.3.P-PE mode in TT or TN systems ........................................................................................... 40
6.5.4.P-PE mode in IT systems ...................................................................................................... 41
6.5.5.Description of anomalous results........................................................................................... 41
6.6.RA: measurement of the total earth resistance through the socket-outlet ....................... 44
6.6.1.Description of anomalous results........................................................................................... 46
6.7.123: Phase sequence test............................................................................................... 49
6.7.1.Description of anomalous results........................................................................................... 52
6.8.AUX: real time measurement of the environmental parameters ..................................... 52
6.8.1.AIR, RH, TMP °F, TMP °C, Lux mode ................................................................................... 54

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6.8.2.Description of anomalous results........................................................................................... 54
6.9.LEAK: real time measurement of the leakage current through an external clamp .......... 55
6.9.1.Description of anomalous results........................................................................................... 56
7.MAINS ANALYSIS......................................................................................................57
7.1.PWR: real time measurement of the mains parameters ................................................. 57
7.1.1.PAR mode.............................................................................................................................. 58
7.1.2.HRM V ane HRM I mode ....................................................................................................... 58
8.MEMORY ...................................................................................................................59
8.1.How to save a measure................................................................................................... 59
8.1.1.Description of anomalous results........................................................................................... 59
8.2.Saved data management ................................................................................................ 60
8.2.1.How to recall a measure ........................................................................................................ 60
8.2.2.How to delete the last measure or all of them ....................................................................... 61
8.2.3.Description of anomalous results........................................................................................... 61
9.CONNECTING THE INSTRUMENT TO THE PC .......................................................62
10.MAINTENANCE..........................................................................................................63
10.1.General............................................................................................................................ 63
10.2.Battery replacement ........................................................................................................ 63
10.3.Instrument cleaning ......................................................................................................... 63
10.4.End of life ........................................................................................................................ 63
11.SPECIFICATIONS......................................................................................................64
11.1.Technical feratures.......................................................................................................... 64
11.2.Reference guidelines....................................................................................................... 68
11.2.1.General .................................................................................................................................. 68
11.2.2.Reference standards for verification measurements............................................................. 68
11.3.General characteristics.................................................................................................... 68
11.4.ENVIRONMENT.............................................................................................................. 68
11.4.1.Environmental working conditions ......................................................................................... 68
11.5.Accessories..................................................................................................................... 68
12.SERVICE....................................................................................................................69
12.1.Warranty conditions......................................................................................................... 69
12.2.Service ............................................................................................................................ 69
13.PRACTICAL REPORTS FOR ELECTRICAL TESTS .................................................70
13.1.Continuity measurement on protective conductors ......................................................... 70
13.1.1.Purpose of the test................................................................................................................. 70
13.1.2.Installation parts to be checked ............................................................................................. 70
13.1.3.Allowable values .................................................................................................................... 70
13.2.Insulation resistance measurement................................................................................. 71
13.2.1.Purpose of the test................................................................................................................. 71
13.3.Check of the circuit separation........................................................................................ 74
13.3.1.Definitions .............................................................................................................................. 74
13.3.2.Purpose of the test................................................................................................................. 74
13.3.3.Installation parts to be checked ............................................................................................. 74
13.3.4.Allowable values .................................................................................................................... 74
13.4.Working test of RCDS ..................................................................................................... 76
13.4.1.Purpose of the test................................................................................................................. 76
13.4.2.Installation parts to be checked ............................................................................................. 76
13.4.3.Allowable values .................................................................................................................... 76
13.4.4.Note........................................................................................................................................ 76
13.5.Test of RCD tripping current............................................................................................ 77
13.5.1.Purpose of the test................................................................................................................. 77
13.5.2.Installation parts to be checked ............................................................................................. 77
13.5.3.Allowable values .................................................................................................................... 77
13.5.4.Note........................................................................................................................................ 77
13.6.Measurement of short-circuit impedance ........................................................................ 78
13.6.1.Purpose of the test................................................................................................................. 78
13.6.2.Installation parts to be checked ............................................................................................. 78
13.6.3.Allowable values .................................................................................................................... 78

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13.7.Fault loop impedance measurement ............................................................................... 78
13.7.1.Purpose of the test................................................................................................................. 78
13.7.2.Installation parts to be checked ............................................................................................. 78
13.7.3.Allowable values .................................................................................................................... 78
13.8.Earth resistance measurementin TT systems ................................................................. 79
13.8.1.Purpose of the test................................................................................................................. 79
13.8.2.Installation parts to be checked ............................................................................................. 79
13.8.3.Allowable values .................................................................................................................... 79
13.9.Voltage and current Harmonics....................................................................................... 80
13.9.1.Theory .................................................................................................................................... 80
13.9.2.Limit values for harmonics ..................................................................................................... 80
13.9.3.Presence of harmonics: causes............................................................................................. 81
13.9.4.Presence of harmonics: consequences................................................................................. 82
13.10.Power and Power Factor definition ................................................................................. 82
13.10.1.Note........................................................................................................................................ 83
13.10.2.Conventions on powers and power factors ........................................................................... 83

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EN - 4
1. SAFETY PRECAUTIONS AND PROCEDURES
The models of 400 Series (ISO410, SPEED418S, COMBI419S, COMBI420S and
COMBI421) were designed in compliance with the following Directives IEC/EN61557 and
IEC/EN61010, relative to electronic. Before and while measuring, carefully follow the
instructions below:
Do not perform voltage or current measurements in humid environments.
Do not perform measurements near explosive gas or material and fuels or in dusty
environments.
Avoid contact with the circuit tested if no measurement is being performed.
Avoid contact with exposed metal parts, test terminals not in use, circuits, etc.
Do not perform any measurement if instrument anomalies are detected, such as
deformations, breaks, leakage of substances, no display reading, etc.
Pay special attention when measuring voltages above 25V in special environments
(building yards, swimming pools...) and above 50V in ordinary environments, as there is a
risk of electric shock.
Only use original HT accessories.
In this manual, following symbols are used:
CAUTION: Follow the instructions given in this manual; improper use may
damage the instrument, its components or create dangerous situations for the
operator.
DC or AC voltage or current.
Unidirectional pulsating voltage or current.
1.1. PRELIMINARY INSTRUCTIONS
This instrument has been designed for use in the environmental conditions specified in
§ 11.2.1 and § 11.4.1. Do not use in different environmental conditions.
The instrument may be used for measuring and verifying the safety of electrical
systems. Do not use on systems exceeding the limit values specified in § 11.2.1.
We recommend following the ordinary safety rules aimed at: your protection against
dangerous currents, the instrument’s protection against improper use.
Only the accessories provided with the instrument guarantee compliance with safety
standards. They must be in good conditions and must be replaced, if necessary, with
identical models.
Check that batteries are correctly inserted.
Before connecting the test leads to the circuit being tested, check that the desired
function has been selected.
1.2. DURING USE
We recommend carefully reading the following recommendations and instructions:
CAUTION
Failure to comply with the CAUTIONs and/or instructions may damage the
instrument and/or its components or cause dangers for the operator.
Before changing function, disconnect the test leads from the circuit tested.
When the instrument is connected to the circuit tested, never touch any lead, even if
not in use

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Avoid measuring resistance with external voltages; although the instrument is protected,
an excessive voltage may cause damage.
While measuring current, place the clamp toroid as far as possible from the conductors
not involved in measurement, as the magnetic field they produce could interfere with
the measuring operations.
During current measurement, place the conductor as much as possible in the middle of
the toroid so as to optimize precision.
While measuring voltage, current, etc., if the value of the quantity being tested remains
unchanged, check and, if necessary, disable the STOP function.
CAUTION
The symbol indicates the charge level. When there are five bars
next to the battery symbol, it means that batteries are fully charged; a
decrease in the number of bars to " " indicates that the batteries
are almost low. In this case, interrupt tests and replace the batteries
according to the indications given in § 10.2. The instrument is able to keep
data stored also with no batteries.
1.3. AFTER USE
When measuring operations are completed, turn off the instrument by pressing and
holding the ON/OFF key for a few seconds. Should the instrument remain unused for a
long time, remove batteries and follow the indications given in § 3.4.
1.4. OVERVOLTAGE CATEGORIES - DEFINITIONS
Standard IEC/EN61010-1 (Safety requirements for electrical equipment for measurement,
control and laboratory use, Part 1: General requirements) defines what a measurement
category (usually called “overvoltage category”) is. At § 6.7.4: Measuring circuits it says:
Circuits are divided into the following measurement categories:
Measurement category IV is for measurements performed at the source of the low-
voltage installation.
Examples are electricity meters and measurements on primary overcurrent protection
devices and ripple control units.
Measurement category III is for measurements performed in the building installation.
Examples are measurements on distribution boards, circuit breakers, wiring, including
cables, bus-bars, junction boxes, switches, socket-outlets in the fixed installation, and
equipment for industrial use and some other equipment, for example, stationary motors
with permanent connection to fixed installation.
Measurement category II is for measurements performed on circuits directly
connected to the low voltage installation.
Examples are measurements on household appliances, portable tools and similar
equipment.
Measurement category I is for measurements performed on circuits not directly
connected to MAINS.
Examples are measurements on circuits not derived from MAINS, and specially
protected (internal) MAINS-derived circuits. In the latter case, transient stresses are
variable; for that reason, the norm requires that the transient withstand capability of the
equipment is made known to the user.

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EN - 6
2. GENERAL DESCRIPTION
2.1. INTRODUCTION
This user manual is referred to the following models ISO410, SPEED418S, COMBI419S,
COMBI420S and COMBI421. Unless otherwise specified, the “instrument” is referred to
COMBI421 model. The following Table 1 shows the possible measuring functions:
Funzione ISO410 SPEED418S COMBI419S COMBI420S COMBI421
AUTO (Ra + RCD + M) 
LOW
M
RCD e

Ra

LOOP

123 
AUX

LEAKAGE

POWER

Table 1: Characteristics of models
2.2. INSTRUMENT OPERATION
The instrument can perform following tests (compatibly with the characteristics described
in the table above):
AUTO Test which automatically performs the following test sequence: total
earth resistance through socket, tripping time of the differential switch,
insulation resistance between phase and earth.
LOWContinuity test of earth conductors, protective conductors and equipotential
conductors with test current higher than 200mA and open circuit voltage
between 4V and 24V.
MInsulation resistance measurement with a direct test voltage of 50V, 100V,
250V, 500V or 1000V.
RCD Measurement of following parameters on A-type ( ) and AC-type ( )
general and/or selective differential switches with nominal current up to 1A:
tripping time, tripping current, contact voltage (Ut), total earth resistance (RA).
LOOP Measurement of line impedance and fault loop impedance with
calculation of the assumed fault current.
Ra Measurement of total earth resistance with 15mA without causing the
differential protections’ tripping.
123 Indication of the phase sequence.
AUX Measurement of the environmental parameters (temperature, humidity, air
speed and lighting) by means of optional probes.
LEAKAGE Function for measuring leakage current in real time by means of an
(optional) HT96U clamp.
POWER Real-time displaying the values of the electrical quantities in a single-
phase system and the harmonic analysis of voltage and current up to
the 49th harmonic with THD% calculation.

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3. PREPARATION FOR USE
3.1. INITIAL CHECKS
Before shipment, the instrument’s electronics and mechanics have been carefully checked.
All possible precautions have been taken in order for the instrument to be delivered in
optimum conditions. However, we recommend rapidly checking the instrument in order to
detect possible damage occurred during transport. Should you detect anomalies, please
immediately contact the dealer.
It is also recommended to check that the package contains all parts indicated in § 11.5. In
case of discrepancies, please contact the dealer. Should it be necessary to return the
instrument, please follow the instructions given in § 12.
3.2. INSTRUMENT POWER SUPPLY
The instrument is battery supplied. For battery type and life, see § 11.3.
The symbol " " indicates the charge level. When there are five bars next to the
battery symbol, it means that batteries are fully charged; a decrease in the number of bars
to " " indicates that the batteries are almost low. In this case, interrupt tests and
replace the batteries according to the indications given in § 10.2.
The instrument is able to keep data stored also with no batteries.
For the insertion of batteries, follow the indications given in § 10.2.
The instrument is provided with advanced algorithms to maximize the batteries’ life. In
particular:
The instrument automatically turns off the display’s back lighting after ca. 5 seconds.
In order to increase battery autonomy, should the voltage supplied by batteries be too
low, the instrument disables the display’s back-lighting function.
3.3. CALIBRATION
The instrument’s technical specifications are those described in this manual. Its
performance is warranted for one year from the date of purchase.
3.4. STORAGE
In order to guarantee precise measures, after the instrument has remained stored for a
long time under extreme environmental conditions, wait for the instrument to return to
normal conditions (see the environmental specifications listed in § 11.4.1).

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4. NOMENCLATURE
4.1. INSTRUMENT DESCRIPTION
CAPTION:
1. Inputs
2. Display
3. Connector for optoisolated cable
4. ,, , / ENTER key
5. GO/STOP key
6. SAVE key
7. ON/OFF key
8. HELP key
9. ESC/MENU key
Fig. 1: Description of the front part of the instrument
CAPTION:
1. Connector for remote probe
2. E, N, P inputs
3. In1 input
Fig. 2: Description of the upper part of the instrument
CAPTION:
1. Connector for optoisolated cable
Fig. 3: Description of the instrument’s side
4.2. BACKLIGHTING
During instrument operation, a further short pressing of the key turns on the display’s
backlighting (if battery voltage level is sufficiently high). In order to preserve battery efficiency,
backlighting automatically turns off after ca. 20 seconds.
A frequent use of back lighting reduces the batteries’ life.

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4.3. KEYBOARD DESCRIPTION
The keyboard includes following keys:
ON/OFF key to switch on/off the instrument
ESC key to exit the selected menu without confirming
MENU key to activate menu management
keys to move the cursor through the different screens in order to
select the desired programming parameters
ENTER key to confirm the modifications and the selected programming
parameters and to select the function from the menu
GO key to start measurements
STOP key to stop measurements
SAVE key to save the measured values
HELP key (long pressure) to display an indicative scheme of the connections
between the instrument and the system being tested in the function set
key (short pressure) to turn on the display’s backlighting
4.4. DISPLAY DESCRIPTION
The display is a graphic module with a resolution of 128 x 128
dots. The display’s first line indicates the type of active
measurement and the battery charge indicator
LOW
-.-- 
R+ R-
-.---.--
--- mA --- mA
Measuring…
AUTO 1.000.12
Func Lim CAL
4.5. INITIAL SCREEN
When turning on the instrument the instrument displays an
initial screen for a few seconds. It displays the following:
the instrument’s model
the manufacturer’s name
the serial number (SN:) of the instrument
the firmware version (FW:) in the instrument's memory
the date of calibration (Calibration:).
COMBI 421
HT ITALIA
SN: 14020100
FW: 1.22
Calibration:
22/05/2014
Then, the instrument switches to the last function selected.

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5. MAIN MENU
Pressing the MENU/ESC key in any allowable condition of the instrument displays the
following screen, in which the instrument may be set, the saved measures can be
displayed and the desired measuring function may be set.
MENU
AUTO : Ra, RCD, M 
LOW
 : continuity
M
 : insulation
RCD : RCD tripping
LOOP : impedance
Ra : earth res.
123 : phase sequen.
AUX : environment
LEAK : leakage curr.
PWR : analyzer
 SET : settings
MEM : memory
RS232: data transfer
5.1. AUTO ÷ PWR
By selecting one of the measurements listed between AUTO and PWR with the cursor,
compatibly with the characteristics reported in Table 1 and confirming selection with
ENTER, the desired measurement is accessed.
5.2. SET – INSTRUMENT SETTINGS
Move the cursor to SET by means of the arrow keys (,)
and confirm with ENTER. Subsequently, the displays shows
the screen which allows accessing the various instrument
settings.
The settings will remain valid also after switching off the
instrument.
SET
Language
Auto power off
Nominal V
Frequency
System

VAL
5.2.1. Language
Move the cursor to Language by means of the arrow keys
(,) and confirm with ENTER. Subsequently, the displays
shows the screen which allows setting the instrument
language.
Select the desired option by means of the arrow keys (,).
To store settings, press the ENTER key, to exit the changes
made, press the ESC key.
LNG
Italiano
English
Español
Deutsch
Français
Svenska
Norsk
Dansk

VAL

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5.2.2. Auto Power OFF
Move the cursor to Auto power off by means of the arrow
keys (,) and confirm with ENTER. Subsequently, the
displays shows the setting screen which allows
enabling/disabling the auto power off of the instrument after a
period of 5 minutes inactivity.
Select the desired option by means of the arrow keys (,).
To store settings, press the ENTER key, to exit the changes
made, press the ESC key.
OFF
ON 5 min
OFF

VAL
5.2.3. Nominal voltage
Move the cursor to Nominal V by means of the arrow keys
(,) and confirm with ENTER. Subsequently, the displays
shows the screen which allows setting the value of the
voltage to be used for calculating the prospective short-circuit
current.
Select the desired option by means of the arrow keys (,).
To store settings, press the ENTER key, to exit the changes
made, press the ESC key.
VNOM
Vp-n=230V Vp-p=400V
Vp-n=240V Vp-p=415V

VAL
5.2.4. Frequency
Move the cursor to Frequency by means of the arrow keys
(,) and confirm with ENTER. Subsequently, the displays
shows the screen which allows setting the value of the mains
frequency.
Select the desired option by means of the arrow keys (,).
To store settings, press the ENTER key, to exit the changes
made, press the ESC key.
FREQ
50 Hz
60 Hz

VAL
5.2.5. System
Move the cursor to System by means of the arrow keys
(,) and confirm with ENTER. Subsequently, the display
shows the screen which allows selecting the type of electric
power supply system. The “GO STOP” item allows to
eventually disable the check of voltage on PE conductor by
pressing the GO/STOP key
Select the desired option by means of the arrow keys (,).
To store settings, press the ENTER key, to exit the changes
made, press the ESC key.
SYS
TT/TN system
IT system
GO STOP

VAL
5.3. MEM
By selecting MEM with the cursor and confirming selection with ENTER, the memory
management is accessed (§ 8)
5.4. RS232
Select the item RS232 to enable the management of data transfer to PC (see § 9)

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6. OPERATING INSTRUCTIONS
Press (short pressure) the key to activate the display’s backlighting should it
be difficult to read the display.
Press (long pressure) the HELP key to display an indicative scheme of the
connections between the instrument and the system being tested in the function set
Should more help screens be available for the same function, use the and 
keys to scroll them.
Press the ESC key to exit the on-line help and go back to the selected
measurement.
6.1. AUTO
This function enables performing an automatic sequence of tests, including the main tests
regarding the electric safety of a system, i.e.:
Measurement of earth resistance through socket-outlet
Measurement of RCD tripping time
Measurement of insulation resistance between phase and earth
CAUTION
Testing the RCD’s tripping time causes the RCD’s tripping. Therefore, check
that there are NO users or loads connected downstream of the RCD
being tested which could be damaged by a system downtime.
Disconnect all loads connected downstream of the RCD as they could
produce leakage currents further to those produced by the instrument, thus
invalidating the results of the test
Fig. 4: Instrument connection through shuko cable
Fig. 5: Instrument connection by means of single cables and remote probe

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1.
Press the MENU key, move the cursor to
AUTO in the main menu by means of the
arrow keys (,) and confirm with ENTER.
Subsequently the instrument displays a screen
similar to the one reported here to the side.
AUTO
Ra = ----
Trcd = ----ms
RP-Pe = ----M
30mA 50V 500V
IdN RCD UL VNom
2.
Use the , keys to select the parameter to be modified, and the , keys
to modify the parameter value.
It is not necessary to confirm the selection with ENTER.
IdN The virtual IdN key allows setting the nominal value of the RCD’s
tripping current, which may be: 10mA, 30mA, 100mA, 300mA,
500mA, 650mA, 1A
CAUTION
Make sure to select the correct value when setting the RCD’s test current. If
setting a current higher than the nominal current of the device being tested,
the RCD would be tested at a current higher than the correct one, thus
facilitating a faster tripping of the switch
RCD The virtual RCD key enables the selection of the RCD type, which
may be: AC, AC S, A, A S (the options A, A S are not available if
the electrical system set is IT)
CAUTION
When activating the test option for selective RDCs (symbol S), the time
interval between the tests is 60 seconds (30 seconds for tests with ½IdN).
The instrument display shows a timer indicating the time remaining before
the instrument can automatically perform the test.
UL The virtual UL key allows setting the limit value of contact voltage
for the system being tested, which may be: 25V, 50V
VNom The virtual VNom allows setting the value of test voltage for insulation
measurement, which may be: 50V, 100V, 250V, 500V, 1000V
3. Insert the green, blue and black connectors of the three-pin shuko cable into the
corresponding input leads E, N and P of the instrument. As an alternative, use the
single cables and apply the relevant alligator clips to the free ends of the cables. It is
also possible to use the remote probe by inserting its multipolar connector into the
input lead P. Connect the shuko plug, the alligator clips or the remote probe to the
electrical mains according to Fig. 4 and Fig. 5
4.
Press the GO/STOP key on the instrument or the START key on remote
probe. The instrument will start the automatic test sequence.

400 Series
EN - 14
CAUTION
If message “Measuring…” appears on the display, the instrument is
performing measurement. During this whole stage, do not disconnect the
test leads of the instrument from the mains.
5. Once the test is completed, if
all measured values are
correct, the instrument gives
a double acoustic signal and
displays the message “OK”,
which signals that the test
has been completed
successfully, and a screen
similar to the one reported
here to the side
AUTO
Ra = 49.1
Trcd = 24ms
RP-Pe > 999M
Value of earth resistance
Value of the RCD’s tripping time
Value of the phase-to-earth
insulation resistance
OK
30mA 50V 500V
IdN RCD UL VNom
6.
The results displayed can be saved by pressing the SAVE key twice or the
SAVE key and, subsequently, the ENTER key (§ 8.1)
6.1.1. Description of anomalous results
1. The instrument detects a
resistance higher than the
calculated limit value UL/IdN
(1666Ω@ UL=50V and
IdN=30mA) or higher than
the full scale value. A screen
similar to the one reported
here to the side is displayed,
a long acoustic signal is
given and the automatic test
is interrupted
AUTO
Ra = 1789
Trcd = ----ms
RP-Pe = ----M
Value of earth resistance
NOT OK
30mA 50V 500V
IdN RCD UL VNom
2. The instrument detects that
the RCD trips out of its limit
time, or does not trip at all.
A
screen similar to the one
reported here to the side is
displayed, a long acoustic
signal is given and the
automatic test is interrupted
AUTO
Ra = 1789
Trcd > 999ms
RP-Pe = ----M
Value of earth resistance
Value of the RCD’s tripping time
NOT OK
30mA 50V 500V
IdN RCD UL VNom

400 Series
EN - 15
3. If the measured phase-to-
earth insulation value is
lower than the set limit, the
instrument displays a screen
similar to the one reported
here to the side and gives a
long acoustic signal
AUTO
Ra = 1789
Trcd > 999ms
RP-Pe = 0.01M
Value of earth resistance
Value of the RCD’s tripping time
Value of the phase-to-earth
insulation resistance
NOT OK
30mA 50V 500V
IdN RCD UL VNom
4.
The results displayed can be saved by pressing the SAVE key twice or the
SAVE key and, subsequently, the ENTER key (§ 8.1)
5. If the instrument detects that
the phase and neutral leads
are inverted, the message
reported here to the side is
displayed. Rotate the shuko
plug or check the connection
of the single cables
AUTO
Ra = ----
Trcd = ----ms
RP-Pe = ----M
REVERSE P-N The phase and neutral conductors
are inverted
30mA 50V 500V
IdN RCD UL VNom
6. If the instrument detects that
the phase and earth leads
are inverted, the message
reported here to the side is
displayed. check the
connection of the cables
AUTO
Ra = ----
Trcd = ----ms
RP-Pe = ----M
REVERSE P-PE The phase and earth conductors are
inverted
30mA 50V 500V
IdN RCD UL VNom
7. If the instrument detects a
phase-to-neutral voltage and
a phase-to-earth voltage
lower than the limit, the
message reported here to
the side is displayed. Check
that the system being tested
is energized
AUTO
Ra = ----
Trcd = ----ms
RP-Pe = ----M
Low voltage Insufficient voltage
30mA 50V 500V
IdN RCD UL VNom

400 Series
EN - 16
8. If the instrument detects a
phase-to-neutral voltage or a
phase-to-earth voltage higher
than the limit, the message
reported here to the side is
displayed. Check that the
instrument is not phase-to-
phase connected
AUTO
Ra = ----
Trcd = ----ms
RP-Pe = ----M
High voltage High voltage detected
30mA 50V 500V
IdN RCD UL VNom
9. The previous anomalous results cannot be saved

400 Series
EN - 17
6.2. LOWOHM: CONTINUITY TEST OF EARTH LEADS WITH 200mA
This function is performed in compliance with standard IEC/EN61557-4 and allows
measuring the resistance of protective and equipotential conductors. The following
operating modes are available:
CAL compensation of the resistance of the cables used for measurement. The
instrument automatically subtracts the value of cable resistance from the
measured resistance value. It is therefore necessary that this value is measured
(by means of the CAL function) each time the test cables are changed or
extended
AUTO the instrument performs two measurements with inverted polarity and displays
the average value of the two measures. Recommended mode for continuity test
R+ measurement with positive polarity and with the possibility of setting a test
duration time. In this case, the operator may set a measuring time long enough
to be able to move the protective conductors while the instrument is performing
the test, in order to detect a possible bad connection
R- measurement with negative polarity and with the possibility of setting a test
duration time. In this case, the operator may set a measuring time long enough
to be able to move the protective conductors while the instrument is performing
the test, in order to detect a possible bad connection.
CAUTION
The continuity test is performed by supplying a current higher than
200mA in case the resistance is not higher than ca. 10(including
resistance of the test cables saved in the instrument as offset after
performing the calibration procedure). For higher resistance values, the
instrument performs the test with a current lower than 200mA.
Fig. 6: Instrument connection by means of single cables and remote probe
1.
Press the MENU key, move the cursor to
LOWin the main menu by means of the arrow
keys (,) and confirm with ENTER.
Subsequently the instrument displays a screen
similar to the one reported here to the side.
LOW
----
R+ R-
--------
---mA ---mA
CAL 4.00----
Func Lim CAL

400 Series
EN - 18
2.
Use the , keys to select the parameter to be modified, and the , 
keys to modify the parameter value.
It is not necessary to confirm the selection with ENTER.
Func The virtual Func key allows setting the measuring mode of
the instrument, which may be: CAL, AUTO, R+, R-
Lim The virtual Lim key allows setting the maximum continuity
limit, which may have the following values: 1.00, 2.00,
3.00, 4.00, 5.00
3. Insert the blue and black connectors of the single cables into the corresponding input
leads N and P of the instrument. Apply the relevant alligator clips to the free ends of
the cables. It is also possible to use the remote probe by inserting its multipolar
connector into the input lead P.
4. Should the length of the cables provided be insufficient for the measurement to be
performed, extend the blue cable.
5. Select the CAL mode to compensate the resistance of the cables used for measuring
according to the instructions given in § 6.2.1.
6.
Use the arrow keys , to select the virtual Func key and set the desired
test mode by means of the arrow keys , .
It is not necessary to confirm the selection with ENTER.
CAUTION
Before connecting the test leads, make sure that there is no voltage at
the ends of the conductor to be tested.
7. Connect the test leads to the ends of the conductor to be tested as in Fig. 6.
CAUTION
Always make sure, before any test, that the compensation resistance
value of the cables is referred to the cables currently used. In case of
doubt, repeat the cable calibration procedure as in 6.2.1.
8.
Press the GO/STOP key on the instrument or the START key on remote
probe. The instrument will start the measurement.
CAUTION
If message “Measuring…” appears on the display, the instrument is
performing measurement. During this whole stage, do not disconnect
the test leads of the instrument from the conductor under test.
9.
In case the R+ or R- mode has been selected, pressing the GO/STOP
key on the instrument or the START key on remote probe stops the test
before the set time has elapsed.