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

400 Series
EN - 2
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

400 Series
EN - 3
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

400 Series
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

400 Series
EN - 5
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.

400 Series
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.

400 Series
EN - 7
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).

400 Series
EN - 8
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.