GEO416 GEO416
User manual
GEO416
GEO416GS
 Copyright HT ITALIA 2012
Release EN 2.00 - 04/10/2012
GEO416 - GEO416GS
Table of contents:
1. SAFETY PRECAUTIONS AND PROCEDURES .......................................................... 2 1.1. Preliminary instructions ..................................................................................................... 2 1.2. During use ......................................................................................................................... 3 1.3. After use ............................................................................................................................ 3 1.4. Definition of measurement category (Overvoltage) ........................................................... 3 2. GENERAL DESCRIPTION ........................................................................................... 4 2.1. Instrument description ....................................................................................................... 4 3. PREPARING THE INSTRUMENT ................................................................................ 4 3.1. Initial check........................................................................................................................ 4 3.2. Power supply ..................................................................................................................... 4 3.3. Calibration ......................................................................................................................... 4 3.4. Storage .............................................................................................................................. 4 4. WORKING INSTRUCTIONS ........................................................................................ 5 4.1. Instrument description ....................................................................................................... 5 4.2. MEASURING ACCESSORIES DESCRIPTION ................................................................ 5 Fig. 2: Measuring accessories description................................................................................................ 5 4.2.1. Switching on ............................................................................................................................. 6 4.2.2. Auto power off .......................................................................................................................... 6 4.3. EARTH 3W – 3 wire earth resistance measurement......................................................... 7 4.4. EARTH 2W – 2 wire earth resistance measurement......................................................... 9 4.5.  - Ground resistivity measurement ................................................................................ 12 4.5.1. Anomalous measuring applications ....................................................................................... 15 5. MANAGEMENT OF STORED DATA.......................................................................... 17 5.1. How to save a measurement........................................................................................... 17 5.2. how to cancel one or several measurements .................................................................. 17 5.3. How to recall a measurement.......................................................................................... 18 6. INSTRUMENT RESET ............................................................................................... 19 7. INSTRUMENT CONNECTION TO PC ....................................................................... 19 8. MAINTENANCE ......................................................................................................... 20 8.1. General............................................................................................................................ 20 8.2. Battery replacement ........................................................................................................ 20 8.3. Instrument cleaning ......................................................................................................... 20 8.4. End of life ........................................................................................................................ 20 9. TECHNICAL SPECIFICATIONS ................................................................................ 21 9.1. Technical features ........................................................................................................... 21 9.1.1. Reference standards .............................................................................................................. 22 9.1.2. General features .................................................................................................................... 22 9.2. Environment .................................................................................................................... 22 9.2.1. Operating environmental conditions ...................................................................................... 22 9.3. Accessories ..................................................................................................................... 22 9.3.1. Standard and optional accessories GEO416......................................................................... 22 9.3.2. Standard accessories GEO416GS ........................................................................................ 22 10. SERVICE .................................................................................................................... 23 10.1. Warranty terms ................................................................................................................ 23 10.2. After-sales service ........................................................................................................... 23 11. PRACTICAL REPORTS FOR ELECTRICAL TESTS ................................................. 24 11.1. Earth resistance in tt systems ......................................................................................... 24 11.2. Earth resistance, voltaamperemetric method .................................................................. 25 11.2.1. Creating cables extensions .................................................................................................... 25 11.2.2. Method for small-sized earth rods.......................................................................................... 25 11.2.3. Method for large-sized earth rods .......................................................................................... 25 11.3. Ground resistivity............................................................................................................. 26 11.3.1. Approximate evaluation of intentional rods' contribution ....................................................... 27 EN - 1
GEO416 - GEO416GS
1. SAFETY PRECAUTIONS AND PROCEDURES
The instrument was designed in compliance with standards IEC/EN61557 and
IEC/EN61010-1 relative to electronic equipment.
CAUTION
For your own safety and to avoid damaging the instrument you are
recommended to follow the procedures described in this manual and read
carefully all instructions preceded by this symbol
Before and during measurements keep to the following instructions:
 Do not take measurements in wet places as well as in the presence of explosive gas
and combustibles or in dusty places
 Even though you are not taking any measurement avoid any contact with the circuit
under test, with exposed metal parts, unused measuring terminals, circuits etc
 Do not take any measurement any measurement whenever anomalous conditions
occur such as deformations, breaks, leakages, blind display etc
 Pay utmost attention when taking measurements of voltage higher than 25V in special
places (building yards, swimming pools, etc.) and higher than 50V in ordinary places
due to the risk of electric shock.
The following symbols are used in this manual as well as on the instrument:
CAUTION: Please read carefully this manual in order to understand the
nature of the potential danger and the actions to undertake
Refer to the instruction manual. An improper use may damage the instrument or
its components as well as endanger the user
DC or AC voltage and current
High voltage danger: risk of electric shock
Double insulation
1.1. PRELIMINARY INSTRUCTIONS
 This instrument was designed for use in environments with pollution degree 2
 It can be used for voltage and current measurements on electrical installations with
CAT III 240V to earth and maximum voltage of 415V between inputs
 You are recommended to respect the usual safety regulations aimed at protecting you
against dangerous currents and the instrument against improper use
 Only the original accessories supplied along with the instrument guarantee compliance
with the safety standards in force. They must be in a good condition and, if necessary,
replaced with identical ones
 Do not test nor connect to any circuit exceeding the specified overload protection
 Do not take measurements under environmental conditions exceeding the limits
indicated in this manual
 Make sure that batteries are correctly installed
 Before connecting test leads to the circuit under test check that the right function was
selected.
EN - 2
GEO416 - GEO416GS
1.2. DURING USE
You are recommended to read carefully the following instructions:
CAUTION
Failure to comply with warnings and instructions may damage the instrument
and/or its components as well as injure the operator. If the low battery symbol
is displayed during use interrupt testing and replace batteries following the
procedure described in § 8.2




Before selecting a new function disconnect the test leads from the circuit under test
When the instrument is connected to the circuit under test never touch any unused
terminal
Do not measure resistance in the presence of external voltages; although the
instrument is protected, an excessive voltage may cause malfunction
Avoid submitting the instrument to voltage while measuring (i.e. a test lead slipping off
the measuring point accidentally touching an energized point).
1.3. AFTER USE
 Turn off the instrument pressing ON/OFF key after using it
 If you expect not to use the instrument for a long time remove the batteries.
1.4. DEFINITION OF MEASUREMENT CATEGORY (OVERVOLTAGE)
The standards IEC/EN61010-1: Safety requirements for electrical equipment for
measurement, control and laboratory use, Part 1: General requirements, define what a
measurement category, usually called over voltage category, means. Under § 6.7.4:
Measuring circuits, it quotes:
Circuits are divided into the following measurement categories:
 Measurement category IV is for measurements performed at the source of a lowvoltage installation.
Examples are electricity meters and measurements on primary excess current
protection devices as well as ripple control units.
 Measurement category III is for measurements performed in the building installations.
Examples are measurements on distribution boards, circuit breakers, wiring, including
cables, bus-bars, junction boxes, switches, socket-outlets in the fixed installations, and
equipment for industrial use as well as some other equipment, for example, stationary
motors with permanent connection to fixed installations.
 Measurement category II is for measurements performed on circuits directly
connected to the low voltage installations.
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
(internally) protected MAINS-derived circuits. In this latter case, transient stresses are
variable; for this reason, the norm requires that the transient withstanding capability of
the equipment is made known to the user.
EN - 3
GEO416 - GEO416GS
2. GENERAL DESCRIPTION
This instrument will grant you accurate and reliable measurements provided that is used
according to the instructions given in this manual. You will enjoy the highest safety thanks
to a development of newest conception assuring double insulation and over voltage
category III.
2.1. INSTRUMENT DESCRIPTION
 EARTH 2W: 2-wire earth resistance measurement
 EARTH 3W: 3-wire earth resistance measurement
 ρ: 4-wire ground resistivity measurement.
3. PREPARING THE INSTRUMENT
3.1. INITIAL CHECK
This instrument was checked both mechanically and electrically prior to shipment. All
possible cares and precautions were taken to let you receive the instrument under perfect
conditions.
Notwithstanding we suggest you to check it rapidly to check any damage which may have
occurred during transport. Should it be the case please contact immediately the forwarder
or your dealer.
Make sure that all standard accessories mentioned in the enclosed packing list (see § 9.3)
are included in the packaging. In case of discrepancies contact your dealer. Should you
have to return back the instrument for any reason please follow the instructions mentioned
under § 10.
3.2. POWER SUPPLY
The instrument is powered by batteries (see § 9.1.2). The battery charge is displayed on
the right top side. The symbol
indicates that batteries are fully charged, while the
symbol
indicates that batteries are low and shall be replaced.
To replace/insert batteries follow the instructions indicated under § 8.2.
3.3. CALIBRATION
The instrument complies with the technical specifications reported in this manual and such
a compliance Is guaranteed for one year after purchase date.
3.4. STORAGE
After a period of storage under extreme environmental conditions exceeding the limits let
the instrument resume normal measuring conditions before using it (see § 9.2.1). This
precaution will grant accurate measurements without risking to damage the instrument.
EN - 4
GEO416 - GEO416GS
4. WORKING INSTRUCTIONS
4.1. INSTRUMENT DESCRIPTION
CAPTION:
1.
2.
3.
4.
5.
6.
7.
8.
Inputs
ENTER/,,,keys
ESC/ key
RCL/CLR key
Display
GO key
SAVE key
ON/OFF key
Fig. 1: Instrument’s description
ENTER key to select measuring mode
Arrow keys to move the cursor selecting the required parameters
key to turn on the display backlight for 30 seconds
ESC key to quit without selecting any mode
RCL key to recall data stored in the instrument’s memory
CLR key to cancel the selected measurements from the instrument’s memory
GO key to start a measurement
SAVE key to store measurements
ON/OFF key to turn on/off the instrument
4.2. MEASURING ACCESSORIES DESCRIPTION
CAPTION:
1. Barrier
2. Hand-Held Area
Fig. 2: Measuring accessories description
EN - 5
GEO416 - GEO416GS
4.2.1. Switching on
When switching on the instrument a brief tone is audible along
with display of all segments for about one second.
Subsequently the last firmware version as well as the last
selected measuring mode are displayed before switching off.
4.2.2. Auto power off
The instrument automatically turns off 3 minutes after the last key pressing. To resume
operation turn on the instrument pressing the on/off key.
EN - 6
GEO416 - GEO416GS
4.3. EARTH 3W – 3 WIRE EARTH RESISTANCE MEASUREMENT
The measurement is carried out in compliance with standards IEC 781, VDE 0413,
IEC/EN61557-5.
CAUTION




The instrument can be used for voltage and current measurements on
installations with over voltage category CAT III 240V to earth and maximum
voltage of 415V between inputs. Do not connect the instrument to
installations whose voltages exceed the limits indicated in this manual.
Exceeding such limits may cause electric shock to the user and damage
the instrument
Always connect the cables to the instrument and to the alligator clips when
the latter are not connected to the plant under test
Always respect the Hand-held area of probe (see § 4.2)
If the length of the supplied cables isn’t suitable for the plant under test (see
§ 11), You can create your own extensions following indications in § 11.2.1
Fig. 3: Three-wire earth resistance measurement
1.
Turn on the instrument pressing the ON/OFF key
2.
Pressing right/left arrow keys ,  select MOD, then pressing up/down arrow
keys ,  select 3W option
3.
A screen similar to the one beside
appears where the input interfering
voltage value of the instrument is
displayed
Input interfering
value
4.
voltage
Connect the blue, red, green and black cables to the corresponding instrument’s input
terminals H, S, ES, E then adding crocodiles if necessary
EN - 7
GEO416 - GEO416GS
5.
Extend, if necessary, the blue and red measuring cables separately using cables with
proper section. Adding any extension does not require calibration and does not affect
the measured earth resistance value
6.
Drive the auxiliary rods into the ground keeping to the distance instructions provided
by the standards (§ 11.2)
7.
Connect crocodiles to the auxiliary rods and to the installation under test (see Fig. 3)
8.
9.
Press GO key, the instrument starts carrying out measurement
While the instrument is measuring a
screen similar to the one beside
appears where the instrument’s input
interfering voltage value is displayed.
When the message
is displayed
do not disconnect or touch the test
leads
Input interfering
value
voltage
CAUTION
When starting measurement the input interfering voltage is measured at both
the volt and ampere circuit. Should it range between 3 V and 9 V, the
instrument carries out measurement and displays the symbol
uncertainty decline of the measurement (§ 9.1)
10. When the test is over, should the earth
resistance value be lower than the full
scale, the instrument emits a double
tone indicating the positive outcome of
the test and displays the resistance
measurement as well as the interfering
voltage value at the time of measuring
indicating the
Earth
measurement
resistance
Input interfering
value
voltage
CAUTION
The resistance measurement is effected with 4-wire volt ampere method
without being affected by the resistance value of the cables. It is therefore not
necessary to effect compensation of cable resistance or of any extension
11. When the test is over, should the earth
resistance value be higher than the full
scale, the instrument emits a long tone
indicating the negative outcome of the
test and displays the screen beside
12.
Earth resistance value
higher than full scale
Input interfering
value
The measurements can be stored pressing the SAVE key twice (§ 5.1)
EN - 8
voltage
GEO416 - GEO416GS
4.4. EARTH 2W – 2 WIRE EARTH RESISTANCE MEASUREMENT
CAUTION




The instrument can be used for voltage and current measurements on
installations with over voltage category equal to CAT III 240V to earth and
maximum voltage of 415V between inputs. Do not connect the instrument
to installations whose voltages exceed the limits indicated in this manual.
Exceeding such limits may cause electric shock to the user and damage
the instrument
Always connect the cables to the instrument and to the alligator clips when
the latter are not connected to the plant under test
Always respect the Hand-held area of probe (see § 4.2)
If the length of the supplied cables isn’t suitable for the plant under test (see
§ 11), You can create your own extensions following indications in § 11.2.1
Whenever it is not possible to drive rods into the ground to take a three-wire measurement
(i.e. historical centres), it is possible to use the simplified two-wire method which gives an
excess value for the sake of safety. To carry out the test a suitable auxiliary rod is
necessary; an auxiliary rod is deemed as suitable when its earth resistance is negligible
and independent of the earth installation under test.
In Fig. 4 a lamp post is used as auxiliary rod, however any metal body driven into the
ground can be used provided that the above mentioned requirements are met.
CAUTION
The instrument displays the sum value of RA+RT as result (see Fig. 4 and Fig.
5). Therefore the measurement achieved is the closer to RA (prospective
value) the more negligible is the value RT of the auxiliary rod with respect to
RA itself. In addition the measurement will be increased “for safety sake” by
RT, i.e. if RA+RT results to be coordinated with protective conductors, RA alone
will be far more coordinated
Fig. 4: Two-wire earth resistance measurement using an auxiliary rod
In the TT systems (see Fig. 5) it is possible to perform a two-wire earth measurement
using the NEUTRAL conductor provided by the national Energy Board taken directly from
a socket or panel board as an auxiliary rod; if also the earth connection is available, the
measurement can be taken on the socket directly, between NEUTRAL and EARTH.
EN - 9
GEO416 - GEO416GS
CAUTION
If you wish to effect the measurement using the neutral and earth conductors
of an ordinary socket, you may accidentally connect to phase; in this case the
detected voltage as well as the warning symbol
for wrong entering will be
displayed and no measurement will be effected even though the GO key is
pressed
Fig. 5: Two-wire earth resistance measurement from the panel board
1.
Turn the instrument on pressing the ON/OFF key
2.
Pressing the right and left arrow keys ,  select MOD, then pressing the up
and down arrow keys ,  select 2W option
3.
A screen similar to the one beside
appears where the input interfering
voltage value of the instrument is
displayed
Input interfering
value
voltage
4.
Connect the blue, red, green and black cables to the corresponding instrument’s input
terminals H, S, ES, E then adding crocodiles if necessary
5.
Extend, if necessary, the blue and red measuring cables separately using cables with
proper section. Adding any extension does not require calibration and does not affect
the measured earth resistance value
6.
7.
Connect crocodiles to the auxiliary rods and to the installation under test (see Fig. 4
and Fig. 5)
Press GO key, the instrument starts carrying out measurement
EN - 10
GEO416 - GEO416GS
8.
While the instrument is measuring a
screen similar to the one beside
appears where the instrument’s input
interfering voltage value is displayed.
When the message
is displayed
do not disconnect or touch the test
leads
Input interfering
value
voltage
CAUTION
When starting measurement the input interfering voltage is measured at both
the volt and ampere circuit. Should it range between 3 V and 9 V, the
instrument carries out measurement and displays the symbol
uncertainty decline of the measurement (§ 9.1)
9.
When the test is over, should the earth
resistance value be lower than the full
scale, the instrument emits a double
tone indicating the positive outcome of
the test and displays the resistance
measurement as well as the interfering
voltage value at the time of measuring
indicating the
Earth
measurement
resistance
Input interfering
value
voltage
CAUTION
The resistance measurement is effected with 4-wire volt ampere method
without being affected by the resistance value of the cables. It is therefore not
necessary to effect compensation of cable resistance or of any extension
10. When the test is over, should the earth
resistance value be higher than the full
scale, the instrument emits a long tone
indicating the negative outcome of the
test and displays the screen beside
11.
Earth
resistance
measurement higher than
full scale
Input interfering
value
The measurements can be stored pressing the SAVE key twice (§ 5.1)
EN - 11
voltage
GEO416 - GEO416GS
4.5.  - GROUND RESISTIVITY MEASUREMENT
The ground resistivity value is an essential parameter to calculate the resistance value of
the earth rods to be used for the earth installation’s construction. The measurement is
effected according to standards IEC 781, VDE 0413, IEC/EN61557-5.
CAUTION




The instrument can be used for voltage and current measurements on
installations with over voltage category equal to CAT III 240V to earth and
maximum voltage of 415V between inputs. Do not connect the instrument
to installations whose voltages exceed the limits indicated in this manual.
Exceeding such limits may cause electric shock to the user and damage
the instrument
Always connect the cables to the instrument and to the alligator clips when
the latter are not connected to the plant under test
Always respect the Hand-held area of probe (see § 4.2)
If the length of the supplied cables isn’t suitable for the plant under test (see
§ 11), You can create your own extensions following indications in § 11.2.1
Fig. 6: Ground resistivity measurement
1.
Turn on the instrument pressing the ON/OFF key
2.
Pressing right/left arrow keys ,  select MOD, then pressing up/down arrow
keys ,  select  option
EN - 12
GEO416 - GEO416GS
3.
4.
5.
A screen similar to the one beside
appears where both the input interfering
voltage of the instrument and the rods’
distance value are displayed
Should you need to modify the
rods’ distance press the arrow
keys ,  and select DIST,
then pressing the arrow keys
,  set the desired distance
(ranging from 1 up to 10 metres,
by steps of one or from 3 up to
30 feet by steps of three)
To set the distance measuring
unit press the arrow keys , 
and select UNIT, then pressing
the arrow keys ,  set the
desired measuring unit (m or ft)
Value of input interfering
voltage and rods' distance
set
Value of rods' distance set
Measuring unit selected
6.
Connect the blue, red, green and black cables to the corresponding instrument’s input
terminals H, S, ES, E then adding crocodiles if necessary
7.
Extend, if necessary, the blue and red measuring cables separately using cables with
proper section. Adding any extension does not require calibration and does not affect
the measured ground resistivity value
8.
Drive the auxiliary rods into the ground placing them on a line at a mutual distance
equal to that selected on the instrument. Setting a distance other than the actual
distance between the earth rods may affect the measurement (§11.3)
9.
Connect crocodiles to the auxiliary rods (see Fig. 6)
10.
Press GO key, the instrument starts carrying out measurement
EN - 13
GEO416 - GEO416GS
11. While the instrument is measuring a
screen similar to the one beside
appears where the instrument’s input
interfering voltage value and the
distance set between auxiliary rods are
displayed. When the message
is displayed do not disconnect or touch
the test leads
Value of input interfering
voltage and rods' distance
set
CAUTION
When starting measurement the input interfering voltage is measured at both
the volt and ampere circuit. Should it range between 3 V and 9 V, the
instrument carries out measurement and displays the symbol
uncertainty decline of the measurement (§ 9.1
12. When the test is over, should the
ground resistivity value be lower than
the full scale, the instrument emits a
double tone indicating the positive
outcome of the test and displays the
resistivity measurement as well as the
interfering voltage value at the time of
measuring
indicating the
Measurement
resistivity
of
ground
Value of input interfering
voltage and rods' distance
set
CAUTION
The resistivity measurement is effected with 4-wire volt ampere method without
being affected by the resistance value of the cables. It is therefore not
necessary to effect compensation of cable resistance or of any extension.
13. When the test is over, should the
ground resistivity value be higher than
the full scale, the instrument emits a
long tone indicating the negative
outcome of the test and displays the
screen beside
Measurement of ground
resistivity higher than the
full scale
Value of input interfering
voltage and rods' distance
set
CAUTION
The full scale is calculated as ρMAX = 2  DIST R where DIST is the value set
for the distance among the rods and R the maximum resistance value which
can be measured by the instrument. The full scale of ground resistivity
measurement depends on the setting of the distance among the rods
14.
The measurements can be stored pressing the SAVE key twice (§ 5.1)
EN - 14
GEO416 - GEO416GS
4.5.1. Anomalous measuring applications
1.
When starting a measurement the
Volt circuit’s resistance too
instrument checks the continuity of
high
measuring cables. If the volt circuit
(red cable S and green cable ES) is
interrupted or its resistance value is
Value of input interfering
voltage
too high, the instrument displays a
screen similar to the one beside. Check
that terminals are properly connected
Example for 3W mode
and that the earth rod is connected to
terminal S and not driven into a pebbly or scarcely conductive ground. In this latter
case pour water around the rod to decrease its resistance value (§ 11.2).
RP>top is displayed when:
 The S rod’s resistance RS > 50KΩ is summed up to the volt circuit
 The resistance of rod S exceeds the value 1200 + 100 RX [Ω] (where RX is the
earth resistance value)
2.
When starting a measurement the
Ampere circuit’s resistance
instrument checks the continuity of
too high
measuring cables.
If the ampere
circuit (blue cable H and black cable
Value of input interfering
E) is interrupted or its resistance
voltage
value is too high, the instrument
displays a screen similar to the one
Example for 3W mode
beside. Check that terminals are
properly connected and that the earth
rod is connected to
terminal H and not driven into a pebbly or scarcely conductive ground. In this latter
case pour water around the rod to decrease its resistance value (§ 11.2).
RC>top is displayed when:
 The H rod’s resistance RH > 50KΩ is summed up to the ampere circuit
 The resistance of rod H exceeds the value 1200 + 100 RX [Ω] (where RX is the
earth resistance value)
3.
When starting a measurement the
Both volt and ampere
instrument checks the continuity of
circuits’ resistance too high
measuring cables. If the volt circuit
(red cable S and green cable ES) and
Value of input interfering
voltage
the ampere circuit (blue cable H and
black cable E) are both interrupted or
Example for 3W mode
their resistance values are too high,
the instrument displays a screen similar
to the one beside. Check that the
terminals are properly connected and that the earth rods connected to terminals S
and H are not driven into a pebbly or scarcely conductive ground. In this latter case
pour water around the rods to decrease their resistance value (§ 11.2).
RP, RC>top is displayed when:
 The S rod’s resistance RS > 50KΩ is summed up to the volt circuit and the H
rod’s resistance H RH > 50KΩ is summed up to the ampere circuit
 Both the S rod’s resistance and the H rod’s resistance exceed the value 1200 +
100 RX [Ω] (where RX is the earth resistance value)
EN - 15
GEO416 - GEO416GS
4.
When starting a measurement, if the
red cable (connected to S terminal)
and the green cable (connected to ES
terminal) are reversed, the instrument
do not perform the test, emits a long
sound tone and displays the screen
beside
Red and
reversed
green
cables
Example under ρ mode
5.
When starting a measurement, if an
interfering voltage higher than 9V is
detected at the volt circuit’s input,
the instrument do not perform the test,
emits a long sound tone and displays
the screen beside
Too high input interfering
voltage at volt circuit
Input interfering
value
voltage
Example under 2W mode
6.
When starting a measurement, if an
interfering voltage higher than 9V is
detected at the ampere circuit’s
input, the instrument do not perform the
test, emits a long sound tone and
displays the screen beside
Too high input interfering
voltage at ampere circuit
Input interfering
value
voltage
Example under 2W mode
7.
When starting a measurement, if an
interfering voltage higher than 9V is
detected at both the ampere and volt
circuits’ inputs, the instrument do not
perform the test, emits a long sound
tone and displays the screen beside
Too high input interfering
voltage at both ampere
and volt circuits
Input interfering
value
voltage
Example under 2W mode
8.
If battery voltage is too low the
instrument displays the symbol of low
battery as well as the message
and no measurement is allowed. It is
however possible to carry out settings,
reading of stored data, etc
Too low power supply, low
batteries
Input interfering voltage
value and distance set
among rods
Example under ρ mode
9.
The above said anomalous cases cannot be stored
EN - 16
GEO416 - GEO416GS
5. MANAGEMENT OF STORED DATA
5.1. HOW TO SAVE A MEASUREMENT
After taking a measurement
press SAVE key, the instrument
displays a screen similar to the
one beside
1.
Last
value
set
parameters L and P
for
Should you need to modify the values of the parameters L and P press the
arrow keys ,  and select L or P, then pressing the arrow keys ,  set
the desired value (from 1 to 255). These values can enable you to trace back
the place where the measurement was effected
2.
3.
No. of memory location
where the measurement
has to be saved
OR
Confirm measurement storing pressing SAVE key or ENTER
key
5.2. HOW TO CANCEL ONE OR SEVERAL MEASUREMENTS
1.
Press RCL key, the instrument
displays a screen similar to the
one beside
Number of the last memory
location used
Values of
parameters
2.
Press the arrow keys ,  to
select
the memory location
where cancellation of data is to
be started , the displays a
screen similar to the one beside
L
and
P
Number of the memory
location where cancellation
is to be started
Values of
parameters
L
and
P
CAUTION
Confirming cancellation of data causes removal of all stored data starting from
the selected location till the last memory location
EN - 17
GEO416 - GEO416GS
Press the CLR key, the
instrument displays a screen
similar to the one beside
3.
First and last memory
location to be cancelled
and confirmation required
Alternatively:
4.
Confirm cancellation of measurements pressing ENTER key, the
instrument emits a double sound tone confirming cancellation of the
selected measurements
4.
Press ESC key to go back to previous screen
Or:
5.3. HOW TO RECALL A MEASUREMENT
1.
Press the RCL key, the
instrument displays a screen
similar to the one beside
Number of the last memory
location
Values of
parameters
2.
3.
4.
Press the arrow keys ,  to
select the memory location
whose content is to be
displayed
Press the ENTER key to display
the measurement stored inside
the selected memory location,
the instrument
displays a
screen similar to the one beside
L
and
P
Number of the memory
location whose content is
to be displayed
Values of
parameters
L
and
P
Measurement stored in the
selected memory location
Values
of
interfering
voltage at measurement
Press the ESC key to go back to previous screen and press the ESC key
again to exit the memory management
EN - 18
GEO416 - GEO416GS
6. INSTRUMENT RESET
CAUTION
BEFORE CARRYING OUT THE INSTRUMENT’S RESET SAVE ALL DATA
RELATIVE TO THE MEASUREMENTS EFFECTED BY DOWNLOADING
THEM TO A PC
1.
When the instrument is off press the RCL/CLR key
2.
Keeping down the RCL/CLR key, press the switch
on key. The instrument emits a short sound tone
showing all display segments for approx. 1
second. Then it emits a second short sound tone
displaying the screen beside
for approx. 3
seconds
CAUTION
The HARD RESET procedure deletes all data previously stored and the
parameter DST resumes its default value (1 m or 3 ft)
7. INSTRUMENT CONNECTION TO PC
The instrument can be connected to a PC by means of the serial port or USB and opt
insulated cable provided along with the software package. First it’s necessary to select the
COM port used for the transmission and the correct baud rate (9600 bps). To set these
parameters install the software and consult the help on line.
The selected port shall be free of any other device or application such as mouse, modem, etc.
CAUTION
Optical port emits Laser radiations , Don’t locate beam at eye level. Class 1M
laser apparatus according to EN 60825-1
To transfer stored data to PC keep to the following procedure:
1.
2.
3.
Turn on the instrument pressing the power key
Connect the instrument to a PC by means of the opt insulated cable provided with the
software package. Communication is enabled at any function except for
measurements as well as when memory management is active (§ 5)
Use the data management software to download the
instrument’s stored data to a PC. During the data transfer
the instrument displays a screen as beside, then after
completing the data transfer goes back to the previously
selected mode
EN - 19
GEO416 - GEO416GS
8. MAINTENANCE
8.1. GENERAL
This is a precision instrument. Strictly follow the instructions for use and storage reported
in this manual to avoid any possible damage or danger during use.
Do not use this tester under unfavorable conditions of high temperature or humidity. Do
not expose to direct sunlight.
Be sure to turn off the tester after use. If the instrument is not to be used for a long period
you are recommended to remove batteries to avoid leakages of battery liquid which may
damage its internal circuits.
8.2. BATTERY REPLACEMENT
When the low battery indication (see § 9.1.2) is displayed the batteries are to be replaced.
CAUTION
Only skilled technicians can open the instrument and replace batteries. Before
removing batteries disconnect all cables from input terminals
1.
2.
3.
4.
Turn off the instrument pressing the ON/OFF key for a while
Disconnect the cables from the input terminals
Remove the battery cover screws and detach the battery cover
Replace batteries with new ones of the same type (see § 9.1.2) keeping to the right
polarity signs
5. Replace cover and screws
6. Use the appropriate battery disposal methods for your area
8.3. INSTRUMENT CLEANING
Use a soft dry cloth to clean the instrument. Do not use wet clothes, solvents, water etc.
8.4. END OF LIFE
Caution: this symbol indicates that equipment and its accessories shall be
subject to a separate collection and correct disposal.
EN - 20
GEO416 - GEO416GS
9. TECHNICAL SPECIFICATIONS
9.1. TECHNICAL FEATURES
Accuracy indicated as [%reading + (number dgts * resolution)] at 23 ± 5°C, <80%RH
3- and 2-wire earth resistance measurement - EARTH 3W and EARTH 2W
Measurement range (**)
Accuracy (*)
Resolution []
Reading []
Measure []
0.01
0.01  19.99
0.08  19.99
0.1
20.0  199.9
20.0  199.9
1
(2.5%rdg + 2dgt)
200  1999
200  1999
0.01k
2.00  19.99k
2.00  19.99k
0.1k
20.0  49.9k
20.0  49.9k
Ground resistivity measurement -  (distance among the rods=1m)
Range (**)
Accuracy (*)
Resolution [m]
Reading [m]
Measure m]
0.01
0.06  19.99
0.50  19.99
0.1
20.0  199.9
20.0  199.9
1
200  1999
200  1999
(2.5%rdg+2dgt)
0.01k
2.00  19.99k
2.00  19.99k
0.1k
20.0  199.9k
20.0  199.9k
1k
200  314k
200  314k


Measuring frequency: 77.5Hz; Test current:  12mA; Open loop voltage: < 25Vrms
Disturbance voltage on ampere and volt circuits: the measurement is taken with the stated accuracy if the interfering
voltage is  3V, while for interfering voltages ranging from > 3V and  9V, the accuracy decreases progressively;
with an interfering voltage equal to 9V the instrument does not perform the test
(*) If RP > 1200 + 100 RX and/or RC > 1200 + 100 RX, RP > 50k and/or RC > 50k and the instrument carries out the
test, the accuracy of the instrument is (10% reading) where:
RP = resistance of the voltage circuit; RC = resistance of the current circuit; RE = measured earth resistance
(**) Automatic selection of the range
Interfering voltage measurement
Range (**)
Reading [V]
Measure [V]
0  460
7  460
Resolution [V]
Uncertainty
1
(2.0%rdg+2dgt)
(**) Automatic selection of the range
EN - 21
GEO416 - GEO416GS
9.1.1. Reference standards
Safety:
Measuring accessories’ safety:
Technical literature:
Insulation:
Mechanical protection:
Pollution level:
Measurement category:
Max height of use:
IEC/EN61010-1, IEC/EN61557-1, IEC/EN61557-5
IEC/EN61010-031
IEC/EN61187
double insulation
IP50 according IEC/EN60529
2
CAT III 240V (to earth), maximum 415V between inputs
2000m (6562ft)
9.1.2. General features
Mechanical features
Dimensions (L x W x H):
Weight (including batteries):
235 x 165 x 75mm (9 x 6 x 3in)
1kg (2lv)
Power supply
Battery type:
Low battery indication:
Battery life:
Auto Power OFF:
6x1.5V batteries type AA LR6 or
6x1.2V rechargeable batteries NI-MH AA LR6 2100mA
” is displayed
symbol “
approx. 500 tests
after 3 min of idleness
Display
Features:
LCD custom with back-light 73x65 mm
Memory
Features:
999 memory locations
PC connection
Features:
optoinsulated port for bi-directional communication
9.2. ENVIRONMENT
9.2.1. Operating environmental conditions
Reference calibration temperature: 23 ± 5°C (73 ± 41°F)
Working temperature:
0 ÷ 40°C (32°F ÷ 104°F)
Maximum relative humidity:
<80%RH
Storage temperature:
-10 ÷ 60°C (14°F ÷ 140°F)
Storage humidity:
<80%RH
This instrument complies with the requirements of the European Low Voltage
Directive 2006/95/CE (LVD) and EMC Directive 2004/108/CE
9.3. ACCESSORIES
9.3.1. Standard and optional accessories GEO416
See enclosed packing list
9.3.2. Standard accessories GEO416GS
 Set of 4 cables, banana-banana, L=1m
 Set of 4 alligator clips
 Carrying bag
 ISO9000 calibration certificate
 User manual
EN - 22
KIT416CV
COC4-UK
BORSA2000N
GEO416 - GEO416GS
10.
SERVICE
10.1. WARRANTY TERMS
This instrument is guaranteed against material or manufacturing defects, in accordance
with general sales conditions. During the warranty period the manufacturer reserves the
right to decide either to repair or replace the product.
Should you need for any reason to return back the instrument for repair or replacement
take prior agreements with your local distributor. Freight charges are up to the customer.
Do not forget to enclose a report describing the reasons for returning the unit as well as
the detected fault.
Use only original packaging. Any damage occurred in transit due to no-original packaging
will be charged anyhow to the customer.
The manufacturer will not be responsible for any damage to persons or things.
The warranty doesn’t apply to the following cases:
 Repair and/or replacement of accessories and batteries (not covered by warranty)
 Repairs made necessary due to improper use (including adaptation to particular
applications not foreseen in the instructions manual) or improper combination with
incompatible accessories or equipment
 Repairs made necessary due to improper shipping material causing damages in transit
 Repairs made necessary due to previous attempts for repair carried out by unskilled or
unauthorized personnel
 Instruments for whatever reason modified by the customer himself without explicit
authorization of our Technical Dept
 Use not provided by the instrument's specifications or in the instruction manual.
The contents of this manual may not be duplicated in any form whatsoever without the
manufacturer’s authorization.
Products are patented and logotypes registered. The manufacturer reserves the
right to modify specifications and prices in view of technological improvements or
developments which might be necessary.
10.2. AFTER-SALES SERVICE
Shouldn’t the instrument work properly, before contacting your distributor make sure that
batteries are correctly installed and working, check the test leads and replace them if
necessary.
Make sure that your operating procedure corresponds to the one described in this manual.
Should you need for any reason to return back the instrument for repair or replacement
take prior agreements with your local distributor. Freight charges are up to the customer.
Do not forget to enclose a report describing the reasons for returning the unit as well as
the detected fault.
Use only original packaging. Any damage occurred in transit due to no-original packaging
will be charged anyhow to the customer.
The manufacturer will not be responsible for any damage to persons or things.
EN - 23
GEO416 - GEO416GS
11.
PRACTICAL REPORTS FOR ELECTRICAL TESTS
11.1. EARTH RESISTANCE IN TT SYSTEMS
The test is aimed at checking that the RCD is coordinated with the earth resistance value.
It is not possible to assume an earth resistance value as reference limit when controlling
the test result, while it is necessary to check every time that the co-ordination complies
with the requirements of the Standards.
The parts to be checked are represented by the whole earth installation under working
conditions. The check is to be effected without disconnecting the earth rods.
The earth resistance value measured shall meet the following relation RA < 50 / Ia where:
RA = resistance of the earth installation whose value can be set with the following
measurements:
 Three-wire earth resistance with volt ampere method
 Two-wire earth resistance with volt ampere method
 Phase to earth fault loop impedance (*)
 Two-wire earth resistance in the socket with volt ampere method (**)
 Earth resistance obtained by the measurement of contact voltage Ut (**)
 Earth resistance obtained by the tripping time test of the RCDs (A, AC),RCD S
(A, AC) (**)
Ia = tripping current in 5s of the automatic RCD; rated tripping current of the RCD (in
case of RCD S 2 In) in ampere
50 = safety limit voltage (reduced down to 25V in special environments)
(*)
If the installation is protected by an RCD the measurement shall be effected
upstream or downstream the RCD short-circuiting it to avoid its tripping
(**)
This method, even though not presently provided for by standards, provide values,
which compared with numberless reference 3-wire tests resulted to be reliable for
earth resistance
Example
Let's assume an installation protected by an RCD Ia = 30 mA. The earth resistance is
measured using one of the methods quoted above. To evaluate whether the installation
resistance is complying with the standards in force multiply the result by 0.03A (30 mA). If
the result is lower than 50V (or 25V for special environments) the installation can be
considered as coordinated as it meets the above said relation.
In case of 30 mA RCDs (most civil installations) the maximum earth resistance allowed is
50 V/ 0.03=1666Ω permitting to use even simplified methods which though do not provide
extremely accurate values, give values approximate enough to calculate the coordination.
EN - 24
GEO416 - GEO416GS
11.2. EARTH RESISTANCE, VOLTAAMPEREMETRIC METHOD
11.2.1. Creating cables extensions
If the length of the supplied cables isn’t suitable for the plant under test, You can create
your own extensions without influencing the instrument’s accuracy.
For your own safety and to avoid damaging the instrument you are recommended to
respect the following indications:
 Always use cable characterized by Insulation voltage and Insulation class complying to
Nominal voltage and measurement category (Overvoltage) of the plant under test
 Always use terminal connectors characterized by measurement category (Overvoltage)
and Nominal voltage complying to Nominal voltage of the plant under test (see § 1.4). It
is recommended the 1066-IECN optional accessory
11.2.2. Method for small-sized earth rods
Let a current stream between the earth rod under test and an auxiliary probe placed at a
distance equal to fivefold the diagonal of the area limiting the earth installation itself. Place
the voltage probe at approximately half way between the earth rod and the current probe,
finally measure voltage between both of them.
Fig. 7: Earth resistance measurement – small-sized earth rods
11.2.3. Method for large-sized earth rods
This procedure is based on the volt ampere metric method as well, however it is mainly
used whenever it is difficult to place an auxiliary current rod at a distance equal to fivefold
the diagonal of the area limiting the earth installation. Place the current probe at a
distance equal to the diagonal of the earth installation. To make sure that the voltage
probe is placed outside the area affected by the rod under test as well as the auxiliary rod,
take several measurements, firstly placing the voltage probe at half way between the
installation and the auxiliary current probe, later moving the probe to both the installation
under test and the auxiliary current probe. Such measurements shall give compatible
results, any difference among measurement values taken indicates that the voltage rod
was driven within the influence area of the installation under test or of the auxiliary current
rod. Such measurements cannot be considered as reliable.
In this instance it is necessary to further extend distance between the auxiliary current rod
and the rod under test, then repeat the whole procedure as above described.
EN - 25
GEO416 - GEO416GS
Fig. 8: Earth resistance measurement – large-sized earth rods
11.3. GROUND RESISTIVITY
This test aims at analyzing the resistivity value of the ground in order to define the type of
rods to be used when designing the installation. For the resistivity test correct or not
correct values do not exist. The various values measured by positioning the rods at
growing distances “a” must be quoted in a graph. According to the resulting curve, suitable
rods will be chosen. As the test result can be affected by metal parts buried such as pipes,
cables or other rods etc., it is advisable in case of doubts to take a second measurement
positioning the rods at an equal distance "a", but rotating their axis by 90°.
Fig. 9: Measurement of ground resistivity
The resistivity value is given by the following relation: E = 2  a R where:
E =
a=
R=
ground resistivity
distance between probes [m]
resistance measured by the instrument []
EN - 26
GEO416 - GEO416GS
The measuring method allows defining the specific resistivity of a ground layer up to the
depth corresponding approximately to the distance “a” between the rods. If you increase
the distance “a” you can reach deeper ground layers and check the ground homogeneity.
After several measurements you can trace a profile according to which the most suitable
rod is chosen.
Curve 1: as  decreases only in depth, it’s
advisable to use a very deep rod
Curve 2: as E decreases only until the depth
a, it’s not useful to increase the
depth of the rod beyond a
Curve 3: the ground resistivity is quite
constant, so increasing depth does
not make E decrease, therefore a
ring rod must be used
Fig. 10: Measurement of ground resistivity
11.3.1. Approximate evaluation of intentional rods' contribution
The resistance of a rod Rd can be calculated with the following formulas ( = average
resistivity of the ground).
a) resistance of a vertical rod
Rd =  / L
where L = length of the element touching the ground
b) resistance of an horizontal rod
Rd = 2 / L
where L = length of the element touching the ground
c) resistance of linked elements
The resistance of a complex system made of more elements in parallel is always higher
than the resistance, which could result from a simple calculation of single elements in
parallel, especially if those elements are close to each other and therefore interactive. For
this reason, in case of a linked system the following formula is quicker and more effective
than the calculation of the single horizontal and vertical elements:
Rd =  / 4r
where r = radius of the circle which circumscribes the link
EN - 27
NOTE
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Via della Boaria 40
48018 – Faenza (RA) - Italy
Tel: +39-0546-621002 (4 linee r.a.)
Fax: +39-0546-621144
Email: ht@htitalia.it
Web :www.ht-instruments.com
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