Gossen MetraWatt METRACLIP EARTH Operating Instructions Manual
METRACLIP EARTH
EARTH CLAMP
Operating Instructions
E N G L I S H
2
Thank you for purchasing a METRACLIP EARTH earth clamp. For best results
from your instrument:
■ read these operating instructions carefully,
■ comply with the precautions for use.
Symbol
Meaning
WARNING, risk of DANGER! The operator must refer to these
instructions whenever this danger symbol appears.
Equipment protected throughout by double or reinforced insulation.
Application or withdrawal authorized on uninsulated or bare
conductors at dangerous voltages.
The product has been declared recyclable after analysis of
its life cycle in accordance with the ISO 14040 standard.
An Eco-Design approach has been adopted in order to design this
appliance. Analysis of the complete lifecycle has enabled us to
control and optimize the effects of the product on the environment.
In particular this appliance exceeds regulation requirements with
respect to recycling and reuse.
The CE marking indicates conformity with European directives, in
particular LVD and EMC.
The rubbish bin with a line through it indicates that, in the European
Union, the product must undergo selective disposal in compliance
with Directive WEEE 2012/19/EU. This equipment must not be
treated as household waste
Useful information or tip.
Definition of measurement categories:
■ Measurement category IV corresponds to measurements taken at the source
of low-voltage installations.
Example: power feeders, counters and protection devices.
■ Measurement category III corresponds to measurements on building
installations.
Example: distribution panel, circuit-breakers, machines or fixed industrial
devices.
■ Measurement category II corresponds to measurements taken on circuits
directly connected to low-voltage installations.
Example: power supply to domestic electrical appliances and portable tools.
3
PRECAUTIONS FOR USE
This instrument and its accessories comply with safety standards EN 61010-1,
EN 61010-030, and EN 61010-2-032 for voltages of 600V in category IV at an
altitude of less than 2000 m, indoors, with a degree of pollution of not more than
2.
Failure to observe the safety instructions may result in electric shock, fire,
explosion, and destruction of the instrument and of the installations.
■ The operator and/or the responsible authority must carefully read and clearly
understand the various precautions to be taken in use. Sound knowledge and
a keen awareness of electrical hazards are essential when using this
instrument.
■ If you use this instrument other than as specified, the protection it provides
may be compromised, thereby endangering you.
■ Do not use the instrument on networks of which the voltage or category
exceeds those mentioned.
■ Do not use the instrument if it seems to be damaged, incomplete, or poorly
closed.
■ Before each use, check the condition of the insulation on housing. Any item of
which the insulation is deteriorated (even partially) must be set aside for repair
or scrapping.
■ Use personal protection equipment systematically.
■ When handling the instrument, keep your fingers behind the physical guard.
■ All troubleshooting and metrological checks must be performed by competent
and accredited personnel.
■ Avoid impacts on the measurement head, in particular the air gap.
■ Keep the surfaces of the air gap clean; even a little dirt can cause the clamp to
malfunction.
Note: Bluetooth® is a registered trade mark.
4
CONTENTS
Page
............................................................................................................................... 1
DEFINITION OF MEASUREMENT CATEGORIES: .............................................. 2
CONTENTS ........................................................................................................... 4
1. GETTING STARTED ......................................................................................... 7
1.1 Scope of supply ............................................................................................ 7
1.2 INSERTING THE BATTERIES ..................................................................... 7
1.3 Setting the date and time .............................................................................. 7
1.4 EXAMPLE OF DISPLAY .............................................................................. 8
2. DESCRIPTION OF THE DEVICE ...................................................................... 8
2.1 FUNCTIONS OF THE DEVICE .................................................................... 9
2.2 FRONT PANEL .......................................................................................... 10
2.3 DEVICE–REAR PANEL ............................................................................. 12
2.4 DISPLAY UNIT ........................................................................................... 13
2.5 AUDIBLE SIGNALS.................................................................................... 15
3. MEASUREMENT PRINCIPLE ......................................................................... 16
4. USE.................................................................................................................. 17
4.1 INSERTING THE BATTERIES ................................................................... 17
4.2 COMMISSIONING THE DEVICE ............................................................... 17
4.3 SETTING THE INTERNAL CLOCK ............................................................ 17
4.4 STANDARD OR ADVANCED MODE ......................................................... 18
4.5 USE OF THE FUNCTIONS ........................................................................ 18
4.6 USE OF THE Hold KEY ............................................................................. 18
4.7 USE OF Pre-Hold ....................................................................................... 19
4.8 STORAGE OF THE DATA ......................................................................... 19
4.8.1 Conditions ......................................................................................... 19
4.8.2 EFFECTIVE STORAGE .................................................................... 19
4.8.3 INFORMATION CONCERNING THE STORED DATA ..................... 19
4.8.4 MEMORY FULL ................................................................................ 19
4.8.5 READING THE STORED DATA ....................................................... 20
4.9 MANAGEMENT OF THE ALARMS ............................................................ 20
4.9.1 NO ALARM DETECTION.................................................................. 20
4.9.2 VOLTAGE ALARM ............................................................................ 20
4.9.3 CURRENT ALARM ........................................................................... 21
4.9.4 IMPEDANCE ALARM ....................................................................... 21
5. Ω+A POSITION ................................................................................................ 23
5.1 USE IN Standard MODE ............................................................................ 23
5.1.1 OBJECT ............................................................................................ 23
5
5.1.2 PARAMETERIZING THE MEASUREMENT ..................................... 23
5.1.3 MEASUREMENT .............................................................................. 23
5.1.4 MEASUREMENT RESULT ............................................................... 24
5.1.5 STORAGE OF THE MEASUREMENTS ........................................... 24
5.1.6 PRESENCE OF ALARMS ................................................................ 24
5.2 USE IN ADVANCED MODE ....................................................................... 24
5.2.1 OBJECT ............................................................................................ 24
5.2.2 SELECTION ...................................................................................... 24
5.2.3 PARAMETERIZING THE MEASUREMENT ..................................... 24
5.2.4 MEASUREMENT .............................................................................. 25
5.2.5 MEASUREMENT RESULT ............................................................... 25
5.3 COMPLEMENTARY INFORMATION ......................................................... 26
5.3.1 PRODUCT ZXI GREATER THAN 50V ............................................. 26
5.3.2 IMPEDANCE GREATER THAN 1500Ω ............................................ 27
5.3.3 PERTURBING LEAKAGE CURRENT .............................................. 27
5.3.4 CURRENT GREATER THAN 10A .................................................... 27
5.3.5 STORAGE OF THE MEASUREMENTS ........................................... 28
5.3.6 PRESENCE OF ALARMS ................................................................ 28
6. POSITION A .................................................................................................... 29
6.1 OBJECT ..................................................................................................... 29
6.2 PARAMETERIZING THE MEASUREMENT ............................................... 29
6.3 MEASUREMENT ....................................................................................... 29
6.4 MEASUREMENT RESULT ........................................................................ 29
6.5 PRESENCE OF ALARMS .......................................................................... 29
6.6 MANAGEMENT OF THE ALARMS ............................................................ 30
7. MEMORY READ (MR) ..................................................................................... 31
7.1 OBJECT ..................................................................................................... 31
7.2 SELECTION OF THE memory read MODE ............................................... 31
7.3 DATA DISPLAYED ..................................................................................... 31
7.3.1 DATA DISPLAYED IN Standard MODE ........................................... 31
7.3.2 DATA DISPLAYED IN ADVANCED MODE ...................................... 32
7.3.3 USE OF THE KEYS .......................................................................... 33
7.3.4 ERASURE OF THE STORED DATA ................................................ 33
7.3.5 EXITING FROM THE READ MODE ................................................. 34
8. SET-UP ............................................................................................................ 35
8.1 OBJECT ..................................................................................................... 35
8.2 ACCESS TO THE SET-UP MENUS ........................................................... 35
8.3 DISPLAY OF THE SET-UP MENUS .......................................................... 35
8.4 SELECTING A SPECIFIC MENU ............................................................... 36
8.5 DETAILS OF THE SET-UP MENUS .......................................................... 36
9. OFF POSITION ................................................................................................ 42
9.1 MANUAL SWITCHING OFF ....................................................................... 42
9.2 AUTOMATIC SWITCHING OFF ................................................................. 42
9.3 BACKUP OF THE CONFIGURATION ........................................................ 42
6
9.4 PROLONGED STOP .................................................................................. 42
10. TECHNICAL CHARACTERISTICS ................................................................ 43
10.1 REFERENCE CONDITIONS .................................................................... 43
10.2 ELECTRICAL CHARACTERISTICS ......................................................... 43
10.2.1 LOOP RESISTANCE MEASUREMENT ........................................... 43
10.2.2 LOOP INDUCTANCE MEASUREMENT ........................................... 44
10.2.3 ESTIMATE OF THE CONTACT VOLTAGE ...................................... 44
10.2.4 CURRENT MEASUREMENT ............................................................ 44
10.3 VARIATIONS IN THE DOMAIN OF USE ................................................. 45
10.4 POWER SUPPLY ..................................................................................... 45
THE BATTERIES WILL BE WITHDRAWN FOR LONG-TERM STORAGE. ........ 45
10.5 ENVIRONMENTAL CONDITIONS ........................................................... 46
10.6 MECHANICAL CHARACTERISTICS ....................................................... 46
10.7 COMPLIANCE WITH INTERNATIONAL STANDARDS ........................... 46
10.8 Electromagnetic compatibility ................................................................... 46
THE DEVICE IS COMPLIANT WITH STANDARD IEC-61326-1. ........................ 46
11. SERVICING AND MAINTENANCE ................................................................ 47
11.1 Cleaning ................................................................................................... 47
11.2 Replacement of the batteries .................................................................... 47
11.2.1 PROCEDURE ................................................................................... 47
11.2.2 PRESERVATION OF STORED DATA ............................................. 48
11.3 CHECK OF ACCURACY .......................................................................... 48
11.3.1 OBJECT AND EQUIPMENT NECESSARY ...................................... 48
11.3.2 EQUIPMENT ..................................................................................... 48
11.3.3 PROCEDURE ................................................................................... 48
11.4 ADJUSTMENT ......................................................................................... 48
11.4.1 OBJECT AND EQUIPMENT NECESSARY ...................................... 48
11.4.2 EQUIPMENT ..................................................................................... 48
11.4.3 PROCEDURE ................................................................................... 49
11.5 Metrological check, Repair and Replacement Parts Service, Calibration
Center............................................................................................................... 49
11.6 Product support ........................................................................................ 49
12. WARRANTY .................................................................................................. 50
13. TO ORDER .................................................................................................... 51
7
1. GETTING STARTED
1.1 SCOPE OF SUPPLY
Rep.
Designation
1
Carrying case.
2
METRACLIP EARTH earth clamp.
3
Set of 4 AA batteries (1.5 V).
4
CD containing the operating instructions.
5
Verification certificate.
6
Safety data sheet (20 languages)
7
Quick Start guide
Fig. 1
1.2 INSERTING THE BATTERIES
Refer to §11.2.
1.3 SETTING THE DATE AND TIME
Set the function switch to Ω+A. All icons of the display unit light for approximately 2
seconds. The device waits for the date and time of the device to be set using the ▲,
▼, and ► keys; refer to § 4.3 for a detailed description of the procedure.
8
1.4 EXAMPLE OF DISPLAY
The figure opposite shows a
display, upon first use, with the
device set to Ω+A. The measured
current is 30.0 mA and the
impedance is 7.9 Ω.
The buzzer is active and the
memory is empty.
Note: This display corresponds to
the Standard mode. In the
Advanced mode, 2 additional
screens are available; see §5.2.
Fig. 2
The figure opposite shows a
display, upon first use, with the
device set to A. The current
measured is 30.0 mA.
The buzzer is active and the
memory is empty.
Fig. 3
2. DESCRIPTION OF THE DEVICE
The earth clamp is intended for testing the resistances of any conducting system
having the characteristics of a conducting loop. It is used to perform:
■ Earth resistance measurements if the earth is in series in a loop with its
continuity conductor;
■ Other earth measurements: earth extended, for example by means of a guard
wire between power transmission or telecommunication poles;
■ Or the distributed earths of a single earth plane.
9
2.1 FUNCTIONS OF THE DEVICE
■ Easy-to-use device intended for measurement of the loop impedance in a
parallel earth network, by a simpler method than the traditional method with 2
auxiliary rods.
Loop ohmmeter: measurement of loop impedances from 0.01 Ω to 1,500 Ω.
The ohmmeter function makes allowance for the presence of inductances
in the loop, making impedance measurements more accurate at low
values.
Ammeter: current measurements from 0.2 mA to 40 A.
Contact voltage: the contact voltage is estimated by calculating the product of
the loop impedance by the leakage current. The value found is an upper
bound on the voltage between the measurement point and earth, since the
impedance taken into account is that of the whole loop.
■ Large multi-function OLED display unit.
■ Display in Standard mode (only 1 screen) or Advanced mode (3 screens).
■ Clamping diameter 35 mm.
■ Storage of measurements ( and/or A, with time-stamping).
METRACLIP EARTH: up to 2000 measurements stored.
■ Possibility of reading out the stored measurements on the clamp itself.
METRACLIP EARTH: Read-out also possible via Bluetooth®
■ Measurement hold by the HOLD key and/or by opening the clamp (PRE-
HOLD mode).
■ Weight limited by the use of powerful magnetic materials.
■ Opening the clamp made easy by a trigger with a force compensation system.
■ Advanced ergonomics (grip and reading of the display unit).
■ Small influence of spurious currents.
10
2.2 FRONT PANEL
Measurement
head
1
HOLD key, to freeze
the display
4
Rotary switch used to
select a measurement
function, SET-UP, or
memory read
3
Guard
2
OLED display unit
5
Trigger
6
Display backlight key
7
MEM key, to store
measurements
8
► key, for validation and
browsing in the
measurement screens
9
Fig. 4
11
Rep.
Designation
See §
1
Measurement head.
-
2
Guard. The user's hand must be below this zone and not
touch the measurement head (item 1).
-
3
Function switch.
4.5
OFF: device off.
9
Ω+A: simultaneous selection of the Loop impedance
measurement and the Leakage current measurement.
5
A: selection of the Current measurement.
6
MR: (Memory Read) display of the data stored when MEM
(item 8) was pressed.
7
SET-UP: access to configuration of the parameters and to
erasure of the stored measurements.
8
4
HOLD key: freezes the measured and displayed values, at
any time, along with the various functional indications.
4.6
: When the function switch is set to MR or SET-UP,
pressing this key activates or deactivates the Bluetooth®
connection.
5
OLED display unit.
2.4
6
Measurement head opening trigger.
-
7
Dual-function key:
-
(when device is set to Ω+A or A): increases the
brightness of the OLED display unit; makes it easier
to read the display unit in an environment with strong
background illumination. Highlighting activated for 30
seconds.
-
▲ (when device is set to SET-UP or MR): serves as up
arrow when browsing in the menus and values. The
brightness of the display unit does not change when
device is set to SET-UP or MR.
-
8
Dual-function key.
-
MEM (when device is set to Ω+A or A): records the
measured value. All of the data are recorded, in the
Standard or Advanced mode.
4.8
▼ (when device is set to SET-UP or MR): serves as
down arrow when browsing in the menus and
values.
-
12
Rep.
Designation
See §
9
► Function that depends on the setting of the function
switch, as follows:
When the device is set to Ω+A (Advanced Mode)
Short press: switches the display through the
following 3 modes, in order:
5.2.5
■ Display of the impedance recalculated at the
selected frequency.
■ Display of the contact voltage (product Z*I).
■ Display of R and L.
Long press: activates or deactivates the audible
alarms.
2.5
when device is set to SET-UP
Validation when browsing in the menus and values.
-
when device is set to MR (Advanced Mode)
Switches the display through the measurement
screens and the measurement date/time.
2.3 DEVICE–REAR PANEL
Fig. 5
Rep.
Designation
See §
10
Battery compartment cover locking screws.
11.2
11
Battery compartment cover.
11.2
12
Batteries (4 AA – LR6, 1.5 V).
11.2
13
2.4 DISPLAY UNIT
Fig. 6
Rep.
Designation
See §
1
■ Display of the buzzer active state; the icon is masked when
the buzzer is inactive.
8.5
■ Selection of the buzzer operating mode via SET-UP menu 2.
8.5
2
Indicator of freezing of the measurement display when the HOLD
key is pressed or in the Pre-Hold mode
4.6
1.1
3
Indicates that the main display shows the date (with the function
switch set to MR or SET-UP).
7
4
Symbol reporting the presence of perturbations (current) in the
loop making it impossible to be sure of the impedance
measurement.
-
5
Upper display unit. 4,000-counts current measurement and 500-
counts loop inductance measurement (Advanced mode).
-
6
Signalling indicating incorrect closing of the clamp; the
measurement cannot be made in this case. If the Pre-hold mode
is activated, the Hold icon blinks and the measurement is frozen.
4.6
Selection of the Pre-Hold mode via SET-UP menu 11.
8.5
7
Permanent operation of the clamp (automatic switching off
disabled).
Selection of the automatic switching off mode in SET-UP menu 3.
8.5
8
Battery charge indicator with 3 states:
■ Not displayed: batteries charged.
■ Blinking: batteries low. The device remains functional, but the
batteries will have to be replaced soon.
■ Steady: batteries discharged. The display unit indicates Lo
bat. It is impossible to make measurements, read records, or
configure parameters.
11.2.1
9
Units of the top measurements display unit:
■ mH: loop inductance measurement unit.
■ mA or A: current measurement unit (mA or A).
-
14
10
Units of the central measurements display unit:
■ V: contact voltage measurement unit.
■ Ω: impedance measurement unit. Symbol used for
impedances at the measurement frequency, for impedances
referred to the network frequency, or for the resistive
component.
-
11
Unit of the alarm displayed. The alarm can be defined on an
impedance, a voltage, or a current, depending on the
measurement chosen (Ω+A or A).
■ A: current measurement alarm.
■ Ω: resistance measurement alarm.
■ V: voltage measurement alarm.
8.5
12
Alarm threshold display unit:
■ Display of one of the alarms (1000-counts display unit) with
the various units.
8.5
■ These 3 digits are also used when configuring the time display
mode (A. for A.M., P. for P.M. or 24H) in SET-UP menu 8.
13
Alarm threshold over(under-)shoot indicator (operational use or
parameterizing):
▲
Alarm threshold overshoot indicator.
AL
Alarm threshold adjustment mode or Alarm function.
▼
Alarm threshold undershoot indicator.
8.5
14
Signal indicating potentially hazardous voltage. Blinks when the
contact voltage exceeds 50V.
-
15
METRACLIP EARTH: Remains displayed while the Bluetooth
connection is being established. Blinks for the duration of the
communication.
-
16
Memory index display unit. 4-digit digital display (0 to 9999
counts):
■ Of the measurement sequence number, of the current memory
in normal operation associated with the Read (MR) or Storage
(MEM) indications.
■ Of the date stamp (year) when the device is parameterized.
-
17
Memory read mode.
7
18
Data storage mode.
4.8
19
In the Advanced mode, these symbols identify the value
displayed (resistance or impedance).
5.2
20
Main display unit:
■ Measurement of the impedance or voltage.
■ Display of the date and time (month-day and hour-minute) in
parameterizing and stored values read mode.
-
21
In Advanced mode, indication displayed when the inductive
component is negligible with respect to the resistive component.
5.2.5
22
Indicates selection of the Advanced mode.
5.2
Remark: when switched on, the device performs a rapid self-test of the entire
display unit. All available segments are displayed briefly. During this stage, a
sustained press on HOLD prolongs the display of all segments.
15
2.5 AUDIBLE SIGNALS
The device can generate audible signals of four types:
Type of
sound
Duration
Meaning
Low-pitched
Short
Normal use (key pressed).
Permanent
Over(under-)shoot of a measurement alarm
threshold
(Ω, A).
High-pitched
Short
Abnormal use (for example, memory full).
Permanent
Overshoot of a safety alarm threshold (V).
The audible signal can be activated or deactivated in SET-UP (see chapter 8,
menu 2). The
icon (Fig. 6, item 1) behaves as follows:
icon
Meaning
Visible
Buzzer activated; an alarm or a key press causes an audible
signal to be emitted.
Missing
No audible signal is emitted.
This programming is backed-up and retrieved at each reset. The audible alarm
can be de-activated in the SET-UP menu (see chapter 8, menu 2).
During a measurement, a long press on the ► key toggles between activation and
deactivation of the buzzer.
Since the measurement frequency is audible, the operator hears a
discontinuous audible signal (beep-beep). This is neither an operating fault nor
an alarm, and it cannot be eliminated. This audible signal is amplified by the
presence of current in the loop.
16
3. MEASUREMENT PRINCIPLE
The schematic diagram below illustrates the general case of measurement of the
resistance of a loop comprising:
■ The earth electrode Rx;
■ The earth;
■ Several earth electrodes of resistance Ri;
■ A guard wire looping all of these earths, introducing an inductive component.
The clamp combines two functions in the measurement head:
■ The generator winding of the clamp emits an alternating voltage having a
constant level E.
■ The receiver winding (current measurement) senses I=E/Z
loop
.
Knowing E imposed by the generator and I measured, the value Z
loop
can be
deduced and displayed on the device. The Advanced mode makes it possible to
distinguish the resistive and inductive parts and to refer the impedance to the
network frequency.
More generally, this principle can be used to search for a defective earth. This is
because the loop resistance comprises:
■ Rx (the value sought);
■ Z
earth
(a value that is normally very low, less than 1 Ω);
■ R1//R2...// Rn (a negligible value: case of multiple earths in parallel);
■ Z
guard wire
(a value that is normally very low, less than 1 Ω).
■ R
loop
=Rx+Z
earth
+(R//R...//R )+Z
guard wire;
As an approximation, Z
loop
can therefore be treated as equivalent to Rx.
If this value is very high, an inspection of this earth electrode is strongly
recommended.
Z
earth
Z
guard wire
Fig. 7
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