Gossen MetraWatt GEOHM C Manual


GEOHM C
Ground Resistance Tester
Battery operated tester for the measurement of ground resistance meets
international standards for performing such tests. This instrument allows
measurement of soil resistivity and ohmic resistance by means of the
ammeter-voltmeter test method.
Features
• 3 or 4-wire measurement selectable from menu
• No balancing required
• Continuous monitoring of interference voltage and
auxiliary earth electrode resistance with indication
of limit value violations
• Indication is displayed if maximum probe resistance is
exceeded at the beginning of the measurement
• Voltage measurement with automatic switch-over function
between direct voltage and alternating voltage:
Direct voltage measuring range 1.0  250 V
(with polarity display)
Alternating voltage measuring range 0  300 V

Applications


The GEOHM C is a compact instrument for the measurement of
ground resistance in electrical systems in accordance with:
DIN VDE 0100 Installation of power systems with
nominal voltages of up to 1000 V
DIN VDE 0141 Grounding in AC systems with nominal
voltages of greater than 1 kV
DIN VDE 0800 Installation and operation of telecom-
munications systems including data
processing systems: equipotential
bonding and grounding
Testing of lightning protection systems in accordance with
DIN VDE 0185
The instrument is also capable of determining soil resistivity which
is essential in calculating dimensions for grounding systems.
It can thus be taken advantage of for simple, geological surveys,
and for the planning of grounding systems.
Beyond this, ohmic resistance can be measured at both solid and
liquid conductors, as well as internal resistance at conductive
elements, as long as these are capacitance and induction-free.

Special Functions

• Hold function: The measurement value is frozen at the display
after the measurement key is released.
• Storage of measurement values to memory
• Data Interface for the transmission of measurement values
and for software updates
• Convenient report generating software,
can be expanded into a comprehensive database
GMC-I Messtechnik GmbH

Display

The LCD consists of a backlit dot matrix
display at which menus, setup options, measuring results and
online help can be viewed. Various display languages can be
selected depending upon the country in which the instrument is
used.

Signal Lamps

The instrument automatically recognizes errors which occur
during measurement, and signals them with four LEDs as shown
in the table below.
LED Status Measuring Function
U
Stör/
red Interference voltage
U
noise
Netz
red Voltage
Mains
R >max red Probe resistance
S
R >max Auxiliary earth electrode
H
red
resistance

Operation

The instrument is easy to operate. A multifunction key allows for
one-hand operation for menu selections and the initialization of
measurements. Basic functions and sub-functions are selected
with the help of four softkeys.
The instrument functions in accordance with the ammeter-
voltmeter principle, and thus requires no balancing. Automatic
measuring range selection, limit value monitoring and direct
selection of 3 or 4-wire measurement assure easy
operation as well.
3-349-088-03
11/9.09
QUALITY MANAGEMENT SYSTEM
DQS certified per
DIN EN ISO 9001:2000
Reg.No.1262
Meaning
U > 10 V
Mains voltage is present
Limit value exceeded
Limit value exceeded