User Manual
48 GMC-I Messtechnik GmbH
13 Maintenance
13.1 Housing Maintenance
No special maintenance is required for the housing. Keep outside 
surfaces clean. Use a slightly dampened cloth for cleaning. Avoid 
the use of cleansers, abrasives or solvents.
13.2 Testing the Color Display and the Buzzer 
(self-test parameter)
The color display can be tested for failure of individual segments 
and loss of color components on page 3/3 of the setup menu in 
the SETUP switch position under the self-test parameter.
Beyond this, the buzzer can be tested for 3 different frequencies.
13.3 Software Update (system info parameter)
The current firmware or software version can be queried via the 
system info parameter (setup 3/3).
The test instrument’s firmware can be updated via the USB port 
with the help of a PC. Updating is only possible via the “
Firmware 
Update Tool
” application, which is integrated into thefirmware. Cali-
bration data are not overwritten during updating.
The most up-to-date version of the software (firmware) can be 
downloaded from the mygmc page of our website as a ZIP file, if 
you have registered your test instrument:
http://www.gossenmetrawatt.com 
 Products  Software  Software for Testers 
 Utilities 
Firmware Update Tool 
 myGMC
Under this Iink you can also find an instruction manual for the 
Firm-
ware Update Tool
.
Attention!
!
The interface cable may not be disconnected while up-
dating the firmware via the USB port. 
Attention!
!
The test instrument may not be disconnected from sup-
ply power while updating the firmware via the USB port.
13.4 Backup Battery for Real-Time Clock
The backup battery (lithium cell) should be replaced no later than 
after 8 years. Replacement can only be executed by the service 
department.
If backup battery voltage is too low, the date and time assigned to 
the test data no longer correspond to the actual time of recording. 
This may also influence sorting in ETC report generating software.
The instrument’s database itself is not affected by a depleted 
backup battery.
13.5 Fuse Replacement
The fuses may only be replaced when the instrument is voltage-
free, i.e. the instrument must be disconnected from mains supply 
power and may not be connected to a measuring circuit.
The fuse type must comply with the specifications in the technical 
data or the labeling on the instrument.
13.6 Recalibration
The measuring tasks performed with your instrument, and the 
stressing it’s subjected to, influence aging of its components and 
may result in deviation from the specified levels of accuracy.
In the case of strict measuring accuracy requirements, as well as 
in the event of use at construction sites with frequent stress due 
to transport and considerable temperature fluctuation, we recom-
mend a relatively short calibration interval of once per year. If your 
instrument is used primarily in the laboratory and indoors without 
considerable climatic or mechanical stressing, a calibration inter-
val of once every 2 to 3 years is sufficient as a rule.
During recalibration* at an accredited calibration laboratory 
(DIN EN ISO/IEC 17025), deviations from traceable standards 
demonstrated by your measuring instrument are documented. 
Ascertained deviations are used to correct display values during 
later use of the instrument.
We would be happy to perform DAkkS or factory calibration for 
you at our calibration laboratory. Further information is available at 
our website:
www.gossenmetrawatt.com ( Company  DAkkS Calibration 
Center or  FAQs  Questions and Answers Regarding Calibra-
tion).
According to DIN VDE 0701-0702, only test instruments which 
are tested and calibrated at regular intervals may be used for test-
ing.
Recalibration of your instrument at regular intervals is essential for 
the fulfillment of requirements according to quality management 
systems per DIN EN ISO 9001.
* Examination of the specification, as well as adjustment, are not included in calibra-
tion. However, in the case of our own products, any required adjustment is per-
formed and adherence to the specification is confirmed.
13.7 Technical Safety Inspections
Subject your test instrument to technical safety inspections at 
regular intervals. We recommend the same interval for inspections 
as is also used for recalibration.
The SECUTEST... is designed as a totally insulated device in 
accordance with IEC 61010 and VDE 0404. The protective con-
ductor is used for measuring purposes only, and is thus not 
accessible in the idle state. The protective conductor at the test 
socket can be tested as follows:
➭ Connect the SECUTEST... to a multiple distributor.
➭ Conduct a touch current measurement for permanently con-
nected DUTs (nothing may be connected to the test socket).
➭ Measure protective conductor resistance between the neigh-
boring socket at the multiple distributor and the test socket.
➭ The measured value may not exceed 0.3 .
For technical reasons, insulation resistance between LN and PE 
inside the SECUTEST... is roughly 1 M. 
This must be taken into consideration during technical safety 
inspections or, instead of the insulation resistance measurement, 
the protective conductor current measurement must result in a 
value of less than 3.5 mA (or less than 7 mA if the equivalent leak-
age current method is used).
There are also 4 accessible conductive parts on the SECUT-
EST..., at which the touch current measurement must result in a 
value of less than 0.5 mA:
• Connector for service plug (jack socket)
•USB ports
• Metallized start key
• Protective conductor bar in the test socket










