GMC-I Gossen-Metrawatt GmbH
9
Discharging the Device Under Test
The device under test is automatically
discharged when the insulation test is
switched off (turn switch to R
PE
or I
D
).
The LEDs light up rapidly, one after the other
from left to right, during discharging.
Furthermore, residual voltage appears at the
display (not for
MINI
TEST
⏐
B
ASE
).
Leave the DUT connected to the test
instrument during the discharging sequence.
5.2
Measurements at the Mains Outlet(s)
Differential current and/or contact current
measurements are performed at the mains
outlet(s). The DUT must be unplugged, and
plugged back in again.
In the case of mains
plugs which are not polarity protected, testing
must be conducted with the mains plug poled in
both directions.
Attention
!
!
The mains outlet(s) always con-
duct(s) voltage as soon as the test in-
strument has been switched on.
Note!
Make sure that the device under test
is switched off before plugging it into
the mains outlet.
The device under test must be switched on during
testing.
The device under test must be switched
back off before it is unplugged from the
mains outlet.
Differential Current Measurement, I
D
Total current from all phase conductors is
measured during differential current mea-
surement. For safety class I devices, this
corresponds to the amount of current which
is conducted by the protective conductor.
Differential current is displayed in mA at the
LCD (not for
MINI
TEST
⏐
B
ASE
).
Evaluating the Measured Values
Measured values of less than 0.5 mA are
indicated by means of a green LED.
Measured values of greater than 3.5 mA are
indicated by means of a red LED. These
devices may be dangerous,
however, for
example for 3-phase current devices, there may
be higher admissible limit values of e.g. 1 mA per
kW up to 10 mA, depending on the manufac-
turer’s specifications. These cases are all indi-
cated with the red LED.
Evaluation must be
conducted by a qualified electrician in this
case.
Measured values of between 0.5 and 3.5 mA
are indicated by means of a yellow LED. An
evaluation of electrical safety should be con-
ducted by a qualified electrician in this case.
Contact Current Measurement, I
C
When measuring contact current, current is
measured which is conducted via the probe
at the
PROBE PE/I
C
socket to the protective
conductor terminal at the device under test.
Evaluating the Measured Values
Measured values of less than 0.25 mA are
indicated by means of a green LED. There is
no danger in touching these parts.
Measured values of greater than 0.5 mA are
indicated by means of a red LED. Devices
which demonstrate these values are
dangerous because persons who touch
them are startled, which may result in
consequential accidents.
These devices may not be placed back into
service.
Measured values of between 0.25 and
0.5 mA are indicated by means of a yellow
LED. Current within this range is not
dangerous, but the threshold of perception
is approximately 0.1 mA depending upon
sensitivity, which causes mild tingling. This is
unpleasant for some people, for which
reason devices of this sort should be
examined.
Self-Test
A device self-test is conducted when the
selector switch is turned to the LED Test
position.
Testing is indicated by the LEDs which light
up one after the other from left to right.
