6
GMC-I Messtechnik GmbH
Minimum Permissible Limit Values for Insulation Resistance
Relative to Insulation Test Voltage per EN 62446
Note
If the limit value is fallen short of,
< 1 M
or < 0.5 M
appears for R
ISO
.
Example
9.5
General Insulation Resistance Measurement
The
PROFITEST PV
SUN
test instrument is additionally equipped with
system-independent insulation testing. This is helpful, for exam-
ple, when testing systems or supply lines when no modules have
yet been installed. All insulations tests known to date can be per-
formed.
Warning!
The test object must be potential-free. Assure absence
of voltage with the help of a suitable measuring instru-
ment, for example the METRAVOLT 12D+L voltage tester.
Note
General insulation measurement is executed between
short circuited (–) and (
) terminals.
➭
Connect the (–) and (
) terminals at the
PROFITEST PV
SUN
to the
device under test.
➭
Switch the
PROFITEST PV
SUN
test instrument on.
Selecting the Test Voltage
➭
Press and hold the
RISO/250V/500V/1000V
key for at least 2
seconds.
The currently selected test voltage appears at the display.
➭
Select the required insulation test voltage by briefly and re-
peatedly pressing the
R
ISO
/250V/500V/1000V
key.
The last selected value is saved after a short period of time, and is
then cleared from the display.
Example
Executing the Insulation Resistance Measurement
➭
Press the
R
ISO
/250V/500V/1000V
key and read the measured
value from the display.
Example
Note
If the minimum permissible limit value is fallen short of,
< 1 M
or < 0.5 M
appears for R
ISO
.
9.6
Ground Fault Test
If the test instrument recognizes an inadmissible, low insulation
value during
I
SC
/
R
ISO
measurement, the instrument tests for pos-
sible ground fault.
If a ground fault occurs within the system, the error can be nar-
rowed down on the basis of the voltage ratio.
Warning!
Disconnect all solar modules from the system before
performing the measurement.
➭
Connect the
PROFITEST PV
SUN
to the module with the help of
suitable solar plugs.
➭
Connect the ground terminal at the
PROFITEST PV
SUN
to the
module frame.
➭
Switch the
PROFITEST PV
SUN
test instrument on.
Momentary open circuit voltage is displayed.
At the same time, a second voltage (
Ue
) appears in the event of a
ground fault.
Example
System Voltage (U0
x 1.25)
Test Voltage
Limit Value
< 120 V
250 V
0.5 M
120 to 500 V
500 V
1 M
> 500 V
1000 V
1 M
U
0
: 0 V
I
SC
: 0.0 A
R
ISO
: < 1 M
U
0
: 0 V
I
SC
: 0.0 A
R
ISO
: ---
Uiso = 1000 V
U
0
: 0 V
I
SC
: 0.0 A
R
ISO
: > 20 M
U
0
: 144 V
I
SC
: 0.0 A
Ue: 48 V
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