Operation Manual

20 GMC-I Messtechnik GmbH
Combined Testing – Differential Protective Conductor Resistance
Zero balancing is also possible for protective conductor measurement. With
zero balancing, all subsequent measurements are adjusted with an offset
such that 0  is displayed for a selected reference point which is con-
nected to the protective conductor. When test points are contacted with
the probe which are electrically connected to this reference point, differen-
tial resistance R
PE
between the reference point and the contacted test
point is displayed. The mains release key must be activated during
measurement in order to perform zero balancing. Press key
„Store
value“ in order to save the reference and/or correction value. The meas-
sage „Zero point corrected“ concerning the reference value is displayed
during all future measurements.
Attention: It is absolutely essential to delete the reference value after the
reference value has been stored and the test has been performed as it is
taken into account in all future tests. To delete the value, the procedure is
the same as for storage, press key
„Delete value“.
9.1 Maximum Allowable Limit Values for Protective Conductor Resistance
for Connector Cables with a Length of up to 5 m
1)
This value may not exceed 1  for permanently connected data processing
systems (DIN VDE 0701-702, DIN VDE 0701, part 240).
2)
Permanently connected cable
3)
Feature G00 = 10 A / G01 = 25 A
10 Insulation Measurement
10.1 Insulation Resistance R
INS
.
Definition
Safety Class I
Insulation resistance is
measured between short-
circuited mains terminals and
the protective conductor.
Safety Classes II and III
Insulation resistance is
measured between short-
circuited mains terminals and
external conductive parts
which can be contacted with
the probe.
Test Sta ndard Test Current
Open-Circuit
Voltage
R
PE
Housing –
Device Plug
R
PE
Housing –
Mains Plug
VDE 0701-
0702:2008
> 200 mA
4 V < U
L
< 24 V
0.3 
1)
+ 0.1 
2)
additional 7.5 m
IEC 62353
(VDE 0751-1)
EN 61010
10 A
~/25 A
3)
to test socket
only
0.2  0.3 
0.2  0.2 
EN 60335
EN 60950
EN 60601 0.1  0.2 
2)
Iso / HV

f
o
r
S
C
I
I