30 GMC-I Messtechnik GmbH
Test Sequence
Prerequisite for Testing
The measurement of insulation resistance may not be
conducted on protection class I devices which have not
passed the protective conductor resistance test.
The insulation test cannot be performed for all DUTs, for
example electronic devices, EDP equipment etc. Leak-
age current measurements must be performed for these
DUTs (see Section 8.7).
Observe the notes in the service instructions.
Touching the DUT During Measurement
Testing is conducted with up to 500 V, and although cur-
rent is limited (I < 3.5 mA), if the DUT is touched electrical
shock may occur which could result in consequential ac-
cidents.
Switch Settings at the DUT
All switches at the DUT must be set to the on position
during measurement of insulation resistance, including
temperature controlled switches and temperature regula-
tors as well.
Measurement must be performed in all program steps
for devices equipped with program controllers.
➭ Set the rotary switch to the R
ISO
position.
➭ Select the measurement type and the test voltage.
➭ The Up– and Up+ keys provide you with direct access to the
test voltage parameters: each time this key is pressed, the
setpoint value shown in the measuring window, Up(set), is re-
duced or increased by 10 V.
➭ Connect the DUT to the test socket.
➭ Start the test: press the START/STOP key.
The measurement is disabled if a voltage of greater than
25 V is measured between the terminals.
➭ The measured values are displayed. The measured
value recording symbol shown at the right appears.
Each time this key is pressed, the currently displayed
measured value is saved to the buffer.
Removing the Connector Cable
Do not remove the DUT’s connector cable until the test
has been stopped, in order to assure that the capacitors
have been discharged.
➭ Stop the test: press the START/STOP key.
The save symbol appears (floppy disk showing the
number of measured values stored to buffer memory)
and prompts you to save the measured values to an ID
number.
➭ Read the measured values and compare them with the
table of permissible limit values.
➭ Press the ESC key in order to discard the measured
values stored to buffer memory and acknowledge by
pressing the key shown at the right.
Minimum Allowable Limit Values for Insulation Resistance
* With switched on heating elements
(if heating power > 3 kW and R
ISO
< 0.3 MΩ: leakage current measure-
ment is required)
Notes
Insulation resistance and/or leakage current must be measured
by contacting all exposed, conductive parts with test probe P1 for
protection class II and III devices, as well as for battery powered
devices.
Batteries must be disconnected during testing of battery powered
devices.
8.7 Measuring Leakage Current
Measurement with DUT Connected to Line Voltage
It’s absolutely essential to assure that the device under
test is operated with line voltage during performance of
leakage current measurements with the direct or differential
current method. Exposed conductive parts may conduct
dangerous touch voltage during testing, and may not
under any circumstances be touched. (Mains power is
disconnected if leakage current exceeds approx.
10 mA.)
Frequency response in
accordance with the
figure to the right is
taken into consider-
ation for all leakage
current measure-
ments (IPE, IB, IG, IP)
(direct, differential,
alternative).
Test
Standard
Test Volta ge
R
ISO
LN → PE
LN →
Probe
Probe →
PE
PC III Heating
VDE 0701-
0702:2008
500 V
1MΩ 2MΩ 5MΩ 0.25 MΩ 0.3 MΩ *
DIN EN 60974-4
VDE 0544-
4:2009-06
2MΩ 5MΩ 5MΩ
Test Standard
Test
Voltage
R
ISO
PC I PC II
IEC 62353
(VDE 0751-1)
500 V
2MΩ 7MΩ
BF or CF BF or CF
70 MΩ 70 MΩ
10 10
2
10
3
10
4
10
5
10
6
+20
0
–20
–40
–60
Frequency (f) in Hz
Relative Magnitude (dB):
U(f)
U(f=10)
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