User manual

16 GMC-I Messtechnik GmbH
5.4 Measuring Insulation Resistance
This measurement may only be performed if the device under test has successfully completed protec-
tive conductor resistance testing. If the DUT is equipped with all-pole electrical switches, e.g.
undervoltage releases or relays, this test only covers the supply conductor. The device can-
not be switched on without being connected to the mains, consequently, it cannot be sub-
jected to an effective insulation test. For testing in conformance with VDE, it is necessary to
measure the leakage current under mains voltage.
Attention!
!
Do not touch the instrument’s terminal contacts during insulation resistance measurements!
If nothing has been connected to the terminal contacts, or if a resistive load component has
been connected for measurement, your body would be exposed to a current of approx. 1 mA
at a voltage of 500 V. The resulting electrical shock is not life endangering. However, the
noticeable shock may lead to injury (e.g. resulting from a startled reaction etc.).
Attention!
!
If measurement is performed at a capacitive object such as a long cable, it becomes
charged with up to approx. 500 V! Touching such objects is life endangering!
➭ Connect the DUT as shown in the following picture
Safety Class I
Safety Class II
➭ Set the measuring function selector switch to the “R
ISO
20 MΩ” range.
➭ Activate all functions of the DUT, and be certain, for example, that contacts for tempera-
ture sensitive switches and the like are also closed.
➭ Read the measured value in “MΩ” from the LCD (11).
Insulation resistance may not fall short of the following values:
R
iso
To test socket
R
iso
To test socket
To ex pose d meta l
parts
KS17-4