MI 3103 GigaOhm Measurements
10
4. Measurements
4.1 Insulation resistance
Warnings!
Make sure that the item to be tested is disconnected (mains voltage
disconnected) before starting the insulation resistance measurement!
When measuring insulation resistance between conductors, all loads must
be disconnected and all switches closed!
Do not touch tested item while the test is in operation, risk of electric shock!
In case of capacitive test item (capacitive compensation of reactive power,
long tested cable, etc.) automatic discharge of the item may not be done
immediately after finishing the measurement. Falling voltage will be
displayed in that case – do not disconnect test leads until the voltage drops
below 30 V! Measurement is finished when voltage drops below 8V.
The following figure shows connection of the instrument to the tested item for testing
insulation resistance on one and three phase electrical installations. The measurement
should be carried out between all conductors.
L1
L2
L3
N
PE
RCD
PE N
L3 L2 L1
TEST
GigaOhm 1kV
MI 3 10 3
CAL
disconnected
switches
Fig. 5. Example of instrument connection for measuring insulation resistance between
L and N terminal
There may be also other items to test such as motor windings, ground cables, antistatic
floor coatings, walls, etc., see the booklet
Measurements on electric installations in
theory and practice.