Accessories
4.8 Residual current devices
3VA molded case circuit breakers with IEC certificate
Manual, 03/2019, A5E03603177010-03
401
Operator controls
Insulation tests
It is absolutely essential to isolate the evaluation electronics circuit while insulation tests are
in progress in order to protect the circuit against potential damage on the one hand and to
prevent detection of insulation faults due to the power pack on the other. This is done simply
by withdrawing (15 to 17 mm) the circuit breaker which is anchored in the enclosure.
Disconnection of the main conductor connections is thus unnecessary. On completion of the
tests, the circuit breaker must be pushed back into position before the residual current
device is commissioned.
Testing and resetting the residual current device
Testing
Depending on operating conditions, the test button on the front panel of the residual current
device should be pressed in order to function-test the device. The test button is labeled with
the letter "T". If the test button is pressed, the device is tested immediately irrespective of the
current delay time setting.
If the test button is pressed, a residual current is simulated on a test winding attached to the
summation current transformer. If the residual current device is functioning properly, it must
trip the molded case circuit breaker/switch disconnector.
The test button must be held down for at least two seconds. The design of the test button
prevents unintentional actuation.
Note
The residual current device can be successfully tested only if it is connected to a voltage
equal to at least 85% of the minimum rated operational voltage.
