HT MULTITEST M72 User Manual page 37

MULTITEST M72 - M73 - M74 - M75
5. If during measurement the green probe is
connected to the phase conductor and
the black probe is connected to the
protective conductor, the instrument does
not perform the test and emits a
prolonged sound to signal the anomalous
situation. The screen beside is displayed
for 5 seconds after which the instrument
displays the default screen of Ra test
This can happen even if the wrong connection is performed on the back side of the
power socket
EN - 36