Amprobe MultiTest 1000 Manual Del Usuario página 35

4.4.1.1. Earth resistance measurement from a socket
On TT installations it's possible to take an earth measurement with a simplified method
that gives an excess value (therefore safer), using the NEUTRAL of the national Energy
Board taken directly from a socket as an auxiliary rod; if also the earth connection is
available, naturally the measurement can be taken on the socket directly, between
NEUTRAL and EARTH.
Although this test is not provided for by CEI 64.8 at present, it gives a value which many 3-
wires comparison tests proved to be revealing for earth resistance.
If you want to take the measurement using the neutral and the earth of a
standard wall socket, you may accidentally connect to the hot leg. In this
case the display will show the voltage, the symbol
won't take any measurement even if START/STOP is pressed.
Never disconnect the test leads while the word "Measuring" is being
displayed.
Earth measurement with simplified method on panel board
WARNING
WARNING
B1 B4
B2 B3
(wrong insertion) and