HT instruments SIRIUS87 - Manual (Page 55)

SIRIUS 87
EN - 53
4.6.1.1. Earth resistance measurement from a socket
On TT installations it’s possible to take an earth measurement with a simplified method,
which 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.
This test gives a value which many 3-wires comparison tests proved to be revealing for
earth resistance.
Fig. 20: Earth measurement with simplified method on panel board
CAUTION
If you want to take the measurement using the neutral and the earth of a
normal socket, you may happen to connect to the phase. In this case the
display will show the voltage, the symbol
(wrong inserting) and won’t take
any measurement even if
START/STOP is pressed.
CAUTION
The display of
“Measuring” means that the instrument is measuring. During
this phase never disconnect test leads.