Figure 15: Resistance reading between ‘X’ and ‘Y’ terminals
Three-terminal resistance measurement (DET3TA)
Figure 16: Connections for measuring three-terminal ground rod
resistance
1. With the selector switch in the ‘OFF’ position, connect the instrument
as shown in Figure 16.
2. Set the selector switch to the 3 point resistance measurement setting
marked ‘3P’.
3. The ground noise voltage is indicated on the analogue display.
4. If the ground noise voltage is within acceptable limits, push and hold
17
1. With the selector switch set to the ‘OFF’ position, connect the
instrument as shown in Figure 13.
2. Set the selector switch to the ground noise voltage setting marked ‘V’.
3. A voltage reading will be indicated on the analogue display, as shown in
Figure 14.
Figure 14: Analogue display indicating ground noise voltage measurement
Two-terminal resistance measurement (DET3TA)
1. With the selector switch in the ‘OFF’ position, connect the instrument
as shown in Figure 13, but connected to the part of the installation you
are testing.
2. Set the selector switch to the 2 point resistance measurement setting
marked ‘2P’.
3. The ground noise voltage is indicated on the analogue display
4. If the ground noise voltage is within acceptable limits, press and hold
down the TEST button.
5. The instrument will then check for ground noise voltage, the
parameters of the current and voltage circuits and the integrity of the
fuse during which time the Rc LED will flash.
6. A resistance reading will be indicated on the analogue display, as shown
in Figure 15.
7. Release TEST button.
Potential
spike
Current
spike
Earth system
under test
