Fluke Fluke 4325181 User Manual
Product codes
4325181
1625-2
Users Manual
26
Measurements on High Voltage Pylons
Measuring the Earthing Resistance without Disengaging the Overhead Earth Wire Using the
Selective Clamp Method
Selective Clamp Method
The measurement of the earth resistance of a single high voltage pylon usually requires
the overhead earth wire to be disengaged (lifted off) or the separation of the earthing
system from the pylon construction. Otherwise, false reading of the resistance of the
pylon earth electrode are liable to occur because of the parallel circuit of the other pylons
connected to each other by an overhead earth wire.
the overhead earth wire to be disengaged (lifted off) or the separation of the earthing
system from the pylon construction. Otherwise, false reading of the resistance of the
pylon earth electrode are liable to occur because of the parallel circuit of the other pylons
connected to each other by an overhead earth wire.
The new measuring method employed in this instrument - with its external current
transformer to measure the true current flowing through the earth electrode - allows
measurements of earth electrode resistances without disconnection of the earthing
system or disengaging the overhead earth wire. See Figure 7.
transformer to measure the true current flowing through the earth electrode - allows
measurements of earth electrode resistances without disconnection of the earthing
system or disengaging the overhead earth wire. See Figure 7.
1
2
3
4
START
>20 m
>20 m
H/C2
S/P2
4 Probe
edw016.eps
Figure 7. Earthing Resistance without Disengaging the Overhead Earth Wire