●
The clamping point (A) is used for the earth resistance measurement of the
metal case of high voltage appliance.
Connect the earth (A) to the known good earth by the subsidiary lead wire to
create the loop circuit.
●
The clamping point (B) is used for the PEN earth resistance measurement.
In this case, simply clamp the measuring point by the injection CT and the
measuring CT.
●
The clamping point (C) is used for the earth resistance measurement of the
lighting rod.
Connect a temporary link to the iron/steel frame of the building by the
subsidiary lead wire to create a loop circuit as the drawing.
Equivalent circuit
Earth resistance
Earth resistance of the iron frame
of the lighting rod
of the building
R
2
R = R
1
+ R
2
R
1
＞
R
2
R
≒
R
1
The instrument measures the whole loop resistance. If the earth resistance
(R
2
) is much lower than (R
1
), then the correct measurement is enabled.
●
The clamping point (D) is used for the earth resistance measurement of the
accessible parts of low voltage appliance. In this case, simply clamp the
measuring point by the injection CT and the measuring CT.
●
The clamping point (E) is used
to check the poor connection
of bonding conductor for the
equipotential bonding system.
For poor connection, the higher
resistance value will be dis-
played.
- 17 -
R
1
