Earth/Ground Measurements With Two Clamps - AEMC 6471 User Manual

5.7 Earth/Ground Measurements with Two Clamps

This is a quick way to measure the value of the earth.
The current clamp connected to terminal H (Z) applies a voltage to the circuit to be
measured. The value of the resulting current is determined by the impedance of
the circuit to be measured. The current flowing in the loop is measured using the
clamp connected to terminal ES (Xv). The device then calculates loop resistance
R
LOOP
Set the switch to
1.
2. Connect a clamp to terminal H (Z) and clamp it to a point down stream from
the rod under test that is a serial path to the earth.
3. Connect the other clamp to terminal ES (Xv) and clamp it to the rod or elec-
trode system to be measured.
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H
S
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S
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ES
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E
NOTE: The two clamp method typically yields a measurement higher than the
fall of potential method since it uses a higher frequency to perform the test,
resulting in an impedance measurement.
from these quantities.
NOTE: Use only SR182 or MN82 current clamps, which are specially designed
to operate with the Model 6471.
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R
R
R
E1
E2
E3
Ground Resistance Tester Model 6471
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H
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ES
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