13
R
——
meter readings, total grounding resistance of the entire grounding
system;
R1...rn - are all independent grounding points, and grounding bodies are not
connected together under the ground;
RH
—
ground resistance of auxiliary current pole H;
RS - ground resistance of auxiliary voltage pole S;
n - the number of independent grounding points, the more points, the smaller
the R value.
6.Three-wire Test Grounding Resistance
Three-wire test: As shown in the figure below, short-circuit the FR
and E interfaces of the instrument, that is, the three-wire test, and the
instrument operation is the same as the four-wire test. The three-wire test
can not eliminate the influence of the wire resistance on the measurement,
nor can it eliminate the influence of the change of the contact resistance
between the instrument and the test wire and between the test wire and
the auxiliary grounding rod, and the oxide layer on the surface of the
ground body to be measured needs to be removed.
7
．
Two-wire easy Test Grounding Resistance
