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Second, have R
B
and R
C
linked up, as shown in the following figure.
Use the Meter to get the second reading R
2
.
Third, have R
C
and R
A
linked up, as shown in the following figure.
Use the Meter to get the third reading R
3
.
In the above three steps, the reading measured in each step is the
value of the two series grounding resistance. In this way, we can
easily calculate the value of each grounding resistance:
From: R1=RA+RB R2=RB+RC R3=RC+RA
We get: RA=
（
R1+R3-R2
）
÷2
This is the grounding resistance value of the grounding body R
A
.
To facilitate the memory of the above formula, these three groun-
ding bodies scan be viewed as a triangle; then the measured re-
sistance is equivalent to the value of the resistance values of the
adjacent edges plus or minus resistance value of the opposite
sides, and divided by 2.
As the reference points, the grounding resistance values of the
