AEMC 4500 - Soil Resistivity Measurement Procedure (4-Point)

Digital Ground Resistance Tester Model 4500 33
Where:A=distancebetweentheelectrodesincentimeters
B=electrodedepthincentimeters
If A > 20 B, the formula becomes:
ρ=2πAR(withAincm)
ρ=191.5AR(withAinfeet)
ρ=Soilresistivity(ohm-cm)
This value is the average resistivity of the ground at a depth equivalent to
the distance “A” between two electrodes.
Z
Y
X
X
v
BATTERY
CHARGE
BLINKING DISPLAY
AND
POINTER INDICATE
EXCESSIVE
- TRANSIENT NOISE
- ELECTRODE
RESISTANCE
EXTERNAL BATTERY
12 V
TEST RANGETEST CURRENT
mA
2
10
50
Ω
κΩ
2
20
200
2
20
50/60/400 Hz_110V
b<
1a
20
aaa
Z electrodeY electrodeXv electrode
X electrode
DIGITAL GROUND
RESISTANCE
TESTER
MODEL 4500
Figure 18
4.9 Soil Resistivity Measurement Procedure (4-Point)
Given a sizeable tract of land in which to determine the optimum soil resis-
tivity,someintuitionisinorder.Assumingthattheobjectiveislowresis-
tivity, preference should be given to an area containing moist loam as
opposed to a dry sandy area. Consideration must also be given to the
depth at which resistivity is required.