TENTECH EM4058 Manual De Uso página 18

Press the key. The EM-4058 will automatically apply Wenner's
equation (below) based on collected data.
4 Ra
=
a
-
1 +
2 2 2 2
a + 4 p a + p
Legend:
= soil resistivity value; will be shown on the display
a= distance (in meters) between rods; specified by the operator
p= insertion depth (in meters) of the rods – the EM-4058 uses 0,25 m
R= resistance value used by the equipment to calculate ρ
The display will then show the soil resistivity value, as in the example
below:
To properly evaluate soil resistivity, measurements must cover the whole
area to be influenced by the grounding system. For an area of up to
10,000 m², it is recommended to perform measurements in at least five
points, arranged as shown in the next image. Two sets of measurements
should be needed for the central point.
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