Fluke 1625 User Manual

1625
Users Manual
46
1. Four earth spikes of the same length are positioned into the soil in an
even line and with the same distance "a" to each other. The earth
spikes should not be hammered in deeper than a maximum of 1/3 of
"a".
2. Turn central rotary switch to position "R
E
4pole".
The instrument is to be wired according to picture and notices given
on the display.
A flashing of the sockets symbols EFGH or B, points to an
incorrect or incomplete connection of the measuring lead.
3. Push "START TEST" button.
4. Read out measured value R
E
.
From the indicated resistance value R
E
, the soil resistivity calculates according
to the equation:
EE
Ra..2
π
ρ
=
ρ
E
...... mean value of soil resistivity (Ωm)
R
E
...... measured resistance (Ω)
a ...... probe distance (m)
The measuring method according to Wenner determines the soil resistivity
down to a depth of approx. the distance "a" between two earth spikes. By in-
creasing "a", deeper strata can be measured and checked for homogenity. By
changing "a" several times, a profile can be measured from which a suitable
earth electrode can be determined.
According to the depth to be measured, "a" is selected between 2 m and 30 m.
This procedure results in curves depicted in the graph below.

Fluke 1625 Specifications

General

Storage Temperature	-20 °C to 60 °C
Testing Methods	3-pole fall-of-potential, 4-pole
Measurement Frequency	128 Hz
Power Supply	6 x 1.5 V AA batteries or optional AC adapter
Safety Rating	CAT II 300 V
Safety Standards	IEC 61010-1