Application Note

H/C2
OFF
3
POLE
4
POLE
4
POLE
2
POLE
S/P2
ES/P1
E/C1
START
TEST
DISPLAY
MENU
CHANGE
ITEM
SELECT
1625-2
ADVANCED EARTH / GROUND TESTER GEO
E S H
AC
Rresistance
300kΩEarth/Ground Resistance 300kΩ
DC
Resistance 3kΩ
RA
R
—
R
~
2
POLE
3
POLE
3
POLE
4
POLE
EI-162X
SENSING CURRENT
TRANSFORMER
EI-162AC
INDUCING CURRENT
TRANSFORMER
>10 cm (4 in)
What are the methods of earth ground testing?
Stakeless measurement
The Fluke 1625-2 earth ground tester is able to
measure earth ground loop resistances for multi-
grounded systems using only current clamps.
This test technique eliminates the dangerous
and time consuming activity of disconnecting
parallel grounds, as well as the process of
finding suitable locations for auxiliary ground
stakes. You can also perform earth ground tests
in places you have not considered before: inside
buildings, on power pylons or anywhere you
don’t have access to soil.
With this test method, two clamps are placed
around the earth ground rod or the connecting
cable and each are connected to the tester.
Earth ground stakes are not used at all. A known
voltage is induced by one clamp, and the current
is measured using the second clamp. The tester
automatically determines the ground loop resis-
tance at this ground rod. If there is only one path
to ground, like at many residential situations, the
Stakeless method will not provide an acceptable
value and the Fall-of-Potential test method must
be used.
The Fluke 1625-2 works on the principle that
in parallel/multi-grounded systems, the net
resistance of all ground paths will be extremely
low as compared to any single path (the one
under test). So, the net resistance of all the
parallel return path resistances is effectively
zero. Stakeless measurement only measures
individual ground rod resistances in parallel to
earth grounding systems. If the ground system
is not parallel to earth then you will either have
an open circuit, or be measuring ground loop
resistance.
H/C2
OFF
3
POLE
4
POLE
4
POLE
2
POLE
S/P2
ES/P1
E/C1
START
TEST
DISPLAY
MENU
CHANGE
ITEM
SELEC
T
1625-2
ADVANCED EARTH / GROUND TESTER GEO
E S H
AC
Rresistance
300kΩ
Earth/Ground Resistance 300kΩ
DC
Resistance 3kΩ
RA
R
—
R
~
2
POLE
3
POLE
3
POLE
4
POLE
Source
Measure
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON
EI-1
62
X
S
ENS
I
N
G
CURRE
N
T
T
RA
N
S
F
O
RMER
E
I-1
62
AC
IN
DUCING CU
RRE
N
T
TRA
NS
FO
RM
E
R
Setup for the stakeless method
using the 1625-2.
Test current paths in the stakeless method.
10