30
GMC-I Messtechnik GmbH
10.3
Measuring Earth Electrode Potential (function U
E
)
Earth Resistance Measurement with Probe (Mains Powered) – Connection Circuit Diagram
This measurement is only possible with a probe, see section 10.1.
Earth electrode potential U
E
is the voltage which occurs at the
earth electrode between the earth electrode terminal and refer-
ence earth if a short-circuit occurs between the phase conductor
and the earth electrode. The measurement of earth electrode
potential is required by Swiss standard SEV 3755.
Measuring Method
In order to determine earth electrode potential the instrument first
measures earth electrode loop resistance R
ELoop
, and
immediately thereafter earthing resistance R
E
. -The instrument
stores both values and then calculates earth electrode potential
with the following equation:
The calculated value is displayed at the display panel.
Select the Measuring Function
Connection
Connected components:
2-pole adapter and probe
Set parameters
q
Measuring range:
10
/ U
E
q
Connection type:
2-pole a probe
q
Contact voltage:
UL < 25 V, < 50 V, < 65 V, freely adjustable
voltage, see section 5.7
q
Transformer ratio:
without significance in this case
Start Measurement
Note
The following diagram appears if the
2-pole adapter is connected
incorrectly.
PRO
FITE
ST
Ri
wa
ter
pip
e
S
E
2
E
1
B
UE
UN RE
RELoop
--------------------
=
R
E
Limit value
:
R
E
< limit value
U
L
R
L
