Instructions

GMC-I Messtechnik GmbH 35
10.5 Earthing Resistance Measurement, Mains Powered – Measurement of Earth Electrode Voltage (U
E
function)
This measurement is only possible with a probe (see section
10.4). Earth electrode potential U
E
is the voltage which occurs at
the earth electrode between the earth electrode terminal and ref-
erence earth if a short-circuit occurs between the phase conduc-
tor and the earth electrode. Measurement of earth electrode
potential is required by Swiss standard NIV/NIN SEV 1000.
Measuring Method
In order to determine earth electrode potential, the instrument first
measures earth electrode loop resistance R
ELoop
, and immedi-
ately thereafter earthing resistance R
E
. The instrument stores both
values and then calculates earth electrode potential with the fol-
lowing equation:
The calculated value is displayed at the display panel.
Select Measuring Function
Select Operating Mode Select measuring range
Connection
2-pole adapter and probe are connected.
Set Parameters
❑ Measuring range: 10 Ω / U
E
❑ Connection type: 2-pole adapter + probe
❑ Contact voltage: UL < 25 V, < 50 V, < 65 V, see section 5.7 re-
garding freely selectable voltage.
❑ Test current waveshape: sinusoidal only in this case (full-wave)!
❑ System type: TN/TT, IT
❑ Transformer ratio: irrelevant in this case
Start Measurement
Note
The following diagram appears if the
2-pole adapter is connected incor-
rectly.
P
R
O
F
I
T
E
S
T
Ri
W
a
t
e
r
P
i
p
e
SE
2
E
1
B
U
E
U
N
R
E
⋅
R
E
Loop
-------------------=
R
E
Limit value:
R
E
> Limit Value
U
L
⏐ R
L