26
GMC-I Messtechnik GmbH
I
K
Short-circuit current calculated by the instrument (at nominal
voltage)
Z
Earth-fault loop impedance
Ia Tripping current
(see data sheets regarding circuit breakers / fuses)
% Test instrument intrinsic error
TAB
Limit values in accordance with technical connection con-
ditions for connection to the low-voltage mains
between
the distribution network and the measuring device
DIN
Limit value per DIN 18015-1:
U < 3% between
measuring device and consumer
VDE
Limit value per DIN VDE 0100-520:
U < 4% between
distribution network and consumer (adjustable up to 10%
in this case)
Start Measurement
Significance and Display of
U (per DIN VDE 100, part 600)
Voltage drop from the intersection of the distribution network and
the consumer system to the point of connection of an electrical
power consumer (electrical outlet or device connector terminals)
should not exceed 4% of nominal line voltage.
Voltage drop calculation:
U = Z
L-N
• nominal current of the fuse
U as % =
U / U
L-N
Display of U
L-N
(U
N
/ f
N
)
If the measured voltage value lies within a range of
10% of the
respective nominal line voltage of 120 V, 230 V or 400 V, the
respectively corresponding nominal line voltage is displayed. In
the case of measured values outside of the
10% tolerance, the
actual measured value is displayed.
q
Z
OFFSET
ON
/
OFF
Voltage Drop up to the Transfer Point or the Measuring Device
Proceed as follows:
Ð
Set
Z
OFFSET
from OFF to ON. “
Z
OFFSET
= 0.00
” appears in the
footer.
Ð
Connect the 2-pole adapter to the transfer point (measuring
device / meter).
Ð
Start offset measurement with I
N
.
Measuring Z
OFFSET
Z
OFFSET
x.xx
appears in the footer at the display, where x.xx is a
value within a range of 0.00 to 9.99
. This value is now sub-
tracted for the calculation of
U for all subsequent Z
LN
measure-
ments, insofar as the
Z
OFFSET
ON/OFF
softkey has been set to
ON
.
Z
OFFSET
must be recalculated in the following cases:
• After switching from ON to OFF and back again.
Error messages appear in a popup window in the following cases:
–
Z
OFFSET
> 10
–
Z
OFFSET
> Z
x
(offset value greater than the measured value at
the power consuming system)
Limit value
:
I
K
< limit value
U
L
R
L
I
K
Limit value
:
U % > Limit / Grenzwert
U
L
R
L
U
