GMC-I Messtechnik GmbH 27
Special Case: Suppressing Display of the Limit Value
The limit value cannot be
ascertained. The inspec-
tor is prompted to evalu-
ate the measured val-
ues himself, and to
acknowledge or reject
them with the help of the
softkeys.
Measurement passed:
✔ key
Measurement failed: X
key
The measured value can
only be saved after it has
been evaluated.
8.3 Settings for Calculating Short-Circuit Current –
Parameter I
K
Short-circuit current I
K
is used to test shutdown by means of an
overcurrent protective device. In order for an overcurrent protec-
tive device to be tripped on time, short-circuit current I
K
must be
greater than tripping current Ia (see table 6 in section 19.1). The
variants which can be selected with the “Limits” key have the fol-
lowing meanings:
I
K
: Ia The measured value displayed for I
K
is used without
any correction to calculate Z
L-PE
.
I
K
: Ia+% The measured value displayed for Z
L-PE
is corrected
by an amount equal to the test instrument’s measuring
uncertainty in order to calculate I
K
.
I
K
: 2/3 Z In order to calculate I
K
, the measured value displayed
for Z
L-PE
is corrected by an amount corresponding to
all possible deviations (these are defined in detail by
VDE 0100-60 as Z
s(m)
2/3 x U
0
/Ia).
I
K
: 3/4 Z Z
s(m)
3/4 x U
0
/Ia
I
K
Short-circuit current calculated by the instrument (at nominal voltage)
Z Fault loop impedance
Ia Tripping current (see data sheet for circuit breakers / fuses)
%
Test instrument inherent error
Special case: I
k
> I
kmax
, see page 28.
See page 28 on accessing the fuse table via the
HELP
key.
9 Measuring Line Impedance (Z
L-N
function)
Measuring Method (internal line resistance measurement)
Line impedance Z
L-N
is measured by means of the same method
used for loop impedance Z
L-PE
(see section 8 on page 25). How-
ever, the current loop is completed via neutral conductor N rather
than protective conductor PE as is the case with loop impedance
measurement.
Select the Measuring Function
Schuko Connection
(country specific)
Connection: 2-pole
Set Parameters
Press the softkey shown at the left in order to switch
back and forth between the country-specific measur-
ing adapter, e.g. PRO-Schuko measuring adapter
(Z503K) / 3-pole measurement and the KS-PROFIT-
EST INTRO (Z503L) for 2-pole measurement. The selected con-
nection type is displayed inversely (white on black).
Limit Value:
I
K
< limit value
LIMIT
Nom. current:
2 ... 160 A, 9999 A
Diameter: 1.5 to 70 sq. mm
Cable types: NY..., H07...
Number of wires:
1 to 10-strand
Tripping characteristics:
A, B/L, C/G, D, E, H, K, GL/GG & factor
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