User Manual

26 GMC-I Messtechnik GmbH
8.1 Measurements with Suppression of RCD Tripping
8.1.1 Measurement with Positive Half-Waves
Measurement by means of half-waves plus direct current makes it
possible to measure loop impedance in systems which are
equipped with RCCBs. In the case of DC measurement with half-
waves, selection can be made from two variants:
DC-L: Minimal bias current allowing for faster measurement
DC-H: Higher bias current providing more reliability with regard
to non-tripping of the RCD
Select the Measuring Function
Set Parameters
* Parameters which are only used for report generation and do not influence the measure-
ment
Sinusoidal (full-wave) Setting for circuit without RCD
15 mA sinusoidal Setting for motor protection switch only
with small nominal current
DC + half-wave Setting for circuit with RCD
Measurement Cable Compensation
The resistance of the respectively connected measurement cable or the
country-specific measuring adapter must be compensated for each loop
impedance measurement, i.e. it must be subtracted from the measure-
ment results as an offset. Proceed as described in section 4.5
under „OFFSET RL-PE / RN-PE / RL-N“ on page 12 to this end, in order
to ascertain offset values
RLPE-OFFSET and RNPE-OFFSET .
Start Measurement
Semiautomatic
Measurement
8.2 Evaluation of Measured Values
The maximum allowable
loop impedance Z
L-PE
which may be displayed
after allowance has
been made for maxi-
mum operating mea-
surement error (under
normal measuring con-
ditions) can be deter-
mined with the help of
Table 1 on page 54.
Intermediate values can
be interpolated.
The maximum allowable
nominal current for the
protective device (fuse
or circuit breaker) for a line voltage of 230 V after allowance has
been made for maximum measuring error can be determined with
the help of Table 5 on page 55 based upon measured short-cir-
cuit current (corresponds to DIN VDE 0100-600).
Z
L-PE
Nom. current: 2 ... 160 A , ... 9999 A
Tripping characteristics:
Diameter*: 1.5 to 70 sq. mm
Cable types*: NY.... - H07...
Number of wires*: 1 to 10-strand
A, B/L, C/G, D, E, H, K, GL/GG & factor
Sinusoidal
15 mA sinusoidal
Waveform:
DC-L and positive half-wave
Touch voltage:
DC-H and positive half-wave
2-pole measurement
Meas. with country-specific
measuring adapter (e.g. Schuko)
Note
Selecting the test probe, as well as Lx-
PE
reference or AUTO, is only relevant with
regard to report generation.
Semiautomatic measurement
See also section 5.8 regarding the
AUTO parameter.
Polarity selection