24 GMC-I Messtechnik GmbH
7.3.4 Type G or R RCCB
In addition to standard RCCBs and selective RCDs, the special
characteristics of the type G RCCB can also be tested with the
test instrument.
The type G RCCB is an Austrian specialty and complies with the
ÖVE/ÖNORM E 8601 device standard. Erroneous tripping is min-
imized thanks to its greater current carrying capacity and short-
term delay.
Select the Measuring Function
Set Parameter – Type G/R (VSK)
Touch voltage and time to trip can be measured in the G/R-RCD
switch position.
It must be observed that time to trip for type G RCCBs
may be as long as 1000 ms when measurement is made
at nominal residual current. Set the limit value corre-
spondingly.
➭ Then select 5 x I
N
in the menu (this is selected automatically
for the G/R setting) and repeat the tripping test beginning with
the positive half-wave at 0° and the negative half-wave at
180°. The longer of the two tripping times is decisive regard-
ing the condition of the tested RCCB.
Set the Parameter – Start with Positive or Negative Half-Wave
Set the Parameter – 5 Times Nominal Current
The following restrictions apply to the selection of tripping
current multiples relative to nominal current:
500 mA: 1 x, 2 x I
N
Start Measurement
In both cases tripping time must be between 10 ms (minimum
delay time for type G RCCBs!) and 40 ms.
Type G RCCBs with other nominal residual current values must
be tested with the corresponding parameter setting under menu
item I
N
. In this case as well, the limit value must be appropriately
adjusted.
The RCD parameter setting for selective RCCBs is not
suitable for type G RCCBs.
7.4 Testing Residual Current Circuit Breakers in TN-S Systems
Connection
RCCBs can only be
used in TN-S systems.
An RCCB would not
work in a TN-C system
because PE is directly
connected to the neu-
tral conductor in the out-
let (it does not bypass
the RCCB). This means
that residual current
would be returned via
the RCCB and would
not generate any differ-
ential current, which is
required in order to trip
the RCCB.
As a rule, the display for touch voltage is also 0.1 V, because the
nominal residual current of 30 mA together with minimal loop
resistance result in a very small voltage value:
180°: Start with negative half-wave
0°: Start with positive half-wave
Waveform:
Positive direct current
UINR
E
IN 1 30mA 30mV 0 03V,== ==
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