Manual

Gossen Metrawatt GmbH 51
Set Parameter – 5 Times Nominal Current
Note
The following restrictions apply to the selection of
tripping current multiples relative to nominal current:
500 mA: 1 ×, 2 × 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.
Note
The RCD parameter setting for selective RCCBs is not
suitable for type G RCCBs.
12.4 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
neutral conductor in the outlet (it does not bypass the RCCB).
This means that residual current would be returned via the RCCB
and would not generate any differential 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:
5 times tripping current
S
U
IN
= R
E
×I
N
= 1  × 30 mA = 30 mV = 0.03 V