33
Figure 12 shows the tripping range of the different versions of residual current
protective devices. It can be clearly seen that the tripping ranges of the standard
version and the super-resistant version are identical in terms of the maximum
value. Only the minimum value is higher in the case of Type
K
. The Type
S
responds selectively to these two versions.
The Type
K
super-resistant residual current protective devices exploit the maxi-
mum permissible tripping range of the standard. They have a minimum time delay
of approximately 10 ms. In other words, short-time leakage currents and high
surge currents (8/20 μs) are ignored for this length of time. Only when a residual
current ows for longer than the delay time is disconnection from the supply
initiated. Protection against electric shock is provided by this residual current
protective device too.
The devices can be used without restriction for all the protective measures (with
disconnection from the supply) required in the installation conditions. The installa-
tion is not disconnected unnecessarily and its availability is considerably increased.
Figure 12: Break time t
A
as a function of the tripping current I
Δ
t
A
ms
1.000
100
10
1
I
Δn
300 mA
S
I
Δn
30 mA
K
I
Δn
30 mA
K
10 30 100 300 1.000 I
Δ
/ mA
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