23
Ensure adequate selectivity if the new RCD is installed
downstream of an existing circuit breaker. In order to
ensure complete selectivity of two residual current
devices connected in series, the fault current of
upstream RCD
A
must be at least 3 times as high as
that of RCD
F
used to protect the Vitovalor PA2.
Adjust the response times of both RCDs connected in
series in such a way that the disconnection time of
RCD
F
is less than the shortest disconnection time
for RCD
A
. These two conditions ensure that RCD
F
of the Vitovalor PA2 responds earlier than upstream
RCD
A
.
l in A
t in s
A
F
Fig. 11
Response characteristics of the residual cur-
rent devices
Preparing for installation
Notes on connecting to the mains supply
(cont.)
5839343
Installation
Summary of Contents for E00T
Page 8: ...8 14 Keyword index 95 Index Index cont 5839343 ...
Page 97: ...97 5839343 ...
Page 98: ...98 5839343 ...
Page 99: ...99 5839343 ...
