26
As an option, a selective RCCB with I
Δn
= 300 mA can be connected upstream of
the entire installation. This RCCB protects installations with branches against faults
and re. If the stipulations of DIN 18015-2:2000-08 and RAL RG 678:2004-09
are taken as the basis for the same extent of equipment and for the same living
area, the additional space required in the circuit distribution board when the
recommended RCBOs are used is only slightly more than the space required in an
installation with separate RCCBs and miniature circuit breakers.
4.4.3 SIQUENCE universal current-sensitive RCCB
Type B and Type B+
Type A residual current protective devices – for sinusoidal AC residual currents
and pulsating DC residual currents – are not capable of detecting possible smooth
DC residual currents. Due to pre-magnetization of the transformer, DC residual
currents can even result in the inability of Type A residual current protective
devices to detect AC residual currents. For these reasons, Siemens introduced the
universal current-sensitive Type B residual current operated circuit breaker, which
is also used for smooth DC residual currents, in 1994, the rst manufacturer to do
so. Since then, the required residual current operated circuit breaker technology
can be used in many applications in which smooth DC residual currents occur. As
universal current-sensitive residual current operated circuit breakers are used for
the widest variety of applications, these are always also designed for use under
harsh ambient conditions like our SIGRES version (see paragraph 4.4.6).
In addition to the residual current waveforms described above, AC residual cur-
rents of different frequencies can originate in the case of electronic components,
for instance on the outgoing side of a frequency converter (also see section 5.3.2).
The Type B residual current operated circuit breakers intended for use in three-
phase systems (not in DC voltage systems) are therefore specied in draft DIN VDE
0664-100 (for RCCBs) and draft DIN VDE 0664-200 (for RCBOs) in the extended
tripping conditions up to 2 kHz. The tripping characteristics of the SIQUENCE
universal current-sensitive Type B RCCBs with rated residual currents of 30 mA and
300 mA are shown in gure 10. The tripping value of the circuit breaker always
lies within the limit values of the device specication and, for 30 mA rated residual
current, is well below the limit curve for dangerous ventricular brillation (accor-
ding to IEC 60479-2).
Residual current protective devices
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