Chapter A General rules of electrical installation design

H12
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H - LV switchgear: functions & selection
Fig. H25 : Domestic-type circuit-breaker providing overcurrent
protection and circuit isolation features
Fig. H26 : Domestic-type circuit-breaker as above (Fig. H25)
with incorparated protection against electric shocks
OF1 SD SDE OF2
OF2
SDE
SD
OF1
Fig. H28 : Example of a modular (Compact NS) industrial type
of circuit-breaker capable of numerous auxiliary functions
4 Circuit-breaker
Some models can be adapted to provide sensitive detection (30 mA) of earthleakage
current with CB tripping, by the addition of a modular block, while other
models (RCBOs, complying with IEC 61009 and CBRs complying with IEC 60947-2
Annex B) have this residual current feature incorporated as shown in Figure H26.
Apart from the above-mentioned functions further features can be associated with
the basic circuit-breaker by means of additional modules, as shown in Figure H27;
notably remote control and indication (on-off-fault).
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Schneider Electric - Electrical installation guide 2008
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2
O-OFF O-OFF - O-OFF -
Fig. H27 : “Multi 9” system of LV modular switchgear components
Moulded-case type industrial circuit-breakers complying with IEC 60947-2 are now
available, which, by means of associated adaptable blocks provide a similar range of
auxiliary functions to those described above (see Figure H28).
Heavy-duty industrial circuit-breakers of large current ratings, complying with
IEC 60947-2, have numerous built-in communication and electronic functions
(see Figure H29).
In addition to the protection functions, the Micrologic unit provides optimized
functions such as measurement (including power quality functions), diagnosis,
communication, control and monitoring.
Fig. H29 : Examples of heavy-duty industrial circuit-breakers. The “Masterpact” provides many
automation features in its “Micrologic” tripping module
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