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3
Protection
of LV
distribution
systems
page A-2
Protection
of
motors feeders
(AC 220/690 V)
page A-35
Control and
isolation
using
switch-
disconnectors
page A-37
Service
connection
Source
changeover
systems
page A-44
Protection for:
distribution systems supplied by transformers
b
distribution systems supplied by engine
b
generator sets
long cables in IT and TN systems.
b
Installation :
in power switchboards.
b
All circuit breakers in the Compact NS range offer
positive contact indication
and are suitable for isolation in compliance with
standards IEC 60947-1 and 2.
When combined with a motor starter, Compact NS
circuit breakers protect the cables and the starter
against short-circuits.
Equipped with an electronic trip unit, Compact NS
circuit breakers also protect the cables, starter and
motor against overloads.
The exceptional current-limiting capacity of
Compact NS circuit breakers automatically
ensures type-2 coordination with the motor starter,
in compliance with standard IEC 60947-4-1.
Compact NS service connection circuit breakers are
specially designed for the service-connection function:
lead seals and locking systems
b
tripping curves certified by utilities
b
fast overload curves to limit the power supplied, etc.
b
Interpact INV switch-disconnectors offering visible
break (see the corresponding catalogue) can be
combined with Compact NS circuit breakers to
constitute the various types of service connections
and meet the needs of all installation configurations.
A switch-disconnector version of Compact NS circuit
breakers exists for circuit control and isolation.
All the additional functions may be combined with the
basic switch-disconnector function, including:
earth-leakage protection
b
motor mechanism.
b
For information on other switch-disconnector ranges,
see the Interpact (offering positive contact indication
and visible break) and Fupact (fuse switch) catalogues.
To ensure a continuous supply of power, some
electrical installations are connected to two power
sources:
a normal source
b
a replacement source to supply the installation
b
when the normal source is not available.
Amechanical and/or electrical interlocking system
between two circuit breakers or switch-disconnectors
avoids all risk of parallel connection of the sources
during switching.
A source-changeover system can be:
manual with mechanical device interlocking
b
remote controlled with mechanical and/or electrical
b
device interlocking
automatic by adding a controller to manage
b
switching from one source to the other on
the basis of external parameters.
(See Source-changeover catalogue for dimensions,
connections and electrical drawings).
Additional earth-leakage protection protects life
and property against the risks of faulty insulation
in the installation.
Depending on the circuit breaker,
earth-leakage protection is provided by:
using a specific Micrologic control unit
b
using a Vigirex relay and separate toroids.
b
Earth
leakage
page A-36