Technical information

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1SDC210033D0202
Accessories
Electrical Accessories
Residual current releases
Both circuit-breakers and switch-disconnectors are pre-engineered for assembly combined with
residual current releases.
Residual current circuit-breakers derived from the circuit-breaker are known as “mixed”, meaning
that, besides protection against the typical overloads and short-circuits of circuit-breakers, they also
provide protection for people and against earth fault currents, thus protecting against direct, indirect
contacts and the risk of fires.
Residual current circuit-breakers derived from the switch-disconnector are “pure” residual current
circuit-breakers, i.e. they only provide residual current protection and not the protections typical of
circuit-breakers. “Pures” residual current circuit-breakers are only sensitive to earth fault current and
are generally used as main switches in small panels for distribution to end users.
Use of “pure” and “mixed” residual current circuit-breakers allows the insulation state of the instal-
lation to be continuously monitored. It ensures efficient protection against the risks of fires and
explosions and, in the case that detect fault at I6n<30mA devices, also protects people against
indirect and direct contacts, thereby integrating the compulsory measures established by the ac-
cident prevention standards and regulations.
The residual current releases comply with the following Standards:
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IEC 60947-2 annex B;
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IEC 61000: for protection against unwarranted tripping.
The table gives all the residual current devices which can be used with the Tmax XT family of circuit-
breakers:
XT1 XT2 XT3 XT4
3p 4p 3p 4p 3p 4p 3p 4p
RC Inst F F F F
RC Sel XT1-XT3 F F F F
RC Sel 200 F
Rc Sel XT2-XT4 F-P-W F-P-W
RC B type F
F = Fixed, P = Plug-in, W = Withdrawable
All Tmax XT residual current devices:
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feature microprocessor technology and act directly on the circuit-breaker by means of a dedi-
cated opening solenoid (supplied with the residual current release and also available as a spare
part) which must be housed in the relative slot formed in the third pole are to the left of the op-
erating lever;
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do not need an auxiliary supply as they are powered directly from the mains;
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can be supplied either from above or below;
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functionality is guaranteed even with a single phase plus neutral or just two live phases and in
the presence of pulsating unidirectional currents with direct components (minimum auxiliary volt-
age PHASE-NEUTRAL 85 Vrms);
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all possible connection combinations are permitted, as long as the neutral connection to the first
pole on the left in the four-pole version is guaranteed.