Page 199 - SACE Tmax XT - Catalogue

ACCESSORIES 7/53

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Residual current protection

Residual current release
Both circuit-breakers and switch-disconnectors are pre-engineered for assembly combined with resid-
ual 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, they also provide protection for
people and against earth fault currents, thus protecting against direct, indirect contacts and risk of fire.
Residual current circuit-breakers derived from switch-disconnectors are “pure” residual current circuit-
breakers, i.e. they only provide residual current protection and not the protection typical of circuit-
breakers. “Pure” residual current circuit-breakers are only sensitive to earth fault currents and are gen-
erally 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 installation
to be continuously monitored. It ensures efficient protection against the risk of fire and explosions and
also protects people against indirect and direct contacts, thereby integrating the compulsory measures
established by the accident prevention standards and Regulations.
The residual current releases comply with the following standards:
• IEC 60947-2 Annex B;
• IEC 61000 for protection against unwanted tripping.
The table gives all the residual current devices that can be used in combination with SACE Tmax XT
family:

XT1 XT2 XT3 XT4 XT5
3p 4p 3p 4p 3p 4p 3p 4p 3p 4p
Instantaneous residual RC Inst F F F F
current device
Selective residual RC Sel F F F F
current device XT1-XT3 07
RC Sel 200 F
RC Sel F-P-W F-P-W
XT2-XT4
RC Sel XT5 F-P-W
Type B residual current device RC Type B XT3 F
Tmax XT residual current devices:
• are designed for XT1, XT2, XT3 and XT4 microprocessor technology and act directly on the circuit-
breaker by means of a dedicated opening solenoid (supplied with the residual current release and also
available as a spare part) which must be housed in the relevant slot formed in the third pole on the left
of the operating lever;
• are designed for XT5 feature microprocessor technology and act directly on the circuit-breaker by
means of a dedicated mechanism integrated in the residual current itself;
• do not need an auxiliary supply as they are powered directly from the mains;
• can be supplied either from above or below;
• provide guaranteed functionality 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 voltage
PHASE-NEUTRAL 85 Vrms);
• permit all possible connection combinations, as long as the neutral connection to the first pole on the
left in the four-pole version is guaranteed.