SIST EN 50557:2012

Automatic reclosing devices for circuit breakers-RCBOs-RCCBs for household and similar uses (ARDs)

This European Standard applies to Automatic Reclosing Devices (hereinafter referred to as “ARD”) for household and similar uses, for rated voltage not exceeding 440 V a.c. intended to be used in combination with circuit-breakers and/or RCCBs and/or RCBOs, and designed either for factory assembly or for assembly on site.
These devices are intended to reclose main protective devices (hereinafter referred to as “MPD”) such as circuit-breakers complying to EN 60898-1 and/or EN 60898-2, RCCBs complying to EN 61008-1 and RCBOs complying to EN 61009-1 after tripping of those devices in order to re-establish continuity of service.
In detail, this European Standard applies to the following types of ARD:
−ARD with assessment means, reclosing only if both the prospective line current and the prospective earth-fault current do not exceed given values;
−ARD with assessment means, reclosing only if the prospective line current does not exceed a given value;
−ARD with assessment means, reclosing only if the prospective earth-fault current does not exceed a given value;
−ARD that reclose without any assessment.
NOTE 1 The assessment cannot substitute the verifications required by HD 60364-6:2007.
NOTE 2 The requirements and tests for the assessment function in IT systems are under consideration.
This European Standard does not apply to ARDs with multiple settings adjustable by means accessible to the user in normal service.
This European Standard states:
−the terms and definitions used for ARD (Clause 3);
−the classification of ARD (Clause 4);
−the characteristics of ARD (Clause 5);
−the preferred values of the operating and influencing quantities (Clause 5);
−the marking and information to be provided for ARD (Clause 6);
−the standard conditions for installation and operation in service (Clause 7);
−the requirements for construction and operation (Clause 8);
−the list of minimum requirements to be tested (Clause 9).

Automatisch wiedereinschaltende Einrichtungen für Leitungsschutzschalter sowie Fehlerstrom-Schutzschalter mit und ohne eingebautem Überstromschutz (RCBOs und RCCBs) für Hausinstallationen und für ähnliche Anwendungen (ARDs)

Prescriptions pour les dispositifs à refermeture automatique (DRA) pour disjoncteurs, ID et DD, pour usages domestiques et analogues

Naprave za avtomatski ponovni vklop odklopnikov - Odklopniki na diferenčni tok z nadtokovno zaščito (RCBOs) - Odklopniki na diferenčni tok (RCCBs) za gospodinjsko in podobno uporabo (ARDs)

Ta evropski standard se uporablja za naprave za avtomatski ponovni vklop (ARD)  v gospodinjski in podobni uporabi, kadar naznačena napetost ne presega 440 V izmenične napetosti, pri čemer so te naprave namenjene uporabi v kombinaciji z odklopniki in/ali odklopniki na diferenčni tok (RCCB) in/ali odklopniki na diferenčni tok z nadtokovno zaščito (RCBO) ter zasnovane za sestavo v tovarni ali na kraju samem.
Te naprave so namenjene ponovnemu vklopu glavnih zaščitnih naprav (MPD), kot so odklopniki, skladni s standardom EN 60898-1 in/ali EN 60898-2, odklopniki na diferenčni tok, skladni s standardom EN 61008-1, in odklopniki na diferenčni tok z nadtokovno zaščito, skladni s standardom EN 61009-1, po njihovem izklopu, da se znova vzpostavi neprekinjeno delovanje.
Ta evropski standard se uporablja za naslednje vrste naprav za avtomatski ponovni vklop:
− naprave za avtomatski ponovni vklop z možnostjo ocene, ki napravo znova vklopijo le, če pričakovani linijski tok in pričakovani zemeljskostični tok ne presegata navedenih vrednosti;
– naprave za avtomatski ponovni vklop z možnostjo ocene, ki napravo znova vklopijo le, če pričakovani linijski tok ne presega navedene vrednosti;
– naprave za avtomatski ponovni vklop z možnostjo ocene, ki napravo znova vklopijo le, če pričakovani zemeljskostični tok ne presega določene vrednosti;
– naprave za avtomatski ponovni vklop, ki napravo znova vklopijo brez kakršne koli ocene.
OPOMBA 1: Ocena ne more nadomestiti preverjanj, zahtevanih v standardu HD 60364-6:2007.
OPOMBA 2: Zahteve in preskusi za funkcijo ocenjevanja v sistemih IT se obravnavajo.
Ta evropski standard se ne uporablja za naprave za avtomatski ponovni vklop z več nastavitvami, ki jih lahko uporabnik nastavi med običajnim delovanjem.
Ta evropski standard določa:
− izraze in definicije, ki se uporabljajo za napravo za avtomatski ponovni vklop (točka 3);
− klasifikacijo naprave za avtomatski ponovni vklop (točka 4);
− značilnosti naprave za avtomatski ponovni vklop (točka 5);
− prednostne vrednosti obratovalnih in vplivnih veličin (točka 5);
− označevanje in informacije, ki se predložijo za napravo za avtomatski ponovni vklop (točka 6);
− standardne pogoje za nameščanje in delovanje med obratovanjem (točka 7);
− zahteve za izdelavo in delovanje (točka 8);
− seznam minimalnih zahtev, ki jih je treba preskusiti (točka 9).

General Information

• Status: Withdrawn
• Public Enquiry End Date: 30-Aug-2010
• Publication Date: 22-Dec-2011
• Withdrawal Date: 09-Dec-2020
• ICS: 29.120.50 - Fuses and other overcurrent protection devices
• Technical Committee: EPR - Electrical accessories
• Current Stage: 9900 - Withdrawal (Adopted Project)
• Start Date: 09-Dec-2020
• Due Date: 01-Jan-2021
• Completion Date: 10-Dec-2020
• Directive: 2004/108/EU - DIRECTIVE 2004/108/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 15 December 2004 on the approximation of the laws of the Member States relating to electromagnetic compatibility and repealing Directive 89/336/EEC
• Directive: 2006/95/EC - Directive 2006/95/EC of the European Parliament and of the Council of 12 December 2006 on the harmonisation of the laws of Member States relating to electrical equipment designed for use within certain voltage limits (codified version)
• Directive: 2014/30/EU - Directive 2014/30/EU of the European Parliament and of the Council of 26 February 2014 on the harmonisation of the laws of the Member States relating to electromagnetic compatibility (recast)
• Directive: 2014/35/EU - Directive 2014/35/EU of the European Parliament and of the Council of 26 February 2014 on the harmonisation of the laws of the Member States relating to the making available on the market of electrical equipment designed for use within certain voltage limits
• Ref Project: EN 50557:2011 - Requirements for automatic reclosing devices (ARDs) for circuit breakers-RCBOs-RCCBs for household and similar uses

Relations

• Replaced By: SIST EN 63024:2018 - Requirements for automatic reclosing devices (ARDs) for circuit-breakers, RCBOs and RCCBs for household and similar uses (IEC 63024:2017)
• Effective Date: 01-May-2018
• Replaced By: SIST EN 63024:2018 - Requirements for automatic reclosing devices (ARDs) for circuit-breakers, RCBOs and RCCBs for household and similar uses (IEC 63024:2017)
• Effective Date: 07-Jun-2022

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 50557:2012
01-februar-2012
1DSUDYH]DDYWRPDWVNLSRQRYQLYNORSRGNORSQLNRY2GNORSQLNLQDGLIHUHQþQLWRN]
QDGWRNRYQR]DãþLWR5&%2V2GNORSQLNLQDGLIHUHQþQLWRN5&&%V]D
JRVSRGLQMVNRLQSRGREQRXSRUDER$5'V
Automatic reclosing devices for circuit breakers-RCBOs-RCCBs for household and
similar uses (ARDs)
Automatisch wiedereinschaltende Einrichtungen für Leitungsschutzschalter sowie
Fehlerstrom-Schutzschalter mit und ohne eingebautem Überstromschutz (RCBOs und
RCCBs) für Hausinstallationen und für ähnliche Anwendungen (ARDs)
Prescriptions pour les dispositifs à refermeture automatique (DRA) pour disjoncteurs, ID
et DD, pour usages domestiques et analogues
Ta slovenski standard je istoveten z: EN 50557:2011
ICS:
29.120.50 9DURYDONHLQGUXJD Fuses and other overcurrent
PHGWRNRYQD]DãþLWD protection devices
SIST EN 50557:2012 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 50557:2012

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SIST EN 50557:2012

EUROPEAN STANDARD
EN 50557
NORME EUROPÉENNE
December 2011
EUROPÄISCHE NORM

ICS 29.120.50


English version
Requirements for automatic reclosing devices (ARDs) for circuit breakers-
RCBOs-RCCBs for household and similar uses

Prescriptions pour les dispositifs à Automatisch wiedereinschaltende
refermeture automatique (DRA) pour Einrichtungen für Leitungsschutzschalter
disjoncteurs, ID et DD, pour usages sowie Fehlerstrom-Schutzschalter mit und
domestiques et analogues ohne eingebautem Überstromschutz
(RCBOs und RCCBs) für
Hausinstallationen und für ähnliche
Anwendungen (ARDs)

This European Standard was approved by CENELEC on 2011-07-19. CENELEC members are bound to comply
with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard
the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the CEN-CENELEC Management Centre or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and notified
to the CEN-CENELEC Management Centre has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus,
the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia,
Spain, Sweden, Switzerland and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Management Centre: Avenue Marnix 17, B - 1000 Brussels


© 2011 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 50557:2011 E

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SIST EN 50557:2012
EN 50557:2011 – 2 –
Contents
Foreword . 5
Introduction . 6
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 8
4 Classification . 10
4.1 According to the method of construction . 10
4.2 According to the MPD . 10
4.3 According to the type of assessment means . 10
4.4 According to the safety means during the assessment . 11
4.5 According to the range of ambient air temperature (only for ARD according to 4.2.2 and
4.2.3) . 11
4.6 According to the connection to FE . 11
4.7 According to maximum number of reclosing operations . 11
4.8 According to mechanical interlock between MPD operating means and ARD
enabling/disabling system . 11
5 Characteristics . 11
5.1 Summary of characteristics . 11
5.2 Rated quantities . 12
6 Marking and other product information . 13
6.1 Standard marking . 13
6.2 Instructions for assembly and operation . 14
7 Standard conditions for operation in service . 15
7.1 General . 15
7.2 Conditions of installation . 15
7.3 Pollution degree . 15
8 Requirements for construction and operation . 15
8.1 Mechanical design . 15
8.2 Protection against electric shock . 19
8.3 Dielectric properties and isolating capability . 19
8.4 Temperature rise . 20
8.5 Mechanical and electrical endurance . 20
8.6 Performance at short-circuit currents . 20
8.7 Resistance to mechanical shock and impact . 20
8.8 Resistance to heat . 20
8.9 Resistance to abnormal heat and to fire . 20
8.10 Behaviour at low ambient air temperature . 21
8.11 Operating characteristic . 21
8.12 Assessment means for ARD according to 4.3.2 . 22
8.13 Safety in blocked condition . 23
8.14 Test device. 23
8.15 Ageing . 23
8.16 Electromagnetic compatibility (EMC) . 23
9 Tests . 23
9.1 General . 23
9.2 Test condition . 23
9.3 Measurement of the reclosing time after the tripping of the MPD . 24

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SIST EN 50557:2012
– 3 – EN 50557:2011
9.4 Test of indelibility of marking . 24
9.5 Verification of the non influence of the ARD on the correct operation of the MPD . 24
9.6 Tests of creepage distances and clearances for electronic circuits (abnormal conditions) . 26
9.7 Requirements for capacitors and specific resistors and inductors used in electronic circuits . 28
9.8 Test of reliability of screws, current-carrying parts and connections . 28
9.9 Test of reliability of terminals for external conductors . 29
9.10 Verification of protection against electric shock. 29
9.11 Test of dielectric properties and isolating capability . 29
9.12 Temperature rise . 30
9.13 Verification of the mechanical and electrical endurance – Verification of the reclosing system
of the ARD . 30
9.14 Short-circuit test . 30
9.15 Resistance to mechanical shock and impact . 31
9.16 Test of resistance to heat . 31
9.17 Resistance to abnormal heat and to fire . 32
9.18 Verification of the correct operation at low ambient air temperatures for RCCBs for use at
temperatures between -25 °C and +40 °C . 32
9.19 Verification of the operating characteristics . 32
9.20 Verification of the safety during the assessment . 33
9.21 Verification of the operation of the test device at the limits of rated voltage . 34
9.22 Verification of ageing . 34
9.23 Electromagnetic compatibility . 35
Annex A (informative) Classification of ARDs according to 4.3.1 . 43
Annex B (informative) Classification of ARDs according to 4.3.2.1 a) and/or 4.3.2.2 a) . 44
Annex C (informative) Classification of ARDs according to 4.3.2.1 b) and/or 4.3.2.2 b) . 45
Annex D (normative) Number of samples for full test procedure . 46
Annex E (normative) Test sequences . 47
Annex F (informative) A-deviations . 48
Annex ZZ (informative) Coverage of Essential Requirements of EC Directives. 49
Bibliography . 50

Figures
Figure 1 – Minimum creepage distances and clearances measured in millimetres . 37
Figure 2 – Minimum creepage distances and clearances as a function of peak value of operating
voltage . 38
Figure 3 – Verification of the reclosing subordinated to the measurements of the resistance to earth for
ARD without functional earthing (9.19.1 a) – 9.19. 1 b) – 9.20.2) . 39
Figure 4 – Verification of the reclosing subordinated to the measurements of the resistance to earth for
ARD with functional earthing (9.19.1 a) – 9.19. 1 b) – 9.20.2) . 40
Figure 5 – Verification of the reclosing subordinated to the measurements of the resistance between live
parts (9.19.2 a) – 9.19.2 b)) . 41
Figure 6 – Test circuit for the verification of the maximum current in FE under normal condition . 42
Figure A.1 – Classification of ARDs according to 4.3.1 . 43
Figure B.1 – Classification of ARDs according to 4.3.2.1 a) and/or 4.3.2.2 a) . 44
Figure C.1 – Classification of ARDs according to 4.3.2.1 b) and/or 4.3.2.2 b) . 45

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SIST EN 50557:2012
EN 50557:2011 – 4 –

Tables
Table 1 – Minimum admissible R values . 12
d
Table 2 – Minimum clearances and creepage distances . 18
Table 3 – Behaviour of the ARD in enable condition . 22
Table 4 – Maximum permissible temperatures under abnormal conditions . 27
Table 5 – Low frequency immunity test conditions . 35
Table 6 – High-frequency immunity test conditions . 36
Table 7 – Test conditions for electrostatic discharges . 36
Table D.1 – Number of samples for full test procedure . 46
Table D.2 – Additional tests for ARD already fully tested together with one kind of MPD . 46
Table E.1 – Test sequences . 47

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SIST EN 50557:2012
– 5 – EN 50557:2011
Foreword
This document (EN 50557:2011) has been prepared by CLC/TC 23E "Circuit breakers and similar devices
for household and similar applications".
The following dates are fixed:
• latest date by which this document has
(dop) 2012-07-19
to be implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national
(dow) 2014-07-19
standards conflicting with this
document have to be withdrawn
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such patent rights.
This document has been prepared under a mandate given to CENELEC by the European Commission and
the European Free Trade Association, and supports essential requirements of EU Directive(s).
For the relationship with EU Directive(s) see informative Annex ZZ, which is an integral part of this
document.
__________

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SIST EN 50557:2012
EN 50557:2011 – 6 –
Introduction
Automatic Reclosing Devices are intended to reclose circuit-breakers-RCBOs-RCCBs after tripping in order
to re-establish continuity of service.
1 Scope
This European Standard applies to Automatic Reclosing Devices (hereinafter referred to as “ARD”) for
household and similar uses, for rated voltage not exceeding 440 V a.c. intended to be used in combination
with circuit-breakers and/or RCCBs and/or RCBOs, and designed either for factory assembly or for assembly
on site.
These devices are intended to reclose main protective devices (hereinafter referred to as “MPD”) such as
circuit-breakers complying to EN 60898-1 and/or EN 60898-2, RCCBs complying to EN 61008-1 and RCBOs
complying to EN 61009-1 after tripping of those devices in order to re-establish continuity of service.
In detail, this European Standard applies to the following types of ARD:
− ARD with assessment means, reclosing only if both the prospective line current and the prospective
earth-fault current do not exceed given values;
− ARD with assessment means, reclosing only if the prospective line current does not exceed a given value;
− ARD with assessment means, reclosing only if the prospective earth-fault current does not exceed a
given value;
− ARD that reclose without any assessment.
NOTE 1 The assessment cannot substitute the verifications required by HD 60364-6:2007.
NOTE 2 The requirements and tests for the assessment function in IT systems are under consideration.
This European Standard does not apply to ARDs with multiple settings adjustable by means accessible to
the user in normal service.
This European Standard states:
− the terms and definitions used for ARD (Clause 3);
− the classification of ARD (Clause 4);
− the characteristics of ARD (Clause 5);
− the preferred values of the operating and influencing quantities (Clause 5);
− the marking and information to be provided for ARD (Clause 6);
− the standard conditions for installation and operation in service (Clause 7);
− the requirements for construction and operation (Clause 8);
− the list of minimum requirements to be tested (Clause 9).
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
EN 55014-1:2006 + A1:2009, Electromagnetic compatibility – Requirements for household appliances,
electric tools and similar apparatus – Part 1: Emission (CISPR 14-1:2005 + A1:2008)
EN 60065:2002 + A1:2006 + corr. Aug. 2007 + A11:2008 + A2:2010, Audio, video and similar electronic
apparatus – Safety requirements (IEC 60065:2001, mod. + A1:2005, mod. + A2:2010, mod.)

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SIST EN 50557:2012
– 7 – EN 50557:2011
EN 60112:2003 + A1:2009, Method for the determination of the proof and the comparative tracking indices of
solid insulating materials (IEC 60112:2003 + A1:2009)
EN 60384-14 series, Fixed capacitors for use in electronic equipment (IEC 60384 series)
EN 60384-14:2005, Fixed capacitors for use in electronic equipment –
Part 14: Sectional specification – Fixed capacitors for electromagnetic interference suppression and
connection to the supply mains (IEC 60384-14:2005)
EN 60664-1:2007, Insulation coordination for equipment within low-voltage systems –
Part 1: Principles requirements and tests (IEC 60664-1:2007)
EN 60664-3:2003 + A1:2010, Insulation coordination for equipment within low-voltage systems –
Part 3: Use of coating, potting or moulding for protection against pollution
(IEC 60664-3:2003 + A1:2010 + corr. Nov. 2010)
EN 60898-1:2003 + corr. Feb. 2004 + A1:2004 + A11:2005 + A12:2008, Electrical accessories –
Circuit-breakers for overcurrent protection for household and similar installations –
Part 1: Circuit-breakers for a.c. operation (IEC 60898-1:2002, mod. + A1:2002, mod.)
EN 60898-2:2006, Electrical accessories – Circuit-breakers for overcurrent protection for household and
similar installations – Part 2: Circuit-breakers for a.c. and d.c. operation
(IEC 60898-2:2000, mod. + A1:2003, mod.)
EN 60947-5-1:2004 + corr. Jul. 2005 + A1:2009, Low-voltage switchgear and controlgear – Part 5-1: Control
circuit devices and switching elements – Electromechanical control circuit devices
(IEC 60947-5-1:2003 + A1:2009)
EN 60950-1:2006 + A11:2009 + A1:2010, Information technology equipment – Safety –
Part 1: General requirements (IEC 60950-1:2005, mod. + A1:2009, mod.)
EN 61008-1:2004 + A11:2007 + A12:2009, Residual current operated circuit-breakers without integral
overcurrent protection for household and similar uses (RCCBs) – Part 1: General rules
(IEC 61008-1:1996, mod. + A1:2002, mod.)
EN 61009-1:2004 + A11:2008 + A12:2009 + A13:2009, Residual current operated circuit-breakers with
integral overcurrent protection for household and similar uses (RCBOs) – Part 1: General rules
(IEC 61009-1:1996, mod. + A1:2002, mod. + corr. May 2003)
EN 61000-4-2:2009, Electromagnetic compatibility (EMC) –
Part 4-2: Testing and measurement techniques – Electrostatic discharge immunity test (IEC 61000-4-2:2008)
EN 61000-4-3:2006 + A1:2008 + A2:2010, Electromagnetic compatibility (EMC) –
Part 4-3: Testing and measurement techniques – Radiated, radio-frequency, electromagnetic field immunity
test (IEC 61000-4-3:2006 + A1:2007 + A2:2010)
EN 61000-4-4:2004 + A1:2010, Electromagnetic compatibility (EMC) –
Part 4-4: Testing and measurement techniques – Electrical fast transient/burst immunity test
(IEC 61000-4-4:2004 + A1:2010)
EN 61000-4-5:2006, Electromagnetic compatibility (EMC) –
Part 4-5: Testing and measurement techniques – Surge immunity test (IEC 61000-4-5:2005)
EN 61000-4-6:2009, Electromagnetic compatibility (EMC) –
Part 4-6: Testing and measurement techniques – Immunity to conducted disturbances, induced by radio-
frequency fields (IEC 61000-4-6:2008)
EN 61000-4-16:1998 + A1:2004 + A2:2011, Electromagnetic compatibility (EMC) –
Part 4-16: Testing and measurement techniques – Test for immunity to conducted, common mode
disturbances in the frequency range 0 Hz to 150 kHz (IEC 61000-4-16:1998 + A1:2001 + A2:2009)
EN 61189-2, Test methods for electrical materials, printed boards and other interconnection structures and
assemblies – Part 2: Test methods for materials for interconnection structures (IEC 61189-2)

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SIST EN 50557:2012
EN 50557:2011 – 8 –
EN 61543:1995 + corr. Dec. 1997 + A11:2003 + A12:2005, Residual current-operated protective devices
(RCDs) for household and similar use Electromagnetic compatibility (IEC 61543:1995 + A2:2005)
EN 61558 series, Safety of power transformers, power supply units and similar products (IEC 61558 series)
EN 62019, Electrical accessories – Circuit-breakers and similar equipment for household use – Auxiliary
contact units (IEC 62019)
EN ISO 306:2004, Plastics – Thermoplastic materials – Determination of Vicat softening temperature (VST)
(ISO 306:2004)
ISO 7000:2004, Graphical symbols for use on equipment – Index and synopsis
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 60898-1:2003, EN 61008-1:2004,
EN 61009-1:2004 and the following apply.
3.1
actuator
part of the actuating system to which an external force is applied when the ARD is installed as in normal use
[IEV 441-15-22, mod.]
NOTE The actuator may take the form of a handle, knob, push-button, roller, plunger, etc.
3.2
assessment using a method based on the limitation of the test current
type of assessment that is designed in such a way that, under normal operating in tripped and blocked
conditions, the assessment is carried out by means of a non hazardous current flowing in the installation
NOTE The limit values of currents are specified in 8.12.3.
3.3
assessment using a method based on the limitation of the test voltage
type of assessment that is designed in such a way that, under normal operating in tripped and blocked
conditions, the assessment is carried out by means of a non hazardous voltage applied at the installation by
means of a transformer with a reinforced insulation between the primary and the secondary circuit
NOTE The limit values of voltage are specified in 8.12.2.
3.4
automatic reclosing
function intended to reclose, under specified conditions, the MPD after tripping
3.5
automatic reclosing device
ARD
electromechanical device intended to produce the automatic reclosing of the MPD to which is intended to be
associated with
3.6
blocked condition
condition of the ARD for which the MPD is tripped and the ARD shall not reclose it automatically
NOTE This condition can be removed only by manual reset operation according to the manufacturer’s instructions.
3.7
consecutive reclosing operations
number of consecutive reclosing operations that leads the ARD in blocked condition within a period of time
3.8
disabled (condition)
condition of the ARD for which automatic reclosing function is de-activated and MPD can never be
automatically reclosed

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SIST EN 50557:2012
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3.9
earth fault current
current flowing from the live parts of the installation to earth due to an insulation fault
3.10
enabled (condition)
condition of the ARD for which automatic reclosing function is activated and MPD may be automatically
reclosed (under specific condition)
3.11
functional earth
FE
wire or terminal intended to be connected to the PE so as to provide a reference point to the ARD for
assessment means
3.12
main protective device
MPD
device to which the ARD is intended to be associated with and that recloses under specified conditions
NOTE The MPD is a circuit-breaker (EN 60898-1 and/or EN 60898-2) or a RCCB (EN 61008-1) or a RCBO (EN 61009-1).
3.13
non operating resistance between live parts
maximum value of resistance between live parts, below which the automatic reclosing of the MPD is not
permitted under specified conditions
3.14
non operating resistance to earth
maximum value of resistance between live parts and earth, below which the automatic reclosing of the MPD
is not permitted under specified conditions
3.15
operating resistance between live parts
minimum value of resistance between live parts, for which the automatic reclosing of the MPD is ensured
under specified conditions
3.16
operating resistance to earth
minimum value of resistance between live parts and earth, for which the automatic reclosing of the MPD is
ensured under specified conditions
3.17
prospective line current
current likely to flow through live parts in case of reclosing of the MPD
3.18
prospective line current assessment
assessment of the current likely to flow through
– each phase and neutral and
– each phase and each other phase and
– each phase and earth
after reclosing the MPD
NOTE This is generally achieved by evaluating the resistance.
3.19
prospective residual current
current likely to flow from the live parts of the installation to earth in case of reclosing of the MPD

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