SC 17A - Switching devices

IEC TS 62271-316:2024 is applicable to direct current (DC) converter by-pass switches (CBPS) and paralleling switches (PS) designed for indoor or outdoor installation and for operation on HVDC transmission systems having direct voltages of 100 kV and above. Switches other than mechanical switching devices used for the same applications specified here are not covered by this document.

IEC/IEEE 62271-37-013:2021 is applicable to three-phase AC high-voltage generator circuit-breakers, hereafter called generator circuit-breakers, designed for indoor or outdoor installation and for operation at frequencies of 50 Hz and 60 Hz on systems having voltages above 1 kV and up to 38 kV.
This document is published as an IEC/IEEE Dual Logo standard.
The IEEE Std C37.013™-1997 (R2008) was revised and converted into the first edition of the IEC/IEEE Dual Logo International Standard IEC/IEEE 62271-37-013 published in 2015.
This second edition cancels and replaces the first edition published in 2015. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
content has been added to address the requirements of the other components of the generator circuit breaker system;
requirements for the application of generator circuit-breakers in power plants with multiple generators connected to one step-up transformer have been added;
requirements for testing and application of Tee-OFF generator circuit-breakers have been added;
requirements for application of generator circuit-breakers in power plants with doubly-fed induction machines, pumped-storage power plants, and wind farms have been added;
the clause numbering has been aligned with the numbering in IEC 62271-1:2017;
the topic of reference mechanical characteristics has been revised to improve clarity;
the modifying effects of capacitors on the prospective TRVs for out-of-phase and load current switching has been addressed in Annex M and in Annex N with use of the tool named "GenCB TRV calculator". This tool provides the values of KE2, RRRV0, KRRRV-U, KRRRV-I, td0, Ktd-U, Ktd-I, as well as the values of the parameters of the prospective TRV modified by the capacitors of the generator circuit-breaker.
This document contains attached files in the form of Excel spreadsheets ("GenCB TRV calculator"). These files are intended to be used as a complement and do not form an integral part of the document.

IEC TS 62271-319:2024 is applicable to alternating current circuit-breakers with intentional non-simultaneous pole operation designed for indoor or outdoor installations and for operation at frequencies of 50 Hz and 60 Hz on systems having voltages above 1 000 V. This document provides additional ratings and type tests to be conducted for this type of circuit-breaker and is intended to be used in conjunction with IEC 62271‑100:2021. Intentional non-simultaneous pole operation can be implemented by mechanical or electrical means and both methods are within the scope of this document.

IEC 62271-100:2021 is applicable to three-phase AC circuit-breakers designed for indoor or outdoor installation and for operation at frequencies of 50 Hz and/or 60 Hz on systems having voltages above 1 000 V. This document includes only direct testing methods for making-breaking tests. For synthetic testing methods refer to IEC 62271-101.
This third edition cancels and replaces the second edition published in 2008, Amendment 1:2012 and Amendment 2:2017. This edition constitutes a technical revision.
The main changes with respect to the previous edition are listed below:
– the document has been updated to IEC 62271-1:2017;
– Amendments 1 and 2 have been included;
– the definitions have been updated, terms not used have been removed;
– Subclauses 7.102 through 7.108 have been restructured.
The contents of the corrigendum of December 2021, July 2022 and January 2024 have been included in this copy.

IEC TS 62271-314:2024, a Technical Specification, applies to high-voltage direct current disconnectors and earthing switches, designed for indoor and outdoor installations and for operation on HVDC transmission systems having direct voltages of 100 kV and above.
It also applies to the operating devices of these disconnectors and earthing switches and their auxiliary equipment.
NOTE Disconnectors in which the fuse forms an integral part are not covered by this document

IEC 62271-100:2021 is applicable to three-phase AC circuit-breakers designed for indoor or outdoor installation and for operation at frequencies of 50 Hz and/or 60 Hz on systems having voltages above 1 000 V. This document includes only direct testing methods for making-breaking tests. For synthetic testing methods refer to IEC 62271-101.
This third edition cancels and replaces the second edition published in 2008, Amendment 1:2012 and Amendment 2:2017. This edition constitutes a technical revision.
The main changes with respect to the previous edition are listed below:
– the document has been updated to IEC 62271-1:2017;
– Amendments 1 and 2 have been included;
– the definitions have been updated, terms not used have been removed;
– Subclauses 7.102 through 7.108 have been restructured.
The contents of the corrigendum of December 2021 and July 2022 have been included in this copy.

IEC 62271-110:2023 is applicable to AC switching devices designed for indoor or outdoor installation, for operation at frequencies of 50 Hz and 60 Hz on systems having voltages above 1 000 V and applied for inductive current switching. It is applicable to switching devices (including circuit-breakers in accordance with IEC 62271-100) that are used to switch high‑voltage motor currents and shunt reactor currents and also to high-voltage contactors used to switch high-voltage motor currents as covered by IEC 62271-106. This fifth edition cancels and replaces the fourth edition published in 2017. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: references to IEC 62271-100 and IEC 62271-106 have been updated to the latest editions.

IEC 62271-102:2018 applies to alternating current disconnectors and earthing switches, designed for indoor and outdoor installations for nominal voltages above 1 000 V and for service frequencies up to and including 60 Hz.
This second edition cancels and replaces the first edition published in 2001, Amendment 1:2011 and Amendment 2:2013. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:  
new numbering according to IEC 17/1025/RQ to harmonize with ISO/IEC Directives, Part 2, and IEEE Std. C37.100.1;
clause numbering has been aligned with IEC 62271-1:2017;
the Scope has been extended to cover all indoor and outdoor installations. Consideration of switching devices having disconnecting and/or earthing switch functionalities, apart from other functions, are also covered by this document;
ratings have been moved from Annexes B, C and E to Clause 5; the order of the subclauses now corresponds to the order of subclauses in Clause 7;
new rating values for bus-transfer current and bus-transfer voltage have been assigned;
new class of mechanical endurance for earthing switches has been added (M1);
subclause "Rated values of electrical endurance for earthing switches" is now called "Classification of earthing switches for short-circuit making capability";
new subclause with ratings for ice-coating has been added;
new subclause with classification of bus-charging switching capability has been added;
new withstand requirements for interlocking devices have been added;
the way to comply with the requirements of the isolating distance of disconnectors has been modified;
design and construction requirements for position-indicating devices have been modified, aligning the requirements for position indication and signalling;
the value of the operating force has been changed;
the test procedures and validation criteria have been revised and modified where necessary;
requirements for applied voltage during single-phase test on non-simultaneous closing earthing switches have been changed;
non-verifiable requirements have been deleted;
a new subclause has been added for testing mechanical interlocking devices;
the high- and low-temperature test is mandatory if the temperature limits for the service conditions of the apparatus (defined by the manufacturer) are above +40 °C or below −5 °C, and a more detailed testing procedure is given;
the testing procedure to verify the proper functioning of the position-indicating device allows a more practicable testing for every technology used;
a new Annex B has been added with title: "Current-switching capability required of disconnectors and earthing switches";
a new Annex C has been added with title: "Tolerances on test quantities for type tests";
a new Annex E has been added with title: "Extension of validity of type tests".

IEC 62271-101:2021 mainly applies to AC circuit-breakers within the scope of IEC 62271-100. It provides the general rules for testing AC circuit-breakers, for making and breaking capacities over the range of test duties described in 7.102 to 7.111 of IEC 62271-100:2021, by synthetic methods.
It has been proven that synthetic testing is an economical and technically correct way to test high-voltage AC circuit-breakers according to the requirements of IEC 62271-100 and that it is equivalent to direct testing.
The methods and techniques described are those in general use. The purpose of this document is to establish criteria for synthetic testing and for the proper evaluation of results. Such criteria will establish the validity of the test method without imposing restraints on innovation of test circuitry.
This third edition cancels and replaces the second edition published in 2012 and Amendment 1:2017. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the second edition:
a) alignment with the third edition of IEC 62271-100:2021;
b) update this document with the last methods and techniques used for synthetic tests.
The contents of the corrigendum of October 2021 have been included in this copy.

IEC 62271-112:2021 applies to AC high-speed earthing switches (hereinafter termed HSES) designed for indoor and outdoor installation and for operation at service frequencies of 50 Hz and 60 Hz on systems having rated voltages of 550 kV and above. HSESs described in this document are intended to extinguish the secondary arc remaining after clearing faults on transmission lines by the circuit-breakers. For more detailed information on HSESs, refer to Annex A. This second edition cancels and replaces the first edition published in 2013. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: The document has been updated to the second edition of IEC 62271-1:2017.

IEC 62271-105:2021 applies to three-pole units for public and industrial distribution systems which are functional assemblies of switches composed of switches or switch-disconnectors and current-limiting fuses designed so as to be capable of
- breaking, at the rated voltage, any current up to and including the rated short-circuit breaking current;
- making, at the rated voltage, circuits to which the rated short-circuit breaking current applies.
This third edition cancels and replaces the second edition published in 2012. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
- the document has been updated to be in alignment with the second edition of IEC 62271-1:2017;
- rated TRV has been removed (TRV is only a test parameter), as in the latest revision of IEC 62271-100;
- differentiation has been introduced between requirements expressed for fulfilling the function expected from a switch-fuse combination, from requirements only relevant when the function is performed by a stand-alone device. The goal is to avoid duplication or conflicts of requirements with a standard dealing with assemblies, when the function is implemented within such an assembly.

IEC 62271-103:2021 is applicable to three-phase, alternating current switches and switch-disconnectors for their switching function, having making and breaking current ratings, for indoor and outdoor installations, for rated voltages above 1 kV up to and including 52 kV and for rated frequencies from 162/3 Hz up to and including 60 Hz. This document is also applicable to single-pole switches used on three-phase systems. This second edition cancels and replaces the first edition published in 2011. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
- this document has been aligned with IEC 62271-1:2017 and IEC 62271-102:2018;
- clarifications regarding the behaviour of the switch during breaking tests regarding current interruption and restrikes have been added;
- conditions of the switch after making and breaking tests have been clarified;
- a new informative Annex B intended to provide guidance for the calculation of Ief1 and Ief2 has been added;
- new rules for the combination of 50 Hz and 60 Hz switching tests have been defined and a new table (Table 7) has been added;
- tests with specified TRV have been modified to be in accordance with the practice described in IEC 62271-100;
- the behaviour of the switch during breaking tests has been clarified and boundaries for restrike allowance have been defined;
- explanations for short-circuit making tests have been added;
- vacuum integrity check after mechanical operations has been defined;
- all test voltages for single-phase capacitive testing have been grouped under 7.101.7.3.2 and have been confirmed by simulation and calculation.

IEC 62271-106:2021 applies to AC contactors and/or contactor-based controllers and motor-starters designed for indoor installation and operation at frequencies up to and including 60 Hz on systems having voltages above 1 kV and up to and including 24 kV. This document also includes additional requirements for outdoor installations where the equipment is housed in an additional protective enclosure.
This second edition cancels and replaces the first edition published in 2011. It constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
document numbered to correspond to IEC 62271-1 2017.

IEC 62271-104:2020 is applicable to three-pole alternating current switches for rated voltages higher than 52 kV, having making and breaking current ratings, for indoor and outdoor installations, and for rated frequencies up to and including 60 Hz.
This third edition replaces and cancels the second edition published in 2015. It constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
- new numbering, following IEC 62271-1:2017.

IEC 62271-108:2020 applies to high-voltage alternating current disconnecting circuit-breakers for operation at frequencies of 50 Hz and 60 Hz on systems having voltages above 52 kV.
This second edition cancels and replaces the first edition published in 2005. This edition contains the following significant technical changes with respect to the previous edition:
- The document has been restructured according to IEC 62271-1:2017.
- The document has been adapted to some of the changes introduced in IEC 62271-100:–[1].
- The document has been adapted to some of the changes introduced in IEC 62271-102:2018.
- References have been reviewed and updated.
- Some definitions have been reviewed and adapted to the latest IEV editions.
- Rated static terminal load and static terminal load test have been removed and a design requirement for static mechanical loads has been included.
- Additional type tests for auxiliary and control circuits have been included.
- X-radiation test procedure for vacuum interrupters has been included.
- Type test for testing of interlocking device and type test for testing of temporary mechanical locking devices have been included.
- Special requirements for making and breaking tests on class E2 disconnecting circuit-breakers have been removed.
[1] Under preparation. Stage at the time of publication: IEC CDV 62271-100:2020.

IEC 62271-107:2019 applies to three-pole-operated fused circuit-switchers designed with rated voltages above 1 kV up to and including 52 kV for use on three-phase alternating current systems of either 50 Hz or 60 Hz. This third edition cancels and replaces the second edition published in 2012. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a) technical changes introduced by the second edition of IEC 62271-1 are applied, where relevant;
b) rated TRV is removed and TRV is now treated as a test parameter), as in IEC 62271-100;
c) the term "thermal current" is no longer used; the rated continuous current is linked to the installed fuse-links, and values shall be provided by the manufacturer together with the list of the acceptable fuse-links; for tests purpose, the highest rated continuous current listed is referred, where previously the wording was "rated maximum thermal current", for consistency with IEC 62271-105;
d) making and breaking test duties are independent type tests (as some may be omitted if the switching device has been validated as a load-break switch). However, TDIt0 and TDIlow are kept as a sequence as they are linked to the same rated value (It0);
e) differentiation has been introduced between requirements expressed for fulfilling the function expected from a fused circuit-switcher, from requirements only relevant when the function is performed by a stand-alone device. The goal is to avoid duplication or conflicts of requirements with a standard dealing with assemblies, when the function is implemented within such an assembly.

IEC 62271-109:2019 is applicable to AC series capacitor by-pass switches designed for outdoor installation and for operation at frequencies of 50 Hz and 60 Hz on systems having voltages above 52 kV. It is only applicable to by-pass switches for use in three-phase systems. This document is also applicable to the operating devices of by-pass switches and to their auxiliary equipment. This third edition cancels and replaces the second edition published in 2008 and Amendment 1:2013. This edition constitutes a technical revision. This edition contains the following significant technical changes with respect to the previous edition:
a) the document has been restructured according to edition 2.0 of IEC 62271-1;
b) the rated voltage assignation across the by-pass switch has been aligned to the rule defined in IEC 60143-1;
c) clarification has been given regarding rated continuous current of compensated and uncompensated line;
d) some clarifications have been given following a loss of "suitable precautions";
e) as per Amendment 2 of IEC 62271-100, the section "Rated time quantities" has been moved to Clause 6 under "Time quantities";
f) as per Amendment 2 of IEC 62271-100, the section "Test for static mechanical loads" have been moved to Clause 6 under "Static mechanical loads";
g) additional rules have been introduced for vacuum interrupters during impulse tests;
h) additional clarifications have been given regarding the number of reduced impulses during impulse tests;
i) a wider tolerance on the current damping during by-pass making current test-duty has been introduced.

IEC 62271-111:2019 applies to all overhead, pad-mounted, dry vault and submersible single or multi-pole alternating current automatic circuit reclosers for rated maximum voltages above 1 000 V and up to and including 38 kV.
Devices that require a dependent manual operation are not covered by this document.
In order to simplify this document where possible, the term recloser (or reclosers) has been substituted for automatic circuit recloser(s) or cutout mounted recloser(s) or both.
This third edition cancels and replaces the second edition, published in 2012, and constitutes a technical revision. The main changes with respect to the previous edition are as follows:
a) Deletion of the fault interrupter from the title, scope and body of the standard including the original Annex G. IEEE will develop a separate standard for this type of equipment used primarily in North America to be designated as IEEE C37.62;
b) Adoption of IEC 62271-1:2017 as a normative reference replacing both IEEE C37.100.1-2007 and IEC 62271-1:2007;
c) Adoption of the “standard test method” for the conduction of wet tests for both IEEE and IEC voltage ratings, reference 7.2.7.2 and Tables 2 and 3;
d) Line and cable charging tests in 7.101.6: added test voltage level requirements;
e) Added test specifications in 7.103.3 and 7.103.5 for effectively earthed neutral systems (first-pole-to-clear factor kpp = 1,3) making this an optional rating. The kpp parameters are used in lieu of the system terms;
f) Added low current tests in 7.104 as a replacement of the critical current tests;
g) Adopted the revised allowable temperature rise table of IEC 62271-1:2017 with an increase in the allowable temperature rise for certain points in non-oxidizing gases (NOG);
h) Time-current test requirements in 7.108: several changes including increased number of test current levels and tests at each level. Specified minimum number of curves to be tested;
i) Mechanical duty tests in 7.109: added requirements for testing at high and low temperature;
j) Replaced normative references IEC 60255-22-1 and IEC 60255-22-4 with IEC 60255-26 in 7.111.1;
k) Added pass/fail criteria for fault interruption tests with restrikes in 7.112.1;
l) Added Clauses 9, 10, 11, 12 and 13 similar to those in IEC 62271-1 but tailored to the recloser;
m) Deleted Annex A: Information and technical requirements to be given with enquiries, tenders and orders.
International Standard IEC 62271-111/IEEE Std C37.60 has been jointly revised by the Switchgear Committee of the IEEE Power and Energy Society, in cooperation with subcommittee 17A: Switching devices, of IEC technical committee 17: High-voltage switchgear and controlgear, under the IEC/IEEE Dual Logo Agreement.

The contents of the corrigendum of January 2018 have been included in this copy.

IEC 62271-110:2017 is applicable to AC switching devices designed for indoor or outdoor installation, for operation at frequencies of 50 Hz and 60 Hz on systems having voltages above 1 000 V and applied for inductive current switching. It is applicable to switching devices (including circuit-breakers in accordance with IEC 62271-100) that are used to switch high‑voltage motor currents and shunt reactor currents and also to high-voltage contactors used to switch high-voltage motor currents as covered by IEC 62271-106. This fourth edition cancels and replaces the third edition published in 2012 and constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
- all switching devices are now covered, not only circuit-breakers;
- a limited number of T10 tests no longer covers shunt-reactor switching tests below 52 kV;
- evaluation and reporting of a re-ignition-free arcing time window has been added.
The contents of the corrigendum of December 2017 and of February 2018 have been included in this copy.

The contents of the corrigendum 1 of January 2018 have been included in this copy.

IEC/IEEE 62271-37-013:2015(E) is applicable to three-phase a.c. high-voltage generator circuit-breakers, hereafter called generator circuit-breaker, designed for indoor or outdoor installation and for operation at frequencies of 50 Hz and 60 Hz on systems having voltages above 1 kV and up to 38 kV. It is applicable to generator circuit-breakers that are installed between the generator and the transformer terminals. Requirements relative to generator circuit-breakers intended for use with generators and transformers rated 10 MVA or more are covered specifically. Generator circuits rated less than 10 MVA and pumped storage installations are considered special applications, and their requirements are not completely covered by this standard. This standard is also applicable to the operating mechanisms of generator circuit-breakers and to their auxiliary equipment. This standard has been prepared by a joint working group comprised of members both from IEC 17A/WG 52 representing subcommittee 17A: High-voltage switchgear and controlgear, of IEC technical committee 17: Switchgear and controlgear, in cooperation with IEEE WG P62271-37-013 representing the Switchgear Committee of the Power and Energy Society of the IEEE, under the IEC/IEEE Dual Logo Agreement.
The contents of the corrigendum of June 2017 have been included in this copy.

IEC 62271-104:2015 is applicable to three-pole alternating current switches for rated voltages higher than 52 kV, having making and breaking current ratings, for indoor and outdoor installations, and for rated frequencies up to and including 60 Hz. This standard is also applicable to the operating devices of these switches and to their auxiliary equipment. This second edition replaces and cancels the first edition published in 2009 and constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
- the title was changed such that the voltage range now is >52 kV instead of ≥52 kV;
- the references have been updated;
- the comments in 17A/1063/RVC have been addressed.
This publication is to be read in conjunction with IEC 62271-1:2007, IEC 62271-100:2008, IEC 62271-102:2001  and IEC 62271-110:2012.

Gives guidance on the selection of appropriate electrical apparatus, protected by flame-proof enclosure or designed to be intrinsically safe, according to the gas or vapour in which it is intended to be used.[
]This publication has the status of a technical Report, type 3.

IEC 62271-4:2013 applies to the procedures for handling of SF6 during installation, commissioning, normal and abnormal operations, disposal at the end of life of high voltage switchgear and controlgear. This first edition cancels and replaces the first edition of IEC/TR 62271-303 published in 2008. This first edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a) the description of the potential effects on health of SF6 by products (former Annex D of IEC/TR 62271-303:2008) has been replaced by the calculation methods for evaluating of the potential effects on health of SF6 by products (see Annex H);
b) information about cryogenic reclaim of SF6. Have been added (see Annex I);
c) handling procedures for the most popular SF6 mixtures have been added (see Annex J).

IEC 62271-112:2013 applies to a.c. high-speed earthing switches designed for indoor and outdoor installation and for operation at service frequencies of 50 Hz and 60 Hz on systems having voltages of 550 kV and above. High-speed earthing switches described in this standard are intended to extinguish the secondary arc remaining after clearing faults on transmission lines by the circuit-breakers.
This publication is to be read in conjunction with IEC 62271-1:2007.

Applies to alternating current disconnectors and earthing switches, designed for indoor and outdoor enclosed and open terminal installations for voltages above 1 000 V and for service frequencies up to and including 60 Hz. It also applies to the operating devices of these disconnectors and earthing switches and their auxiliary equipment. Additional requirements for disconnectors and earthing switches in enclosed switchgear and controlgear are given in IEC 60298, IEC 60466 and IEC 60517. Note: Disconnectors in which the fuse forms an integral part are not covered by this standard. This first edition cancels and replaces the third edition of IEC 60129 published in 1984, amendment 1 (1992) and amendment 2 (1996) and constitutes a technical revision. In addition, it replaces IEC 61128, IEC 61129 and IEC 61259, which are hereby withdrawn and cancelled. This bilingual version (2003-07) replaces the English version. The contents of the corrigenda of April 2002, May 2003, February 2005 and June 2014 have been included in this copy.

IEC/TR 62271-306:2012(E) is applicable to a.c. circuit-breakers designed for indoor or outdoor installation and for operation at frequencies of 50 Hz and 60 Hz on systems having voltages above 1 000 V. This technical report addresses utility, consultant and industrial engineers who specify and apply high-voltage circuit-breakers, circuit-breaker development engineers, engineers in testing stations, and engineers who participate in standardization. It is intended to provide background information concerning the facts and figures in the standards and provide a basis for specification for high-voltage circuit-breakers. Thus, its scope will cover the explanation, interpretation and application of IEC 62271-100 and IEC 62271-1 as well as related standards and technical reports with respect to high-voltage circuit-breakers.

IEC/IEEE 62271-37-082:2012(E) provides methods for the measurement of sound pressure level produced by outdoor alternating current circuit-breakers in a free-field environment. These methods may also be used indoors or in restricted field, provided that precautions are observed in the measurement and interpretation of the results. This standard has been prepared by subcommittee 17A: High-voltage switchgear and controlgear, of IEC technical committee 17: Switchgear and controlgear, in cooperation with the Switchgear Committee of the IEEE Power & Energy Society, under the IEC/IEEE Dual Logo Agreement between IEC and IEEE. The contents of the corrigendum of January 2014 have been included in this copy.

IEC 62271-101:2012 mainly applies to a.c. circuit-breakers within the scope of IEC 62271-100. It provides the general rules for testing a.c. circuit-breakers, for making and breaking capacities over the range of test duties described in 6.102 to 6.111 of IEC 62271-100:2008, by synthetic methods. This second edition cancels and replaces the first edition published in 2007 and its Amendment 1 published in 2011. It constitutes a technical revision. This edition includes the following significant technical changes with respect to the first edition:
- addition of the new rated voltages of 1 100 kV and 1 200 kV;
- revision of Annex F regarding circuit-breakers with opening resistors;
- alignment with the second edition of IEC 62271-100:2008 and its Amendment 1 (2012).
This publication is to be read in conjunction with IEC 62271-100:2008.

IEC 62271-105:2012 applies to three-pole units for public and industrial distribution systems which are functional assemblies of switches including switch-disconnectors and current-limiting fuses designed so as to be capable of
- breaking, at the rated recovery voltage, any current up to and including the rated short-circuit breaking current;
- making, at the rated voltage, circuits to which the rated short-circuit breaking current applies.
It does not apply to fuse-circuit-breakers, fuse-contactors, combinations for motor-circuits or to combinations incorporating single capacitor bank switches. This second edition cancels and replaces the first edition of IEC 62271-105, published in 2002, and constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
- implementation of figures at the place where they are cited first;
- renumbering of tables;
- addition of some of the proposals from IEC paper 17A/852/INF;
- addition of missing subclauses of IEC 62271-1;
- implementation of 6.105 "Extension of validity of type tests" and consequently removing of the relevant parts in the different existing clauses;
- change of 7th paragraph of 6.101.4 as there is now a definition of NSDD given in 3.7.4 of IEC 62271-1:2007. Harmonization with IEC 62271-107;
- some referenced clauses in other standards like IEC 60282-1 were changed and therefore changed the editions under 1.2 to the ones referred to;
- addition of a new Annex C defining tolerances.
This publication is to be read in conjunction with IEC 62271-1:2007.