EN IEC 63066:2026

• Abstract:

  This document applies to docking connectors (hereinafter referred to as accessories) incorporated in or fixed to electrical equipment, intended to connect energy storage units, either removable or swappable, or both, to a dedicated electric power conversion unit, to an energy consuming unit or to another energy storage unit.; These accessories are intended for DC and can include either a protective earth contact or optional auxiliary contacts for signalling and data transmission, or both. These accessories have a rated current of up to 2 000 A and rated operating voltages not exceeding 1 500 V DC.; This document also applies to accessories intended to be used at extra-low voltage.; The list of preferred ratings is not intended to exclude other ratings.; These accessories are not suitable for mating or unmating under load. These accessories are intended to be installed by instructed persons (IEC 60050-195:2021, 195-04-02) or skilled persons (IEC 60050-195:2021, 195-04-01) only.; This document applies to accessories for use under environmental conditions as described in Clause 31.; These accessories are intended to be connected to current carrying parts in copper or copper ; alloy only, plated or not plated.; In locations where special conditions prevail, additional requirements can apply.; NOTE For conditions other than operation, additional requirements can be applicable, for instance, IEC 62133 (all parts) and UN Recommendations on the Transport of Dangerous Goods (2002), section 38.338.3.

• Status: Published
• Publication Date: 10-Sep-2026
• ICS: 29.120.30 - Plugs, socket-outlets, couplers
• Technical Committee: CLC/TC 23H - Plugs, Socket-outlets and Couplers for industrial and similar applications, and for Electric Vehicles
• Current Stage: 6060 - Document made available - Publishing
• Start Date: 11-Sep-2026
• Due Date: 02-Nov-2026
• Completion Date: 11-Sep-2026
• Ref Project: SIST EN IEC 63066:2026 - Low-voltage docking connectors for removable energy storage units (IEC 63066:2026)

• Refers: EN 60352-5:2001/A1:2003 - Solderless connections - Part 5: Press-in connections - General requirements, test methods and practical guidance
• Effective Date: 04-Aug-2026
• Refers: EN 60352-7:2002 - Solderless connections - Part 7: Spring clamp connections - General requirements, test methods and practical guidance
• Effective Date: 04-Aug-2026
• Refers: EN 60352-4:1994 - Solderless connections - Part 4: Solderless non-accessible insulation displacement connections - General requirements, test methods and practical guidance
• Effective Date: 04-Aug-2026
• Refers: EN 60352-2:1994/A1:1997 - Solderless connections - Part 2: Solderless crimped connections - General requirements, test methods and practical guidance
• Effective Date: 04-Aug-2026
• Refers: EN IEC 62619:2022 - Secondary cells and batteries containing alkaline or other non-acid electrolytes - Safety requirements for secondary lithium cells and batteries, for use in industrial applications
• Effective Date: 04-Aug-2026
• Refers: EN 60068-2-60:2015 - Environmental testing - Part 2-60: Tests - Test Ke: Flowing mixed gas corrosion test
• Effective Date: 04-Aug-2026
• Refers: EN IEC 60068-2-52:2018 - Environmental testing - Part 2-52: Tests - Test Kb: Salt mist, cyclic (sodium chloride solution)
• Effective Date: 04-Aug-2026
• Refers: EN 60352-6:1997 - Solderless connections - Part 6: Insulation piercing connections - General requirements, test methods and practical guidance
• Effective Date: 04-Aug-2026
• Refers: EN 60352-2:1994/A2:2002 - Solderless connections - Part 2: Solderless crimped connections - General requirements, test methods and practical guidance
• Effective Date: 04-Aug-2026
• Refers: EN IEC 60068-2-2:2025 - Environmental testing - Part 2-2: Tests - Test B: Dry heat
• Effective Date: 04-Aug-2026
• Refers: EN IEC 60068-2-14:2023 - Environmental testing - Part 2-14: Tests - Test N: Change of temperature
• Effective Date: 04-Aug-2026
• Refers: EN 50525-2-31:2011 - Electric cables - Low voltage energy cables of rated voltages up to and including 450/750 V (U0/U) - Part 2-31: Cables for general applications - Single core non-sheathed cables with thermoplastic PVC insulation
• Effective Date: 04-Aug-2026
• Refers: EN 60512-2-2:2003 - Connectors for electronic equipment - Tests and measurements - Part 2-2: Electrical continuity and contact resistance tests - Test 2b: Contact resistance - Specified test current method
• Effective Date: 04-Aug-2026
• Refers: EN 60352-5:2008 - Solderless connections - Part 5: Press-in connections - General requirements, test methods and practical guidance
• Effective Date: 04-Aug-2026
• Refers: HD 60364-5-54:2011 - Low-voltage electrical installations - Part 5-54: Selection and erection of electrical equipment - Earthing arrangements and protective conductors
• Effective Date: 04-Aug-2026

SLOVENSKI STANDARD
01-december-2026
Nizkonapetostni priključni konektorji za odstranljive enote za shranjevanje
energije (IEC 63066:2026)
Low-voltage docking connectors for removable energy storage units (IEC 63066:2026)
Niederspannungs-Andockstecker für abnehmbare Energiespeicher (IEC 63066:2026)
Connecteurs de raccordement à basse tension pour unités de stockage d'énergie
amovibles (IEC 63066:2026)
Ta slovenski standard je istoveten z: EN IEC 63066:2026
ICS:
29.120.30 Vtiči, vtičnice, spojke Plugs, socket-outlets,
couplers
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 63066

NORME EUROPÉENNE
EUROPÄISCHE NORM September 2026
ICS 29.120.30
English Version
Low-voltage docking connectors for removable energy storage
units
(IEC 63066:2026)
Connecteurs de raccordement à basse tension pour unités Niederspannungs-Andockstecker für abnehmbare
de stockage d'énergie amovibles Energiespeicher
(IEC 63066:2026) (IEC 63066:2026)
This European Standard was approved by CENELEC on 2026-08-14. 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, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 63066:2026 E
European foreword
The text of document 23H/592/FDIS, future edition 1 of IEC 63066, prepared by SC 23H "Plugs,
Socket-outlets and Couplers for industrial and similar applications, and for Electric Vehicles" of
IEC/TC 23 "Electrical accessories" was submitted to the IEC-CENELEC parallel vote and approved by
CENELEC as EN IEC 63066:2026.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2027-09-30
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2029-09-30
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 shall not be held responsible for identifying any or all such patent rights.
This document is read in conjunction with EN IEC 60309-1:2022.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 63066:2026 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standard indicated:
IEC 61851-23 NOTE Approved as EN 61851-23
IEC 62133 (series) NOTE Approved as EN 62133-2:2017/A1 (series)
IEC 62196-3:2026 NOTE Approved as EN IEC 62196-3:2026 (not modified)
ISO 2768 (series) NOTE Approved as EN 22768-1 (series)
ISO 14405-1:2025 NOTE Approved as EN ISO 14405-1:2025 (not modified)
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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.
NOTE 1  Where an International Publication has been modified by common modifications, indicated by (mod),
the relevant EN/HD applies.
NOTE 2  Up-to-date information on the latest versions of the European Standards listed in this annex is available
here: www.cencenelec.eu.
Clause 2 of EN IEC 60309-1:2022 applies, except as follows:
Publication Year Title EN/HD Year
IEC 60068-2-2 - Environmental testing - Part 2-2: Tests - EN IEC 60068-2-2 -
Test B: Dry heat
IEC 60068-2-14 - Environmental testing - Part 2-14: Tests - EN IEC 60068-2-14 -
Test N: Change of temperature
IEC 60068-2-30 - Environmental testing - Part 2-30: Tests - EN IEC 60068-2-30 -
Test Db: Damp heat, cyclic (12 h + 12 h
cycle)
IEC 60068-2-38 - Environmental testing - Part 2-38: Tests - EN IEC 60068-2-38 -
Test Z/AD: Composite
temperature/humidity cyclic test
IEC 60068-2-52 - Environmental testing - Part 2-52: Tests - EN IEC 60068-2-52 -
Test Kb: Salt mist, cyclic (sodium chloride
solution)
IEC 60068-2-60 - Environmental testing - Part 2-60: Tests - EN 60068-2-60 -
Test Ke: Flowing mixed gas corrosion test
IEC 60227-3 - Polyvinyl chloride insulated cables of rated - -
voltages up to and including 450/750 V -
Part 3: Non-sheathed cables for fixed
wiring
IEC 60309-1 2021 Plugs, fixed or portable socket-outlets and EN IEC 60309-1 2022
appliance inlets for industrial purposes -
Part 1: General requirements
IEC 60352 series Solderless connections - Part 1: Wrapped EN 60352 series
connections - General requirements, test
methods and practical guidance
IEC 60364-5-54 2011 Low-voltage electrical installations - Part 5- HD 60364-5-54 2011
54: Selection and erection of electrical
equipment - Earthing arrangements and
protective conductors
- - + A11 2017
+ A1 2021
IEC 60417 - Graphical symbols for use on equipment. - -
Index, survey and compilation of the single
sheets.
IEC 60512-2-2 - Connectors for electronic equipment - EN 60512-2-2 -
Tests and measurements - Part 2-2:
Electrical continuity and contact resistance
tests - Test 2b: Contact resistance -
Specified test current method
IEC 61140 2016 Protection against electric shock - EN 61140 2016
Common aspects for installation and
equipment
IEC 61373 2010 Railway applications - Rolling stock EN 61373 2010
equipment - Shock and vibration tests
IEC 62619 2022 Secondary cells and batteries containing EN IEC 62619 2022
alkaline or other non-acid electrolytes -
Safety requirements for secondary lithium
cells and batteries, for use in industrial
applications
IEC 62840-2 2025 Electric vehicle battery swap system - Part EN IEC 62840-2 2025
2: Safety requirements
IEC PAS 62840-3 2021 Electric vehicle battery swap system - Part - -
3: Particular safety and interoperability
requirements for battery swap systems
operating with removable RESS/battery
systems
ISO/IEC/TR 29106 2007 Information technology - Generic cabling - - -
Introduction to the MICE environmental
classification
+ A1 2012
+A2 2019
ISO 16750-3 2023 Road vehicles - Environmental conditions - -
and testing for electrical and electronic
equipment – Part 3: Mechanical loads

Copper and copper alloys - Copper rod, EN 13601 2021
bar and wire for general electrical purposes
DIN 43671 1975-12 Stromschienen aus Kupfer; Bemessung für - -
Dauerstrom, only available in German

IEC 63066 ®
Edition 1.0 2026-07
INTERNATIONAL
STANDARD
Low-voltage docking connectors for removable energy storage units

ICS 29.120.30  ISBN 978-2-8327-1362-4

IEC 63066:2026-07(en)
IEC 63066:2026 © IEC 2026
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 9
4 General . 10
4.1 General requirements. 10
4.2 General notes on tests . 10
4.3 Type of accessories . 10
4.4 General construction . 11
4.5 Visual examination tests . 12
4.6 Cable to be used . 12
4.7 Voltage and current for test purposes . 12
5 Standard ratings . 12
6 Classification of accessories . 13
7 Marking . 15
7.1 Information to be marked . 15
7.2 Symbols . 15
7.3 Marking of rewirable accessories. 16
7.4 Pre-wired accessories . 16
7.5 Instructions . 16
7.6 Marking shall be easily legible . 16
8 Dimensions . 16
9 Protection against electric shock . 17
10 Provision for earthing . 18
11 Terminals and terminations . 18
12 Interlocks . 19
13 Resistance to ageing of rubber and thermoplastic material . 19
14 Construction. 19
15 Construction of accessories . 20
16 Degrees of protection . 20
17 Insulation resistance and dielectric strength . 20
18 Mechanical endurance . 20
19 Temperature rise . 21
20 Mechanical strength . 21
21 Screws, current-carrying parts and connections . 21
22 Creepage distances, clearances and distances through sealing compound . 21
23 Resistance to heat, to fire and to tracking . 21
24 Conditional short-circuit current withstand test . 21
25 Electromagnetic compatibility . 21
26 Dynamic mechanical severities . 22
26.1 Minimum degree of dynamic mechanical severities . 22
26.2 Vibration test . 22
IEC 63066:2026 © IEC 2026
26.3 Shock test . 22
27 Thermal endurance . 23
27.1 General requirements. 23
27.2 Temperature burden . 23
27.3 Damp heat . 23
27.4 Contact resistance . 24
28 Climatic endurance for contacts . 24
28.1 General requirements for contacts . 24
28.2 Thermal change for contacts . 24
28.3 Dry heat for contacts . 24
28.4 Corrosion resistance for contacts . 25
28.5 Damp heat for contacts . 25
29 Salt stress endurance . 25
29.1 General requirements for accessories . 25
29.2 Salt stress resistance . 25
30 Operation with misalignments . 26
30.1 Misalignment at normal operation . 26
30.2 Misalignment after unmating . 29
30.3 Misalignment by terminated wires . 29
30.4 Mating process effected by misalignment . 30
31 Environmental conditions . 31
STANDARD SHEET 1-I – Electrically-powered two-wheeler (e-PTW) docking connector
– General . 33
STANDARD SHEET 1-III – DOCKING CONNECTOR TYPE A . 34
STANDARD SHEET 1-II – DOCKING CONNECTOR TYPE B . 35
STANDARD SHEET 1-IV – DOCKING CONNECTORS, TYPE A – TYPE B – Overview
of the interface . 36
STANDARD SHEET 2-I – Light electric vehicle (LEV) docking connector – GENERAL . 37
STANDARD SHEET 2-II – DOCKING CONNECTOR TYPE A . 38
STANDARD SHEET 2-III – DOCKING CONNECTOR TYPE B . 39
STANDARD SHEET 3-I – Battery System for Modularity (BASYMO) – GENERAL . 40
STANDARD SHEET 3-II – DOCKING CONNECTOR TYPE A – Top connection . 41
STANDARD SHEET 3-II – DOCKING CONNECTOR TYPE A – Top connection . 42
STANDARD SHEET 3-II – DOCKING CONNECTOR TYPE A – Bottom connection . 43
STANDARD SHEET 3-III – DOCKING CONNECTOR TYPE B – Top connection . 44
STANDARD SHEET 3-III – DOCKING CONNECTOR TYPE B – Wall connector /
bottom connection . 45
STANDARD SHEET 4-I – Busbar connection system – GENERAL . 46
STANDARD SHEET 4-II . 47
STANDARD SHEET 4-II – Dimensions. 48
STANDARD SHEET 5-I – Electrically-powered two-wheeler (e-PTW) docking connector
– GENERAL . 49
STANDARD SHEET 5-II – Electrically-powered two-wheeler (e-PTW) docking
connector – DOCKING CONNECTOR TYPE A. 50
STANDARD SHEET 5-III – Electrically-powered two-wheeler (e-PTW) docking
connector – DOCKING CONNECTOR TYPE B. 51
IEC 63066:2026 © IEC 2026
STANDARD SHEET 5-IV – Electrically-powered two-wheeler (e-PTW) docking
connector – Configuration DOCKING CONNECTOR TYPE A and B . 52
STANDARD SHEET 6-I – GENERAL . 53
STANDARD SHEET 6-II – DOCKING CONNECTOR TYPE A . 54
STANDARD SHEET 6-III – DOCKING CONNECTOR TYPE B . 55
STANDARD SHEET 6-IV – Overview of the basic interface – Configuration DOCKING
CONNECTOR TYPE A AND B . 56
STANDARD SHEET 6-V – Service condition (mated) – DOCKING CONNECTOR TYPE
A AND B . 57
Annex A (normative) Electrical endurance test cycle . 58
Annex B (informative) Examples of accessories on the market . 59
B.1 General . 59
B.2 Accessory example 1 . 59
B.3 Accessory example 2 . 63
Bibliography . 66

Figure 1 – Diagram showing the use of the accessories. 11
Figure 2 – Short-circuit scheme for line contacts . 19
Figure 3 – Orthogonal misalignment – front view. 27
Figure 4 – Angular misalignment – side view . 27
Figure 5 – Angular misalignment – top view . 27
Figure A.1 – Test cycle for electrical endurance. 58
Figure B.1 – Layout of accessory example 1 . 60
Figure B.2 – Accessory example 1 Type A . 61
Figure B.3 – Accessory example 1 Type B . 62
Figure B.4 – Accessory example 2 Type A . 64
Figure B.5 – Accessory example 2 Type B . 65

Table 1 – General design and usage of accessories . 11
Table 2 – Preferred rated currents . 12
Table 3 – Dimensions of misalignments . 27
Table 4 – Combinations of misalignments . 28
Table 5 – Misalignment due to wire size. 30
Table 6 – Environmental performance classes . 31
Table 7 – Severities for environmental performance classes . 32
Table B.1 – Parameters for accessory example 1 . 59
Table B.2 – Parameters for accessory example 2 . 63

IEC 63066:2026 © IEC 2026
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Low-voltage docking connectors for removable energy storage units

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their
preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
may participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for
Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence between
any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
may be required to implement this document. However, implementers are cautioned that this may not represent
the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
IEC 63066 has been prepared by subcommittee 23H: Plugs, socket-outlets and couplers for
industrial and similar applications, and for electric vehicles, of IEC technical committee 23:
Electrical accessories. It is an International Standard.
This first edition cancels and replaces the first edition of IEC TS 63066 published in 2017. This
edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) introduction of standard sheets;
b) alignment with IEC 60309-1:2021;
c) technical improvements, e.g. short circuit tests according the I t- methodology.
IEC 63066:2026 © IEC 2026
The text of this International Standard is based on the following documents:
Draft Report on voting
23H/592/FDIS 23H/615/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
In this document, the following print types are used:
– requirements proper: in roman type;
– test specifications: in italic type;
– explanatory matter: in smaller roman type.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
This document is to be used in conjunction with IEC 60309-1:2021.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
– reconfirmed,
– withdrawn, or
– revised.
IEC 63066:2026 © IEC 2026
INTRODUCTION
Pluggable energy storage technology has a perspective of a large demand in certain areas.
With the advent of electric vehicles, which are expected to become one of the most significant
types of electric users of electric energy, together with the heating and cooling of buildings, the
demand of electric energy from renewable sources rather than from fossil fuels will rapidly
increase.
Due to the intrinsic discontinuity of the renewable sources (wind, solar light), energy storage
units for renewable energy are becoming a possible solution to cover peak power demands,
when in an increasingly decentralized electric power network infrastructure.
Guidance is needed to ensure safe and reliable operation, interoperability, environmental
protection and efficiency of energy storage technology, once made available in a connectorized,
thus pluggable, form.
This document is intended to meet the industry needs of standardized docking connector
interfaces as a means to promote the development of this promising technology and the
popularization of pluggable energy storage units.
Compared to other accessories, for the connectors required by this technology several specific
aspects are considered:
– the connector mating process cannot have haptic support by the operator to find the correct
position between the two parts of the connector;
– the connector mating process can have a mechanical feed which precludes the finding of
the correct position between the two parts of the connector.
To overcome these issues, the design of the accessories can consist partly of moveable parts
to compensate a mechanical feed and constructional tolerances.

IEC 63066:2026 © IEC 2026
1 Scope
This document applies to docking connectors (hereinafter referred to as accessories)
incorporated in or fixed to electrical equipment, intended to connect energy storage units, either
removable or swappable, or both, to a dedicated electric power conversion unit, to an energy
consuming unit or to another energy storage unit.
These accessories are intended for DC and can include either a protective earth contact or
optional auxiliary contacts for signalling and data transmission, or both. These accessories
have a rated current of up to 2 000 A and rated operating voltages not exceeding 1 500 V DC.
This document also applies to accessories intended to be used at extra-low voltage.
The list of preferred ratings is not intended to exclude other ratings.
These accessories are not suitable for mating or unmating under load. These accessories are
intended to be installed by instructed persons (IEC 60050-195:2021, 195-04-02) or skilled
persons (IEC 60050-195:2021, 195-04-01) only.
This document applies to accessories for use under environmental conditions as described in
Clause 31.
These accessories are intended to be connected to current carrying parts in copper or copper
alloy only, plated or not plated.
In locations where special conditions prevail, additional requirements can apply.
NOTE For conditions other than operation, additional requirements can be applicable, for instance, IEC 62133 (all
parts) and UN Recommendations on the Transport of Dangerous Goods (2002), section 38.338.3.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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.
Clause 2 of IEC 60309-1:2021 applies, except as follows:
Additional normative references:
IEC 60068-2-2, Environmental testing - Part 2-2: Tests - Test B: Dry heat
IEC 60068-2-14, Environmental testing - Part 2-14: Tests - Test N: Change of temperature
IEC 60068-2-30, Environmental testing - Part 2-30: Tests - Test Db: Damp heat, cyclic
(12 h + 12 h cycle)
IEC 60068-2-38, Environmental testing - Part 2-38: Tests - Test Z/AD: Composite
temperature/humidity cyclic test
IEC 60068-2-52, Environmental testing - Part 2-52: Tests - Test Kb: Salt mist, cyclic (sodium
chloride solution)
IEC 60068-2-60, Environmental testing - Part 2-60: Tests - Test Ke: Flowing mixed gas
corrosion test
IEC 63066:2026 © IEC 2026
IEC 60227-3, Polyvinyl chloride insulated cables of rated voltages up to and including
450/750 V - Part 3: Non-sheathed cables for fixed wiring
IEC 60309-1:2021, Plugs, fixed or portable socket-outlets and appliance inlets for industrial
purposes - Part 1: General requirements
IEC 60352 (all parts), Solderless connections
IEC 60364-5-54:2011, Low-voltage electrical installations - Part 5-54: Selection and erection of
electrical equipment - Earthing arrangements and protective conductors
IEC 60364-5-54:2011/AMD1:2021
IEC 60417, Graphical symbols for use on equipment, available at http://www.graphical-
symbols.info/equipment
IEC 60512-2-2, Connectors for electronic equipment – Tests and measurements – Part 2-2:
Electrical continuity and contact resistance tests – Test 2b: Contact resistance – Specified test
current method
IEC 61140:2016, Protection against electric shock - Common aspects for installation and
equipment
IEC 61373:2010, Railway applications - Rolling stock equipment - Shock and vibration tests
IEC 62619:2022, Secondary cells and batteries containing alkaline or other non-acid
electrolytes – Safety requirements for secondary lithium cells and batteries, for use in industrial
applications
IEC 62840-2:2025, Electric vehicle battery swap system – Part 2: Safety requirements
IEC PAS 62840-3:2021, Electric vehicle battery swap system - Part 3: Particular safety and
interoperability requirements for battery swap systems operating with removable RESS/battery
systems
ISO/IEC TR 29106:2007, Information technology - Generic cabling - Introduction to the MICE
environmental classification
ISO/IEC TR 29106:2007/AMD1:2012
ISO/IEC TR 29106:2007/AMD2:2019
ISO 16750-3:2023, Road vehicles - Environmental conditions and testing for electrical and
electronic equipment - Part 3: Mechanical loads
EN 13601:2021, Copper and copper alloys - Copper rod, bar and wire for general electrical
purposes
DIN 43671:1975-12, Stromschienen aus Kupfer; Bemessung für Dauerstrom, only available in
German
IEC 63066:2026 © IEC 2026
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60309-1:2021 and
the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
– IEC Electropedia: available at https://www.electropedia.org/
– ISO Online browsing platform: available at https://www.iso.org/obp
3.1
docking connector
electrical connection accessory where the two complementary accessories are equipped with
guiding means allowing their connection without the haptic support of an operator
3.2
unmated condition
position of the accessory without any contact between both parts
3.3
mated condition
service condition and position where the two parts of the accessory are in a position as
described in the relevant standard sheet
3.4
guiding means
mechanical structure intended to ensure the proper alignment of the two complementary
accessories before their mating
3.5
RESU
removable energy storage unit
energy storage unit, which can be easily detached and inserted into a rack to establish the
electrical connection with an accessory
3.6
rack
mechanical structure intended to incorporate one or more removable energy storage units
3.7
electric power conversion unit
device converting electric energy from one form to another, converting between AC and DC, or
changing the voltage or frequency, or a combination of these
3.8
shutter
movable part incorporated into an accessory arranged to automatically shield at least the live
contacts when the complementary accessory is withdrawn
[SOURCE: IEC 60884-1:2022, 3.29, modified – "socket-outlet" is replaced with "an accessory",
and "socket-contacts automatically when the plug is withdrawn" is replaced with " contacts when
the complementary accessory is withdrawn".]
3.9
superordinate system
overall technical system as a set of components or systems with relationships between the
components or systems and between their attributes
IEC 63066:2026 © IEC 2026
4 General
Clause 4 of IEC 60309-1:2021 applies, except as follows:
4.1 General requirements
Replacement of the fourth paragraph with:
Accessories shall have a minimum IP degree of protection as indicated in Table 7, test variable
TV1.
In the case of a superordinate system providing the IP degree of protection, the IP-tests shall
be performed with the superordinate system.
4.2 General notes on tests
Subclause 4.2 of IEC 60309-1:2021 applies.
Additional subclause:
4.3 Type of accessories
Requirements mentioned for docking accessories called fixed socket-outlet or portable socket-
outlet are applicable for accessories Type A.
Requirements mentioned for complementary docking accessories called plug or appliance inlet
are applicable for accessories Type B.
Figure 1 shows an example of how the accessory can be used.
IEC 63066:2026 © IEC 2026
Key
A docking accessory Type A
B complementary docking accessory Type B
C removable energy storage unit
D rack
E guiding means (optional)
Figure 1 – Diagram showing the use of the accessories
4.4 General construction
Different possibilities for the movement, adjustment and mating of components and accessories
are stated in Table 1.
Table 1 – General design and usage of accessories
Case Accessory Type A Accessory Type B RESU
of
Possibility of Self-adjustment to Possibility of Self-adjustment to Possibility of
use
movement relative the nominal movement relative the nominal movement
to the structure of position of the to the structure of position of the relative to the
the rack or RESU movable part after the RESU movable part after rack
disconnecting disconnecting
1 Not movable No Not movable No Not movable
2 Not movable No Not movable No Movable
3 Not movable No Movable No Not movable
4 Not movable No Movable Yes Not movable
5 Movable Yes Not movable No Not movable
6 Movable No Not movable No Not movable
NOTE Other combinations are not excluded.

IEC 63066:2026 © IEC 2026
See standard sheets for implementations of accessories. Annex B shows additional accessories
for information only.
4.5 Visual examination tests
If required by a test and unless otherwise specified, visual examination tests shall be performed
with the naked eye. The following characteristics shall be checked:
– quality of assembling before test;
– marking;
– materials;
– marks of corrosion;
– colour, change of colour after the test;
– impurities, contamination, particles of abrasion after the test;
– damages, holes, cracks;
– damaged and loosened parts;
– status and location of lubrication and glues.
No noticeable problems shall occur which could impair normal operation or show a deviation
from this document.
4.6 Cable to be used
Unless otherwise specified by the manufacturer, the following stranded cable shall be used for
the power contacts: H07V as specified in IEC 60227-3.
NOTE The DUT's technical specifications are a factor in cable selection.
4.7 Voltage and current for test purposes
As deviation from the referred test standards, tests can be performed with AC or DC.
5 Standard ratings
Clause 5 of IEC 60309-1:2021 applies, except as follows:
5.2 Replacement:
Preferred rated currents are given in Table 2.
Table 2 – Preferred rated currents
Rated current
A DC
IEC 63066:2026 © IEC 2026
Additional subclause:
5.3 Ratings for data, communication and control
Rated current for data, communication and control circuit purposes is 2 A or less according to
the manufacturer's specification.
Rated voltage for data, communication and control circuit purposes is 30 V or less according to
the manufacturer's specification.
6 Classification of accessories
Clause 6 of IEC 60309-1:2021 does not apply.
Replacement:
6.1 According to the type:
– accessories of Type A;
– accessories of Type B.
6.2 According to where the specified IP rating is provided:
– accessories that themselves provide the specified IP protection rating;
– accessories where the specified IP degree of protection is provided by the superordinate
system.
NOTE Minimum IP rating is specified by Table 7.
6.3 According to earthing facilities:
– accessories without earthing contact;
– accessories with earthing contact.
6.4 According to the method of connecting the cable:
– rewirable accessories;
– non-rewirable accessories.
6.5 According to interlocking facilities:
– accessories without interlock;
– accessories with mechanical interlock (with latching device);
– accessories with electrical interlock (without latching device);
– accessories with latching device and electrical interlock.
6.6 According to the type of terminals:
– screw type terminals;
– screwless type terminals;
– insulation displacing terminals.
6.7 According to the type of conductors for screwless type and insulation displacing terminals:
– for solid conductors only;
– for rigid (both solid and stranded) conductors only;
– for rigid (both solid and stranded) and flexible conductors.
IEC 63066:2026 © IEC 2026
6.8 According to accessibility to live parts when unmated:
– accessories providing for less than IPXXB;
– accessories providing for IPXXB;
– accessories providing for IPXXD.
6.9 According to locking facilities:
– non-lockable accessories;
– lockable accessories.
6.10 According to the presence of shutter(s):
– accessories without shutter(s);
– accessories with shutter(s).
6.11 According to their environmental performance class:
– accessories tested for use in environmental performance class C;
– accessories tested for use in environmental performance class O;
– accessories tested for use in environmental performance class I;
– accessories tested for use in environmental performance class X;
– accessories tested for use in environmental performance class R;
– accessories tested for use in environmental performance class T.
6.12 According to the case of use:
– accessories intended for use in case 1;
– accessories intended for use in case 2;
– accessories intended for use in case 3;
– accessories intended for use in case 4;
– accessories intended for use in case 5;
– accessories intended for use in case 6;
– accessories intended for use in other cases.
6.13 According to the exposure of corrosive gases:
– accessories intended for usage in an environment with corrosive gases;
– accessories not intended for usage in an environment with corrosive gases.
6.14 According to cable weight:
– as described in Table 5;
– as defined by the manufacturer
IEC 63066:2026 © IEC 2026
7 Marking
Clause 7 of IEC 60309-1:2021 does not apply.
Replacement:
7.1 Information to be marked
Accessories shall be marked with:
– either the name or trademark of the manufacturer or of the responsible vendor;
– rated current(s) in ampere;
– rated operat
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