IEC 63522-33:2025

Electrical relays - Tests and measurements - Part 33: Continuity of protective earthing connection

IEC 63522-33:2025 This part of IEC 63522 is used for testing all kind of electrical relays and for evaluating their ability to perform under expected conditions of transportation, storage and all aspects of operational use.
This document provides test methods to ensure that the connection between an earthing terminal and parts required to be connected thereto is of low resistance.

Relais électriques - Essais et mesurages - Partie 33: Continuité de la connexion de terre de protection

IEC 63522-33:2025 La présente partie de l'IEC 63522 traite des essais de tous les types de relais électriques et elle évalue leur aptitude à fonctionner dans les conditions prévues de transport, de stockage et dans tous les aspects de leur utilisation opérationnelle. Le présent document donne des méthodes d’essai permettant d’assurer que la connexion entre une borne de terre et les parties qui doivent y être raccordées est de faible résistance.

General Information

• Status: Published
• Publication Date: 18-Aug-2025
• ICS: 29.120.70 - Relays
• Technical Committee: TC 94 - Electrical relays
• Drafting Committee: WG 3 - TC 94/WG 3
• Current Stage: PPUB - Publication issued
• Start Date: 19-Aug-2025
• Completion Date: 12-Sep-2025

Overview

IEC 63522-33:2025 – Electrical relays – Tests and measurements – Part 33: Continuity of protective earthing connection is an international standard developed by the International Electrotechnical Commission (IEC). This standard specifies test methods to evaluate the ability of all types of electrical relays to maintain a reliable and low-resistance connection between an earthing terminal and parts required to be connected during transportation, storage, and all aspects of operational use.

Ensuring the continuity of the protective earthing connection is a vital safety aspect for electrical relays, particularly those intended for connection to mains circuits. Proper earthing helps prevent electric shock, protects against equipment failure, and ensures compliance with global safety requirements.

Key Topics

• Scope of Application
  IEC 63522-33 applies to various types of electrical relays, including electromechanical relays, reed relays, time relays, solid state relays, and combinations of these technologies. The standard is relevant for all relays equipped with an earthing terminal intended for use in systems connected to the mains.

• Test Methods
  The document outlines methods to verify that the connection between the earthing terminal and required parts maintains a low resistance:

  • Application of a defined test current (at least 1.5 times the rated current, not less than 25A) at a controlled voltage (maximum 12V AC or DC).
  • Measurement of voltage drop to determine the resistance of the earthing connection.
  • Alternative test procedures may be used if they yield consistent and repeatable results.

• Test Conditions
  The standard specifies critical parameters to be set before testing, including:

  • Test current and voltage
  • Identification of all parts that require earthing connection
  • Resistance limit (commonly not exceeding 0.1 Ω)
  • Any deviations from the main procedure

• Reporting and Evaluation
  Detailed guidance is provided for evaluating results and reporting:

  • Confirmation that the measured resistance does not exceed specified limits
  • Documentation of test conditions, devices under test, probe application points, and test equipment
  • Recommendations for standalone or integrated test reporting

Applications

IEC 63522-33:2025 is essential for:

• Manufacturers
  Ensuring consistent manufacturing quality and safety compliance of relays intended for international markets. Verification of earthing integrity risk-reduces product liability and field issues.

• Testing Laboratories
  Providing a uniform method for safety and compliance testing of electrical relays before market entry or as part of certification schemes.

• Product Designers and Engineers
  Assisting in the proper design and construction of relay products with reliable earthing connections, facilitating compliance from the outset.

• Regulatory and Certification Bodies
  Offering a clear standard against which products can be assessed for conformity to earthing continuity requirements.

Related Standards

• IEC 63522-0
  Electrical relays – Tests and measurements – Part 0: Testing – General and guidance (foundational document for series)

• IEC 60050-195
  International Electrotechnical Vocabulary (IEV) – Part 195: Earthing and protection against electric shock (for terminology)

Users of IEC 63522-33:2025 should consult these related standards for comprehensive testing, terminology, and guidance on electrical relays and earthing requirements.

Keywords: IEC 63522-33, electrical relays, earthing continuity, protective earthing connection, relay testing, low resistance, relay standards, relay safety, international electrotechnical standards, electrical safety compliance.

Standards Content (Sample)

IEC 63522-33 ®
Edition 1.0 2025-08
INTERNATIONAL
STANDARD
Electrical relays- Tests and measurements -
Part 33: Continuity of protective earthing connection
ICS 29.120.70  ISBN 978-2-8327-0649-7

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or
by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either
IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC copyright
or have an enquiry about obtaining additional rights to this publication, please contact the address below or your local
IEC member National Committee for further information.

IEC Secretariat Tel.: [phone]
3, rue de Varembé [e-mail]
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About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
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CONTENTS
FOREWORD . 2
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Test procedure . 4
4.1 Purpose . 4
4.2 Procedure . 5
4.3 Conditions . 5
5 Evaluation . 5
5.1 General . 5
5.2 Test report . 5
Bibliography . 6

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Electrical relays - Tests and measurements -
Part 33: Continuity of protective earthing connection

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
...

IEC 63522-33 ®
Edition 1.0 2025-08
NORME
INTERNATIONALE
Relais électriques - Essais et mesurages -
Partie 33: Continuité de la connexion de terre de protection
ICS 29.120.70  ISBN 978-2-8327-0649-7

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite ni
utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie et
les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des
questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
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A propos de l'IEC
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Normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

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SOMMAIRE
AVANT-PROPOS . 2
1 Domaine d'application . 4
2 Références normatives . 4
3 Termes et définitions. 4
4 Procédure d'essai . 4
4.1 Objet . 4
4.2 Procédure . 5
4.3 Conditions . 5
5 Évaluation . 5
5.1 Généralités . 5
5.2 Rapport d'essai . 5
Bibliographie . 6

COMMISSION ÉLECTROTECHNIQUE INTERNATIONALE
____________
Relais électriques - Essais et mesurages -
Partie 33: Continuité de la connexion de terre de protection

AVANT-PROPOS
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ou au crédit qu
...

IEC 63522-33 ®
Edition 1.0 2025-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electrical relays - Tests and measurements -
Part 33: Continuity of protective earthing connection

Relais électriques - Essais et mesurages -
Partie 33: Continuité de la connexion de terre de protection
ICS 29.120.70  ISBN 978-2-8327-0649-7

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or
by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either
IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC copyright
or have an enquiry about obtaining additional rights to this publication, please contact the address below or your local
IEC member National Committee for further information.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite ni
utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie et
les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des
questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.

IEC Secretariat Tel.: [phone]
3, rue de Varembé [e-mail]
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.

IEC publications search - IEC Products & Services Portal - products.iec.ch
webstore.iec.ch/advsearchform Discover our powerful search engine and read freely all the
The advanced search enables to find IEC publications by a publications previews, graphical symbols and the glossary.
variety of criteria (reference number, text, technical With a subscription you will always have access to up to date
committee, …). It also gives information on projects, content tailored to your needs.
replaced and withdrawn publications.
Electropedia - www.electropedia.org
IEC Just Published - webstore.iec.ch/justpublished The world's leading online dictionary on electrotechnology,
Stay up to date on all new IEC publications. Just Published containing more than 22 500 terminological entries in English
details all new publications released. Available online and and French, with equivalent terms in 25 additional languages.
once a month by email. Also known as the International Electrotechnical Vocabulary
(IEV) online.
IEC Customer Service Centre - webstore.iec.ch/csc
If you wish to give us your feedback on this publication or
need further assistance, please contact the Customer
Service Centre: [e-mail].
A propos de l'IEC
La Commission Electrotechnique Internationale (IEC) est la première organisation mondiale qui élabore et publie des
Normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

A propos des publications IEC
Le contenu technique des publications IEC est constamment revu. Veuillez vous assurer que vous possédez l’édition la
plus récente, un corrigendum ou amendement peut avoir été publié.

Recherche de publications IEC -  IEC Products & Services Portal - products.iec.ch
webstore.iec.ch/advsearchform Découvrez notre puissant moteur de recherche et consultez
La recherche avancée permet de trouver des publications gratuitement tous les aperçus des publications, symboles
IEC en utilisant différents critères (numéro de référence, graphiques et le glossaire. Avec un abonnement, vous aurez
texte, comité d’études, …). Elle donne aussi des toujours accès à un contenu à jour adapté à vos besoins.
informations sur les projets et les publications remplacées
ou retirées. Electropedia - www.electropedia.org

Le premier dictionnaire d'électrotechnologie en ligne au
IEC Just Published - webstore.iec.ch/justpublished monde, avec plus de 22 500 articles terminologiques en
Restez informé sur les nouvelles publications IEC. Just anglais et en français, ainsi que les termes équivalents
Published détaille les nouvelles publications parues. dans 25 langues additionnelles. Egalement appelé
Disponible en ligne et une fois par mois par email. Vocabulaire Electrotechnique International (IEV) en ligne.

Service Clients - webstore.iec.ch/csc
Si vous désirez nous donner des commentaires sur cette
publication ou si vous avez des questions contactez-
nous: [e-mail].
CONTENTS
FOREWORD . 2
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Test procedure . 4
4.1 Purpose . 4
4.2 Procedure . 5
4.3 Conditions . 5
5 Evaluation . 5
5.1 General . 5
5.2 Test report . 5
Bibliography . 6

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Electrical relays - Tests and measurements -
Part 33: Continuity of protective earthing connection

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
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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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 63522-33 has been prepared by IEC technical committee 94: Electrical relays. It is an
International Standard.
The text of this International Standard is based on the following documents:
Draft Report on voting
94/1129/FDIS 94/1161/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.
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 International Standard is to be used in conjunction with IEC 63522-0:— .
A list of all parts of IEC 63522 series, published under the general title Electrical relays – Tests
and measurements, can be found on the IEC website.
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.
___________
Under preparation: Stage at the time of publication: IEC/CDV 63522-0:2024.
1 Scope
This part of IEC 63522 is used for testing all kind of electrical relays and for evaluating their
ability to perform under expected conditions of transportation, storage and all aspects of
operational use.
NOTE Examples for electrical relays in the sense of this document include electromechanical relays, reed relays,
reed contacts, reed switches, solid state relays, time relays and technology combinations of these.
This document provides test methods to ensure that the connection between an earthing
terminal and parts required to be connected thereto is of low resistance.
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.
IEC 63522-0:—, Electrical relays - Tests and measurements - Part 0: Testing - General and
guidance
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 63522-0:— 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
earthing terminal
terminal provided on equipment and intended for the electric connection with the earthing
arrangement
Note 1 to entry: Earthing terminals are indicated by the protected earth sign in the proximity of the terminal.
[SOURCE: IEC 60050-195:2021, 195-02-31, modified – Note 1 to entry has been added.]
4 Test procedure
4.1 Purpose
To ensure that the connection between an earthing terminal and parts required to be connected
thereto is of low resistance. This test applies only to relays suitable to be connected to mains
circuits and which are provided with an earthing terminal.
NOTE Typically, product standards give constructional requirements on earthing terminals like cross section of
wires, place of earthing terminal, tightening forces of screws, etc.
___________
Under preparation: Stage at the time of publication: IEC/CDV 63522-0:2024
4.2 Procedure
A current of 1,5 times the rated current, but not less than 25 A, derived from a source with a
no-load voltage not exceeding 12 V (AC or DC), is applied between the earthing terminal and
each of
...