EN IEC 63522-18:2025

Electrical relays - Tests and measurements - Part 18: Thermal resistance of the coil

IEC 63522-18:2025 This part of IEC 63522 is used for testing along with the appropriate severities and conditions for measurements and tests designed to assess the ability of DUTs to perform under expected conditions of transportation, storage and all aspects of operational use. The object of this test is to determine the thermal resistance of the relay coil.

Elektrische Relais - Mess- und Prüfverfahren - Teil 18: Thermischer Widerstand der Spule

Relais électriques - Essais et mesurages - Partie 18: Résistance thermique de la bobine

IEC 63522-18:2025 La présente partie de l'IEC 63522 traite des essais ainsi que des sévérités et conditions appropriées pour les mesurages et essais destinés à évaluer l'aptitude de DUT à fonctionner dans des conditions prévues de transport, de stockage, et de tous les aspects d'utilisation opérationnelle. L'objet de cet essai est de déterminer la résistance thermique de la bobine du relais.

Električni releji - Preskusi in meritve - 7-18. del: Toplotna upornost tuljave

Ta del standarda IEC 63522 se uporablja za preskušanje, vključno z ustreznimi stopnjami strogosti ter pogoji za meritve in preskuse, ki so bili zasnovani za ocenjevanje zmožnosti delovanja preskušanih naprav (DUT), v pričakovanih pogojih med transportom in skladiščenjem ter v vseh vidikih operativne uporabe.
Cilj tega preskusa je določiti toplotno upornost tuljave releja.

General Information

• Status: Published
• Publication Date: 03-Jul-2025
• ICS: 29.120.70 - Relays
• Technical Committee: CLC/SR 94 - All-or-nothing electrical relays
• Drafting Committee: IEC/TC 94 - IEC_TC_94
• Current Stage: 6060 - Document made available - Publishing
• Start Date: 04-Jul-2025
• Due Date: 19-Apr-2024
• Completion Date: 04-Jul-2025
• Ref Project: SIST EN IEC 63522-18:2025 - Electrical relays - Tests and Measurements - Part 7-18: Thermal resistance of the coil

Relations

• Refers: EN IEC 63522-10:2025 - Electrical relays - Tests and measurements - Part 10: Heating
• Effective Date: 03-Feb-2026
• Refers: prEN IEC 63522-0:2025 - Electrical relays - Tests and measurements - Part 0: General and guidance
• Effective Date: 03-Feb-2026

Overview

EN IEC 63522-18:2025 - "Electrical relays - Tests and measurements - Part 18: Thermal resistance of the coil" - establishes standardized procedures to test and measure the thermal resistance of relay coils. This European Standard, published by CENELEC (CLC), is essential for assessing the capability of relays to operate reliably under conditions of transportation, storage, and use. The document defines conditions and severities for determining the temperature rise and thermal characteristics of the device under test (DUT) in electrical applications.

Thermal resistance testing, as defined in this standard, enables manufacturers, testing laboratories, and quality assurance teams to evaluate relay durability and performance, improve product consistency, and support the integration of relays in demanding electrical and electronic systems.

Key Topics

EN IEC 63522-18:2025 covers the following essential topics for the electrical relay industry:

• Thermal Resistance Measurement: Defines the procedures and criteria for measuring the thermal resistance (R_th) of a relay coil, calculated as the ratio of temperature rise to input power after thermal equilibrium is reached.
• Test Conditions and Parameters: Specifies conditions for mounting, electrical energization, and environmental control to ensure repeatability and comparability.
• Temperature Coefficient Considerations: Addresses different conductor materials and their specific temperature coefficients.
• Four-point Measurement: Requires temperature rise and resistance to be measured at four different points in the operating range to ensure thorough thermal profiling.
• Test Reporting: Outlines the necessary information for documentation-including relay description, measurement values, and connection details-for traceability and compliance.

Applications

Adopting EN IEC 63522-18:2025 brings significant value to stakeholders in electrical relay manufacturing, testing, and application:

• Design and Product Development: Enables engineers to optimize relay coil designs for thermal performance, ensuring reliable function in end-use scenarios.
• Quality Control: Supports standardized acceptance criteria for relay coils, reducing variability and risk of thermal-related failures in service.
• Compliance and Certification: Provides a recognized framework for documenting and demonstrating product conformity to international standards, vital for market access within the EU and beyond.
• Reliability Engineering: Useful for assessing how relays perform under different transportation, storage, and operational stresses, informing lifecycle management.
• Risk Reduction: By understanding and mitigating heat build-up in relay coils, this standard helps prevent overheating, prolongs product life, and safeguards connected equipment.

Related Standards

EN IEC 63522-18:2025 is part of a broader suite of international standards on electrical relays and their performance assessment. Other relevant standards include:

• EN IEC 63522-0: Electrical relays - Tests and measurements - General and guidance. Provides foundational definitions, test environments, and general protocols.
• EN IEC 63522-10: Electrical relays - Tests and measurements - Heating. Addresses the heating characteristics of relays, closely related to thermal resistance measurements.
• IEC 60050-444: International Electrotechnical Vocabulary (IEV) - Elementary relays. Contains critical definitions and terminology for relay technology.

Implementers are encouraged to refer to these documents to ensure a comprehensive approach to relay testing, safety, and operational consistency.

For up-to-date information on standards and compliance resources, visit the CENELEC or IEC official websites.

Standards Content (Sample)

SLOVENSKI STANDARD
01-september-2025
Električni releji - Preskusi in meritve - 7-18. del: Toplotna upornost tuljave
Electrical relays - Tests and Measurements - Part 7-18: Thermal resistance of the coil
Elektrische Relais - Mess- und Prüfverfahren – Teil 18: Thermischer Widerstand der
Spule
Relais électriques - Essais et mesurages - Partie 18: Résistance thermique de la bobine
Ta slovenski standard je istoveten z: EN IEC 63522-18:2025
ICS:
29.120.70 Releji Relays
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 63522-18

NORME EUROPÉENNE
EUROPÄISCHE NORM July 2025
ICS 29.120.70
English Version
Electrical relays - Tests and measurements - Part 18: Thermal
resistance of the coil
(IEC 63522-18:2025)
Relais électriques - Essais et mesurages - Partie 18: Elektrische Relais - Mess- und Prüfverfahren - Teil 18:
Résistance thermique de la bobine Thermischer Widerstand der Spule
(IEC 63522-18:2025) (IEC 63522-18:2025)
This European Standard was approved by CENELEC on 2025-06-25. 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
© 2025 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 63522-18:2025 E

European foreword
The text of document 94/1060/FDIS, future edition 1 of IEC 63522-18, prepared by TC 94 "Electrical
relays" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2026-07-31
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2028-07-31
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 63522-0:—
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 63522-18:2025 was approved by CENELEC as a European
Standard without any modification.

Under preparation. Stage at the time of publication: prEN IEC 63522-0:2024.
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.
Publication Year Title EN/HD Year
2 3
IEC 63522-0 — Electrical relays - Tests and Measurements EN IEC 63522-0 —
- Part 0: General and Guidance
4 5
IEC 63522-10 — Electrical relays - Tests and measurements EN IEC 63522-10 —
- Part 10: Heating
Under preparation. Stage at the time of publication: IEC CDV 63522-0:2024.
Under preparation. Stage at the time of publication: prEN IEC 63522-0:2024.
Under preparation. Stage at the time of publication: IEC FDIS 63522-10:2025.
Under preparation. Stage at the time of publication: FprEN IEC 63522-10:2025.
IEC 63522-18 ®
Edition 1.0 2025-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electrical relays – Tests and measurements –
Part 18: Thermal resistance of the coil

Relais électriques – Essais et mesurages –
Partie 18: Résistance thermique de la bobine
ICS 29.120.70  ISBN 978-2-8327-0403-5

IEC 63522-18:2025-05(en-fr)
– 2 – IEC 63522-18:2025 © IEC 2025
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Test procedure . 6
4.1 Purpose . 6
4.2 Procedure . 6
4.3 Conditions . 7
5 Evaluation . 7
5.1 General . 7
5.2 Test report . 7
Bibliography . 8

IEC 63522-18:2025 © IEC 2025 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRICAL RELAYS –
TESTS AND MEASUREMENTS –
Part 18: Thermal resistance of the coil

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 t
...