SIST EN IEC 63522-24:2025

Electrical relays - Tests and Measurements - Part 7-24: Load transfer

IEC 63522-24:2025 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.
This document defines a test to check that a multipole relay is capable of transferring one source to another.

Elektrische Relais – Mess- und Prüfverfahren – Teil 24: Lastübertragung

Relais électriques - Essais et mesurages - Partie 24: Transfert de charge

IEC 63522-24:2025 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.
Le présent document défini un essai qui permet de vérifier qu'un relais multiple est capable d'effectuer un transfert d'une source à une autre.

Električni releji - Preskusi in meritve - 7-24. del: Prenos obremenitve

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.
Ta dokument določa preskus, s katerim se preverja, ali je večpolni rele zmožen prenesti en vir na drugega.

General Information

• Status: Published
• Public Enquiry End Date: 27-Sep-2023
• Publication Date: 25-Jun-2025
• ICS: 29.120.70 - Relays
• Technical Committee: ISS EIT.ERE - All-or-nothing electrical relays
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 11-Jun-2025
• Due Date: 16-Aug-2025
• Completion Date: 26-Jun-2025
• Ref Project: EN IEC 63522-24:2025 - Electrical relays - Tests and measurements - Part 24: Load transfer

Overview

SIST EN IEC 63522-24:2025 is a European standard developed by the CLC under the International Electrotechnical Commission (IEC) framework. It forms part 24 of the series on Electrical relays - Tests and measurements, specifically focused on Load transfer. This standard defines a standardized test procedure to evaluate the ability of multipole electrical relays to transfer electrical load from one source to another reliably under expected conditions of transportation, storage, and operational use.

The document is critical for manufacturers, testing laboratories, and quality assurance professionals involved in the design, validation, and certification of multipole relays used in three-phase or multiphase electrical systems. Compliance ensures that relays meet necessary functional requirements for load transfer in real-world applications without failure or safety issues.

Key Topics

• Scope and Purpose: The standard is designed to test electrical relays with two or more changeover contacts to verify their capability to switch loads between different power sources under nominal voltages, frequencies, and load parameters.

• Test Conditions:

  • Voltage and frequency set according to product specifications.
  • Load resistors included to simulate operational conditions.
  • A fuse rated at 5% of the rated load current or 100 mA (whichever is greater) to protect the circuit.
  • Relay energization cycles generally fixed at 1,000 cycles, with operate and release times of (5 ± 1) seconds each.

• Test Procedure Overview:
  The relay is connected to a dedicated test circuit simulating real system configurations. It is then repeatedly operated to switch load sources while monitoring for:

  • Contact malfunctions.
  • Phase-to-phase arcing or sparking beyond half a cycle.
  • Fuse integrity (no blowing allowed).

• Performance Evaluation:
  After testing, relays undergo further verification through functional tests (IEC 63522-7), dielectric strength tests (IEC 63522-4), and contact resistance measurements (IEC 63522-6) to confirm operational conformity.

• Test Reporting Requirements:
  Reports must include all relevant technical parameters-energization values, voltage, frequency, load details, fuse rating, cycling times, any anomalies such as breaking or flashovers, and additional observations-to ensure transparency and reproducibility of test results.

Applications

SIST EN IEC 63522-24:2025 is applicable primarily to multipole relays used in electrical power distribution and industrial automation systems, particularly where switching between multiple power sources is required without interrupting load continuity. Typical applications include:

• Automatic transfer switches in power supply systems requiring source redundancy.
• Safety and control relays within critical industrial machinery.
• Electrical grid automation equipment where load transfer reliability is crucial.
• Transportation and storage testing for relays to guarantee robustness over lifecycle conditions.

By applying this standard, manufacturers ensure enhanced relay reliability, increased safety during operation, and compliance with international safety and performance benchmarks. Test laboratories utilize this standard to provide certification services, which support quality assurance and regulatory approvals of relay products.

Related Standards

SIST EN IEC 63522-24:2025 should be used in conjunction with other parts of the IEC 63522 series for comprehensive testing and evaluation of electrical relays:

• IEC 63522-0: Electrical relays - Tests and measurements - Part 0: General and guidance
• IEC 63522-4: Electrical relays - Tests and measurements - Part 4: Dielectric strength test
• IEC 63522-6: Electrical relays - Tests and measurements - Part 6: Contact-circuit resistance or voltage drop
• IEC 63522-7: Electrical relays - Tests and measurements - Part 7: Functional tests

These standards collectively provide a full testing framework covering all critical aspects of relay performance including electrical endurance, insulation capabilities, and functional integrity.

---

SIST EN IEC 63522-24:2025 is an essential international standard promoting reliable load transfer capabilities in multipole electrical relays, supporting manufacturers and users in enhancing product quality, safety, and compliance in diverse electrical systems worldwide.

Standards Content (Sample)

SLOVENSKI STANDARD
01-september-2025
Električni releji - Preskusi in meritve - 7-24. del: Prenos obremenitve
Electrical relays - Tests and Measurements - Part 7-24: Load transfer
Elektrische Relais – Mess- und Prüfverfahren – Teil 24: Lastübertragung
Relais électriques - Essais et mesurages - Partie 24: Transfert de charge
Ta slovenski standard je istoveten z: EN IEC 63522-24:2025
ICS:
29.120.70 Releji Relays
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 63522-24

NORME EUROPÉENNE
EUROPÄISCHE NORM June 2025
ICS 29.120.70
English Version
Electrical relays - Tests and measurements - Part 24: Load
transfer
(IEC 63522-24:2025)
Relais électriques - Essais et mesurages - Partie 24: Elektrische Relais - Mess- und Prüfverfahren - Teil 24:
Transfert de charge Lastübertragung
(IEC 63522-24:2025) (IEC 63522-24:2025)
This European Standard was approved by CENELEC on 2025-05-28. 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 63522-24:2025 E

European foreword
The text of document 94/1054/FDIS, future edition 1 of IEC 63522-24, 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) 2026-06-30
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2028-06-30
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 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 63522-24:2025 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 63522-4 - Electrical relays - Tests and measurements EN IEC 63522-4 -
- Part 4: Dielectric strength test
IEC 63522-6 - Electrical relays - Tests and measurements EN IEC 63522-6 -
- Part 6: Contact-circuit resistance or
voltage drop
IEC 63522-7 - Electrical relays - Tests and measurements EN IEC 63522-7 -
- Part 7: Functional tests
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 63522-4:2024.
Under preparation. Stage at the time of publication: FprEN IEC 63522-4:2024.
IEC 63522-24 ®
Edition 1.0 2025-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electrical relays – Tests and measurements –

Part 24: Load transfer
Relais électriques – Essais et mesurages –

Partie 24: Transfert de charge

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.120.70  ISBN 978-2-8327-0356-4

– 2 – IEC 63522-24:2025 © IEC 2025
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Test procedure . 5
4.1 Purpose . 5
4.2 Procedure . 6
4.3 Conditions . 6
5 Evaluation . 7
5.1 General . 7
5.2 Test report . 7

Figure 1 – Test circuit for load transfer . 6

IEC 63522-24:2025 © IEC 2025 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRICAL RELAYS –
TESTS AND MEASUREMENTS –
Part 24: Load transfer
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 preparator
...