EN IEC 60335-2-51:2023

• Abstract:

  This European Standard deals with the safety of electric stationary circulation pumps for household and similar purposes intended for use in heating systems or in service water systems, their rated voltage being not more than 250 V for single-phase appliances and 480 V for other appliances.

• Status: Published
• Publication Date: 09-Nov-2023
• ICS: 23.080 - Pumps
• ICS: 91.140.10 - Central heating systems
• Technical Committee: CLC/TC 61 - Safety of household and similar electrical appliances
• Drafting Committee: CLC/TC 61 - Safety of household and similar electrical appliances
• Current Stage: 6060 - Document made available - Publishing
• Start Date: 10-Nov-2023
• Due Date: 03-Sep-2022
• Completion Date: 10-Nov-2023
• Directive: Harmonized Standard2006/42/EC - Directive 2006/42/EC of the European Parliament and of the Council of 17 May 2006 on machinery, and amending Directive 95/16/EC (recast)
• Directive:

  ---

  Harmonized Standard2014/35/EU - Directive 2014/35/EU of the European Parliament and of the Council of 26 February 2014 on the harmonisation of the laws of the Member States relating to the making available on the market of electrical equipment designed for use within certain voltage limits
  OJ Ref: 2024/2764, OJ L, OJ L, 2024/2764 OJ Date: 31-Oct-2024
• Mandate: M/396 - Mandate to CEN and Cenelec for standardisation in the field of machinery
• Mandate: M/511 - Mandate to CEN, CENELEC and ETSI relating to harmonised standards in the field of the Low Voltage Directive
• Ref Project: SIST EN IEC 60335-2-51:2024 - Household and similar electrical appliances - Safety - Part 2-51: Particular requirements for stationary circulation pumps for heating and service water installations (IEC 60335-2-51:2019)

• Replaces: EN 60335-2-51:2003/A1:2008 - Household and similar electrical appliances - Safety - Part 2-51: Particular requirements for stationary circulation pumps for heating and service water installations
• Effective Date: 23-Jan-2023
• Replaces: EN 60335-2-51:2003/A2:2012 - Household and similar electrical appliances - Safety - Part 2-51: Particular requirements for stationary circulation pumps for heating and service water installations
• Effective Date: 03-Mar-2020
• Replaces: EN 60335-2-51:2003 - Household and similar electrical appliances - Safety - Part 2-51: Particular requirements for stationary circulation pumps for heating and service water installations
• Effective Date: 03-Mar-2020
• Referred By: EN 12976-1:2021 - Thermal solar systems and components - Factory made systems - Part 1: General requirements
• Effective Date: 09-Feb-2026
• Referred By: EN 12976-1:2017 - Thermal solar systems and components - Factory made systems - Part 1: General requirements
• Effective Date: 09-Feb-2026
• Referred By: EN IEC 60335-2-40:2023 - Household and similar electrical appliances - Safety - Part 2-40: Particular requirements for electrical heat pumps, air-conditioners and dehumidifiers
• Effective Date: 03-Feb-2026
• Referred By: EN 62282-3-100:2012 - Fuel cell technologies - Part 3-100: Stationary fuel cell power systems - Safety
• Effective Date: 03-Feb-2026
• Referred By: EN IEC 62282-3-100:2020 - Fuel cell technologies - Part 3-100: Stationary fuel cell power systems - Safety
• Effective Date: 03-Feb-2026
• Amended By: EN IEC 60335-2-51:2023/A11:2023 - Household and similar electrical appliances - Safety - Part 2-51: Particular requirements for stationary circulation pumps for heating and service water installations
• Effective Date: 03-Mar-2020

Overview

EN IEC 60335-2-51:2023 (adopted from IEC 60335-2-51:2019) is the European safety standard for stationary circulation pumps used in household and similar heating and service water installations. It applies to electric circulation pumps with rated voltages up to 250 V for single‑phase appliances and 480 V for other appliances. This Part 2 standard supplements and modifies the general safety requirements in IEC 60335-1 and is intended for manufacturers, test laboratories and conformity bodies ensuring safe pump design, construction and testing.

Key topics and requirements

EN IEC 60335-2-51 covers specific safety and test requirements, including:

• Scope and classification of circulation pumps for heating and service water systems.
• Marking and instructions: required product labels and user/installation guidance.
• Protection against live parts and safeguards for electrical access.
• Motor starting and power input/current requirements and tests.
• Heating and temperature classification (see Table 101 in the standard).
• Leakage current and electric strength tests at operating temperature, including updated leakage current guidance.
• Moisture resistance, transient overvoltages and insulation requirements.
• Endurance, abnormal operation and overload protection for motors and associated circuits.
• Mechanical strength, stability and construction to prevent mechanical hazards.
• Internal wiring, components, supply connections and earthing provisions.
• Clearances, creepage distances, resistance to heat, fire and rusting, plus radiation/toxicity considerations.
• Routine tests and informative annexes that support conformity assessment and testing procedures.

The document indicates which clauses of IEC 60335-1 are replaced, modified or supplemented, and includes normative and informative annexes for testing and EU Directive relationship.

Practical applications and who uses this standard

EN IEC 60335-2-51 is primarily used by:

• Pump manufacturers designing stationary circulation pumps for domestic heating and potable water systems to meet European safety and regulatory requirements.
• Test and certification laboratories performing safety tests, leakage current and endurance testing.
• Product safety and compliance engineers preparing technical files for CE marking and conformity with EU directives.
• HVAC designers, installers and specifiers who need to select compliant pumps for central heating and service-water installations.
• Regulators and notified bodies assessing product conformity and harmonized standards alignment.

Using this standard helps reduce electrical, thermal and mechanical hazards, supports market access in CENELEC member countries, and ensures compatibility with wiring rules and conformity assessment procedures.

Related standards

• IEC 60335-1 (general requirements for household and similar electrical appliances) - to be used in conjunction with this Part 2.
• Other Part 2 standards of IEC 60335 where multifunction appliances incorporate additional features.

Keywords: EN IEC 60335-2-51, stationary circulation pumps, safety standard, household electrical appliances, circulation pumps for heating, service water installations, CENELEC, IEC 60335-1, leakage current, CE marking, HVAC safety.

SLOVENSKI STANDARD
01-januar-2024
Gospodinjski in podobni električni aparati - Varnost - 2-51. del: Posebne zahteve
za vgrajene obtočne črpalke za grelne sisteme in vodovodne instalacije (IEC 60335
-2-51:2019)
Household and similar electrical appliances - Safety - Part 2-51: Particular requirements
for stationary circulation pumps for heating and service water installations (IEC 60335-2-
51:2019)
Sicherheit elektrischer Geräte für den Hausgebrauch und ähnliche Zwecke - Teil 2-51:
Besondere Anforderungen für ortsfeste Umwälzpumpen für Heizungs- und
Brauchwasseranlagen (IEC 60335-2-51:2019)
Appareils électrodomestiques et analogues - Sécurité - Partie 2-51: Exigences
particulières pour les pompes de circulation fixes pour installations de chauffage et de
distribution d'eau (IEC 60335-2-51:2019)
Ta slovenski standard je istoveten z: EN IEC 60335-2-51:2023
ICS:
23.080 Črpalke Pumps
91.140.10 Sistemi centralnega Central heating systems
ogrevanja
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 60335-2-51

NORME EUROPÉENNE
EUROPÄISCHE NORM October 2023
ICS 23.080; 91.140.10 Supersedes EN 60335-2-51:2003; EN 60335-2-
51:2003/A1:2008; EN 60335-2-51:2003/A2:2012
English Version
Household and similar electrical appliances - Safety - Part 2-51:
Particular requirements for stationary circulation pumps for
heating and service water installations
(IEC 60335-2-51:2019)
Appareils électrodomestiques et analogues - Sécurité - Sicherheit elektrischer Geräte für den Hausgebrauch und
Partie 2-51: Exigences particulières pour les pompes de ähnliche Zwecke - Teil 2-51: Besondere Anforderungen für
circulation fixes pour installations de chauffage et de ortsfeste Umwälzpumpen für Heizungs- und
distribution d'eau Brauchwasseranlagen
(IEC 60335-2-51:2019) (IEC 60335-2-51:2019)
This European Standard was approved by CENELEC on 2023-08-02. 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
© 2023 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 60335-2-51:2023 E

European foreword
This document (EN IEC 60335-2-51:2023) consists of the text of IEC 60335-2-51:2019 prepared by
IEC/TC 61 “Safety of household and similar electrical appliances”.
The following dates are fixed:
• latest date by which this document has to be (dop) 2024–08–02
implemented at national level by publication of an
identical national standard or by endorsement
• latest date by which the national standards conflicting (dow) 2026–08–02
with this 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 60335-2-51:2023/A11:2023.
This document has been prepared under a standardization request addressed to CENELEC by the
European Commission. The Standing Committee of the EFTA States subsequently approves these
requests for its Member States.
For the relationship with EU Directives see informative Annexes ZZA, which is an integral part of
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 60335-2-51:2019 was approved by CENELEC as a European
Standard without any modification.

IEC 60335-2-51 ®
Edition 4.0 2019-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Household and similar electrical appliances – Safety –

Part 2-51: Particular requirements for stationary circulation pumps for heating

and service water installations

Appareils électrodomestiques et analogues – Sécurité –

Partie 2-51: Exigences particulières pour les pompes de circulation fixes pour

installations de chauffage et de distribution d'eau

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 23.080; 91.140.10 ISBN 978-2-8322-6811-7

– 2 – IEC 60335-2-51:2019 © 2019
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 General requirement . 7
5 General conditions for the tests . 7
6 Classification . 7
7 Marking and instructions . 8
8 Protection against access to live parts . 8
9 Starting of motor-operated appliances . 8
10 Power input and current . 8
11 Heating . 9
12 Void . 9
13 Leakage current and electric strength at operating temperature . 9
14 Transient overvoltages . 9
15 Moisture resistance . 9
16 Leakage current and electric strength . 9
17 Overload protection of transformers and associated circuits . 10
18 Endurance . 10
19 Abnormal operation . 10
20 Stability and mechanical hazards . 10
21 Mechanical strength . 10
22 Construction . 10
23 Internal wiring . 10
24 Components . 11
25 Supply connection and external flexible cords . 11
26 Terminals for external conductors . 11
27 Provision for earthing . 11
28 Screws and connections . 11
29 Clearances, creepage distances and solid insulation . 11
30 Resistance to heat and fire . 11
31 Resistance to rusting . 11
32 Radiation, toxicity and similar hazards . 11
Annexes . 12
Annex A (informative) Routine tests . 12
Bibliography . 13

Table 101 – Temperature classification of circulation pumps . 7

IEC 60335-2-51:2019 © 2019 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
HOUSEHOLD AND SIMILAR ELECTRICAL APPLIANCES – SAFETY –

Part 2-51: Particular requirements for stationary circulation pumps
for heating and service water installations

FOREWORD
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9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60335-2-51 has been prepared by IEC technical committee 61:
Safety of household and similar electrical appliances.
This fourth edition cancels and replaces the third edition published in 2002,
Amendment 1:2008 and Amendment 2:2011. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
– some instructions are no longer required (7.12);
– converted some notes to normative text (7.12.1, 11.3, 11.8);
– new instructions for installation of thermal insulation (7.12.1);
– the leakage current value is modified (Clause A.2).

– 4 – IEC 60335-2-51:2019 © 2019
The text of this International Standard is based on the following documents:
FDIS Report on voting
61/5785/FDIS 61/5802/RVD
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance wi
...