IEC 60335-2-51:2002

IEC 60335-2-51
Edition 3.0 2002-10
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: Règles particulières pour les pompes de circulation fixes pour
installations de chauffage et de distribution d’eau

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 la CEI ou du Comité national de la CEI du pays du demandeur.

Si vous avez des questions sur le copyright de la CEI ou si vous désirez obtenir des droits supplémentaires sur cette

publication, utilisez les coordonnées ci-après ou contactez le Comité national de la CEI de votre pays de résidence.

IEC Central Office
3, rue de Varembé
CH-1211 Geneva 20
Switzerland
Email: inmail@iec.ch
Web: www.iec.ch
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 corrigenda or an amendment might have been published.
ƒ Catalogue of IEC publications: www.iec.ch/searchpub
The IEC on-line Catalogue enables you to search by a variety of criteria (reference number, text, technical committee,…).
It also gives information on projects, withdrawn and replaced publications.
ƒ IEC Just Published: www.iec.ch/online_news/justpub
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on-line and also by email.
ƒ Electropedia: www.electropedia.org
The world's leading online dictionary of electronic and electrical terms containing more than 20 000 terms and definitions
in English and French, with equivalent terms in additional languages. Also known as the International Electrotechnical
Vocabulary online.
ƒ Customer Service Centre: www.iec.ch/webstore/custserv
If you wish to give us your feedback on this publication or need further assistance, please visit the Customer Service
Centre FAQ or contact us:
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A propos de la CEI
La Commission Electrotechnique Internationale (CEI) 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 CEI
Le contenu technique des publications de la CEI est constamment revu. Veuillez vous assurer que vous possédez
l’édition la plus récente, un corrigendum ou amendement peut avoir été publié.
ƒ Catalogue des publications de la CEI: www.iec.ch/searchpub/cur_fut-f.htm
Le Catalogue en-ligne de la CEI vous permet d’effectuer des recherches en utilisant différents critères (numéro de référence,
texte, comité d’études,…). Il donne aussi des informations sur les projets et les publications retirées ou remplacées.
ƒ Just Published CEI: www.iec.ch/online_news/justpub
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publications parues. Disponible en-ligne et aussi par email.
ƒ Electropedia: www.electropedia.org
Le premier dictionnaire en ligne au monde de termes électroniques et électriques. Il contient plus de 20 000 termes et
définitions en anglais et en français, ainsi que les termes équivalents dans les langues additionnelles. Egalement appelé
Vocabulaire Electrotechnique International en ligne.
ƒ Service Clients: www.iec.ch/webstore/custserv/custserv_entry-f.htm
Si vous désirez nous donner des commentaires sur cette publication ou si vous avez des questions, visitez le FAQ du
Service clients ou contactez-nous:
Email: csc@iec.ch
Tél.: +41 22 919 02 11
Fax: +41 22 919 03 00
IEC 60335-2-51
Edition 3.0 2002-10
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: Règles particulières pour les pompes de circulation fixes pour
installations de chauffage et de distribution d’eau

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
L
CODE PRIX
ICS 23.080; 91.140.10 ISBN 2-8318-8179-X
– 2 – 60335-2-51 © CEI:2002
SOMMAIRE
AVANT-PROPOS.4

INTRODUCTION.8

1 Domaine d’application.10

2 Références normatives.10

3 Définitions.10

4 Exigences générales .12

5 Conditions générales d’essais .12

6 Classification.12
7 Marquage et instructions .14
8 Protection contre l’accès aux parties actives .14
9 Démarrage des appareils à moteur.14
10 Puissance et courant .14
11 Echauffements.14
12 Vacant.16
13 Courant de fuite et rigidité diélectrique à la température de régime .16
14 Surtensions transitoires.16
15 Résistance à l’humidité.16
16 Courant de fuite et rigidité diélectrique .16
17 Protection contre la surcharge des transformateurs et des circuits associés.16
18 Endurance.18
19 Fonctionnement anormal.18
20 Stabilité et dangers mécaniques .18
21 Résistance mécanique.18
22 Construction.18
23 Conducteurs internes .18
24 Composants.20
25 Raccordement au réseau et câbles souples extérieurs .20
26 Bornes pour conducteurs externes .20
27 Dispositions en vue de la mise à la terre .20

28 Vis et connexions.20
29 Distances dans l'air, lignes de fuite et isolation solide .20
30 Résistance à la chaleur et au feu.20
31 Protection contre la rouille.20
32 Rayonnement, toxicité et dangers analogues.20

Annexes .22

Bibliographie.22

Tableau 101 – Classification des températures des pompes de circulation .12

60335-2-51 © IEC:2002 – 3 –
CONTENTS
FOREWORD.5

INTRODUCTION.9

1 Scope.11

2 Normative references .11

3 Definitions .11

4 General requirement.13

5 General conditions for the tests .13

6 Classification.13
7 Marking and instructions.15
8 Protection against access to live parts.15
9 Starting of motor-operated appliances .15
10 Power input and current .15
11 Heating .15
12 Void.17
13 Leakage current and electric strength at operating temperature.17
14 Transient overvoltages .17
15 Moisture resistance .17
16 Leakage current and electric strength.17
17 Overload protection of transformers and associated circuits .17
18 Endurance.19
19 Abnormal operation .19
20 Stability and mechanical hazards .19
21 Mechanical strength .19
22 Construction .19
23 Internal wiring.19
24 Components .21
25 Supply connection and external flexible cords .21
26 Terminals for external conductors.21
27 Provision for earthing .21

28 Screws and connections .21
29 Clearances, creepage distances and solid insulation .21
30 Resistance to heat and fire.21
31 Resistance to rusting.21
32 Radiation, toxicity and similar hazards.21

Annexes .23

Bibliography.23

Table 101 – Temperature classification of circulation pumps.13

– 4 – 60335-2-51 © CEI:2002
COMMISSION ÉLECTROTECHNIQUE INTERNATIONALE

____________
APPAREILS ÉLECTRODOMESTIQUES ET ANALOGUES –

SÉCURITÉ –
Partie 2-51: Règles particulières pour les pompes de circulation fixes

pour installations de chauffage et de distribution d'eau

AVANT-PROPOS
1) La Commission Electrotechnique Internationale (CEI) est une organisation mondiale de normalisation
composée de l'ensemble des comités électrotechniques nationaux (Comités nationaux de la CEI). La CEI a
pour objet de favoriser la coopération internationale pour toutes les questions de normalisation dans les
domaines de l'électricité et de l'électronique. A cet effet, la CEI – entre autres activités – publie des Normes
internationales, des Spécifications techniques, des Rapports techniques, des Spécifications accessibles au
public (PAS) et des Guides (ci-après dénommés "Publication(s) de la CEI"). Leur élaboration est confiée à des
comités d'études, aux travaux desquels tout Comité national intéressé par le sujet traité peut participer. Les
organisations internationales, gouvernementales et non gouvernementales, en liaison avec la CEI, participent
également aux travaux. La CEI collabore étroitement avec l'Organisation Internationale de Normalisation (ISO),
selon des conditions fixées par accord entre les deux organisations.
2) Les décisions ou accords officiels de la CEI concernant les questions techniques représentent, dans la mesure
du possible, un accord international sur les sujets étudiés, étant donné que les Comités nationaux de la CEI
intéressés sont représentés dans chaque comité d’études.
3) Les Publications de la CEI se présentent sous la forme de recommandations internationales et sont agréées
comme telles par les Comités nationaux de la CEI. Tous les efforts raisonnables sont entrepris afin que la CEI
s'assure de l'exactitude du contenu technique de ses publications; la CEI ne peut pas être tenue responsable
de l'éventuelle mauvaise utilisation ou interprétation qui en est faite par un quelconque utilisateur final.
4) Dans le but d'encourager l'uniformité internationale, les Comités nationaux de la CEI s'engagent, dans toute la
mesure possible, à appliquer de façon transparente les Publications de la CEI dans leurs publications
nationales et régionales. Toutes divergences entre toutes Publications de la CEI et toutes publications
nationales ou régionales correspondantes doivent être indiquées en termes clairs dans ces dernières.
5) La CEI n’a prévu aucune procédure de marquage valant indication d’approbation et n'engage pas sa
responsabilité pour les équipements déclarés conformes à une de ses Publications.
6) Tous les utilisateurs doivent s'assurer qu'ils sont en possession de la dernière édition de cette publication.
7) Aucune responsabilité ne doit être imputée à la CEI, à ses administrateurs, employés, auxiliaires ou
mandataires, y compris ses experts particuliers et les membres de ses comités d'études et des Comités
nationaux de la CEI, pour tout préjudice causé en cas de dommages corporels et matériels, ou de tout autre
dommage de quelque nature que ce soit, directe ou indirecte, ou pour supporter les coûts (y compris les frais
de justice) et les dépenses découlant de la publication ou de l'utilisation de cette Publication de la CEI ou de
toute autre Publication de la CEI, ou au crédit qui lui est accordé.
8) L'attention est attirée sur les références normatives citées dans cette publication. L'utilisation de publications
référencées est obligatoire pour une application correcte de la présente publication.
9) L’attention est attirée sur le fait que certains des éléments de la présente Publication de la CEI peuvent faire

l’objet de droits de propriété intellectuelle ou de droits analogues. La CEI ne saurait être tenue pour
responsable de ne pas avoir identifié de tels droits de propriété et de ne pas avoir signalé leur existence.
La présente partie de la Norme internationale CEI 60335 a été établie par le comité d'études
61 de la CEI: Sécurité des appareils électrodomestiques et analogues.
Cette troisième édition annule et remplace la deuxième édition parue en 1997, dont elle
constitue une révision technique.
Cette version bilingue, publiée en 2005-09, correspond à la version anglaise.
Le texte anglais de cette norme est issu des documents 61/2220/FDIS et 61/2295/RVD. Le
rapport de vote 61/2295/RVD donne toute information sur le vote ayant abouti à l’approbation
de cette norme.
60335-2-51 © IEC:2002 – 5 –
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
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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
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) 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.

This part of International Standard IEC 60335 has been prepared by IEC technical committee 61:
Safety of household and similar electrical appliances.
This third edition cancels and replaces the second edition published in 1997. It constitutes a
technical revision.
This bilingual version, published in 2005-09, corresponds to the English version.
The text of this part of IEC 60335 is based on the following documents:
FDIS Report on voting
61/2220/FDIS 61/2295/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.

– 6 – 60335-2-51 © CEI:2002
La version française de cette norme n’a pas été soumise au vote.

La présente partie 2 doit être utilisée conjointement avec la dernière édition de la CEI 60335-1
et ses amendements. Elle a été établie sur la base de la quatrième édition (2001) de cette
norme.
NOTE 1 L’expression «Partie 1» utilisée dans la présente norme fait référence à la CEI 60335-1.

La présente partie 2 complète ou modifie les articles correspondants de la CEI 60335-1, de
façon à transformer cette publication en norme CEI: Règles particulières pour les pompes de
circulation fixes pour installations de chauffage et de distribution d'eau

Lorsqu'un paragraphe particulier de la Partie 1 n'est pas mentionné dans cette partie 2, ce
paragraphe s'applique pour autant qu’il est raisonnable. Lorsque la présente norme spécifie
“addition”, “modification” ou “remplacement”, le texte correspondant de la Partie 1 doit être
adapté en conséquence.
NOTE 2 Le système de numérotation suivant est utilisé:
– les paragraphes, les tableaux et figures qui sont numérotés à partir de 101 viennent en supplément de ceux de
la Partie 1;
– notes: à l’exception de celles qui sont dans un nouveau paragraphe ou de celles qui concernent des notes de
la Partie 1, les notes sont numérotées à partir de 101, y compris celles des articles ou paragraphes qui sont
remplacés;
– les annexes supplémentaires sont appelées AA, BB, etc.
NOTE 3 Les caractères d'imprimerie suivants sont utilisés:
– exigences: caractères romains;
– modalités d'essais: caractères italiques;
– notes: petits caractères romains.
Les mots en gras dans le texte sont définis à l'Article 3. Lorsqu'une définition concerne un adjectif, l'adjectif et le
nom associé figurent également en gras.
Les différences suivantes existent dans les pays indiqués ci-après.
– 6.1: Les appareils de la classe 0I sont autorisés (Japon).
Le comité a décidé que le contenu de cette publication ne sera pas modifié avant la date de
maintenance indiquée sur le site web de la CEI sous «http://webstore.iec.ch» dans les
données relatives à la publication recherchée. A cette date, la publication sera
• reconduite;
• supprimée;
• remplacée par une édition révisée, ou

• amendée.
60335-2-51 © IEC:2002 – 7 –
The French version of this standard has not been voted upon.

This part 2 is to be used in conjunction with the latest edition of IEC 60335-1 and its
amendments. It was established on the basis of the fourth edition (2001) of that standard.

NOTE 1 When “Part 1” is mentioned in this standard, it refers to IEC 60335-1.

T
...

IEC 60335-2-51
Edition 3.1 2008-07
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: Règles particulières pour les pompes de circulation fixes pour
installations de chauffage et de distribution d'eau

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 la CEI ou du Comité national de la CEI du pays du demandeur.

Si vous avez des questions sur le copyright de la CEI ou si vous désirez obtenir des droits supplémentaires sur cette

publication, utilisez les coordonnées ci-après ou contactez le Comité national de la CEI de votre pays de résidence.

IEC Central Office
3, rue de Varembé
CH-1211 Geneva 20
Switzerland
Email: inmail@iec.ch
Web: www.iec.ch
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 corrigenda or an amendment might have been published.
ƒ Catalogue of IEC publications: www.iec.ch/searchpub
The IEC on-line Catalogue enables you to search by a variety of criteria (reference number, text, technical committee,…).
It also gives information on projects, withdrawn and replaced publications.
ƒ IEC Just Published: www.iec.ch/online_news/justpub
Stay up to date on all new IEC publications. Just Published details twice a month all new publications released. Available
on-line and also by email.
ƒ Electropedia: www.electropedia.org
The world's leading online dictionary of electronic and electrical terms containing more than 20 000 terms and definitions
in English and French, with equivalent terms in additional languages. Also known as the International Electrotechnical
Vocabulary online.
ƒ Customer Service Centre: www.iec.ch/webstore/custserv
If you wish to give us your feedback on this publication or need further assistance, please visit the Customer Service
Centre FAQ or contact us:
Email: csc@iec.ch
Tel.: +41 22 919 02 11
Fax: +41 22 919 03 00
A propos de la CEI
La Commission Electrotechnique Internationale (CEI) 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 CEI
Le contenu technique des publications de la CEI est constamment revu. Veuillez vous assurer que vous possédez
l’édition la plus récente, un corrigendum ou amendement peut avoir été publié.
ƒ Catalogue des publications de la CEI: www.iec.ch/searchpub/cur_fut-f.htm
Le Catalogue en-ligne de la CEI vous permet d’effectuer des recherches en utilisant différents critères (numéro de référence,
texte, comité d’études,…). Il donne aussi des informations sur les projets et les publications retirées ou remplacées.
ƒ Just Published CEI: www.iec.ch/online_news/justpub
Restez informé sur les nouvelles publications de la CEI. Just Published détaille deux fois par mois les nouvelles
publications parues. Disponible en-ligne et aussi par email.
ƒ Electropedia: www.electropedia.org
Le premier dictionnaire en ligne au monde de termes électroniques et électriques. Il contient plus de 20 000 termes et
définitions en anglais et en français, ainsi que les termes équivalents dans les langues additionnelles. Egalement appelé
Vocabulaire Electrotechnique International en ligne.
ƒ Service Clients: www.iec.ch/webstore/custserv/custserv_entry-f.htm
Si vous désirez nous donner des commentaires sur cette publication ou si vous avez des questions, visitez le FAQ du
Service clients ou contactez-nous:
Email: csc@iec.ch
Tél.: +41 22 919 02 11
Fax: +41 22 919 03 00
IEC 60335-2-51
Edition 3.1 2008-07
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: Règles particulières pour les pompes de circulation fixes pour
installations de chauffage et de distribution d'eau

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CD
CODE PRIX
ICS 23.080; 91.140.10 ISBN 2-8318-9741-6
– 2 – 60335-2-51 © IEC:2002+A1:2008

CONTENTS
FOREWORD.3

INTRODUCTION.5

1 Scope.6

2 Normative references .6

3 Definitions .7

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.11
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

Bibliography.12

Table 101 – Temperature classification of circulation pumps.8

60335-2-51 © IEC:2002+A1:2008 – 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
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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
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) 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.
This part of International Standard IEC 60335 has been prepared by IEC technical committee 61:
Safety of household and similar electrical appliances.
This consolidated version of IEC 60335-2-51 consists of the third edition (2002) [documents
61/2220/FDIS and 61/2295/RVD] and its amendment 1 (2008) [documents 61/3556/FDIS and
61/3602/RVD].
The technical content is therefore identical to the base edition and its amendment and has
been prepared for user convenience.
It bears the edition number 3.1.
A vertical line in the margin shows where the base publication has been modified by
amendment 1.
– 4 – 60335-2-51 © IEC:2002+A1:2008

The French version of this standard has not been voted upon.

This part 2 is to be used in conjunction with the latest edition of IEC 60335-1 and its
amendments. It was established on the basis of the fourth edition (2001) of that standard.

NOTE 1 When “Part 1” is mentioned in this standard, it refers to IEC 60335-1.

This part 2 supplements or modifies the corresponding clauses in IEC 60335-1, so as to

convert that publication into the IEC standard: Safety requirements for electric stationary

circulation pumps for heating and service water installations.

When a particular subclause of Part 1 is not mentioned in this part 2, that subclause applies
as far as is reasonable. When this standard states “addition”, “modification” or “replacement”,
the relevant text in Part 1 is to be adapted accordingly.
NOTE 2 The following numbering system is used:
– subclauses, tables and figures that are numbered starting from 101 are additional to those in Part 1;
– unless notes are in a new subclause or involve notes in Part 1, they are numbered starting from 101, including
those in a replaced clause or subclause;
– additional annexes are lettered AA, BB, etc.
NOTE 3 The following print types are used:
– requirements: in roman type;
– test specifications: in italic type;
– notes: in small roman type.
Words in bold in the text are defined in Clause 3. When a definition concerns an adjective, the adjective and the
associated noun are also in bold.
The following differences exist in the countries indicated below.
– 6.1: Class 0I appliances are allowed (Japan).
The committee has decided that the contents of the base publication and its amendments will
remain unchanged until the maintenance result date indicated on the IEC web site under
"http://webstore.iec.ch" in the data related to the specific publication. At this date,
the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
NOTE 4 The attention of National Committees is drawn to the fact that equipment manufacturers and testing
organizations may need a transitional period following publication of a new, amended or revised IEC publication in
which to make products in accordance with the new requirements and to equip themselves for conducting new or
revised tests.
It is the recommendation of the committee that the content of the amendment 1 be adopted for implementation
nationally not earlier than 12 months or later than 36 months from the date of publication.

60335-2-51 © IEC:2002+A1:2008 – 5 –

INTRODUCTION
It has been assumed in the drafting of this International Standard that the execution of its

provisions is entrusted to appropriately qualified and experienced persons.

This standard recognizes the internationally accepted level of protection against hazards such

as electrical, mechanical, thermal, fire and radiation of appliances when operated as in

normal use taking into account the manufacturer's instructions. It also covers abnormal

situations that can be expected in practice and takes into account the way in which

electromagnetic phenomena can affect the safe operation of appliances.

This standard takes into account the requirements of IEC 60364 as far as possible so that
there is compatibility with the wiring rules when the appliance is connected to the supply
mains. However, national wiring rules may differ.
If an appliance within the scope of this standard also incorporates functions that are covered
by another part 2 of IEC 60335, the relevant part 2 is applied to each function separately, as
far as is reasonable. If applicable, the influence of one function on the other is taken into
account.
When a part 2 standard does not include additional requirements to cover hazards dealt with
in Part 1, Part 1 applies.
NOTE 1 This means that the technical committees responsible for the part 2 standards have determined that it is
not necessary to specify particular requirements for the appliance in question over and above the general
requirements.
This standard is a product family standard dealing with the safety of appliances and takes
precedence over horizontal and generic standards covering the same subject.
NOTE 2 Horizontal and generic standards covering a hazard are not applicable since they have been taken into
consideration when developing the general and particular requirements for the IEC 60335 series of standards. For
example, in the case of temperature requirements for surfaces on many appliances, generic standards, such as
ISO 13732-1 for hot surfaces, are not applicable in addition to Part 1 or part 2 standards.
An appliance that complies with the text of this standard will not necessarily be considered to
comply with the safety principles of the standard if, when examined and tested, it is found to
have other features that impair the level of safety covered by these requirements.
An appliance employing materials or having forms of construction differing from those detailed
in the requirements of this standard may be examined and tested according to the intent of
the requirements and, if found to be substantially equivalent, may be considered to comply
with the standard.
– 6 – 60335-2-51 © IEC:2002+A1:2008

HOUSEHOLD AND SIMILAR ELECTRICAL APPLIANCES –

SAFETY –
Part 2-51: Particular requirements for stationary circulation pumps

for heating and service water installations

1 Scope
This clause of Part 1 is replaced by the following.
This International Standard deals with the safety of electric stationary circulation pumps
intended for use in heating systems or in service water systems, having a rated power input
not exceeding 300 W, their rated voltage being not more than 250 V for single-phase
appliances and 480 V for other appliances.
NOTE 101 The hydraulic and electrical parts of the pump may be in the same enclosure, so that the water flows
through the motor and serves as a coolant, or they may be separated.
Appliances not intended for normal household use, but that nevertheless may be a source of
danger to the public, such as appliances intended to be used by laymen in shops, in light
industry and on farms, are within the scope of this standard.
As far as is practicable, this standard deals with the common hazards presented by
appliances that are encountered by all persons in and around the home. However, in general,
it does not take into account
– persons (including children) whose
• physical, sensory or mental capabilities; or
• lack of experience and knowledge
prevents them from using the appliance safely without supervision or instruction;
– children playing with the appliance.
NOTE 102 Attention is drawn to the fact that
– for appliances intended to be used in vehicles or on board ships or aircraft, additional requirements may be
necessary;
– in many countries additional requirements are specified by the national health authorities, the national
authorities responsible for the protection of labour and similar authorities.
NOTE 103 This standard does not apply to
– pumps for circulating liquids other than water;
– pumps, other than circulation pumps (IEC 60335-2-41);
– circulation pumps intended exclusively for industrial purposes;
– circulation pumps intended to be used in locations where special conditions prevail, such as the presence of a
corrosive or explosive atmosphere (dust, vapour, or gas).
2 Normative references
This clause of Part 1 is applicable.

60335-2-51 © IEC:2002+A1:2008 – 7 –

3 Definitions
This clause of Part 1 is applicable except as follows.

3.1.9 Replacement:
normal operation
operation of the circulation pump with the water pressure and flow rate adjusted within their

specified limits, so that the highest power input is attained

4 General requirement
This clause of Part 1 is applicable.
5 General conditions for the tests
This clause of Part 1 is applicable except as follows.
5.7 Addition:
The water temperature at the inlet is maintained between 0 °C and –5 °C of the value
corresponding to the TF class of the pump.
For circulation pumps intended to be located within the enclosure of a boiler, the tests of
Clauses 10, 11 and 13 are carried out at an ambient temperature of 55 °C or at the
temperature specified in the instructions, whichever is higher.
5.101 Circulation pumps having a three-phase motor that does not incorporate a protective
device are installed with an appropriate device, in accordance with the instructions.
6 Classification
This clause of Part 1 is applicable except as follows.
6.1 Modification:
Circulation pumps shall be class I, class II or class III.

6.2 Addition:
Circulation pumps shall be at least IPX2.
6.101 Circulation pumps shall be of one of the classes shown in Table 101.

– 8 – 60335-2-51 © IEC:2002+A1:2008

Table 101 – Temperature classification of circulation pumps

Class Maximum temperature of
the circulating water
°C
TF  60 60
TF  95 95
TF 110 110
Compliance is checked by inspection.
7 Marking and instructions
This clause of Part 1 is applicable except as follows.
7.1 Addition:
Circulation pumps shall be marked with
– the TF class;
– the direction of the water flow;
– the direction of rotation (for pumps having three-phase motors);
– the rated current (for pumps having three-phase motors if a protective device has to be
installed in the fixed wiring).
7.12.1 Addition:
The installation instructions shall state the substance of the following:
– the maximum flow rate or total head;
– the maximum ambient temperature at which the pump is to be used;
– the maximum system pressure;
NOTE 101 The maximum system pressure is to be not less than
• 0,6 MPa, for pumps for heating systems;
• 1,0 MPa, for pumps for service water systems.
– the intended orientation of the pump;

– a protective device is to be installed in the fixed wiring and its characteristics are to be
specified (for pumps having a three-phase motor not incorporating a protective device).
8 Protection against access to live parts
This clause of Part 1 is applicable.
9 Starting of motor-operated appliances
This clause of Part 1 is not applicable.
10 Power input and current
This clause of Part 1 is applicable.

60335-2-51 © IEC:2002+A1:2008 – 9 –

11 Heating
This clause of Part 1 is applicable except as follows.

11.2 Addition:
Circulation pumps that are only fixed by the water pipes are positioned against one wall of the

test corner and away from the other.

11.3 Addition:
NOTE 101 The temperatures t and t , referred to in note 4, are the ambient temperatures of the environment in
1 2
which the pump is installed, for instance inside the enclosure of a boiler.
11.7 Replacement:
Circulation pumps are operated until steady conditions are established.
11.8 Addition:
The temperature rise limits of pumps located within the enclosure of a boiler are reduced by
the difference between the ambient temperature at which the test is carried out and 25 °C.
The temperature rise of the external enclosure is not measured.
For circulation pumps in which water flows through the motor, the temperature rise limits for
windings are increased by 5 K. The temperature rise limits are increased further by
– 5 K, if the winding insulation is class B;
– 10 K, if the winding insulation is class F or H.
NOTE 101 For circulation pumps in which water flows through the motor, the increase of 5 K allowed by
footnote a to Table 3 does not apply.
12 Void
13 Leakage current and electric strength at operating temperature
This clause of Part 1 is applicable.

14 Transient overvoltages
This clause of Part 1 is applicable.
15 Moisture resistance
This clause of Part 1 is applicable.
16 Leakage current and electric strength
This clause of Part 1 is applicable.

– 10 – 60335-2-51 © IEC:2002+A1:2008

17 Overload protection of transformers and associated circuits

This clause of Part 1 is applicable.

18 Endurance
This clause of Part 1 is not applicable.

19 Abnormal operation
This clause of Part 1 is applicable except as follows.
19.1 Addition:
Circulation pumps are also subjected to the test of 19.101.
19.7 Addition:
The test is carried out with the water flow stopped or reduced to 5 l/min, whichever is more
unfavourable.
19.101 Circulation pumps are supplied at rated voltage and operated at approximately half
the maximum system pressure for 5 min, after which the water is drained off and the operation
continued for 7 h. The system is replenished with water and the pump operated again for
5 min at approximately half the maximum system pressure.
If the pump becomes inoperable during the test, it is disconnected from the supply and the
system filled with water.
20 Stability and mechanical hazards
This clause of Part 1 is applicable.
21 Mechanical strength
This clause of Part 1 is applicable.

22 Construction
This clause of Part 1 is applicable except as follows.
22.101 Circulation pumps shall withstand the water pressure occurring in normal use.
Compliance is checked by subjecting the pump to a water pressure equal to 1,2 times the
maximum system pressure for 1 min.
The pump shall not leak.
60335-2-51 © IEC:2002+A1:2008 – 11 –

23 Internal wiring
This clause of Part 1 is applicable.

24 Components
This clause of Part 1 is applica
...

IEC 60335-2-51 ®
Edition 3.2 2012-01
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: Règles particulières pour les pompes de circulation fixes pour
installations de chauffage et de distribution d’eau

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IEC 60335-2-51 ®
Edition 3.2 2012-01
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: Règles particulières pour les pompes de circulation fixes pour

installations de chauffage et de distribution d’eau

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX CD
ICS 23.080; 91.140.10 ISBN 978-2-88912-875-4

– 2 – 60335-2-51  IEC:2002+A1:2008

+A2:2011
CONTENTS
FOREWORD . 3

INTRODUCTION . 5

1 Scope . 6

2 Normative references . 6

3 Definitions . 7

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 . 11
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

Bibliography . 12

Table 101 – Temperature classification of circulation pumps . 8

60335-2-51  IEC:2002+A1:2008 – 3 –

+A2:2011
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
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) 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.
This part of International Standard IEC 60335 has been prepared by IEC technical committee 61:
Safety of household and similar electrical appliances.
This consolidated version of IEC 60335-2-51 consists of the third edition (2002) [documents
61/2220/FDIS and 61/2295/RVD], its amendment 1 (2008) [documents 61/3556/FDIS and
61/3602/RVD] and its amendment 2 (2011) [documents 61/4100/CDV and 61/4198/RVC].
The technical content is therefore identical to the base edition and its amendments and has
been prepared for user convenience.
It bears the edition number 3.2.
A vertical line in the margin shows where the base publication has been modified by
amendments 1 and 2.
– 4 – 60335-2-51  IEC:2002+A1:2008

+A2:2011
The French version of this standard has not been voted upon.

This part 2 is to be used in conjunction with the latest edition of IEC 60335-1 and its
amendments. It was established on the basis of the fourth edition (2001) of that standard.

NOTE 1 When “Part 1” is mentioned in this standard, it refers to IEC 60335-1.

This part 2 supplements or modifies the corresponding clauses in IEC 60335-1, so as to

convert that publication into the IEC standard: Safety requirements for electric stationary

circulation pumps for heating and service water installations.

When a particular subclause of Part 1 is not mentioned in this part 2, that subclause applies
as far as is reasonable. When this standard states “addition”, “modification” or “replacement”,
the relevant text in Part 1 is to be adapted accordingly.
NOTE 2 The following numbering system is used:
– subclauses, tables and figures that are numbered starting from 101 are additional to those in Part 1;
– unless notes are in a new subclause or involve notes in Part 1, they are numbered starting from 101, including
those in a replaced clause or subclause;
– additional annexes are lettered AA, BB, etc.
NOTE 3 The following print types are used:
– requirements: in roman type;
– test specifications: in italic type;
– notes: in small roman type.
Words in bold in the text are defined in Clause 3. When a definition concerns an adjective, the adjective and the
associated noun are also in bold.
The following differences exist in the countries indicated below.
– 6.1: Class 0I appliances are allowed (Japan).
The committee has decided that the contents of the base publication and its amendments will
remain unchanged until the stability date indicated on the IEC web site under
"http://webstore.iec.ch" in the data related to the specific publication. At this date, the
publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
NOTE 4 The attention of National Committees is drawn to the fact that equipment manufacturers and testing
organizations may need a transitional period following publication of a new, amended or revised IEC publication in
which to make products in accordance with the new requirements and to equip themselves for conducting new or
revised tests.
It is the recommendation of the committee that the content of the amendment 1 be adopted for implementation
nationally not earlier than 12 months or later than 36 months from the date of publication.
It is the recommendation of the committee that the content of the amendment 2 be adopted for implementation
nationally not earlier than 12 months or later than 36 months from the date of publication.

60335-2-51  IEC:2002+A1:2008 – 5 –

+A2:2011
INTRODUCTION
It has been assumed in the drafting of this International Standard that the execution of its

provisions is entrusted to appropriately qualified and experienced persons.

This standard recognizes the internationally accepted level of protection against hazards such

as electrical, mechanical, thermal, fire and radiation of appliances when operated as in

normal use taking into account the manufacturer's instructions. It also covers abnormal

situations that can be expected in practice and takes into account the way in which

electromagnetic phenomena can affect the safe operation of appliances.

This standard takes into account the requirements of IEC 60364 as far as possible so that
there is compatibility with the wiring rules when the appliance is connected to the supply
mains. However, national wiring rules may differ.
If an appliance within the scope of this standard also incorporates functions that are covered
by another part 2 of IEC 60335, the relevant part 2 is applied to each function separately, as
far as is reasonable. If applicable, the influence of one function on the other is taken into
account.
When a part 2 standard does not include additional requirements to cover hazards dealt with
in Part 1, Part 1 applies.
NOTE 1 This means that the technical committees responsible for the part 2 standards have determined that it is
not necessary to specify particular requirements for the appliance in question over and above the general
requirements.
This standard is a product family standard dealing with the safety of appliances and takes
precedence over horizontal and generic standards covering the same subject.
NOTE 2 Horizontal and generic standards covering a hazard are not applicable since they have been taken into
consideration when developing the general and particular requirements for the IEC 60335 series of standards. For
example, in the case of temperature requirements for surfaces on many appliances, generic standards, such as
ISO 13732-1 for hot surfaces, are not applicable in addition to Part 1 or part 2 standards.
An appliance that complies with the text of this standard will not necessarily be considered to
comply with the safety principles of the standard if, when examined and tested, it is found to
have other features that impair the level of safety covered by these requirements.
An appliance employing materials or having forms of construction differing from those detailed
in the requirements of this standard may be examined and tested according to the intent of
the requirements and, if found to be substantially equivalent, may be considered to comply
with the standard.
– 6 – 60335-2-51  IEC:2002+A1:2008

+A2:2011
HOUSEHOLD AND SIMILAR ELECTRICAL APPLIANCES –

SAFETY –
Part 2-51: Particular requirements for stationary circulation pumps

for heating and service water installations

1 Scope
This clause of Part 1 is replaced by the following.
This International 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.
NOTE 101 The hydraulic and electrical parts of the pump may be in the same enclosure, so that the water flows
through the motor and serves as a coolant, or they may be separated.
Appliances not intended for normal household use, but that nevertheless may be a source of
danger to the public, such as appliances intended to be used by laymen in shops, in light
industry and on farms, are within the scope of this standard.
As far as is practicable, this standard deals with the common hazards presented by
appliances that are encountered by all persons in and around the home. However, in general,
it does not take into account
– persons (including children) whose
• physical, sensory or mental capabilities; or
• lack of experience and knowledge
prevents them from using the appliance safely without supervision or instruction;
– children playing with the appliance.
NOTE 102 Attention is drawn to the fact that
– for appliances intended to be used in vehicles or on board ships or aircraft, additional requirements may be
necessary;
– in many countries additional requirements are specified by the national health authorities, the national
authorities responsible for the protection of labour and similar authorities.
NOTE 103 This standard does not apply to
– pumps for circulating liquids other than water;
– pumps, other than circulation pumps (IEC 60335-2-41);
– circulation pumps intended exclusively for industrial purposes;
– circulation pumps intended to be used in locations where special conditions prevail, such as the presence of a
corrosive or explosive atmosphere (dust, vapour, or gas).
2 Normative references
This clause of Part 1 is applicable.

60335-2-51  IEC:2002+A1:2008 – 7 –

+A2:2011
3 Definitions
This clause of Part 1 is applicable except as follows.

3.1.9 Replacement:
normal operation
operation of the circulation pump with the water pressure and flow rate adjusted within their

specified limits, so that the highest power input is attained

4 General requirement
This clause of Part 1 is applicable.
5 General conditions for the tests
This clause of Part 1 is applicable except as follows.
5.7 Addition:
The water temperature at the inlet is maintained between 0 °C and –5 °C of the value
corresponding to the TF class of the pump.
For circulation pumps intended to be located within the enclosure of a boiler, the tests of
Clauses 10, 11 and 13 are carried out at an ambient temperature of 55 °C or at the
temperature specified in the instructions, whichever is higher.
5.101 Circulation pumps having a three-phase motor that does not incorporate a protective
device are installed with an appropriate device, in accordance with the instructions.
6 Classification
This clause of Part 1 is applicable except as follows.
6.1 Modification:
Circulation pumps shall be class I, class II or class III.

6.2 Addition:
Circulation pumps shall be at least IPX2.
6.101 Circulation pumps shall be of one of the classes shown in Table 101.

– 8 – 60335-2-51  IEC:2002+A1:2008

+A2:2011
Table 101 – Temperature classification of circulation pumps

Class Maximum temperature of
the circulating water
°C
TF  60 60
TF  95 95
TF 110 110
Compliance is checked by inspection.
7 Marking and instructions
This clause of Part 1 is applicable except as follows.
7.1 Addition:
Circulation pumps shall be marked with
– the TF class;
– the direction of the water flow;
– the direction of rotation (for pumps having three-phase motors);
– the rated current (for pumps having three-phase motors if a protective device has to be
installed in the fixed wiring).
7.12.1 Addition:
The installation instructions shall state the substance of the following:
– the maximum flow rate or total head;
– the maximum ambient temperature at which the pump is to be used;
– the maximum system pressure;
NOTE 101 The maximum system pressure is to be not less than
• 0,6 MPa, for pumps for heating systems;
• 1,0 MPa, for pumps for service water systems.
– the intended orientation of the pump;

– a protective device is to be installed in the fixed wiring and its characteristics are to be
specified (for pumps having a three-phase motor not incorporating a protective device).
8 Protection against access to live parts
This clause of Part 1 is applicable.
9 Starting of motor-operated appliances
This clause of Part 1 is not applicable.
10 Power input and current
This clause of Part 1 is applicable.

60335-2-51  IEC:2002+A1:2008 – 9 –

+A2:2011
11 Heating
This clause of Part 1 is applicable except as follows.

11.2 Addition:
Circulation pumps that are only fixed by the water pipes are positioned against one wall of the

test corner and away from the other.

11.3 Addition:
NOTE 101 The temperatures t and t , referred to in note 4, are the ambient temperatures of the environment in
1 2
which the pump is installed, for instance inside the enclosure of a boiler.
11.7 Replacement:
Circulation pumps are operated until steady conditions are established.
11.8 Addition:
The temperature rise limits of pumps located within the enclosure of a boiler are reduced by
the difference between the ambient temperature at which the test is carried out and 25 °C.
The temperature rise of the external enclosure is not measured.
For circulation pumps in which water flows through the motor, the temperature rise limits for
windings are increased by 5 K. The temperature rise limits are increased further by
– 5 K, if the winding insulation is class B;
– 10 K, if the winding insulation is class F or H.
NOTE 101 For circulation pumps in which water flows through the motor, the increase of 5 K allowed by
footnote a to Table 3 does not apply.
12 Void
13 Leakage current and electric strength at operating temperature
This clause of Part 1 is applicable.

14 Transient overvoltages
This clause of Part 1 is applicable.
15 Moisture resistance
This clause of Part 1 is applicable.
16 Leakage current and electric strength
This clause of Part 1 is applicable.

– 10 – 60335-2-51  IEC:2002+A1:2008

+A2:2011
17 Overload protection of transformers and associated circuits

This clause of Part 1 is applicable.

18 Endurance
This clause of Part 1 is not applicable.

19 Abnormal operation
This clause of Part 1 is applicable except as follows.
19.1 Addition:
Circulation pumps are also subjected to the test of 19.101.
19.7 Addition:
The test is carried out with the water flow stopped or reduced to 5 l/min, whichever is more
unfavourable.
19.101 Circulation pumps are supplied at rated voltage and operated at approximately half
the maximum system pressure for 5 min, after which the water is drained off and the operation
continued for 7 h. The system is replenished with water and the pump operated again for
5 min at approximately half the maximum system pressure.
If the pump becomes inoperable during the test, it is disconnected from the supply and the
system filled with water.
20 Stability and mechanical hazards
This clause of Part 1 is applicable.
21 Mechanical strength
This clause of Part 1 is applicable.

22 Construction
This clause of Part 1 is applicable except as follows.
22.101 Circulation pumps shall withstand the water pressure occurring in normal use.
Compliance is checked by subjecting the pump to a water pressure equal to 1,2 times the
maximum system pressure for 1 min.
The pump shall not leak.
60335-2-51  IEC:2002+A1:2008 – 11 –

+A2:2011
23 Internal wiring
This claus
...