prEN IEC 60335-2-21:2024

SLOVENSKI STANDARD
01-september-2024
Gospodinjski in podobni električni aparati - Varnost - 2-21. del: Posebne zahteve
za akumulacijske grelnike vode
Household and similar electrical appliances - Safety - Part 2-21: Particular requirements
for storage water heaters
Sicherheit elektrischer Geräte für den Hausgebrauch und ähnliche Zwecke - Teil 2-21:
Besondere Anforderungen für Wassererwärmer (Warmwasserspeicher und
Warmwasserboiler)
Appareils électrodomestiques et analogues - Sécurité - Partie 2-21: Exigences
particulières pour les chauffe-eau à accumulation
Ta slovenski standard je istoveten z: prEN IEC 60335-2-21:2024
ICS:
13.120 Varnost na domu Domestic safety
91.140.65 Oprema za ogrevanje vode Water heating equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD DRAFT
prEN IEC 60335-2-21
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2024
ICS 13.120; 91.140.65 Will supersede EN 60335-2-21:2021; EN 60335-2-
21:2021/A1:2021
English Version
Household and similar electrical appliances - Safety - Part 2-21:
Particular requirements for storage water heaters
(IEC 60335-2-21:2022)
Appareils électrodomestiques et analogues - Sécurité - Sicherheit elektrischer Geräte für den Hausgebrauch und
Partie 2-21: Exigences particulières pour les chauffe-eau à ähnliche Zwecke - Teil 2-21: Besondere Anforderungen für
accumulation Wassererwärmer (Warmwasserspeicher und
(IEC 60335-2-21:2022) Warmwasserboiler)
(IEC 60335-2-21:2022)
This draft European Standard is submitted to CENELEC members for enquiry.
Deadline for CENELEC: 2024-09-06.

The text of this draft consists of the text of IEC 60335-2-21:2022.

If this draft becomes a European Standard, 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.

This draft European Standard was established by CENELEC 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.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to
provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.

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
© 2024 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Project: 78879 Ref. No. prEN IEC 60335-2-21:2024 E

1 European foreword
2 This document (prEN IEC 60335-2-21:2024) consists of the text of IEC 60335-2-21:2022 prepared by
3 IEC/TC 61 "Safety of household and similar electrical appliances".
4 This document is currently submitted to the Enquiry.
5 The following dates are proposed:
• latest date by which the existence of this (doa) dor + 6 months
document has to be announced at national
level
• latest date by which this document has to be (dop) dor + 12 months
implemented at national level by publication of
an identical national standard or by
endorsement
• latest date by which the national standards (dow) dor + 36 months
conflicting with this document have to be (to be confirmed or
withdrawn modified when voting)
6 This document is read in conjunction with prEN IEC 60335-2-21:2024/prAA:2024.
7 This document will supersede EN 60335-2-21:2021 and all of its amendments and corrigenda (if any).
8 This document has been prepared under a standardization request addressed to CENELEC by the European
9 Commission. The Standing Committee of the EFTA State subsequently approves these requests for its
10 Member States.
11 For relationship with EU legislation, see informative Annexes ZZA and ZZC, which are an integral part of
12 prEN IEC 60335-2-21:2024/prAA:2024.
IEC 60335-2-21 ®
Edition 7.0 2022-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Household and similar electrical appliances – Safety –

Part 2-21: Particular requirements for storage water heaters

Appareils électrodomestiques et analogues – Sécurité –

Partie 2-21: Exigences particulières pour les chauffe-eau à accumulation

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 13.120; 91.140.65 ISBN 978-2-8322-5858-3

– 2 – IEC 60335-2-21:2022 © IEC 2022
CONTENTS
FOREWORD . 4
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 9
3 Terms and definitions . 9
4 General requirement . 10
5 General conditions for the tests . 10
6 Classification . 10
7 Marking and instructions . 11
8 Protection against access to live parts . 12
9 Starting of motor-operated appliances . 12
10 Power input and current . 12
11 Heating . 12
12 Charging of metal-ion batteries . 13
13 Leakage current and electric strength at operating temperature . 13
14 Transient overvoltages . 13
15 Moisture resistance . 13
16 Leakage current and electric strength . 13
17 Overload protection of transformers and associated circuits . 14
18 Endurance . 14
19 Abnormal operation . 14
20 Stability and mechanical hazards . 15
21 Mechanical strength . 15
22 Construction . 15
23 Internal wiring . 17
24 Components . 18
25 Supply connection and external flexible cords . 19
26 Terminals for external conductors . 19
27 Provision for earthing . 19
28 Screws and connections . 19
29 Clearances, creepage distances and solid insulation . 20
30 Resistance to heat and fire . 20
31 Resistance to rusting . 20
32 Radiation, toxicity and similar hazards . 20
Annexes . 23
Annex A (informative) Routine tests . 23
Annex R (normative) Software evaluation . 24
Annex AA (normative) Additional requirement for immersion heater units intended for
the installation in heat exchange closed water heaters . 25
Bibliography . 28

IEC 60335-2-21:2022 © IEC 2022 – 3 –
Figure 101 – Examples of types of storage water heaters . 21
Figure 102 – Probe for measuring surface temperatures . 22
Figure 103 – Example of positions of the thermocouples . 22

Table 101 – Maximum temperature rises of external accessible surfaces under normal
operating conditions . 13

– 4 – IEC 60335-2-21:2022 © IEC 2022
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
HOUSEHOLD AND SIMILAR ELECTRICAL APPLIANCES –
SAFETY –
Part 2-21: Particular requirements for storage water heaters

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.
IEC 60335-2-21 has been prepared by IEC technical committee 61: Safety of household and
similar electrical appliances. It is an International Standard.
This seventh edition cancels and replaces the sixth edition published in 2012 and
Amendment 1:2018. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) the text has been aligned with IEC 60335-1:2020;
b) some notes have been converted to normative text (Clause 1, 5.2, 15.3, 19.1, 19.2, 19.3,
19.4, 22.47, 22.104, 22.110, Annex AA introduction);
c) updated requirement restricting use of appliance inlets (25.1).

IEC 60335-2-21:2022 © IEC 2022 – 5 –
The text of this International Standard is based on the following documents:
Draft Report on voting
61/6675/FDIS 61/6751/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.
A list of all parts of the IEC 60335 series, under the general title: Household and similar
electrical appliances – Safety, can be found on the IEC website.
This part 2 is to be used in conjunction with the latest edition of IEC 60335-1 and its
amendments unless that edition precludes it; in that case, the latest edition that does not
preclude it is used. It was established on the basis of the sixth edition (2020) 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: Particular requirements for storage water heaters.
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 committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 6 – IEC 60335-2-21:2022 © IEC 2022
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 this publication be adopted for implementation nationally
not earlier than 12 months or later than 36 months from the date of publication.
The following differences exist in the countries indicated below.
– Clause 1: Immersion heater units intended to be retrofitted in a heat exchange closed water
heater are not allowed unless:
• the immersion heater unit has been tested with the tank models and brands listed in the
instructions of the immersion heater unit;
• the tank models and brands list the models of the immersion heater units that can be
retrofitted (Australia, Netherlands, New Zealand).
– 6.1: Class 0I appliances are allowed (Japan).
– 6.2: IPX0 water heaters are allowed (France).
– 7.1: Additional markings are required (Australia, New Zealand and South Africa).
– 7.12.1: Additional instructions are required (South Africa).
– 13.2: An additional leakage current test is required (China).
– 22.101: Pressure reducing valves have to be designed for an inlet pressure of 2 MPa (South
Africa).
– 22.102: The temperature limit is 95 °C (South Africa).
– 22.101: The minimum rated pressure is 1,0 MPa (Denmark, Finland, Norway and Sweden).
– 22.103: Closed water heaters have to incorporate a pressure-relief device sensitive to both
pressure and temperature that operates before the water temperature reaches 99 °C (South
Africa).
– 22.103: Closed water heaters have to incorporate a temperature relief valve or a combined
temperature and pressure-relief valve that operates before the water temperature reaches
100 °C (United Kingdom).
– 22.106: The thermal cut-out of single-phase closed water heaters need only provide single-
pole disconnection (Japan).
– 22.106: For all closed water heaters, the thermal cut-out is to provide all-pole disconnection
(France).
– 22.110: Additional requirements apply to plastic or resin-based containers for open outlet,
cistern type and low pressure type (South Africa).
– 24.1.4 Additional requirements apply to thermal cut-outs (South Africa).
– 24.102: The maximum water temperature is 99 °C (Japan and Norway).
– 24.102: The temperature limit of 130 °C is only allowed for closed water heaters having a
rated pressure of at least 0,4 MPa (South Africa).

IEC 60335-2-21:2022 © IEC 2022 – 7 –
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.
Guidance documents concerning the application of the safety requirements for appliances can
be accessed via TC 61 supporting documents on the IEC website
https://www.iec.ch/tc61/supportingdocuments
This information is given for the convenience of users of this International Standard and does
not constitute a replacement for the normative text in this standard.
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 can 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 publications, basic safety publications and group safety publications 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.
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.
NOTE 3 Standards dealing with non-safety aspects of household appliances are:
– IEC standards published by TC 59 concerning methods of measuring performance;
– CISPR 11, CISPR 14-1 and relevant IEC 61000-3 series standards concerning electromagnetic emissions;
– CISPR 14-2 concerning electromagnetic immunity;
– IEC standards published by TC 111 concerning environmental matters.

– 8 – IEC 60335-2-21:2022 © IEC 2022
HOUSEHOLD AND SIMILAR ELECTRICAL APPLIANCES –
SAFETY –
Part 2-21: Particular requirements for storage water heaters

1 Scope
This clause of Part 1 is replaced by the following.
This part of IEC 60335 deals with the safety of electric storage water heaters for household
and similar purposes and intended for heating water below boiling temperature, their rated
voltage being not more than 250 V for single-phase appliances and 480 V for other appliances
including direct current (DC) supplied appliances and battery-operated appliances.
This standard also deals with:
– appliances not intended for normal household use, but which nevertheless possibly pose a
source of danger to the public, such as appliances intended to be used by laymen in shops
and on farms;
– immersion heater units intended to be retrofitted in a heat exchange closed water heater
having provision for retrofitting. Additional requirements are given in Annex AA.
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.
Attention is drawn to the fact that
– for appliances intended to be used in vehicles or on board ships or aircraft, additional
requirements can 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;
– in many countries regulations exist for the installation of equipment connected to the water
mains.
This standard does not apply to
– appliances for boiling water (IEC 60335-2-15);
– instantaneous water heaters (IEC 60335-2-35);
– commercial dispensing appliances and vending machines (IEC 60335-2-75);
– appliances intended exclusively for industrial purposes;
– appliances intended to be used in locations where special conditions prevail, such as the
presence of a corrosive or explosive atmosphere (dust, vapour or gas).

IEC 60335-2-21:2022 © IEC 2022 – 9 –
2 Normative references
This clause of Part 1 is applicable except as follows:
Addition:
IEC 60584-1, Thermocouples – Part 1: EMF specifications and tolerances
IEC 60730-1:2013, Automatic electrical controls – Part 1: General requirements
IEC 60730-1:2013/AMD1:2015
IEC 60730-1:2013/AMD2:2020
3 Terms and definitions
This clause of Part 1 is applicable except as follows.
3.1 Definitions relating to physical characteristics
3.1.9 Addition:
operation of the appliance after installation in accordance with the instructions and filled with
cold water
3.1.101
rated pressure
water pressure assigned to the appliance by the manufacturer
3.5 Definitions relating to types of appliances
3.5.101
storage water heater
stationary appliance for heating and storing water in a container and incorporating devices to
control the water temperature
3.5.102
closed water heater
unvented storage water heater intended to operate at the pressure of the water system, the
flow of water being controlled by one or more valves in the outlet system
Note 1 to entry: A closed water heater is shown in Figure 101a).
Note 2 to entry: The operating pressure may be the output pressure of a reducing or boosting device.
3.5.103
cistern-fed water heater
storage water heater that is vented to atmosphere and intended to be supplied by water under
gravity from a separate cistern, the flow of water being controlled by one or more valves in the
outlet system
Note 1 to entry: A cistern-fed water heater is shown in Figure 101d).
Note 2 to entry: The water heater may be installed so that the expanded water returns to the cistern.
Note 3 to entry: In a cistern-fed water heater, the pressure in the container results from the column of water in
the cistern.
– 10 – IEC 60335-2-21:2022 © IEC 2022
3.5.104
cistern-type water heater
storage water heater having a container supplied by water under gravity from a cistern
incorporated in the appliance
Note 1 to entry: The expanded water can return to the cistern, the flow of water being controlled by one or more
valves in the outlet system.
Note 2 to entry: A cistern-type water heater is shown in Figure 101c).
Note 3 to entry: In a cistern-type water heater, the surface of the water is always at atmospheric pressure.
3.5.105
open-outlet water heater
storage water heater in which the flow of water is only controlled by a valve in the inlet pipe
and in which the expanded or displaced water flows through the outlet
Note 1 to entry: An open-outlet water heater is shown in Figure 101b).
Note 2 to entry: In an open-outlet water heater, the static pressure at the outlet is always at atmospheric pressure.
3.5.106
low-pressure water heater
storage water heater that is vented to atmosphere and intended to be connected to the water
mains through a pressure reducing valve, the flow of water being controlled by one or more
valves in the outlet system
Note 1 to entry: A low-pressure water heater is shown in Figure 101e).
3.5.107
heat exchange water heater
storage water heater in which heated water is fed into a heat exchanger, such as a coiled tube
or similar device, which is itself immersed in a container with the water to be heated
Note 1 to entry: The heated water fed into the heat exchanger is heated from a pri
...