oSIST prEN IEC 60335-2-73:2026

• Abstract:

  This European standard deals with the safety of electric thermal-storage room heaters intended to heat the room in which they are located, their rated voltage being not more than 250 V for single phase and 480 V for other appliances.

• Status: Not Published
• Public Enquiry End Date: 30-Oct-2026
• ICS: 13.120 - Domestic safety
• ICS: 91.140.65 - Water heating equipment
• Technical Committee: VGA - Safety of household and similar electrical appliances
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 04-Sep-2026
• Due Date: 22-Jan-2027
• 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
• Directive:

  ---

  Harmonized Standard2014/53/EU - Directive 2014/53/EU of The European Parliament and of the Council of 16 April 2014 on the harmonisation of the laws of the Member States relating to the making available on the market of radio equipment and repealing Directive 1999/5/EC
• Directive:

  ---

  Not Harmonized2014/55/EU - Directive 2014/55/EU of the European Parliament and of The Council of 16 April 2014 on Electronic Invoicing in Public Procurement
• Mandate: M/511 - Mandate to CEN, CENELEC and ETSI relating to harmonised standards in the field of the Low Voltage Directive
• Mandate: M/536 - [C(2015)536] Standardisation request as regards radio equipment in support of Directive 2014/53/EU
• Mandate: M/585 - standardisation request to the European Telecommunications Standards Institute as regards radio equipment in support of Directive 2014/53/EU of the European Parliament and of the Council in conjunction with Commission Delegated Regulation
• Ref Project: prEN IEC 60335-2-73:2026 - Household and similar electrical appliances - Safety - Part 2-73: Particular requirements for fixed immersion heaters

• Amended By: oSIST prEN IEC 60335-2-73:2026/oprAA:2026 - Household and similar electrical appliances - Safety - Part 2-73: Particular requirements for fixed immersion heaters
• Effective Date: 10-Sep-2024
• Revises: SIST EN 60335-2-73:2003 - Household and similar electrical appliances - Safety -- Part 2-73: Particular requirements for fixed immersion heaters
• Effective Date: 30-Jul-2024
• Revises: SIST EN 60335-2-73:2003/A1:2006 - Household and similar electrical appliances - Safety -- Part 2-73: Particular requirements for fixed immersion heaters
• Effective Date: 30-Jul-2024
• Revises: SIST EN 60335-2-73:2003/A11:2021 - Household and similar electrical appliances - Safety - Part 2-73: Particular requirements for fixed immersion heaters
• Effective Date: 30-Jul-2024
• Revises: SIST EN 60335-2-73:2003/A2:2010 - Household and similar electrical appliances - Safety -- Part 2-73: Particular requirements for fixed immersion heaters
• Effective Date: 30-Jul-2024

Overview

oSIST prEN IEC 60335-2-73:2026 is a European standard developed by SIST, detailing the safety requirements for fixed immersion heaters intended for household and similar purposes. These electric thermal-storage room heaters are designed for installation in water tanks open to the atmosphere, with rated voltages up to 250 V for single-phase appliances and 480 V for others, including DC-supplied models. The standard addresses the risks associated with the use of fixed immersion heaters, ensuring that appliances provide an internationally recognized level of protection against electrical, mechanical, thermal, fire, and radiation hazards during normal and practically foreseeable misuse.

Key Topics

• Scope and Applicability

  • Fixed electric immersion heaters for heating water in tanks below boiling point.
  • Appliances rated up to 250 V (single-phase) and 480 V (multi-phase/DC).
  • Not limited to domestic use, also includes similar environments like light industry and farms.

• General Safety Requirements

  • Protection against electric shock, overheating, leakage current, and mechanical hazards.
  • Requirements for clear marking and manufacturer instructions, especially regarding installation and initial operation.
  • Protection of live parts and user-accessible surfaces.

• Design and Construction Criteria

  • Mechanical strength and stability of immersion heaters.
  • Construction provisions to prevent water leakage.
  • Safety of wiring, connections, and terminal blocks.
  • Earthing requirements for metal parts in contact with water.

• Testing and Endurance

  • Evaluation under normal and abnormal operation, including empty or overfilled tanks.
  • Control of accessible surface temperatures.
  • Resistance to heat, fire, rust, and humid conditions.

• Markings and Instructions

  • Explicit labeling for multiple supply circuits and warnings (e.g., "Do not cover").
  • Installation instructions regarding tank dimensions, heater positioning, and water level requirements.

Applications

This standard applies directly to:

• Household Hot Water Systems: Ensuring safety in residential water heating installations, such as cistern-fed tanks.
• Commercial Settings: Applicable to shops, farms, and light industrial environments where fixed immersion heaters are accessible to laypersons.
• Central Heating Boilers: Appliances with alternative electrical heating sources up to 25 kW.
• Replacement and Upgrades: Providing guidance for safe installation or retrofitting of immersion heaters in existing water tanks.

Exclusions: The standard does not cover immersion heaters:

• Used exclusively for industrial processes.
• Used in environments with corrosive or explosive atmospheres.
• Incorporated in other appliance types (e.g., storage or instantaneous water heaters, aquarium heaters, portable immersion heaters, or engine preheaters), which are addressed by other IEC standards.

Related Standards

Fixed immersion heaters must also be understood within the context of other relevant international standards for safety and interoperability. Closely related standards include:

• IEC 60335-1: General requirements for all household and similar electrical appliances.
• IEC 60335-2-15: Safety for appliances for heating liquids.
• IEC 60335-2-21: Safety for storage water heaters.
• IEC 60335-2-35: Safety for instantaneous water heaters.
• IEC 60335-2-55: Electrical appliances for aquariums and garden ponds.
• IEC 60335-2-74: Safety requirements for portable immersion heaters.
• ISO 13732-1: Assessment of human responses to contact with hot surfaces.

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oSIST prEN IEC 60335-2-73:2026 brings a harmonized set of safety requirements for fixed immersion heaters, supporting manufacturers, installers, and users in achieving compliance, reducing risk, and enhancing the safe operation of electrical water heating systems in domestic and similar environments across Europe. For water heating safety, appliance reliability, and compliance with European legislative frameworks, this standard is essential.

SLOVENSKI STANDARD
01-oktober-2026
Gospodinjski in podobni električni aparati - Varnost - 2-73. del: Posebne zahteve
za pritrjene potopne grelnike
Household and similar electrical appliances - Safety - Part 2-73: Particular requirements
for fixed immersion heaters
Sicherheit elektrischer Geräte für den Hausgebrauch und ähnliche Zwecke - Teil 2-73:
Besondere Anforderungen für ortsfeste Heizeinsätze
Appareils électrodomestiques et analogues - Sécurité - Partie 2-73: Règles particulières
pour les thermoplongeurs installés à poste fixe
Ta slovenski standard je istoveten z: prEN IEC 60335-2-73:2026
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 60335-2-73
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2026
ICS 91.140.65 Will supersede EN 60335-2-73:2003; EN 60335-2-
73:2003/A1:2006; EN 60335-2-73:2003/A2:2009; EN
60335-2-73:2003/A11:2021
English Version
Household and similar electrical appliances - Safety - Part 2-73:
Particular requirements for fixed immersion heaters
(IEC 60335-2-73:2024)
Appareils électrodomestiques et analogues - Sécurité - Sicherheit elektrischer Geräte für den Hausgebrauch und
Partie 2-73: Règles particulières pour les thermoplongeurs ähnliche Zwecke - Teil 2-73: Besondere Anforderungen für
installés à poste fixe ortsfeste Heizeinsätze
(IEC 60335-2-73:2024) (IEC 60335-2-73:2024)
This draft European Standard is submitted to CENELEC members for enquiry.
Deadline for CENELEC: 2026-11-06.

The text of this draft consists of the text of IEC 60335-2-73:2024.

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
© 2026 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Project: 80416 Ref. No. prEN IEC 60335-2-73:2026 E

European foreword
This document (prEN IEC 60335-2-73:2026) consists of the text of document IEC 60335-2-73:2024,
prepared by IEC/TC 61 "Safety of household and similar electrical appliances".
This document is currently submitted to the Enquiry.
The following dates are proposed:
• latest date by which the existence of this document (doa) dav + 6 months
has to be announced at national level
• latest date by which this document has to be (dop) dav + 12 months
implemented at national level by publication of an
identical national standard or by endorsement
• latest date by which the national standards (dow) dav + 36 months
conflicting with this document have to be withdrawn (to be confirmed or
modified when voting)
This document will supersede EN 60335-2-73:2003 and all of its amendments and corrigenda (if any).
This document is read in conjunction with prEN IEC 60335-2-73:2026/prAA:2026.

IEC 60335-2-73 ®
Edition 3.0 2024-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Household and similar electrical appliances – Safety –
Part 2-73: Particular requirements for fixed immersion heaters

Appareils électrodomestiques et analogues – Sécurité –
Partie 2-73: Règles particulières pour les thermoplongeurs installés à poste fixe
IEC 60335-2-73:2024-03(en-fr)
IEC 60335-2-73 ®
Edition 3.0 2024-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Household and similar electrical appliances – Safety –

Part 2-73: Particular requirements for fixed immersion heaters

Appareils électrodomestiques et analogues – Sécurité –

Partie 2-73: Règles particulières pour les thermoplongeurs installés à poste fixe

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 91.140.65  ISBN 978-2-8322-8459-9

– 2 – IEC 60335-2-73:2024 © IEC 2024
CONTENTS
FOREWORD . 3
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 8
3 Terms and definitions . 8
4 General requirement . 8
5 General conditions for the tests . 8
6 Classification . 8
7 Marking and instructions . 9
8 Protection against access to live parts . 9
9 Starting of motor-operated appliances . 9
10 Power input and current . 9
11 Heating . 9
12 Charging of metal-ion batteries . 10
13 Leakage current and electric strength at operating temperature . 10
14 Transient overvoltages . 10
15 Moisture resistance . 10
16 Leakage current and electric strength . 11
17 Overload protection of transformers and associated circuits . 11
18 Endurance . 11
19 Abnormal operation . 11
20 Stability and mechanical hazards . 11
21 Mechanical strength . 11
22 Construction . 11
23 Internal wiring . 12
24 Components . 12
25 Supply connection and external flexible cords . 12
26 Terminals for external conductors . 12
27 Provision for earthing . 12
28 Screws and connections . 12
29 Clearances, creepage distances and solid insulation . 12
30 Resistance to heat and fire . 12
31 Resistance to rusting . 13
32 Radiation, toxicity and similar hazards . 13
Annexes . 14
Bibliography . 15

Figure 101 – Probe for measuring surface temperatures . 13

Table 101 – Maximum temperature rises for specified external accessible surfaces
under normal operating conditions . 10

IEC 60335-2-73:2024 © IEC 2024 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
HOUSEHOLD AND SIMILAR ELECTRICAL APPLIANCES –
SAFETY –
Part 2-73: Particular requirements for fixed immersion heaters

FOREWORD
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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9) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
may be required to implement this document. However, implementers are cautioned that this may not represent
the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
IEC 60335-2-73 has been prepared by IEC technical committee 61: Safety of household and
similar electrical appliances. It is an International Standard.
This third edition cancels and replaces the second edition published in 2002, Amendment 1:
2006 and Amendment 2: 2009. 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, 19.2);
c) addition of external accessible surface temperatures (Clause 11).

– 4 – IEC 60335-2-73:2024 © IEC 2024
The text of this International Standard is based on the following documents:
Draft Report on voting
61/6954/CDV 61/7055A/RVC
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/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 fixed immersion 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 s
...