IEC 60335-2-35:2012

IEC 60335-2-35 ®
Edition 5.2 2020-06
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Household and similar electrical appliances – Safety –
Part 2-35: Particular requirements for instantaneous water heaters
Appareils électrodomestiques et analogues – Sécurité –
Partie 2-35: Exigences particulières pour les chauffe-eau instantanés
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IEC 60335-2-35 ®
Edition 5.2 2020-06
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Household and similar electrical appliances – Safety –
Part 2-35: Particular requirements for instantaneous water heaters
Appareils électrodomestiques et analogues – Sécurité –
Partie 2-35: Exigences particulières pour les chauffe-eau instantanés
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 13.120; 97.040.50 ISBN 978-2-8322-8457-5

colour
inside
IEC 60335-2-35 ®
Edition 5.2 2020-06
REDLINE VERSION
VERSION REDLINE
colour
inside
Household and similar electrical appliances – Safety –
Part 2-35: Particular requirements for instantaneous water heaters
Appareils électrodomestiques et analogues – Sécurité –
Partie 2-35: Exigences particulières pour les chauffe-eau instantanés
– 2 – IEC 60335-2-35:2012+AMD1:2016
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CONTENTS
FOREWORD . 4
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 9
4 General requirement . 9
5 General conditions for the tests . 9
6 Classification . 10
7 Marking and instructions . 10
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 Void . 13
13 Leakage current and electric strength at operating temperature . 13
14 Transient overvoltages . 14
15 Moisture resistance . 14
16 Leakage current and electric strength . 14
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 . 19
24 Components . 19
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 . 22
32 Radiation, toxicity and similar hazards . 22
Annexes . 24
Annex A (informative) Routine tests . 24
Annex R (normative) Software evaluation . 25
Bibliography . 26
Figure 101 – Diagram for the leakage current measurement for single-phase bare-
element water heaters . 22

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Figure 102 – Diagram for the leakage current measurement for three-phase bare-
element water heaters . 23
Figure 103 – Diagram for the leakage current measurement for single-phase bare-

element water heaters supplied by a supply cord fitted with a plug. 23
Figure 104 – Probe for measuring surface temperatures . 24

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

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INTERNATIONAL ELECTROTECHNICAL COMMISSION

___________
HOUSEHOLD AND SIMILAR ELECTRICAL APPLIANCES –
SAFETY –
Part 2-35: Particular requirements for instantaneous 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.
This consolidated version of the official IEC Standard and its amendments has been
prepared for user convenience.
IEC 60335-2-35 edition 5.2 contains the fifth edition (2012-11) [documents 61/4454/FDIS
and 61/4507/RVD], its amendment 1 (2016-11) [documents 61/5282/FDIS and
61/5299/RVD] and its amendment 2 (2020-06) [documents 61/5932/CDV and
61/6005/RVC].
In this Redline version, a vertical line in the margin shows where the technical content
is modified by amendments 1 and 2. Additions are in green text, deletions are in
strikethrough red text. A separate Final version with all changes accepted is available
in this publication.
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This part of International Standard IEC 60335 has been prepared by IEC technical committee
61: Safety of household and similar electrical appliances.
This fifth edition constitutes a technical revision.
The principal changes in this edition as compared with the fourth edition of IEC 60335-2-35
are as follows (minor changes are not listed):
– converted notes to normative text (7.12, 7.102, 8.1.5, 22.104, and 22.109.3);
– deleted notes in 19.13, 22.109, and A.101;
– added Annex R and 22.108 for appliances with programmable electronic circuits;
– added requirements for water heaters (22.50, 22.51).
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
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 fifth edition (2010) 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 instantaneous 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 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.
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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.
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.
The following differences exist in the countries indicated below.
– 6.1: Bare-element water heaters are not allowed (India).
– 6.1: Class 0I appliances are allowed (Japan).
– 7.1: Marking of rated pressure is different and marking of water resistivity is not required
(USA).
– 19.4: Flow switches tested for reliability are not short-circuited (USA).
– 19.13: The water temperatures are different (USA).
– 22.101: For closed water heaters, the minimum rated pressure is 1,0 MPa (Norway,
Sweden).
– 22.103: Closed water heaters have to incorporate a temperature relief valve or a combined
temperature and pressure relief valve that has to operate before the water temperature
reaches 100 °C (United Kingdom).
– 22.103: The pressure relief valve is not required to be provided with the heater (USA).

IMPORTANT – The “colour inside” logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this publication using a colour printer.

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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.
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HOUSEHOLD AND SIMILAR ELECTRICAL APPLIANCES –
SAFETY –
Part 2-35: Particular requirements for instantaneous water heaters

1 Scope
This clause of Part 1 is replaced by the following.
This International Standard deals with the safety of electric instantaneous 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.
NOTE 101 Instantaneous water heaters incorporating bare heating elements are within the scope of this
standard.
Appliances not intended for normal household use but which nevertheless may be a source of
danger to the public, such as appliances intended for use 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 which 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;
– in many countries regulations exist for the installation of equipment connected to the water mains.
NOTE 103 This standard does not apply to
– appliances for heating liquids (IEC 60335-2-15);
– storage water heaters (IEC 60335-2-21);
– 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);
– commercial dispensing appliances and vending machines (IEC 60335-2-75).
2 Normative references
This clause of Part 1 is applicable.

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3 Terms and definitions
This clause of Part 1 is applicable except as follows.
3.1.9 Replacement:
normal operation
operation of the appliance while supplied with water, the flow being adjusted to attain the
highest outlet water temperature without operation of the thermal cut-out
3.101
instantaneous water heater
stationary appliance for heating water while it flows through the appliance
Note 1 to entry: Instantaneous water heaters are referred to as water heaters.
3.102
closed water heater
instantaneous 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: The operating pressure can be the output pressure of a reducing or boosting device.
3.103
open-outlet water heater
instantaneous water heater in which the flow of water is controlled by a valve in the inlet
pipe, there being no valve in the outlet pipe
3.104
bare-element water heater
instantaneous water heater in which uninsulated heating elements are immersed in the
water
3.105
rated pressure
water pressure assigned to the appliance by the manufacturer
3.106
flow switch
device that operates in response to a flow of water
3.107
pressure switch
device that operates in response to a change in pressure
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.
5.2 Addition:
NOTE 101 Additional samples can be required for the tests of 22.109.

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5.3 Addition:
When the tests are carried out on a single appliance, the tests of 22.102, 22.107, 22.108 and
24.102 are carried out before the tests of Clause 19.
5.7 Addition:
Inlet water having a temperature of 15 °C ± 5 °C is used for the tests unless the inlet water
temperature marked on the appliance will give a more unfavourable result, in which case inlet
water at the marked temperature shall be used.
6 Classification
This clause of Part 1 is applicable except as follows.
6.1 Modification:
Bare-element water heaters shall be class I or class III.
Other water heaters shall be class I, class II or class III.
6.2 Addition:
Water heaters shall be at least IPX1.
NOTE 101 Specific zones in which the water heater is installed require a higher degree of protection as specified
in IEC 60364.
7 Marking and instructions
This clause of Part 1 is applicable except as follows.
7.1 Addition:
The marked rated frequency for bare-element water heaters shall not be less than 50 Hz.
Appliances shall be marked with the rated pressure in pascals.
If the appliance is intended for use as a booster for inlet water heated by other water heating
systems, the maximum inlet water temperature shall be marked.
Bare-element water heaters shall be marked with the minimum water resistivity with which
the appliance may be used, and the marked value shall not be greater than 1 300 Ωcm.
7.12 Addition:
The instructions for open-outlet water heaters to be used with a spray head shall state that
the spray head must be descaled regularly.
The instructions for an appliance not incorporating a flow switch shall include the substance
of the following:
WARNING: Do not switch on if there is a possibility that the water in the heater is frozen.

+AMD2:2020 CSV © IEC 2020
7.12.1 Addition:
The installation instructions for open-outlet water heaters shall state that the outlet must not
be connected to any tap or fitting other than those specified.
If a pressure relief device is required for closed water heaters, the instructions shall state
that it must be fitted during installation, unless it is incorporated in the appliance.
If the appliance is not marked with an inlet water temperature, the installation instructions
shall state the substance of the following:
The water inlet of this appliance shall not be connected to inlet water obtained from
any other water heating system.
The installation instructions for bare-element water heaters shall state the substance of the
following:
– the resistivity of the water supply must not be less than … Ωcm;
– the appliance must be permanently connected to fixed wiring (not necessary if it complies
with the requirements for the connection by a supply cord fitted with a plug specified
in 13.2 and 24.101);
– the appliance must be earthed (for class I appliances only).
When bare-element water heaters cannot be emptied, the installation instruction shall state
that the appliance is not to be installed in locations where freezing can occur.
In a multiple water outlet system where the water temperature can be set at each individual
water outlet, the instructions shall state the substance of the following:
The system shall be installed so that the control for setting the water temperature in
normal use installed at a shower outlet shall take priority over any other controls in the
system that set the water temperature in normal use at other water outlets.
For appliances not intended for potable water heating, such as for heating water for a water-
based space heating system, the instructions shall state the substance of the following:
WARNING: This appliance is not to be used for a potable water supply.
7.15 Addition:
The additional markings for bare-element water heaters shall be visible during the
installation of the appliance.
7.101 The water inlet and water outlet shall be identified. This identification shall not be on
detachable parts. If colours are used, blue shall be used for the inlet and red for the outlet.
An alternative means of identification may be by means of arrows showing the direction of the
water flow.
Compliance is checked by inspection.
7.102 Class I bare-element water heaters shall be marked to state that the appliance must
be earthed.
Compliance is checked by inspection.
The use of a removable label or tag attached to the appliance is an acceptable means of
meeting this requirement.
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8 Protection against access to live parts
This clause of Part 1 is applicable except as follows.
8.1.5 Addition:
The connections to the water mains and electrical supply are assumed to be in position during
the test.
The requirement does not apply to wall-mounted appliances intended to be permanently
connected to fixed wiring by cables having a nominal cross-sectional area more than 2,5 mm .
and there shall
However, the cross-sectional area of the cable entry shall not exceed 25 cm
be no accessible live parts within the projection of the opening.
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.
11 Heating
This clause of Part 1 is applicable except as follows.
11.3 Addition:
Where the external accessible surfaces are suitably flat and access permits, then the test
probe of Figure 104 is used to measure the temperature rises of external accessible
applied with a force of 4 N ± 1 N to the surface
surfaces specified in Table 101. The probe is
between the probe and the surface is ensured.
in such a way that the best possible contact
The measurement is performed after a contact period of 30 s.
The probe may be held in place using a laboratory stand clamp or similar device. Any
measuring instrument giving the same results as the probe may be used.
11.7 Replacement:
The appliance is operated until steady conditions are established.
11.8 Addition:
During the test, the temperature rises are monitored continuously and shall not exceed the
values shown in Table 3 and Table 101.

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Table 101 – Maximum temperature rises for specified external
accessible surfaces under normal operating conditions
a
Surface Temperature rise of external accessible surfaces
K
Bare metal  42
b
Coated metal 49
Glass and ceramic 56
c, d
Plastic and plastic coating > 0,4 mm 62
NOTE The temperature rise limits of knobs, grips, keyboards, keypads and similar parts are specified in
Table 3.
a
Temperature rises are not measured on:
− surfaces that are inaccessible to a 75 mm diameter probe having a hemispherical end, applied with a
force not exceeding 1 N;
− appliances intended for installation on the roof;
− tapping connections, pipes, hoses, plumbing fittings, pressure relief valves and sight gauges.
b
Metal is considered coated when a coating having a minimum thickness of 90 µm made by enamel or
non-substantially plastic coating is used.
c
When the thickness of the plastic coating does not exceed 0,4 mm, the temperature rise limits of coated
metal for underlying metal apply or the temperature rise limits for glass or ceramic material for underlying
glass or ceramic material apply.
d
The temperature rise limit of plastic also applies for plastic material having a metal finish of thickness
less than 0,1 mm.
12 Void
13 Leakage current and electric strength at operating temperature
This clause of Part 1 is applicable except as follows.
13.2 Addition:
Bare-element water heaters are tested with water having the resistivity marked on the
appliance. Inlet water with the appropriate resistivity is prepared with the water at a
temperature of 15 °C ± 5 °C.
NOTE 101 The appropriate resistivity can be obtained by adding ammonium phosphate to the water.
For class I bare-element water heaters, the leakage current is measured between a metal
sieve positioned in the water 10 mm from the orifice of the outlet, and the earthing terminal.
For single-phase appliances, the terminals of the heating element are connected through the
selector switch to each pole of the supply in turn, as shown in Figure 101. For three-phase
appliances, the earthing terminal is connected to the neutral conductor, as shown in
Figure 102.
The leakage current shall not exceed 0,25 mA.
For bare-element water heaters intended to be connected to the power supply by a supply
cord fitted with a plug, the leakage current test is repeated. During this test, the leakage
current is measured between the earthing terminal of the appliance and the neutral conductor,
as shown in Figure 103. The leakage current, measured with the selector switch in each
position, shall not exceed 2,75 mA.

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14 Transient overvoltages
This clause of Part 1 is applicable.
15 Moisture resistance
This clause of Part 1 is applicable except as follows.
15.1.2 Addition:
Wall-mounted appliances are fixed at a distance of 3 mm from the mounting surface, unless
the installation instructions specify a larger value.
16 Leakage current and electric strength
This clause of Part 1 is applicable except as follows.
16.2 Addition:
Bare-element water heaters are tested with water having the resistivity marked on the
appliance. Inlet water with the appropriate resistivity is prepared with the water at a
temperature of 15 °C ± 5 °C.
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.
19.2 Not applicable.
19.3 Not applicable.
19.4 Addition:
For open-outlet water heaters, flow switches and pressure switches that operate during
the test of Clause 11 are short-circuited, the water-control valve being adjusted to the most
unfavourable position.
NOTE 101 The closed position of the valve can be the most unfavourable position.
Flow switches of closed water heaters are short-circuited and any pressure relief device
rendered inoperative, the outlet valve being closed. However, if the appliance has no flow
switch and back-siphonage is likely to occur, the water heater is filled with just sufficient
water to cover the heating element and operated with the outlet valve open.

+AMD2:2020 CSV © IEC 2020
NOTE 102 Back-siphonage is not considered likely to occur if a non-return valve or a pipe interrupter is
incorporated in the appliance or if the instructions state that a non-return valve has to be included in the
installation.
19.13 Addition:
During the test of 19.4, the water container shall not rupture and the water temperature shall
not exceed
– 99 °C, for open-outlet water heaters having a capacity exceeding 1 l;
– 140 °C, for closed water heaters having a capacity exceeding 1 l.
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.
22.6 Addition:
The enclosure shall have a drain hole positioned so that the water can drain without impairing
the electrical insulation, unless water cannot accumulate within the enclosure in normal use.
The hole shall be at least 5 mm in diameter or 20 mm in area with a width of at least 3 mm.
Compliance is checked by inspection and by measurement.
22.33 Addition:
The requirement does not apply to bare-element water heaters.
22.47 Replacement:
Appliances shall withstand the water pressure occurring in normal use.
Compliance is checked by subjecting the appliance to a water pressure of
– twice the rated pressure, for closed water heaters;
– 0,15 MPa, for open-outlet water heaters.
If an open-outlet water heater incorporates a valve that regulates the water flow, a water
pressure of 2 MPa is applied to the inlet of the appliance, the valve being closed.
Pressure-relief devices are rendered inoperative. The pressure is raised at a rate of
0,13 MPa/s to the specified value and is maintained at that value for 5 min.
Water shall not leak from the appliance and there shall be no permanent deformation to such
an extent that compliance with this standard is impaired.
22.48 Not applicable.
– 16 – IEC 60335-2-35:2012+AMD1:2016
+AMD2:2020 CSV © IEC 2020
22.50 Addition:
The requirement is not applicable provided the maximum temperature of the water from the
system cannot exceed 55 °C in normal use.
If the maximum temperature of the water from the system exceeds 55 °C in normal use then
the requirement is not applicable provided that the system is such that a shower outlet normal
use water temperature control takes precedence in setting the system temperature. In the
case of systems with multiple shower outlets, the shower with the lowest temperature setting
shall take precedence, the other shower outlets taking precedence over non-shower outlets.
22.51 Addition:
The requirement is not applicable provided the maximum temperature of the water from the
system cannot exceed 55 °C in normal use.
If the maximum temperature of the water from the system exceeds 55 °C in normal use then
the requirement is not applicable provided that the system is such that the shower outlet
normal use water temperature control takes precedence in setting the system temperature. In
the case of systems with multiple shower outlets, a shower with the lowest temperature
setting shall take precedence, the other shower outlets taking precedence over non-shower
outlets.
22.101 The rated pressure of closed water heaters shall be at least 0,6 MPa.
The rated pressure of closed water heaters intended to be supplied by a pressure reducing
valve shall be at least 0,1 MPa.
NOTE The rated pressure of open-outlet water heaters is 0 Pa.
Compliance is checked by inspection.
22.102 The outlet water of appliances other than those intended to supply water for
showering shall not attain an excessive temperature due to a sudden pressure drop in the
water supply.
Compliance is checked by the following test.
The appliance is operated at rated power input with the controls or switching devices
adjusted to their most unfavourable possible setting to attain the maximum water temperature.
Any regulating valve is fully opened and the water flow is adjusted so that the flow switch or
the pressure switch is on the verge of operating.
Any control devices that operate during the test of Clause 11 are short-circuited. The water
flow is reduced in steps of 10 % per minute until:
– for closed water heaters, the thermal cut-out incorporated to comply with 22.106
operates or steady conditions are established;
– for open-outlet water heaters, a non-self-resetting thermal cut-out operates or steady
conditions are established.
If the rupture of a heating element or an intentionally weak part leads to a permanent open
circuit, the test is repeated on a second sample. This second test shall be terminated in the
same mode unless the test is otherwise satisfactorily completed.
VOID
+AMD2:2020 CSV © IEC 2020
22.103 Closed water heaters having a capacity exceeding 3 l shall be supplied with a
pressure relief device that prevents excessive pressure.
Compliance is checked by inspection and by subjecting the appliance to a slowly increasing
water pressure.
The pressure relief device shall operate before the water pressure exceeds the rated
pressure by more than 0,1 MPa.
NOTE The pressure relief device can be fitted during installation.
22.104 The outlet of open-outlet water heaters shall be constructed so that the water flow
is not limited to such an extent that the container is subjected to a significant pressure in
normal use.
Compliance is checked by inspection.
The requirement is considered to be met if the cross-sectional area of the water outlet is not
le
...

IEC 60335-2-35 ®
Edition 5.1 2016-11
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Household and similar electrical appliances – Safety –
Part 2-35: Particular requirements for instantaneous water heaters

Appareils électrodomestiques et analogues – Sécurité –
Partie 2-35: Exigences particulières pour les chauffe-eau instantanés

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IEC 60335-2-35 ®
Edition 5.1 2016-11
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Household and similar electrical appliances – Safety –

Part 2-35: Particular requirements for instantaneous water heaters

Appareils électrodomestiques et analogues – Sécurité –

Partie 2-35: Exigences particulières pour les chauffe-eau instantanés

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 13.120, 97.040.50 ISBN 978-2-8322-3752-6

IEC 60335-2-35 ®
Edition 5.1 2016-11
CONSOLIDATED VERSION
REDLINE VERSION
VERSION REDLINE
colour
inside
Household and similar electrical appliances – Safety –
Part 2-35: Particular requirements for instantaneous water heaters

Appareils électrodomestiques et analogues – Sécurité –
Partie 2-35: Exigences particulières pour les chauffe-eau instantanés

– 2 – IEC 60335-2-35:2012+AMD1:2016 CSV
© IEC 2016
CONTENTS
FOREWORD . 4
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 9
4 General requirement . 9
5 General conditions for the tests . 9
6 Classification . 10
7 Marking and instructions . 10
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 Void . 12
13 Leakage current and electric strength at operating temperature . 12
14 Transient overvoltages . 13
15 Moisture resistance . 13
16 Leakage current and electric strength . 13
17 Overload protection of transformers and associated circuits . 13
18 Endurance . 13
19 Abnormal operation . 13
20 Stability and mechanical hazards. 14
21 Mechanical strength . 14
22 Construction . 14
23 Internal wiring . 19
24 Components . 19
25 Supply connection and external flexible cords . 20
26 Terminals for external conductors . 20
27 Provision for earthing . 20
28 Screws and connections . 20
29 Clearances, creepage distances and solid insulation . 20
30 Resistance to heat and fire . 20
31 Resistance to rusting . 21
32 Radiation, toxicity and similar hazards . 21
Annexes . 23
Annex A (informative) Routine tests . 23
Annex R (normative) Software evaluation . 24
Bibliography . 25

Figure 101 – Diagram for the leakage current measurement for single-phase bare-
element water heaters . 21

© IEC 2016
Figure 102 – Diagram for the leakage current measurement for three-phase bare-
element water heaters . 22
Figure 103 – Diagram for the leakage current measurement for single-phase bare-
element water heaters supplied by a supply cord fitted with a plug. 22

– 4 – IEC 60335-2-35:2012+AMD1:2016 CSV
© IEC 2016
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
HOUSEHOLD AND SIMILAR ELECTRICAL APPLIANCES –
SAFETY –
Part 2-35: Particular requirements for instantaneous 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.
This consolidated version of the official IEC Standard and its amendment has been prepared
for user convenience.
IEC 60335-2-35 edition 5.1 contains the fifth edition (2012-11) [documents 61/4454/FDIS and
61/4507/RVD] and its amendment 1 (2016-11) [documents 61/5282/FDIS and 61/5299/RVD].
In this Redline version, a vertical line in the margin shows where the technical content is
modified by amendment 1. Additions are in green text, deletions are in strikethrough red text. A
separate Final version with all changes accepted is available in this publication.

© IEC 2016
This part of International Standard IEC 60335 has been prepared by IEC technical committee
61: Safety of household and similar electrical appliances.
This fifth edition constitutes a technical revision.
The principal changes in this edition as compared with the fourth edition of IEC 60335-2-35
are as follows (minor changes are not listed):
– converted notes to normative text (7.12, 7.102, 8.1.5, 22.104, and 22.109.3);
– deleted notes in 19.13, 22.109, and A.101;
– added Annex R and 22.108 for appliances with programmable electronic circuits;
– added requirements for water heaters (22.50, 22.51).
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
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 fifth edition (2010) 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 instantaneous 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 the base publication and its amendment 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.
– 6 – IEC 60335-2-35:2012+AMD1:2016 CSV
© IEC 2016
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.
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.
The following differences exist in the countries indicated below.
– 6.1: Bare-element water heaters are not allowed (India).
– 6.1: Class 0I appliances are allowed (Japan).
– 7.1: Marking of rated pressure is different and marking of water resistivity is not required
(USA).
– 19.4: Flow switches tested for reliability are not short-circuited (USA).
– 19.13: The water temperatures are different (USA).
– 22.101: For closed water heaters, the minimum rated pressure is 1,0 MPa (Norway,
Sweden).
– 22.103: Closed water heaters have to incorporate a temperature relief valve or a combined
temperature and pressure relief valve that has to operate before the water temperature
reaches 100 °C (United Kingdom).
– 22.103: The pressure relief valve is not required to be provided with the heater (USA).

IMPORTANT – The “colour inside” logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this publication using a colour printer.

© IEC 2016
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.
– 8 – IEC 60335-2-35:2012+AMD1:2016 CSV
© IEC 2016
HOUSEHOLD AND SIMILAR ELECTRICAL APPLIANCES –
SAFETY –
Part 2-35: Particular requirements for instantaneous water heaters

1 Scope
This clause of Part 1 is replaced by the following.
This International Standard deals with the safety of electric instantaneous 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.
NOTE 101 Instantaneous water heaters incorporating bare heating elements are within the scope of this
standard.
Appliances not intended for normal household use but which nevertheless may be a source of
danger to the public, such as appliances intended for use 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 which 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;
– in many countries regulations exist for the installation of equipment connected to the water mains.
NOTE 103 This standard does not apply to
– appliances for heating liquids (IEC 60335-2-15);
– storage water heaters (IEC 60335-2-21);
– 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);
– commercial dispensing appliances and vending machines (IEC 60335-2-75).
2 Normative references
This clause of Part 1 is applicable.

© IEC 2016
3 Terms and definitions
This clause of Part 1 is applicable except as follows.
3.1.9 Replacement:
normal operation
operation of the appliance while supplied with water, the flow being adjusted to attain the
highest outlet water temperature without operation of the thermal cut-out
3.101
instantaneous water heater
stationary appliance for heating water while it flows through the appliance
Note 1 to entry: Instantaneous water heaters are referred to as water heaters.
3.102
closed water heater
instantaneous 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: The operating pressure can be the output pressure of a reducing or boosting device.
3.103
open-outlet water heater
instantaneous water heater in which the flow of water is controlled by a valve in the inlet
pipe, there being no valve in the outlet pipe
3.104
bare-element water heater
instantaneous water heater in which uninsulated heating elements are immersed in the
water
3.105
rated pressure
water pressure assigned to the appliance by the manufacturer
3.106
flow switch
device that operates in response to a flow of water
3.107
pressure switch
device that operates in response to a change in pressure
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.
5.2 Addition:
NOTE 101 Additional samples can be required for the tests of 22.109.
5.3 Addition:
– 10 – IEC 60335-2-35:2012+AMD1:2016 CSV
© IEC 2016
When the tests are carried out on a single appliance, the tests of 22.102, 22.107, 22.108 and
24.102 are carried out before the tests of Clause 19.
5.7 Addition:
Inlet water having a temperature of 15 °C ± 5 °C is used for the tests unless the inlet water
temperature marked on the appliance will give a more unfavourable result, in which case inlet
water at the marked temperature shall be used.
6 Classification
This clause of Part 1 is applicable except as follows.
6.1 Modification:
Bare-element water heaters shall be class I or class III.
Other water heaters shall be class I, class II or class III.
6.2 Addition:
Water heaters shall be at least IPX1.
NOTE 101 Specific zones in which the water heater is installed require a higher degree of protection as specified
in IEC 60364.
7 Marking and instructions
This clause of Part 1 is applicable except as follows.
7.1 Addition:
The marked rated frequency for bare-element water heaters shall not be less than 50 Hz.
Appliances shall be marked with the rated pressure in pascals.
If the appliance is intended for use as a booster for inlet water heated by other water heating
systems, the maximum inlet water temperature shall be marked.
Bare-element water heaters shall be marked with the minimum water resistivity with which
the appliance may be used, and the marked value shall not be greater than 1 300 Ωcm.
7.12 Addition:
The instructions for open-outlet water heaters to be used with a spray head shall state that
the spray head must be descaled regularly.
The instructions for an appliance not incorporating a flow switch shall include the substance
of the following:
WARNING: Do not switch on if there is a possibility that the water in the heater is frozen.
7.12.1 Addition:
© IEC 2016
The installation instructions for open-outlet water heaters shall state that the outlet must not
be connected to any tap or fitting other than those specified.
If a pressure relief device is required for closed water heaters, the instructions shall state
that it must be fitted during installation, unless it is incorporated in the appliance.
If the appliance is not marked with an inlet water temperature, the installation instructions
shall state the substance of the following:
The water inlet of this appliance shall not be connected to inlet water obtained from
any other water heating system.
The installation instructions for bare-element water heaters shall state the substance of the
following:
– the resistivity of the water supply must not be less than … Ωcm;
– the appliance must be permanently connected to fixed wiring (not necessary if it complies
with the requirements for the connection by a supply cord fitted with a plug specified
in 13.2 and 24.101);
– the appliance must be earthed (for class I appliances only).
When bare-element water heaters cannot be emptied, the installation instruction shall state
that the appliance is not to be installed in locations where freezing can occur.
In a multiple water outlet system where the water temperature can be set at each individual
water outlet, the instructions shall state the substance of the following:
The system shall be installed so that the control for setting the water temperature in
normal use installed at a shower outlet shall take priority over any other controls in the
system that set the water temperature in normal use at other water outlets.
For appliances not intended for potable water heating, such as for heating water for a water-
based space heating system, the instructions shall state the substance of the following:
WARNING: This appliance is not to be used for a potable water supply.
7.15 Addition:
The additional markings for bare-element water heaters shall be visible during the
installation of the appliance.
7.101 The water inlet and water outlet shall be identified. This identification shall not be on
detachable parts. If colours are used, blue shall be used for the inlet and red for the outlet.
An alternative means of identification may be by means of arrows showing the direction of the
water flow.
Compliance is checked by inspection.
7.102 Class I bare-element water heaters shall be marked to state that the appliance must
be earthed.
Compliance is checked by inspection.
The use of a removable label or tag attached to the appliance is an acceptable means of
meeting this requirement.
– 12 – IEC 60335-2-35:2012+AMD1:2016 CSV
© IEC 2016
8 Protection against access to live parts
This clause of Part 1 is applicable except as follows.
8.1.5 Addition:
The connections to the water mains and electrical supply are assumed to be in position during
the test.
The requirement does not apply to wall-mounted appliances intended to be permanently
connected to fixed wiring by cables having a nominal cross-sectional area more than 2,5 mm .
and there shall
However, the cross-sectional area of the cable entry shall not exceed 25 cm
be no accessible live parts within the projection of the opening.
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.
11 Heating
This clause of Part 1 is applicable except as follows.
11.7 Replacement:
The appliance is operated until steady conditions are established.
12 Void
13 Leakage current and electric strength at operating temperature
This clause of Part 1 is applicable except as follows.
13.2 Addition:
Bare-element water heaters are tested with water having the resistivity marked on the
appliance. Inlet water with the appropriate resistivity is prepared with the water at a
temperature of 15 °C ± 5 °C.
NOTE 101 The appropriate resistivity can be obtained by adding ammonium phosphate to the water.
For class I bare-element water heaters, the leakage current is measured between a metal
sieve positioned in the water 10 mm from the orifice of the outlet, and the earthing terminal.
For single-phase appliances, the terminals of the heating element are connected through the
selector switch to each pole of the supply in turn, as shown in Figure 101. For three-phase
appliances, the earthing terminal is connected to the neutral conductor, as shown in
Figure 102.
The leakage current shall not exceed 0,25 mA.

© IEC 2016
For bare-element water heaters intended to be connected to the power supply by a supply
cord fitted with a plug, the leakage current test is repeated. During this test, the leakage
current is measured between the earthing terminal of the appliance and the neutral conductor,
as shown in Figure 103. The leakage current, measured with the selector switch in each
position, shall not exceed 2,75 mA.
14 Transient overvoltages
This clause of Part 1 is applicable.
15 Moisture resistance
This clause of Part 1 is applicable except as follows.
15.1.2 Addition:
Wall-mounted appliances are fixed at a distance of 3 mm from the mounting surface, unless
the installation instructions specify a larger value.
16 Leakage current and electric strength
This clause of Part 1 is applicable except as follows.
16.2 Addition:
Bare-element water heaters are tested with water having the resistivity marked on the
appliance. Inlet water with the appropriate resistivity is prepared with the water at a
temperature of 15 °C ± 5 °C.
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.
19.2 Not applicable.
19.3 Not applicable.
19.4 Addition:
For open-outlet water heaters, flow switches and pressure switches that operate during
the test of Clause 11 are short-circuited, the water-control valve being adjusted to the most
unfavourable position.
NOTE 101 The closed position of the valve can be the most unfavourable position.

– 14 – IEC 60335-2-35:2012+AMD1:2016 CSV
© IEC 2016
Flow switches of closed water heaters are short-circuited and any pressure relief device
rendered inoperative, the outlet valve being closed. However, if the appliance has no flow
switch and back-siphonage is likely to occur, the water heater is filled with just sufficient
water to cover the heating element and operated with the outlet valve open.
NOTE 102 Back-siphonage is not considered likely to occur if a non-return valve or a pipe interrupter is
incorporated in the appliance or if the instructions state that a non-return valve has to be included in the
installation.
19.13 Addition:
During the test of 19.4, the water container shall not rupture and the water temperature shall
not exceed
– 99 °C, for open-outlet water heaters having a capacity exceeding 1 l;
– 140 °C, for closed water heaters having a capacity exceeding 1 l.
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.
22.6 Addition:
The enclosure shall have a drain hole positioned so that the water can drain without impairing
the electrical insulation, unless water cannot accumulate within the enclosure in normal use.
The hole shall be at least 5 mm in diameter or 20 mm in area with a width of at least 3 mm.
Compliance is checked by inspection and by measurement.
22.33 Addition:
The requirement does not apply to bare-element water heaters.
22.47 Replacement:
Appliances shall withstand the water pressure occurring in normal use.
Compliance is checked by subjecting the appliance to a water pressure of
– twice the rated pressure, for closed water heaters;
– 0,15 MPa, for open-outlet water heaters.
If an open-outlet water heater incorporates a valve that regulates the water flow, a water
pressure of 2 MPa is applied to the inlet of the appliance, the valve being closed.
Pressure-relief devices are rendered inoperative. The pressure is raised at a rate of
0,13 MPa/s to the specified value and is maintained at that value for 5 min.

© IEC 2016
Water shall not leak from the appliance and there shall be no permanent deformation to such
an extent that compliance with this standard is impaired.
22.48 Not applicable.
22.50 Addition:
The requirement is not applicable provided the maximum temperature of the water from the
system cannot exceed 55 °C in normal use.
If the maximum temperature of the water from the system exceeds 55 °C in normal use then
the requirement is not applicable provided that the system is such that a shower outlet normal
use water temperature control takes precedence in setting the system temperature. In the
case of systems with multiple shower outlets, the shower with the lowest temperature setting
shall take precedence, the other shower outlets taking precedence over non-shower outlets.
22.51 Addition:
The requirement is not applicable provided the maximum temperature of the water from the
system cannot exceed 55 °C in normal use.
If the maximum temperature of the water from the system exceeds 55 °C in normal use then
the requirement is not applicable provided that the system is such that the shower outlet
normal use water temperature control takes precedence in setting the system temperature. In
the case of systems with multiple shower outlets, a shower with the lowest temperature
setting shall take precedence, the other shower outlets taking precedence over non-shower
outlets.
22.101 The rated pressure of closed water heaters shall be at least 0,6 MPa.
The rated pressure of closed water heaters intended to be supplied by a pressure reducing
valve shall be at least 0,1 MPa.
NOTE The rated pressure of open-outlet water heaters is 0 Pa.
Compliance is checked by inspection.
22.102 The outlet water of appliances other than those intended to supply water for
showering shall not attain an excessive temperature due to a sudden pressure drop in the
water supply.
Compliance is checked by the following test.
The appliance is operated at rated power input with the controls or switching devices
adjusted to their most unfavourable possible setting to attain the maximum water temperature.
Any regulating valve is fully opened and the water flow is adjusted so that the flow switch or
the pressure switch is on the verge of operating.
Any control devices that operate during the test of Clause 11 are short-circuited. The water
flow is reduced in steps of 10 % per minute until:
– for closed water heaters, the thermal cut-out incorporated to comply with 22.106
operates or steady conditions are established;
– for open-outlet water heaters, a non-self-resetting thermal cut-out operates or steady
conditions are established.
– 16 – IEC 60335-2-35:2012+AMD1:2016 CSV
© IEC 2016
If the rupture of a heating element or an intentionally weak part leads to a permanent open
circuit, the test is repeated on a second sample. This second test shall be terminated in the
same mode unless the test is otherwise satisfactorily completed.
VOID.
22.103 Closed water heaters having a capacity exceeding 3 l shall be supplied with a
pressure relief device that prevents excessive pressure.
Compliance is checked by inspection and by subjecting the appliance to a slowly increasing
water pressure.
The pressure relief device shall operate before the water pressure exceeds the rated
pressure by more than 0,1 MPa.
NOTE The pressure relief device can be fitted during installation.
22.104 The outlet of open-outlet water heaters shall be constructed so that the water flow
is not limited to such an extent that the container is subjected to a significant pressure in
normal use.
Compliance is checked by inspection.
The requirement is considered to be met if the cross-sectional area of the water outlet is not
less than that of the inlet.
22.105 Open oulet water heaters incorporating a flow switch shall be constructed so that
if there is no water flow, the heating element cannot be switched on, and it is switched off if
the water flow ceases.
Compliance is checked by inspection and by manual test.
However, if compliance with this subclause relies on the correct operation of an electronic
circuit, the appliance is further tested as follows.
a) The appliance is operated for one cycle. In addition, the electromagnetic phenomena
tests of 19.11.4.1 to 19.11.4.7 are applied during the test. The tests are carried out with
surge protective devices disconnected, unless they incorporate spark gaps.
If there is no water flow, the heating element shall not be switched on, and it is switched off
without delay if the water flow ceases.
b) The appliance is operated for one cycle. The fault conditions in a) to g) of 19.11.2 are
then considered and applied one at a time to the electronic circuit.
If there is no water flow, the heating element shall not be switched on, and it is switched off
without delay if the water flow ceases.
One cycle consists of opening and closing of the water tap.
If the electronic circuit is programmable, the software shall contain measures to control the
fault/error conditions specified in Table R.1 and is evaluated in accordance with the relevant
requirements of Annex R.
22.106 Closed water heaters shall incorporate a thermal cut-out that operates
independently from a thermostat or flow switch. It shall only be possible to reset the
thermal cut-out after removal of a non-detachable cover.

© IEC 2016
If the capacity does not exceed 1 l and the appliance incorporates a flow switch, an
alternative protective device, such as a pressure switch may be used instead of the
thermal cut-out.
Compliance is checked by inspection.
22.107 Water shall not attain an excessive temperature in normal use.
Compliance
...