IEC 60335-2-81:2024

IEC 60335-2-81 ®
Edition 4.0 2024-10
COMMENTED VERSION
INTERNATIONAL
STANDARD
colour
inside
Household and similar electrical appliances – Safety –
Part 2-81: Particular requirements for foot warmers and heating mats
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

IEC Secretariat Tel.: +41 22 919 02 11
3, rue de Varembé info@iec.ch
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform IEC Products & Services Portal - products.iec.ch
The advanced search enables to find IEC publications by a
Discover our powerful search engine and read freely all the
variety of criteria (reference number, text, technical publications previews, graphical symbols and the glossary.
committee, …). It also gives information on projects, replaced With a subscription you will always have access to up to date
and withdrawn publications. content tailored to your needs.

IEC Just Published - webstore.iec.ch/justpublished
Electropedia - www.electropedia.org
Stay up to date on all new IEC publications. Just Published
The world's leading online dictionary on electrotechnology,
details all new publications released. Available online and
containing more than 22 500 terminological entries in English
once a month by email.
and French, with equivalent terms in 25 additional languages.

Also known as the International Electrotechnical Vocabulary
IEC Customer Service Centre - webstore.iec.ch/csc
(IEV) online.
If you wish to give us your feedback on this publication or

need further assistance, please contact the Customer Service
Centre: sales@iec.ch.
IEC 60335-2-81 ®
Edition 4.0 2024-10
COMMENTED VERSION
INTERNATIONAL
STANDARD
colour
inside
Household and similar electrical appliances – Safety –
Part 2-81: Particular requirements for foot warmers and heating mats
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 13.120, 97.100.10 ISBN 978-2-8322-9856-5
– 2 – IEC 60335-2-81:2024 CMV © IEC 2024
CONTENTS
FOREWORD .4
INTRODUCTION .7
1 Scope .8
2 Normative references .8
3 Terms and definitions .9
4 General requirement . 10
5 General conditions for the tests . 10
6 Classification . 10
7 Marking and instructions . 10
8 Protection against access to live parts . 11
9 Starting of motor-operated appliances . 11
10 Power input and current . 12
11 Heating . 12
12 Void Charging of metal-ion batteries . 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 . 18
23 Internal wiring . 19
24 Components . 19
25 Supply connection and external flexible cords . 19
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. 23
32 Radiation, toxicity and similar hazards . 23
Annexes . 30
Annex B (normative) Battery-operated appliances, separable batteries and detachable
batteries for battery-operated appliances . 31
Bibliography . 32
List of comments . 33

Figure 101 – Probe for measuring surface temperatures . 23
Figure 101 102 – Equipment for the flexing test for foot warmers . 24

Figure 102 103 – Equipment for flexing heating elements and internal wiring . 25
Figure 105 104 – Apparatus for pressure test on connectors . 26
Figure 103 105 – Equipment for the spark ignition test . 27
Figure 104 106 – Details of the mask . 29

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

– 4 – IEC 60335-2-81:2024 CMV © IEC 2024
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
HOUSEHOLD AND SIMILAR ELECTRICAL APPLIANCES –
SAFETY –
Part 2-81: Particular requirements for foot warmers and heating mats

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) 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.
This commented version (CMV) of the official standard IEC 60335-2-81:2024 edition 4.0
allows the user to identify the changes made to the previous IEC 60335-2-
81:2015+AMD1:2017+AMD2:2020 CSV edition 3.2. Furthermore, comments from
IEC TC 61 experts are provided to explain the reasons of the most relevant changes, or
to clarify any part of the content.
A vertical bar appears in the margin wherever a change has been made. Additions are in
green text, deletions are in strikethrough red text. Experts' comments are identified by a
blue-background number. Mouse over a number to display a pop-up note with the
comment.
This publication contains the CMV and the official standard. The full list of comments is
available at the end of the CMV.

IEC 60335-2-81 has been prepared by IEC technical committee 61: Safety of household and
similar electrical appliances. It is an International Standard.
This fourth edition cancels and replaces the third edition published in 2015, Amendment 1:2017
and Amendment 2:2020. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) alignment with IEC 60335-1:2020;
b) conversion of some notes to normative text (Clause 1, 13.2, 16.2, 21.103, 21.104, 21.105,
21.106);
c) addition of test probe 19 for accessibility (8.1.1, 8.1.3, 20.2, B.22.3, B.22.4);
d) addition of external surface temperatures (Clause 11);
e) addition of the test of 21.107 for control units intended to be placed on a surface;
f) alignment of 30.102 with IEC 60335-2-17.
The text of this International Standard is based on the following documents:
Draft Report on voting
61/7272/FDIS 61/7298/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/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 foot warmers and heating
mats.
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:

– 6 – IEC 60335-2-81:2024 CMV © IEC 2024
– requirements: in roman type;
– test specifications: in italic type;
– notes: in small roman type.
Words in bold in the text are defined in Clause 3. When a definition concerns an adjective, the adjective and the
associated noun are also in bold.
The following differences exist in the countries indicated below.
– 6.1: Class 0 appliances are allowed if their rated voltage does not exceed 150 V (Japan)
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, or
• revised.
NOTE 4 The attention of National Committees is drawn to the fact that equipment manufacturers and testing
organizations can 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.

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

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 may 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 and generic standards 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. 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. 1
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. 2

– 8 – IEC 60335-2-81:2024 CMV © IEC 2024
HOUSEHOLD AND SIMILAR ELECTRICAL APPLIANCES –
SAFETY –
Part 2-81: Particular requirements for foot warmers and heating mats

1 Scope
This clause of Part 1 is replaced by the following.
This part of IEC 60335 deals with the safety of electric foot warmers and heating mats for
household and similar purposes, their rated voltage being not more than 250 V including direct
current (DC) supplied appliances and battery-operated appliances. 3
Appliances not intended for normal household use but which nevertheless may can be a source
of danger to the public, such as appliances intended to be used by laymen laypersons in shops,
in light industry and on farms, are within the scope of this standard.
As far as is practicable, this standard deals with the common hazards presented by appliances
that are encountered by all persons in and around the home. However, in general, it does not
take into account
– persons (including children) whose
• physical, sensory or mental capabilities; or
• lack of experience and knowledge
prevents them from using the appliance safely without supervision or instruction;
– children playing with the appliance.
NOTE 101 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.
Additional requirements can be necessary for appliances intended to be used in vehicles or
on-board ships or aircraft. In many countries, additional requirements are specified by the
national health authorities, the national authorities responsible for the protection of labour, the
national water supply authorities and similar authorities.
NOTE 102 This standard does not apply to:
– appliances specifically intended for use under medical supervision;
– electric blankets and pads (IEC 60335-2-17);
– electrically heated carpets (IEC 60335-2-106);
– electrical heating appliances for breeding and rearing animals (IEC 60335-2-71).
2 Normative references
This clause of Part 1 is applicable except as follows.

Addition:
IEC 60320-1, Appliance couplers for household and similar general purposes – Part 1: General
requirements
Standard
IEC 60320-3, Appliance couplers for household and similar general purposes – Part 3:
sheets and gauges
IEC 60584-1, Thermocouples – Part 1: EMF specifications and tolerances
ISO 2439, Flexible cellular polymeric materials – Determination of hardness (indentation
technique)
3 Terms and definitions
This clause of Part 1 is applicable except as follows.
3.1 Definitions relating to physical characteristics
3.1.9 Replacement Modification:
normal operation
Replace the first paragraph with the following:
operation of the appliance under the following conditions:
Foot warmers are unfilled and placed on a horizontal surface.
Heating mats are placed on a horizontal surface and covered by a piece of expanded
polystyrene having dimensions approximately 300 mm × 150 mm × 50 mm.
3 3
Note 101 to entry: The density of the polystyrene is approximately 20 kg/m ± 5 kg/m .
3.5 Definitions relating to types of appliances
3.5.101
foot warmer
appliance into which the user's feet are inserted in order to warm them
3.5.102
heating mat
appliance having an area not exceeding 0,5 m , on which the user's feet are placed in order to
warm them
3.6 Definitions relating to parts of appliances
3.1036.101
heating element with PTC characteristics
heating element of the appliance consisting of a pair of conductors separated by conductive
material that has a rapid non-linear increase in resistance when the temperature is raised
through a particular range
3.6.102
control unit
device, external to the functional part, by means of which the power input of the appliance or
the temperature of the functional part can be adjusted or regulated 4

– 10 – IEC 60335-2-81:2024 CMV © IEC 2024
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:
A 15 m length of heating element or internal wiring is required for the tests of 21.102.
Twelve samples of the enclosure material of foot warmers, each having dimensions
200 mm × 100 mm, are required for the test of 30.101.
5.3 Addition:
Washable appliances are laundered twice in accordance with the instructions before testing is
started.
The tests of Clause 13, Clause 15 and Clause 16 are not carried out on class III appliances
having a rated voltage not exceeding 24 V or on class III constructions having a working
voltage not exceeding 24 V.
5.5 Addition:
If the appliance is provided with a detachable cover, the tests are carried out with or without
this cover, whichever is more unfavourable.
6 Classification
This clause of Part 1 is applicable except as follows.
6.1 Modification:
Replace the first paragraph with the following:
Appliances shall be class II or class III.
7 Marking and instructions
This clause of Part 1 is applicable except as follows.
7.1 Addition:
Washable appliances shall be marked with symbol ISO 7000-3114 (2012-042011-10) and with
symbol ISO 7000-3124 (2012-042011-10).
Appliances to be used with a detachable control unit shall be marked with the reference of
the control unit to be used. 5

7.6 Addition:
[symbol ISO 7000-3114 (2012-042011-10)] do not dry clean

[symbol ISO 7000-3124 (2012-042011-10)] do not bleach

7.12 Addition:
The instructions shall state the substance of include the following:
– the appliance is not to be used if there are signs of damage;
– the appliance is not to be used for warming animals;
– details regarding laundering or cleaning.
The instructions for foot warmers shall state that outdoor shoes must be removed before use.
The instructions for heating mats shall state that the appliance has to be repaired or replaced
if the cover is worn. They shall explain how such wear can be observed.
The instructions for foot warmers intended to be used after preheating without supply and
incorporating an appliance inlet shall state that the cord set must be disconnected from the
supply after preheating.
If symbol ISO 7000-3114 (2012-042011-10) and symbol ISO 7000-3124 (2012-042011-10) are
used, their meaning shall be explained.
The instruction for appliances with detachable control units shall state that the appliances are
only to be used with the type that is marked on the appliances. 6
7.101 Detachable control units shall be marked with a reference number or by other means
of identification.
Compliance is checked by inspection. 7
8 Protection against access to live parts
This clause of Part 1 is applicable except as follows.
8.1.1 Addition:
In addition to the use of test probe 18, test probe 19 of IEC 61032 is also applied wherever test
probe 18 is used and with the same test conditions used for test probe 18. 8
9 Starting of motor-operated appliances
This clause of Part 1 is not applicable.

– 12 – IEC 60335-2-81:2024 CMV © IEC 2024
10 Power input and current
This clause of Part 1 is applicable except as follows.
10.101 The power input of appliances incorporating heating elements with PTC
characteristics shall significantly decrease with an increase in temperature.
Compliance is checked by the following test.
The appliance is supplied at rated voltage and operated under normal operation. The power
input shall have decreased by at least 50 % from the initial value when steady conditions are
established, any control operating during this period being short-circuited.
11 Heating
This clause of Part 1 is applicable except as follows:
11.2 Modification:
Appliances are placed as near as possible to one wall of the test corner and away from the
other wall.
11.3 Addition:
Thermocouples attached to the small blackened disks are also used for measuring the
temperature rise of the surface of the appliance.
Where the external accessible surfaces are suitably flat and access permits, then the test
probe of Figure 101 is used to measure the temperature rises of external accessible surfaces
specified in Table 101. The probe is applied with a force of 4 N ± 1 N to the surface in such a
way that the best possible contact between the probe and the surface is ensured. 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. 9
11.7 Replacement Modification: 10
Replace the first paragraph with the following:
Appliances are operated until steady conditions are established.
11.8 Modification:
Replace the first paragraph with the following:
During the test, the temperature rises are monitored continuously and shall not exceed the
values shown in Table 3 and Table 101. 11
Add the following to footnote "k" of Table 3:
Similar parts held for short periods include handles or grips of vents and air shutters. 12

Addition:
When polyvinyl chloride is used for insulating heating elements, the temperature rise of the
insulation shall not exceed 80 K.
Addition:
The temperature rise of surfaces likely to be in contact with the user's feet shall not exceed
40 K.
Table 101 – Maximum temperature rises for specified external
and other surfaces under normal operating conditions
Surface Temperature rise of
external and other
accessible surfaces
K
Surfaces likely to be in contact with the user's feet 40
Other surfaces of:
– bare metal 38
a
– coated metal
– glass and ceramic 51
b, c
– plastic and plastic coating > 0,4 mm
NOTE The temperature rise limits of handles, knobs, grips, keyboards, keypads and similar parts are specified in
Table 3.
a
Metal is considered coated when a coating having a minimum thickness of 90 µm made of enamel, powder or
non-substantially plastic coating is used.
b
The temperature rise limit of plastic also applies for plastic material having a metal finish of thickness less than
0,1 mm.
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.
12 Void Charging of metal-ion batteries
This clause of Part 1 is applicable. 13
13 Leakage current and electric strength at operating temperature
This clause of Part 1 is applicable except as follows.
13.2 Modification Addition:
When testing the top surface of heating mats, the dimensions of the metal foil are
300 mm × 150 mm.
NOTE 101 If the heating mat is reversible, each surface is tested in turn.
Addition:
Foot warmers are also tested with the inside surface completely covered with metal foil.

– 14 – IEC 60335-2-81:2024 CMV © IEC 2024
14 Transient overvoltages
This clause of Part 1 is applicable.
15 Moisture resistance
This clause of Part 1 is applicable except as follows.
15.1.1 Addition:
Appliances are subjected to the test of IEC 60529:1989, 14.2.1. However, cord sets, switches
and controls in the flexible cord are not subjected to the tests.
15.1.2 Addition:
Foot warmers are orientated so that the base of the appliance is in contact with the support.
Appliance inlets are covered before carrying out the test.
16 Leakage current and electric strength
This clause of Part 1 is applicable except as follows.
16.2 Modification Addition:
When testing the top surface of heating mats, the dimensions of the metal foil are
300 mm × 150 mm.
NOTE 101 If the heated mat is reversible, each surface is tested in turn.
Addition:
Foot warmers are also tested with the inside surface completely covered with metal foil.
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 Addition:
The appliance is covered partially or completely, whichever is more unfavourable, with a sheet
of open-cell polyether approximately 36 mm thick, having the following properties:
+2
• cell count 18 per cm;
+10
• specific mass 30 kg/m + %;
• hardness 120 N to 170 N at 40 % impression, measured according to ISO 2439.
If the foot warmer has a flexible part that covers the user's legs, this part is folded onto the
foot part before covering.
A plywood board, having dimensions approximately 500 mm × 500 mm × 20 mm, is placed on
top of the polyether sheet covering foot warmers.
19.4 Modification Addition:
Heating mats are tested without being covered by the polystyrene block.
19.13 Addition:
The temperature rise of the insulation of heating elements shall not exceed 145 K.
20 Stability and mechanical hazards
This clause of Part 1 is applicable except as follows.
20.2 Addition:
For parts of appliances situated not more than 850 mm above the floor after installation or in
normal use, in addition to the use of test probe 18, test probe 19 of IEC 61032 is also applied
wherever test probe 18 is used and with the same test conditions used for test probe 18. 14
21 Mechanical strength
This clause of Part 1 is applicable except as follows.
21.1 Addition:
Foot warmers are also subjected to the test of 21.101. Control units intended to be placed on
a surface are also subjected to the test of 21.107. 15
21.2 Addition:
This requirement is not applicable to textiles and similar materials forming the enclosure.
21.101 A plywood board, having dimensions approximately 300 mm × 150 mm × 20 mm with
rounded edges, is placed in the leg section of the foot warmer as shown in Figure 101
Figure 102. A load of 30 kg is placed on the board, which is allowed to drop freely from a height
of 200 mm above the base, so that the leg section is flexed, and the appliance is compressed
between the board and the supporting surface. The total mass of the board, its movable support
and the load is 30 kg. If the foot warmer does not have a leg section, the board is allowed to
fall onto the top surface.
– 16 – IEC 60335-2-81:2024 CMV © IEC 2024
The test is carried out 1 000 times at a rate of six times per minute.
The test shall not result in
– damage to the enclosure or displacement of heating elements to such an extent that
compliance with the standard is impaired;
– open-circuiting of heating elements or controls;
– breakage of more than 10 % of the strands of internal wiring;
– failure of constructional stitching, or breakage of glued or welded joints, to such an extent
that compliance with the standard is impaired.
NOTE An example of damage to the enclosure that could impair compliance with the standard is a tear in the
enclosure. Small holes in textiles that are not part of electrical insulation or do not provide protection against moisture
are ignored.
21.102 The insulation of heating elements and internal wiring shall retain adequate flexibility
and insulating characteristics throughout the life of the appliance.
Compliance is checked by the tests of 21.102.1103 and by the tests of 21.102.2104 and
21.102.3105 when the insulation exceeds
– a temperature rise of 50 K during the test of Clause 11, or
– a temperature rise of 110 K during the tests of Clause 19.
The tests are carried out on separate samples of heating element or internal wiring.
For the test of 21.102.1103, one sample measuring approximately 4 m in length is required. For
the tests of 21.102.2104, at least 12 samples are required, each having a length of 300 mm.
For the test of 21.102.3105, 12 samples are required, each having a length of 300 mm.
21.102.1103 The sample of heating element or internal wiring is attached to the equipment
shown in Figure 102 Figure 103. This equipment has a carrier with two pulleys, each having a
groove with a radius of 4 mm, the diameter at the base of the groove being 25 mm.
NOTE 1 For samples not having a circular cross-section, the form of the groove in the pulley is
suitably modified. The pulleys are arranged so that the sample is horizontal where it passes
between them.
The sample is stretched over the pulleys, each end being loaded with a mass of 0,25 kg. If
necessary, the mass at each end is increased in steps of 0,1 kg in order to ensure that the wires
leaving the pulleys are parallel to each other. Restraining clamps are positioned so that the pull
is always applied by the mass in the opposite direction from which the carrier is moving.
The carrier moves over a distance of 1 m with a constant speed of approximately 0,33 m/s for
25 000 cycles.
NOTE 2 A cycle is two movements, one in each direction.
The sample shall not break during the test.
NOTE 3 A monitoring current not exceeding 50 mA can be passed through the sample during
the test to detect breakage of the conductor. 16
For heating elements with PTC characteristics, the power input is measured before and after
the test. The measurement is made with the heating element suspended vertically in free air
and supplied at the rated voltage of the appliance. Both measurements are carried out at the
same ambient temperature and when the power input has stabilized. The power input shall not
increase during the test.
The sample is then immersed in water containing approximately 1 % NaCl. A DC voltage of
approximately 500 V is applied between the conductor and the saline solution.
The insulation resistance is measured 1 min after immersion and shall be at least 1 MΩ.
21.102.2104 The conductors are pulled out from 12 samples of heating element or internal
wiring. If this is not possible, the insulation is slit longitudinally, the conductor is removed and
the insulation allowed to close.
Six of the samples are conditioned by suspending them vertically so that they hang freely in a
heating cabinet at a temperature of 125 °C ± 2 °C for 336 h. The samples are removed from the
cabinet and allowed to cool down to room temperature. When the material has stabilized, the
length of the samples is measured and shall not be less than 90 % of the original length.
NOTE PVC material is considered to will have stabilized by 16 h after removal from the cabinet.
The heating cabinet shall have forced air circulation in order to ensure that there is no
temperature gradient over the length of the samples.
The 12 samples are placed in a tensile machine, in turn, so that the length between the clamps
is at least 50 mm. The machine is operated at a uniform speed of 500 mm/min ± 50 mm/min.
The force and elongation at the instant of rupture are determined.
Results obtained from any sample that ruptured at a force differing from the average value by
more than 10 %, and from samples that ruptured within a distance of 15 mm from the clamp,
are disregarded. Additional samples are tested in order to obtain 12 valid results.
The elongation of each of the unconditioned samples shall not be less than 100 % and their
tensile strength shall not be less than 8,75 MPa.
The average value of both the elongation and tensile strength of the conditioned samples shall
be not less than 75 % of the average value determined for the unconditioned samples.
21.102.3105 A 10 mm length of insulation is removed from each end of 12 samples of heating
element or internal wiring.
Six of the samples are wound in a close helix of six turns on a metal mandrel having a diameter
approximately equal to the external diameter of the samples. Together with the remaining six
samples, they are placed in a heating cabinet at a temperature of 125 °C ± 2 °C for 336 h. The
samples are removed from the cabinet and allowed to cool down to room temperature.
When the material has stabilized, the other six samples are also wound on the mandrel in the
same way.
NOTE PVC material is considered to will have stabilized by 16 h after removal from the cabinet.
The heating cabinet shall have forced air circulation in order to ensure that there is no
temperature gradient over the length of the samples.
The mandrel is immersed for 1 h in water containing approximately 1 % NaCl. The samples are
then subjected to a test voltage of 1 000 V for class II appliances and 500 V for class III
appliances. The voltage is applied for 1 min between the conductors and the solution and there
shall be no breakdown.
The samples are unwound from the mandrel and inspection shall show that there are no visible
cracks.
– 18 – IEC 60335-2-81:2024 CMV © IEC 2024
21.103106 Heating elements with PTC characteristics shall be resistant to crushing.
Compliance is checked by the following test.
The flexible part is fully supported by a piece of plywood 20 mm thick and supplied as specified
in 11.4. When steady conditions are established, the temperature of the heating element is
measured. A block having dimensions of 100 mm × 300 mm and a mass of 80 kg with rounded
edges in contact with the flexible part is applied for 5 min to the surface in the most unfavourable
place. After removing the block, the appliance is again operated until steady conditions are
established and the temperature of the heating element is measured. The temperature of the
heating element where the block has been applied shall not have increased by more than 10 K.
NOTE 1 The edges of the block in contact with the flexible part are rounded.
NOTE 2 The most unfavourable place to apply the block is usually at a loop in the element.
21.107 The control unit is dropped from a height of 40 mm onto a rigidly mounted steel plate
having a thickness of at least 15 mm and a mass of at least 15 kg. It is dropped so that it lands
on its base, the test being carried out 100 times.
...

IEC 60335-2-81 ®
Edition 4.0 2024-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Household and similar electrical appliances – Safety –
Part 2-81: Particular requirements for foot warmers and heating mats
Appareils électrodomestiques et analogues – Sécurité –
Partie 2-81: Exigences particulières pour les chancelières et les carpettes
chauffantes électriques
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.
Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite ni
utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie et
les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des
questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.
IEC Secretariat Tel.: +41 22 919 02 11
3, rue de Varembé info@iec.ch
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.
About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.
IEC publications search - webstore.iec.ch/advsearchform IEC Products & Services Portal - products.iec.ch
The advanced search enables to find IEC publications by a Discover our powerful search engine and read freely all the
variety of criteria (reference number, text, technical publications previews, graphical symbols and the glossary.
committee, …). It also gives information on projects, replaced With a subscription you will always have access to up to date
and withdrawn publications. content tailored to your needs.
IEC Just Published - webstore.iec.ch/justpublished
Electropedia - www.electropedia.org
Stay up to date on all new IEC publications. Just Published
The world's leading online dictionary on electrotechnology,
details all new publications released. Available online and once
containing more than 22 500 terminological entries in English
a month by email.
and French, with equivalent terms in 25 additional languages.
Also known as the International Electrotechnical Vocabulary
IEC Customer Service Centre - webstore.iec.ch/csc
(IEV) online.
If you wish to give us your feedback on this publication or need
further assistance, please contact the Customer Service
Centre: sales@iec.ch.
A propos de l'IEC
La Commission Electrotechnique Internationale (IEC) est la première organisation mondiale qui élabore et publie des
Normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.
A propos des publications IEC
Le contenu technique des publications IEC est constamment revu. Veuillez vous assurer que vous possédez l’édition la
plus récente, un corrigendum ou amendement peut avoir été publié.
Recherche de publications IEC - IEC Products & Services Portal - products.iec.ch
webstore.iec.ch/advsearchform Découvrez notre puissant moteur de recherche et consultez
La recherche avancée permet de trouver des publications IEC gratuitement tous les aperçus des publications, symboles
en utilisant différents critères (numéro de référence, texte, graphiques et le glossaire. Avec un abonnement, vous aurez
comité d’études, …). Elle donne aussi des informations sur les toujours accès à un contenu à jour adapté à vos besoins.
projets et les publications remplacées ou retirées.
Electropedia - www.electropedia.org
IEC Just Published - webstore.iec.ch/justpublished
Le premier dictionnaire d'électrotechnologie en ligne au monde,
Restez informé sur les nouvelles publications IEC. Just
avec plus de 22 500 articles terminologiques en anglais et en
Published détaille les nouvelles publications parues.
français, ainsi que les termes équivalents dans 25 langues
Disponible en ligne et une fois par mois par email.
additionnelles. Egalement appelé Vocabulaire
Electrotechnique International (IEV) en ligne.
Service Clients - webstore.iec.ch/csc
Si vous désirez nous donner des commentaires sur cette
publication ou si vous avez des questions contactez-nous:
sales@iec.ch.
IEC 60335-2-81 ®
Edition 4.0 2024-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Household and similar electrical appliances – Safety –
Part 2-81: Particular requirements for foot warmers and heating mats
Appareils électrodomestiques et analogues – Sécurité –
Partie 2-81: Exigences particulières pour les chancelières et les carpettes
chauffantes électriques
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 13.120, 97.100.10 ISBN 978-2-8322-9684-4
– 2 – IEC 60335-2-81:2024 © IEC 2024
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 . 11
9 Starting of motor-operated appliances . 11
10 Power input and current . 11
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 . 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 . 18
23 Internal wiring . 18
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 . 22
32 Radiation, toxicity and similar hazards . 22
Annexes . 28
Annex B (normative) Battery-operated appliances, separable batteries and detachable
batteries for battery-operated appliances . 29
Bibliography . 30

Figure 101 – Probe for measuring surface temperatures . 22
Figure 102 – Equipment for the flexing test for foot warmers . 23
Figure 103 – Equipment for flexing heating elements and internal wiring . 24

Figure 104 – Apparatus for pressure test on connectors . 25
Figure 105 – Equipment for the spark ignition test . 26
Figure 106 – Details of the mask . 27

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

– 4 – IEC 60335-2-81:2024 © IEC 2024
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
HOUSEHOLD AND SIMILAR ELECTRICAL APPLIANCES –
SAFETY –
Part 2-81: Particular requirements for foot warmers and heating mats

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) 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 60335-2-81 has been prepared by IEC technical committee 61: Safety of household and
similar electrical appliances. It is an International Standard.
This fourth edition cancels and replaces the third edition published in 2015, Amendment 1:2017
and Amendment 2:2020. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) alignment with IEC 60335-1:2020;
b) conversion of some notes to normative text (Clause 1, 13.2, 16.2, 21.103, 21.104, 21.105,
21.106);
c) addition of test probe 19 for accessibility (8.1.1, 8.1.3, 20.2, B.22.3, B.22.4);

d) addition of external surface temperatures (Clause 11);
e) addition of the test of 21.107 for control units intended to be placed on a surface;
f) alignment of 30.102 with IEC 60335-2-17.
The text of this International Standard is based on the following documents:
Draft Report on voting
61/7272/FDIS 61/7298/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/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 foot warmers and heating
mats.
When a particular subclause of Part 1 is not mentioned in this part 2, that subclause applies as
far as is reasonable. When this standard states "addition", "modification" or "replacement", the
relevant text in Part 1 is to be adapted accordingly.
NOTE 2 The following numbering system is used:
– subclauses, tables and figures that are numbered starting from 101 are additional to those in Part 1;
– unless notes are in a new subclause or involve notes in Part 1, they are numbered starting from 101, including
those in a replaced clause or subclause;
– additional annexes are lettered AA, BB, etc.
NOTE 3 The following print types are used:
– requirements: in roman type;
– test specifications: in italic type;
– notes: in small roman type.
Words in bold in the text are defined in Clause 3. When a definition concerns an adjective, the adjective and the
associated noun are also in bold.
The following differences exist in the countries indicated below.
– 6.1: Class 0 appliances are allowed if their rated voltage does not exceed 150 V (Japan)

– 6 – IEC 60335-2-81:2024 © IEC 2024
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, or
• revised.
NOTE 4 The attention of National Committees is drawn to the fact that equipment manufacturers and testing
organizations can 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.

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 60335-2-81:2024 © IEC 2024
HOUSEHOLD AND SIMILAR ELECTRICAL APPLIANCES –
SAFETY –
Part 2-81: Particular requirements for foot warmers and heating mats

1 Scope
This clause of Part 1 is replaced by the following.
This part of IEC 60335 deals with the safety of electric foot warmers and heating mats for
household and similar purposes, their rated voltage being not more than 250 V including direct
current (DC) supplied appliances and battery-operated appliances.
Appliances not intended for normal household use but which nevertheless can be a source of
danger to the public, such as appliances intended to be used by laypersons in shops, in light
industry and on farms, are within the scope of this standard.
As far as is practicable, this standard deals with the common hazards presented by appliances
that are encountered by all persons in and around the home. However, in general, it does not
take into account
– persons (including children) whose
• physical, sensory or mental capabilities; or
• lack of experience and knowledge
prevents them from using the appliance safely without supervision or instruction;
– children playing with the appliance.
Additional requirements can be necessary for appliances intended to be used in vehicles or
on-board ships or aircraft. In many countries, additional requirements are specified by the
national health authorities, the national authorities responsible for the protection of labour, the
national water supply authorities and similar authorities.
This standard does not apply to:
– appliances specifically intended for use under medical supervision;
– electric blankets and pads (IEC 60335-2-17);
– electrically heated carpets (IEC 60335-2-106);
– electrical heating appliances for breeding and rearing animals (IEC 60335-2-71).
2 Normative references
This clause of Part 1 is applicable except as follows.
Addition:
IEC 60320-1, Appliance couplers for household and similar general purposes – Part 1: General
requirements
IEC 60584-1, Thermocouples – Part 1: EMF specifications and tolerances

ISO 2439, Flexible cellular polymeric materials – Determination of hardness (indentation
technique)
3 Terms and definitions
This clause of Part 1 is applicable except as follows.
3.1 Definitions relating to physical characteristics
3.1.9 Modification:
normal operation
Replace the first paragraph with the following:
operation of the appliance under the following conditions:
Foot warmers are unfilled and placed on a horizontal surface.
Heating mats are placed on a horizontal surface and covered by a piece of expanded
polystyrene having dimensions approximately 300 mm × 150 mm × 50 mm.
3 3
Note 101 to entry: The density of the polystyrene is approximately 20 kg/m ± 5 kg/m .
3.5 Definitions relating to types of appliances
3.5.101
foot warmer
appliance into which the user's feet are inserted in order to warm them
3.5.102
heating mat
appliance having an area not exceeding 0,5 m , on which the user's feet are placed in order to
warm them
3.6 Definitions relating to parts of appliances
3.6.101
heating element with PTC characteristics
heating element of the appliance consisting of a pair of conductors separated by conductive
material that has a rapid non-linear increase in resistance when the temperature is raised
through a particular range
3.6.102
control unit
device, external to the functional part, by means of which the power input of the appliance or
the temperature of the functional part can be adjusted or regulated
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:
A 15 m length of heating element or internal wiring is required for the tests of 21.102.

– 10 – IEC 60335-2-81:2024 © IEC 2024
Twelve samples of the enclosure material of foot warmers, each having dimensions
200 mm × 100 mm, are required for the test of 30.101.
5.3 Addition:
Washable appliances are laundered twice in accordance with the instructions before testing is
started.
The tests of Clause 13, Clause 15 and Clause 16 are not carried out on class III appliances
having a rated voltage not exceeding 24 V or on class III constructions having a working
voltage not exceeding 24 V.
5.5 Addition:
If the appliance is provided with a detachable cover, the tests are carried out with or without
this cover, whichever is more unfavourable.
6 Classification
This clause of Part 1 is applicable except as follows.
6.1 Modification:
Replace the first paragraph with the following:
Appliances shall be class II or class III.
7 Marking and instructions
This clause of Part 1 is applicable except as follows.
7.1 Addition:
Washable appliances shall be marked with symbol ISO 7000-3114 (2011-10) and with symbol
ISO 7000-3124 (2011-10).
Appliances to be used with a detachable control unit shall be marked with the reference of
the control unit to be used.
7.6 Addition:
[symbol ISO 7000-3114 (2011-10)] do not dry clean

[symbol ISO 7000-3124 (2011-10)] do not bleach

7.12 Addition:
The instructions shall include the following:
– the appliance is not to be used if there are signs of damage;
– the appliance is not to be used for warming animals;
– details regarding laundering or cleaning.
The instructions for foot warmers shall state that outdoor shoes must be removed before use.
The instructions for heating mats shall state that the appliance has to be repaired or replaced
if the cover is worn. They shall explain how such wear can be observed.
The instructions for foot warmers intended to be used after preheating without supply and
incorporating an appliance inlet shall state that the cord set must be disconnected from the
supply after preheating.
If symbol ISO 7000-3114 (2011-10) and symbol ISO 7000-3124 (2011-10) are used, their
meaning shall be explained.
The instruction for appliances with detachable control units shall state that the appliances are
only to be used with the type that is marked on the appliances.
7.101 Detachable control units shall be marked with a reference number or by other means
of identification.
Compliance is checked by inspection.
8 Protection against access to live parts
This clause of Part 1 is applicable except as follows.
8.1.1 Addition:
In addition to the use of test probe 18, test probe 19 of IEC 61032 is also applied wherever test
probe 18 is used and with the same test conditions used for test probe 18.
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 except as follows.
10.101 The power input of appliances incorporating heating elements with PTC
characteristics shall significantly decrease with an increase in temperature.
Compliance is checked by the following test.
The appliance is supplied at rated voltage and operated under normal operation. The power
input shall have decreased by at least 50 % from the initial value when steady conditions are
established, any control operating during this period being short-circuited.

– 12 – IEC 60335-2-81:2024 © IEC 2024
11 Heating
This clause of Part 1 is applicable except as follows:
11.2 Modification:
Appliances are placed as near as possible to one wall of the test corner and away from the
other wall.
11.3 Addition:
Where the external accessible surfaces are suitably flat and access permits, then the test
probe of Figure 101 is used to measure the temperature rises of external accessible surfaces
specified in Table 101. The probe is applied with a force of 4 N ± 1 N to the surface in such a
way that the best possible contact between the probe and the surface is ensured. 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 Modification:
Replace the first paragraph with the following:
Appliances are operated until steady conditions are established.
11.8 Modification:
Replace the first paragraph with the following:
During the test, the temperature rises are monitored continuously and shall not exceed the
values shown in Table 3 and Table 101.
Add the following to footnote "k" of Table 3:
Similar parts held for short periods include handles or grips of vents and air shutters.
Addition:
When polyvinyl chloride is used for insulating heating elements, the temperature rise of the
insulation shall not exceed 80 K.

Table 101 – Maximum temperature rises for specified external
and other surfaces under normal operating conditions
Surface Temperature rise of
external and other
accessible surfaces
K
Surfaces likely to be in contact with the user's feet 40
Other surfaces of:
– bare metal 38
a
– coated metal
– glass and ceramic 51
b, c
– plastic and plastic coating > 0,4 mm
NOTE The temperature rise limits of handles, knobs, grips, keyboards, keypads and similar parts are specified in
Table 3.
a
Metal is considered coated when a coating having a minimum thickness of 90 µm made of enamel, powder or
non-substantially plastic coating is used.
b
The temperature rise limit of plastic also applies for plastic material having a metal finish of thickness less than
0,1 mm.
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.
12 Charging of metal-ion batteries
This clause of Part 1 is applicable.
13 Leakage current and electric strength at operating temperature
This clause of Part 1 is applicable except as follows.
13.2 Addition:
When testing the top surface of heating mats, the dimensions of the metal foil are
300 mm × 150 mm.
If the heating mat is reversible, each surface is tested in turn.
Foot warmers are also tested with the inside surface completely covered with metal foil.
14 Transient overvoltages
This clause of Part 1 is applicable.

– 14 – IEC 60335-2-81:2024 © IEC 2024
15 Moisture resistance
This clause of Part 1 is applicable except as follows.
15.1.1 Addition:
Appliances are subjected to the test of IEC 60529:1989, 14.2.1. However, cord sets, switches
and controls in the flexible cord are not subjected to the tests.
15.1.2 Addition:
Foot warmers are orientated so that the base of the appliance is in contact with the support.
Appliance inlets are covered before carrying out the test.
16 Leakage current and electric strength
This clause of Part 1 is applicable except as follows.
16.2 Addition:
When testing the top surface of heating mats, the dimensions of the metal foil are
300 mm × 150 mm.
If the heated mat is reversible, each surface is tested in turn.
Foot warmers are also tested with the inside surface completely covered with metal foil.
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 Addition:
The appliance is covered partially or completely, whichever is more unfavourable, with a sheet
of open-cell polyether approximately 36 mm thick, having the following properties:
+2
• cell count 18 per cm;
+10
• specific mass 30 kg/m + %;
• hardness 120 N to 170 N at 40 % impression, measured according to ISO 2439.
If the foot warmer has a flexible part that covers the user's legs, this part is folded onto the
foot part before covering.
A plywood board, having dimensions approximately 500 mm × 500 mm × 20 mm, is placed on
top of the polyether sheet covering foot warmers.
19.4 Addition:
Heating mats are tested without being covered by the polystyrene block.
19.13 Addition:
The temperature rise of the insulation of heating elements shall not exceed 145 K.
20 Stability and mechanical hazards
This clause of Part 1 is applicable except as follows.
20.2 Addition:
For parts of appliances situated not more than 850 mm above the floor after installation or in
normal use, in addition to the use of test probe 18, test probe 19 of IEC 61032 is also applied
wherever test probe 18 is used and with the same test conditions used for test probe 18.
21 Mechanical strength
This clause of Part 1 is applicable except as follows.
21.1 Addition:
Foot warmers are also subjected to the test of 21.101. Control units intended to be placed on
a surface are also subjected to the test of 21.107.
21.2 Addition:
This requirement is not applicable to textiles and similar materials forming the enclosure.
21.101 A plywood board, having dimensions approximately 300 mm × 150 mm × 20 mm with
rounded edges, is placed in the leg section of the foot warmer as shown in Figure 102. A load
of 30 kg is placed on the board, which is allowed to drop freely from a height of 200 mm above
the base, so that the leg section is flexed, and the appliance is compressed between the board
and the supporting surface. The total mass of the board, its movable support and the load is
30 kg. If the foot warmer does not have a leg section, the board is allowed to fall onto the top
surface.
The test is carried out 1 000 times at a rate of six times per minute.
The test shall not result in
– damage to the enclosure or displacement of heating elements to such an extent that
compliance with the standard is impaired;
– open-circuiting of heating elements or controls;
– breakage of more than 10 % of the strands of internal wiring;
– failure of constructional stitching, or breakage of glued or welded joints, to such an extent
that compliance with the standard is impaired.

– 16 – IEC 60335-2-81:2024 © IEC 2024
NOTE An example of damage to the enclosure that could impair compliance with the standard is a tear in the
enclosure. Small holes in textiles that are not part of electrical insulation or do not provide protection against moisture
are ignored.
21.102 The insulation of heating elements and internal wiring shall retain adequate flexibility
and insulating characteristics throughout the life of the appliance.
Compliance is checked by the tests of 21.103 and by the tests of 21.104 and 21.105 when the
insulation exceeds
– a temperature rise of 50 K during the test of Clause 11, or
– a temperature rise of 110 K during the tests of Clause 19.
The tests are carried out on separate samples of heating element or internal wiring.
For the test of 21.103, one sample measuring approximately 4 m in length is required. For the
tests of 21.104, at least 12 samples are required, each having a length of 300 mm. For the test
of 21.105, 12 samples are required, each having a length of 300 mm.
21.103 The sample of heating element or internal wiring is attached to the equipment shown
in Figure 103. This equipment has a carrier with two pulleys, each having a groove with a radius
of 4 mm, the diameter at the base of the groove being 25 mm. For samples not having a circular
cross-section, the form of the groove in the pulley is suitably modified. The pulleys are arranged
so that the sample is horizontal where it passes between them.
The sample is stretched over the pulleys, each end being loaded with a mass of 0,25 kg. If
necessary, the mass at each end is increased in steps of 0,1 kg in order to ensure that the wires
leaving the pulleys are parallel to each other. Restraining clamps are positioned so that the pull
is always applied by the mass in the opposite direction from which the carrier is moving.
The carrier moves over a distance of 1 m with a constant speed of approximately 0,33 m/s for
25 000 cycles.
A cycle is two movements, one in each direction.
The sample shall not break during the test.
A monitoring current not exceeding 50 mA can be passed through the sample during the test to
detect breakage of the conductor.
For heating elements with PTC characteristics, the power input is measured before and after
the test. The measurement is made with the heating element suspended vertically in free air
and supplied at the rated voltage of the appliance. Both measurements are carried out at the
same ambient temperature and when the power input has stabilized. The power input shall not
increase during the test.
The sample is then immersed in water containing approximately 1 % NaCl. A DC voltage of
approximately 500 V is applied between the conductor and the saline solution.
The insulation resistance is measured 1 min after immersion and shall be at least 1 MΩ.
21.104 The conductors are pulled out from 12 samples of heating element or internal wiring.
If this is not possible, the insulation is slit longitudinally, the conductor is removed and the
insulation allowed to close.
Six of the samples are conditioned by suspending them vertically so that they hang freely in a
heating cabinet at a temperature of 125 °C ± 2 °C for 336 h. The samples are removed from the
cabinet and allowed to cool down to room temperature. When the material has stabilized, the
length of the samples is measured and shall not be less than 90 % of the original length. PVC
material will have stabilized by 16 h after removal from the cabinet.
The heating cabinet shall have forced air circulation in order to ensure that there is no
temperature gradient over the length of the samples.
The 12 samples are placed in a tensile machine, in turn, so that the length between the clamps
is at least 50 mm. The machine is operated at a uniform speed of 500 mm/min ± 50 mm/min.
The force and elongation at the instant of rupture are determined.
Results obtained from any sample that ruptured at a force differing from the average value by
more than 10 %, and from samples that ruptured within a distance of 15 mm from the clamp,
are disregarded. Additional samples are tested in order to obtain 12 valid results.
The elongation of each of the unconditioned samples shall not be less than 100 % and their
tensile strength shall not be less than 8,75 MPa.
The average value of both the elongation and tensile strength of the conditioned samples shall
be not less than 75 % of the average value determined for the unconditioned samples.
21.105 A 10 mm length of insulation is removed from each end of 12 samples of heating
element or internal wiring.
Six of the samples are wound in a close helix of six turns on a metal mandrel having a diameter
approximately equal to the external diameter of the samples. Together with the remaining six
samples, they are placed in a heating cabinet at a temperature of 125 °C ± 2 °C for 336 h. The
samples are removed from the cabinet and allowed to cool down to room temperature.
When the material has stabilized, the other six samples are also wound on the mandrel in the
same way. PVC material will have stabilized by 16 h after removal from the cabinet.
The heating cabinet shall have forced air circulation in order to ensure that there is no
temperature gradient over the length of the samples.
The mandrel is immersed for 1 h in water containing approximately 1 % NaCl. The samples are
then subjected to a test voltage of 1 000 V for class II appliances and 500 V for class III
appliances. The voltage is applied for 1 min between the conductors and the solution and there
shall be no breakdown.
The samples are unwound from the mandrel and inspection shall show that there are no visible
cracks.
21.106 Heating elements with PTC characteristics shall be resistant to crushing.
Compliance is checked by the following test.
The flexible part is fully supported by a piece of plywood 20 mm thick and supplied as specified
in 11.4. When steady conditions are established, the temperature of the heating element is
measured. A block having dimensions of 100 mm × 300 mm and a mass of 80 kg with rounded
edges in contact with the flexible part is applied for 5 min to the surface in the most unfavourable
place. After removing the block, the appliance is again operated until steady conditions are
established and the temperature of the heating element is measured. The temperature of the
heating element where the block has been applied shall not have increased by more than 10 K.

– 18 – IEC 60335-2-81:2024 © IEC 2024
NOTE The most unfavourable place to apply the bloc
...