الهيئة السعودية للمواصفات والمقاييس والجودة  
Saudi Standards, Metrology and Quality Org (SASO)  
 
 
 
 
 
FINAL DRAFT  
 
 
 
SASO/FDS/IEC 60335 -2-21:2020 
IEC 60335 -2-21:2018  
 
 
الأجهزة الكهربائية المنزلية وما شابهها- السلامة –الجزء 2-21: متطلبات
خاصة بالسخانات الكهربائية التخزينية 
Household and similar electrical appliances - Safety - Part 2 -21: 
Particular requirements for storage water heaters  
ICS:  91.140.65  
THIS DOCUMENT IS A DRAFT SAUDI STANDARD  CIRCULATED 
FOR COMMENT. IT IS, THEREFORE SUBJECT TO CHANGE AND 
MAY NOT BE REFERRED TO AS A SAUDI STANDARD  UNTIL 
APPROVED BY THE BOARD OF DIRECTORS.  
 SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
1 
  Foreword  
Saudi Standards, Metrology and Quality Organization (SASO) has  adopted Standard No. 
(IEC 60335 -2-21) “Household  and similar electrical appliances - Safety - Part 2 -21: 
Particular requirements for storage water heaters " issued by ( IEC) in English. This 
standard has been approved as a Saudi Standard with national  modifications.  
 
This SASO IEC 6 0335 -2-21:2020 standard is a modified adoption of International 
Standard IEC 60335 -2-21:2018, (Household and similar electrical appliances - Safety - 
Part 2 -21: Particular requirements for storage water heaters). Standard has been varied 
as indicated to ta ke account of Kingdom of Saudi Arabia conditions. The modifications 
are specified in Annex BB.  
 
This Standard supersedes and replaces (SASO -GSO -1858: Storage -type electric water 
heaters for household use) and (SASO -GSO -1859: Methods of test for storage -type 
electric w ater heaters for household use) and (SASO -1698: Safety of household and 
similar electrical appliances – Part 2: Particular requirments – Section 21: Storage water 
heaters) . 
 
  SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
2 
  CONTENTS  
FOREWORD  ................................ ................................ ................................ ...........................  4 
INTRODUCTION  ................................ ................................ ................................ .....................  7 
1 Scope  ................................ ................................ ................................ ...............................  8 
2 Normative references  ................................ ................................ ................................ .......  9 
3 Terms and definitions  ................................ ................................ ................................ .......  9 
4 General requirement  ................................ ................................ ................................ .......  10 
5 General conditions for the tests  ................................ ................................ ......................  10 
6 Classification  ................................ ................................ ................................ ..................  10 
7 Marking and instructions  ................................ ................................ ................................ . 11 
8 Protection against access to live parts  ................................ ................................ ............  12 
9 Starting of motor -operated appliances  ................................ ................................ ............  12 
10 Power input and current ................................ ................................ ................................ .. 12 
11 Heating ................................ ................................ ................................ ...........................  12 
12 Void  ................................ ................................ ................................ ................................  13 
13 Leakage current and electric strength at operating temperature  ................................ ...... 13 
14 Transient overvoltages  ................................ ................................ ................................ ... 13 
15 Moisture resistance  ................................ ................................ ................................ ........  13 
16 Leakage current and electric strength  ................................ ................................ .............  13 
17 Overload protection of transformers and associated  circuits  ................................ ...........  13 
18 Endurance  ................................ ................................ ................................ ......................  14 
19 Abnormal operation  ................................ ................................ ................................ ........  14 
20 Stability and mechanical hazards ................................ ................................ ....................  15 
21 Mechanical strength  ................................ ................................ ................................ .......  15 
22 Construction  ................................ ................................ ................................ ...................  15 
23 Internal wiring  ................................ ................................ ................................ .................  17 
24 Components  ................................ ................................ ................................ ...................  17 
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  ................................ ......................  19 
30 Resistance to heat and fire  ................................ ................................ .............................  19 
31 Resistance to rusting  ................................ ................................ ................................ ...... 20 
32 Radiation, toxicity and similar ha zards  ................................ ................................ ............  20 
Annexes  ................................ ................................ ................................ ...............................  23 
Annex  A (informative)  Routine tests  ................................ ................................ .....................  23 
Annex R (normative)  Software evaluation  ................................ ................................ ............  24 
Annex  AA (normative)  Additional requirement for immersion heater units intended for 
the installation in heat exchange closed water heaters  ................................ ..........................  25 
Annex BB : List of National modifications ………………………………………….…………….……2 8 SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
3 
  Bibliography  ................................ ................................ ................................ ..........................  31 
 
Figure 101 – Examples of types of storage water heaters  ................................ .....................  21 
Figure 102 – Example of positions of the thermocouples  ................................ .......................  22 
Figure 103 – Probe for measuring surfac e temperatures  ................................ .......................  22 
 
Table 101 – Maximum temperature rises of external accessible surfaces under normal 
operating conditions  ................................ ................................ ................................ ..............  13 
 
 
  SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
4 
  INTERNATIONAL ELECTROTECHNICAL COMMISSION  
 
____________ __ 
 
HOUSEHOLD AND SIMILAR ELECTRICAL APPLIANCES –  
SAFETY –  
 
Part 2 -21: Particular requirements for storage water heaters  
 
 
FOREWORD  
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising 
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international 
co-operation on all questions c oncerning 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 (here after 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 o rganizations 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 form al 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 Pub lications 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 respo nsible 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 natio nal 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 certificati on 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 re ferences 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.  
DISCLAIMER  
This Consolidated version  is not an official IEC Standard and has been prepared for 
user convenience.  Only the current version s of the standard and its amendment(s) are  
to be considered the official document s. 
This Consolidated version of IEC 60335 -2-21 bears the edition number 1.1. It consists of 
the first edition (201 2-11) [documents 61/4452/FDIS and 61/4505/RVD ] and its  
corrigendum (2013 -04), and   its amendment 1 (201 8-08) [documents 61/5563/CDV  and 
61/5650A/RVC ]. The technical content is identical to the base edition and its amendment.  
This Final version does not show where the technical content is modified by amendment 
1. A separate Redline versi on with all changes highlighted is available in this publication.  
This part of International Standard IEC 60335 has been prepared by IEC technical committee 
61: Safety of household and similar electrical appliances.  SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
5 
  This six th editi on constitutes a technic al revision.  
The principal changes in this edition as compared with the fifth edition of IEC 60335 -2-21 are 
as follows (minor changes are not listed):  
– added requirements for immersion heater units (fixed immersion heaters) ; 
– removed reference to ISO 13732 -1 from Bibliography.  
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 editio n (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 requireme nts for storage water heaters . 
When a particular subclause of Part 1 is not mentioned in this part 2, that subclause applies as 
far as is reasonable. When this standard states “addition”, “modification” or “replacement”, the 
relevant text in Part 1 is to be adapted accordingly.  
NOTE 2  The following numbering system is used:  
– subclauses, tables and figures that are numbered starting from 101 are additional to those in Part 1;  
– unless notes are in a new subclause or involve notes in Part 1, they are numbered starting from 101, including 
those in a replaced clause or subclause;  
– additional annexes are lettered AA, BB, etc.  
NOTE 3  The following print types are used:  
– requirements: in roman type;  
– test specifications: in italic type;  
– notes: in small  roman type.  
Words in bold in the text are defined in Clause 3. When a definition concerns an adjective, the adjective and the 
associated noun are also in bold.  
The committee has decided that the contents of the base  publication and its amendment will 
rema in unchanged until the stability  date  indicated on the IEC web site under 
"http://webstore.iec.ch" in the data related to the specific publication. At this date, the 
publication will be  
 reconfirmed,  
 withdrawn,  
 replaced by a revised edition, or  
 amended.  
NOTE 4  The attention of National Committees is drawn to the fact that equipment manufacturers and testing 
organizations may need a transitional period following publication of a new, amended or revised IEC publication in 
which to make products in accordance with the new requirements and to equip themselves for conducting new or 
revised tests.  
It is the recommendation of the committee that the content of this publication be adopted for implementation nationally 
not earlier than 12 months or later than 36 month s 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.  SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
6 
  – 6.1: Class 0I appliances are allowed (Japan).  
– 6.2: IPX0 water heaters are allowed (France, United Kingdom and USA).  
– 7.1: Additional markings are required (Australia, New Zealand and South Africa).  
– 7.1: The rated pressure is to be marked in pounds per square  inch (USA).  
– 7.1: Open outlet water heaters are not required to be marked with rated pressure (USA).  
– 7.12.1: Additional instructions are required (South Africa).  
– 11.7: The test is different (USA).  
– 13.2: An additional leakage current test is required (China).  
– 19.1: Appliances incorporating sheathed heating elements are not required to have an outer 
enclosure of metal but their rated power input is limited to 12 kW (USA).  
– 19.101: The test is different (USA).  
– 22.47: The minimum pressure is 2,1 MPa. The t est is not carried out on water heaters having 
a capacity less than 2 l or on appliances having containers open to the atmosphere (USA).  
– 22.101: Pressure reducing valves have to be designed for an inlet pressure of 2 MPa (South 
Africa).  
– 22.102: The tempera ture limit is 95  °C (South Africa).  
– 22.102: The temperature limit is 85  °C (USA).  
– 22.101: The minimum rated pressure is 1,0 MPa (Denmark, Finland,  Norway and Sweden).  
– 22.103: Closed water heaters having a capacity exceeding 50 l or a rated power input 
exce eding 2 kW have to incorporate a pressure -relief device sensitive to both pressure and 
temperature that operates before the water temperature reaches 99  °C (South Africa).  
– 22.103: Closed water heaters have to incorporate a temperature relief valve or a co mbined 
temperature and pressure -relief valve that operates before the water temperature reaches 
100 °C (United  Kingdom).  
– 22.106: The thermal cut -out of single -phase closed water heaters need only provide single -
pole disconnection (Japan).  
– 22.106: For all c losed water heaters, the thermal cut -out is to provide all -pole disconnection 
(France, Netherlands,).  
– 22.109: A tool is not required for draining the appliance (USA).  
– 22.110: Additional requirements apply to plastic or resin -based containers for open outlet, 
cistern type and low pressure type (South Africa).  
– 24.1.4 Additional requirements apply to Thermal cut -outs (South Africa)  
– 24.101: Thermal cut -outs are required to have a trip -free switching mechanism (USA).  
– 24.102: The maximum water temperature is 99  °C (Japan, Norway, Portugal, United 
Kingdom and USA) . 
– 24.102: The temperature limit of 130  °C is only allowed for closed water heaters having a 
rated pressure of at least 0,4 MPa (South Africa).  
 SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
7 
  INTRODUCTION  
It has been assumed in the drafting of this Int ernational 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, fi re 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 aff ect 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 influen ce 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 
preceden ce 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 com plies 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 con sidered to comply with the 
standard.  SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
8 
  HOUSEHOLD AND SIMILAR ELECTRICAL APPLIANCES –  
SAFETY –  
 
Part 2 -21: Particular requirements for storage water heaters  
 
 
 
Scope  
This clause of Part 1 is replaced by the following.  
This International Standard deals with  the safety of electric storage water heaters  for 
household and similar purposes and intended for heating water below boiling temperature, their 
rated voltage  being not more than 250 V for single -phase appliances and 480 V for other 
appliances.  
Appliances not intended for normal household use but which nevertheless may be a source of 
danger to the public, such as appliances intended to be used by laymen in shops, in light 
industry and on farms, are within the scope of this standard.  
This stand ard is also ap plicable to immersion heater  units intended to be retrofitted in a heat 
exchange  closed water heater having provision for retrofitting . Such a unit shall comply with 
the requirements in Annex AA.  
NOTE  Australia, Netherlands and New Zealand  do not allow immersion heater  units intended to be retrofitted in 
a heat exchange  closed water heater unless : 
– the immersion heater  unit has been tested with the tank models and brands listed in the instructions of the  
immersion heater  unit;   
– the tank models and brands list the models of the  immersion heater  units that can be retrofitted.  
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 no t 
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;  
– in many countries regulations exist for the installation of equipment connected to the water mains.  
NOTE 102  This standard does not apply to  
– appliances for boiling water ( IEC 60335 -2-15); 
– instantaneous water heaters ( IEC 60335 -2-35); 
– commercial dispensing appliances and vending machines ( IEC 60335 -2-75); 
– appliances intended exclusively for industrial purposes;  
– appliances intended to be used in locations w here special conditions prevail, such as the presence of a corrosive 
or explosive atmosphere (dust, vapour or gas).  SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
9 
  Normative references  
This clause of Part 1 is applicable  except as follows : 
Addition:  
IEC 60584 -1:2013,  Thermocouples  – Part 1: EMF specific ations and tolerances  
Terms and d efinitions  
This clause of Part 1 is applicable except as follows.  
3.1.9  Replacement:  
normal operation  
operation of the appliance after installation in accordance with the instructions and filled with 
cold water  
3.101  
storage water heater  
stationary appliance  for heating and storing water in a container and incorporating devices to 
control the water temperature  
3.102  
closed water heater  
unvented  storage water heater  intended to operate at the pressure of the water syste m, the 
flow of water being controlled by one or more valves in the outlet system  
Note 1 to entry:  A closed water heater  is shown in Figure 101a.  
Note 2 to entry:  The operating pressure may be the output pressure of a reducing or boosting device.  
3.103  
cistern -fed water heater  
storage water heater  that is vented to atmosphere and intended to be supplied by water under 
gravity from a separate cistern, the flow of water being controlled by one or more valves in the 
outlet system  
Note 1 to entry:  A cistern -fed water heater  is shown in Figure 101d . 
Note 2 to entry:  The water heater may be installed so that the expanded water returns to the cistern.  
Note  3 to entry:  In a cistern -fed water heater , the pressure in the container results from the column of water in 
the cistern.  
3.104  
cistern -type water heater  
storage water heater  having a container supplied by water under gravity from a cistern 
incorporated in the appliance.  
Note 1  to entry:  The expanded water can return to the cistern, the flow of water being con trolled by one or more 
valves in the outlet system  
Note 2 to entry:  A cistern -type water heater  is shown in Figure 101c.  
Note  3 to entry:  In a cistern -type water heater , the surface of the water is always at atmospheric pressure.  
3.105  
open -outlet water h eater  
storage water heater  in which the flow of water is only controlled by a valve in the inlet pipe 
and in which the expanded or displaced water flows through the outlet  SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
10 
  Note 1 to entry:  An open -outlet water heater  is shown in Figure 101b .  
Note  2 to entry:  In an open -outlet water  heater , the static pressure at the outlet is always at atmospheric pressure.  
3.106  
low-pressure water heater  
storage water heater  that is vented to atmosphere and intended to be connected to the water 
mains through a pressure reducing valve, the flow of water being controlled by one or more 
valves in the outlet system  
Note 1  to entry:  A low-pressure water heater  is shown in Figure 1 01e.  
3.107  
rated pressure  
water pressure assigned to the appliance by the manufacturer  
3.108  
heat exchange water heater  
storage water heater in which heated water is fed into a heat exchanger, such as a coiled tube 
or similar device, which is itself imme rsed in a container with the water to be heated.  
Note 1 to entry:  The heated water fed into the heat exchanger is heated from a primary heat source such as a solar 
panel or heat pump.  
Note 2 to entry:  A heat exchange water heater  is shown in Figure 101f . 
General requirement  
This clause of Part 1 is applicable.  
General conditions for the tests  
This clause of Part 1 is applicable except as follows.  
5.2 Addition : 
NOTE 101  Additional appliances can be required if damage occurs during the tests of 19.2 or 19.3.  
5.3 Addition:  
When the tests are carried out on a single appliance, the tests of 22.47, 22.102, 22.103, and 
24.102 are carried out before the tests of Clause 19.  
Classification  
This clause of Part 1 is applicable except as follows.  
6.1 Modification:  
Water heaters shall be class I , class II  or class III . 
6.2 Addition:  
Water heaters for installation outdoors shall be at least IPX4. Other water heaters shall be at 
least IPX1.  SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
11 
  Marking and instructions  
This clause of Part 1 is applicable except as follows.  
7.1 Addition:  
Appliances, other than cistern -type water heaters , shall be marked with the  rated pressure  
in pascals.  
Appliances shall be marked with the rated capacity in litres.  
Closed water heaters  shall be marked with a statement that a pressure -relief  device is to be 
fitted in the installation, unless it is incorporated in the appliance.  
Closed water heaters  having a rated pressure  less than 0,6 MPa and low-pressure water 
heaters  shall be marked with a statement that a pressure reducing valve is to be fitted in the 
installation.  
Open -outlet water heaters  shall be marked, close to the outlet connection or on a tag attached 
to the appliance, with the substance of the following:  
WARNING:  This outlet acts as a vent and must only be connected to a fitting re commended 
by the manufacturer. It must not be connected to a tap.  
7.12  Addition:  
The instructions for closed water heaters shall state the substance of the following:  
– the water may drip from the discharge pipe of the pressure -relief device and that this p ipe 
must be left open to the atmosphere;  
– the pressure -relief device is to be operated regularly to remove lime deposits and to verify 
that it is not blocked;  
– how the water heater can be drained.  
7.12.1  Addition:  
The installation instructions shall state th e substance of the following:  
– the type or characteristics of the pressure -relief device and how to connect it, unless it is 
incorporated in the appliance;  
– a discharge pipe connected to the pressure -relief device is to be installed in a continuously 
downwar d direction and in a frost -free environment;  
– the type or characteristics of a pressure reducing valve and the installation details (for 
appliances having a rated pressure  less than 0,6 MPa).  
The instructions for closed water heaters  incorporating a heat ex changer shall give details on 
the installation of control devices and the temperature settings that are necessary to prevent 
operation of the thermal cut -out caused by the heat from the exchanger.  
The instructions for cistern -fed water heaters  and low-pres sure water heaters  shall contain 
the substance of the following:  
WARNING:  Do not connect any pressure -relief device to the vent pipe of this water heater.  
7.101  The water inlet and the 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.   SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
12 
  An alternative means of identification may be by means of arrows showing the direction of the 
water flow.   
Compliance is checked by inspection.  
Protection aga inst access to live parts  
This clause of Part 1 is applicable.  
Starting of motor -operated appliances  
This clause of Part 1 is not applicable.  
Power input and current  
This clause of Part 1 is applicable.  
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 103 may be used to measure the temperature rises of external accessible 
surfaces  specified in Table 101 . The probe is  applie d 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  Replacement:  
The appliance is operated until steady conditions are established or until the thermostat  
interrupts the current for the first time after 16 h,  whichever is shorter.  
11.8  Modification : 
During the test, the temperature rises are monitored continuously and shall not exceed the 
values shown in Table 3 and Table 101.  
  SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
13 
  Table 101 – Maximum temperature rises of external accessible surfaces  
under normal  operating conditions  
Surface a Temperature rise  
K 
Bare metal  42 
Coated metal b 49 
Glass and ceramic  56 
Plastic and plastic coating >  0,4 mm c,d 62 
a Temperature rises are not measured on:  
– tapping connections, pipes, hoses, plumbing fittings, pressure relief valves and sight gauges;  
– appliances intended for installation on the roof;  
– surfaces  not accessible to the 75  mm diameter probe having a hemispherical end.  
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 The temperature rise limit of plastic also applies for plastic material having a metal finish of thickness less than 
0,1 mm.  
d When the thickness of the plastic coating does not exceed 0,4  mm, the t emperature rise limits of the coated 
metal or of glass and ceramic material apply . 
 
Void  
Leakage current and electric strength at operating temperature  
This clause of Part 1 is applicable.  
Transient overvoltages  
This clause of Part 1 is applicable.  
Moistu re resistance  
This clause of Part 1 is applicable except as follows.  
15.2  Addition:  
The test is only applicable to cistern -type water heaters . 
15.3  Addition:  
NOTE 101  If the appliance is too large for the humidity cabinet, the test can be carried out on those parts that 
contain electrical components.  
Leakage current and electric strength  
This clause of Part 1 is applicable.  
Overload protection of transformers and associated circuits  
This clause of Part 1 is applicable.  SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
14 
  Endurance  
This clause of Part 1 is n ot applicable.  
Abnormal operation  
This clause of Part 1 is applicable except as follows.  
19.1  Modification:  
Instead of the tests specified for appliances incorporating heating elements, the following 
applies.  
For closed water heaters , low-pressure water he aters  and open -outlet water heaters , 
compliance is checked by the tests of 19.2, 19.3 and 19.4 if applicable. However, 19.101 applies 
instead for appliances not liable to be emptied in normal use and having all four of the following 
features:  
– an outer encl osure of meta l or a water container of metal and an outer enclosure of non -
metallic material ; 
NOTE 101  Non-metallic covers can be used for the supply terminals and controls.  
– non-combustible thermal insulation;  
NOTE 102  Insulation withstanding the needle flame test of Annex E is considered to be non -combustible.  
– a capacity exceeding 30 l;  
– a rated power input  not exceeding 6 kW.  
NOTE 103  Appliances are not considered liable to be emptied in normal use if emptying through the inlet is 
prevented by a chec k valve, a pipe interrupter or an air gap. These devices can be fitted in the inlet pipe in accordance 
with the instructions. Emptying through openings provided for servicing purposes only is not considered to be normal 
use. 
NOTE 104  Cistern -fed water heat ers and cistern -type water heaters  are not subjected to the tests.  
19.2  Addition:  
The appliance is operated empty, any thermal control that operates during the test of Clause  11 
being short -circuited.  
NOTE 101  If the appliance is provided with more than on e thermal control, these are short -circuited in turn.  
19.3  Addition:  
NOTE 101  If the water heater has been damaged during the previous test, a new appliance is used.  
19.4  Replacement:  
For open -outlet water heaters , the test of 19.2 is repeated but with the container filled with 
water to a level at least 10 mm above the highest point of the heating element. The appliance 
is operated at 1,15 times rated power input  under normal operation . 
NOTE 101  If the water heater  has been damaged during previous tests, a new appliance is used.  
19.13  Addition:  SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
15 
  There shall be no leakage from the container during the tests.  
19.101  The appliance is tested for 24 h under the conditions specified in Clause 11 but with 
the container empt y. 
Stability and mechanical hazards  
This clause of Part 1 is applicable.  
Mechanical strength  
This clause of Part 1 is applicable.  
Construction  
This clause of Part 1 is applicable except as follows.  
22.6  Addition:  
The enclosure shall have a drain hole posit ioned so that the water can drain without impairing 
electrical insulation, unless condensed water cannot accumulate within the enclosure in normal 
use. The hole shall be at least 5 mm in diameter or 20 mm2 in area with a width of at least 
3 mm. 
Compliance is checked by inspection and measurement.  
22.20  Addition:  
Thermal insulation shall not be used for basic insulation  of internal wiring.  
22.47  Replacement:  
Appliances shall withstand the water pressure occurring in normal use.  
Compliance is checked by subje cting the appliance to a water pressure of  
– twice the rated pressure , for closed water heaters . If the water heater is supplied through 
a pressure reducing valve, the container is subjected to twice the working pressure instead;  
NOTE  1 The pressure reducing valve can be incorporated in the water -inlet pipe.  
NOTE  2 The working pressure is the maximum pressure in the container measured during the test of Clause  11. 
– 1,5 times rated pressure , for cistern -fed water heaters  and low-pressure water heaters ; 
– 0,15 MPa, for open -outlet water heaters ; 
– 0,03 MPa, for cistern -type water heaters . 
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 fo r 15 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.  SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
16 
  NOTE  3 Heat exchangers incorporated in an appliance are subjected to a pressure test based on th eir working 
pressure.  
NOTE  4 Damage to a protective coating on the inside of containers is not considered to be a hazard.  
22.101  The rated pressure  of closed water heaters  intended for direct connection to the 
water main shall be at least 0,6 MPa.  
The rated pressure  of closed water heaters  and low-pressure water heaters , intended to be 
supplied by a pressure reducing valve that is not incorporated in the appliance, shall be at least 
0,1 MPa.  
The rated pressure  of cistern -fed water heaters  shall not exceed 0 ,2 MPa.  
NOTE  The rated pressure  of open -outlet water heaters  is 0 Pa.  
Compliance is checked by inspection.  
22.102  Closed water heaters  shall be constructed so that repeated drawing off does not 
cause the water to boil.  
Compliance is checked by the following test.  
The appliance is operated as specified in Clause 11.  
When the thermostat  has operated for the first time, water is drawn off at a rate of 
approximately 2 l/min or 10  % of the capacity of the appliance per minute, whichever is less, 
until th e thermostat  switches on again.  
When the thermostat  next operates, water is drawn off again at the same rate until the 
thermostat  switches on, this sequence being repeated until steady conditions are established.  
The temperature of the water, measured by m eans of a thermocouple at the outlet, shall not 
exceed 98  °C. 
22.103  Pressure -relief devices of closed water heaters  shall prevent the pressure in the 
container from exceeding the rated pressure  by more than 0,1 MPa.  
Compliance is checked by subjecting the  container to a slowly increasing water pressure.  
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.  
NOTE  This requirement is considered to be met if the cross -sectional area of the water outlet is not less than that 
of the inlet.  
The vent pipe of low pressure water heaters  shall have an internal diameter of at least 20  mm. 
Compliance is checked by inspection and measurement.  
22.105  Cistern -type water heaters  shall be constructed so that the container is always at 
atmosph eric pressure by means of a vent having an area of at least 30 mm2 and a minimum 
dimension of at least 3 mm.  
Compliance is checked by inspection and by measurement.  SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
17 
  22.106  Closed water heaters  shall incorporate a thermal cut -out providing all-pole 
disconnection and which operates independently from the thermostat . However, for 
appliances intended to be connected to fixed wiring, the neutral conductor need not be 
disconnected.  
Compliance is checked by inspection.  
22.107  Heating elements and thermal control sensors in contact with the outer surface of the 
container shall be held in position securely.  
Compliance is checked by inspection.  
22.108  Appliances for wall mounting shall have reliable provision for fixing to a wall, 
independent of the c onnection to the water mains.  
Compliance is checked by inspection.  
22.109  Appliances having a capacity of more than 15 l that cannot be emptied through a drain 
fitted in the water pipes shall incorporate means for draining that requires a tool for its 
oper ation.  
Compliance is checked by inspection and by manual test.  
NOTE 1  Residual water in the container below the end of the inlet pipe is disregarded.  
NOTE 2  The means for draining can be combined with a pressure -relief valve.  
22.110  Open -outlet water heate rs having plastic containers shall be constructed to ensure 
that the appliance is only likely to be installed in the intended orientation.  
NOTE  Appliances marked with the mounting position adjacent to the water connections are considered to meet this 
requi rement.  
Compliance is checked by inspection.  
22.111  Closed water heaters  incorporating a heat exchanger shall be constructed so that 
during normal use the thermal cut -out does not operate due to heat from the exchanger.  
Thermostatic valves, by -pass valves and similar controlling devices used for this purpose shall 
be supplied with the appliance.  
Compliance is checked by inspection.  
Internal wiring  
This clause of Part 1 is applicable.  
Components  
This clause of Part 1 is applicable except as follows.  
24.1.4  Addition:  
Thermal cut -outs  incorporated in closed water heaters  shall comply with the requirements for 
Type 2 .B controls in Clauses 13, 15, 16 17 and 20 of IEC 60730 -1, unless they are tested with 
the appliance.  SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
18 
  24.101  Thermal cut -outs  shall be non -self-resetting. They shall have a trip -free switching 
mechanism or be located so that they can only be reset after removal of a non-detachable 
cover . 
Compliance is checked by inspection.  
24.102  The operating temperature of the thermal cut -out of a closed water heater shall 
ensure that the water temperature cannot exceed 99  °C or that the thermal cut -out operates 
before its temperature exceeds 110  °C. 
Compliance is checked by the test of 24.102.1 for water temperatures not exceeding 99  °C or 
by the t est of 24.102.2 for thermal cut -outs having an operating temperature up to 110  °C. 
24.102.1  The appliance is operated under the conditions specified in Clause 11 until the 
thermostat  operates for the first time. A quantity of water equal to 25  % of the cap acity of the 
container is then drawn off so that it is replaced by cold water.  
Immediately after the thermostat  operates for the second time, it is short -circuited. The test is 
continued until the thermal cut -out operates. The outlet valve is then opened a nd the 
temperature of the water measured at the outlet.  
The temperature shall not exceed 99  °C. 
If compliance relies on the operation of an electronic circuit , the test is repeated under the 
following conditions applied separately:  
– the fault conditions in a) to g) of 19.11.2 applied one at a time to the electronic circuit ; 
– the electromagnetic phenomena tests of 19.11.4.1 to 19.11.4.7 applied to the appliance.  
The temperature of the water at the outlet shall not exceed 99 °C during or after each of the 
tests. 
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.  
24.102.2  The operating temperature of t he thermal cut -out is measured by means of a 
thermocouple positioned on its sensing element or as close as possible to it.  
The water temperature for appliances having vertically oriented metallic water containers is 
measured by a thermocouple attached to t he outer surface of the upper dome. If the water 
container is horizontally oriented, two thermocouples are attached to the outer surface. The 
position of the thermocouple is shown in Figure 102.  
The water temperature for appliances having non -metallic wate r containers is measured at the 
most unfavourable position by a thermocouple positioned 50 mm below the upper inner surface 
of the container.  This method may also be used to measure the water temperature of appliances 
having metallic containers.  
The appli ance is operated at 1,15 times rated power input under normal operation with the 
outlet valve closed and thermostats short -circuited. The test is continued until the thermal 
cut-out operates.  
The thermal cut -out shall operate before its temperature exceeds 110  °C. The water 
temperature shall not exceed 20 K of the maximum permitted operating temperature of the 
thermal cut -out. SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
19 
  If compliance relies on the operation of an electronic circuit , the test is repeated und er the 
following conditions applied separately:  
– the fault conditions in a) to g) of 19.11.2 applied one at a time to the electronic circuit ; 
– the electromagnetic phenomena tests of 19.11.4.2 and 19.11.4.5 applied to the appliance.  
The temperature of the water at the outlet shall not exceed 110 °C during or after each of the 
tests. 
Supply connection and external flexible cords  
This clause of Part 1 is applicable except as follows.  
25.1  Modification:  
Appliances shall not incorporate a n appliance inlet.  
Terminals for external conductors  
This clause of Part 1 is applicable.  
Provision for earthing  
This clause of Part 1 is applicable except as follows.  
27.1  Addition:  
For class I water heaters , the sheath of the heating element shall be per manently and reliably 
connected to the earthing terminal unless  
– the container is provided with inlet and outlet pipes of metal that are permanently and 
reliably connected to the earthing terminal, and  
– other accessible metal parts  of the container in co ntact with the water are permanently 
and reliably connected to the earthing terminal.  
Screws and connections  
This clause of Part 1 is applicable.  
Clearances, creepage distances and solid insulation  
This clause of Part 1 is applicable.  
Resistance to heat an d fire  
This clause of Part 1 is applicable except as follows.  
30.1  Addition:  
The temperature rises occurring during the tests of 19.2, 19.3 and 19.101 are not taken into 
account.  SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
20 
  30.2.2  Not applicable.  
Resistance to rusting  
This clause of Part 1 is applic able.  
Radiation, toxicity and similar hazards  
This clause of Part 1 is applicable.  
  SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
21 
  
 
D 
C E 
F 
G 
B 
A E H 
D 
G 
B 
A B 
A 
a 
d c b 
e B 
A 
F 
B 
A H 
J 
B 
A 
f IEC   211 3/12  
Figure 101 – Examples of types of storage water heaters  
  Key Type  
A heating element  a Closed water heaters  
B container  b Open -outlet water heaters  
C expansion pipe  c Cistern -type water heater  
D overflow pipe  d Cistern -fed water heater  
E ball valve  e Low -pressure water heater  
F water level  f Heat exchange water heater  
G cistern   
H vent pipe  
J heat exchanger   
 SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
22 
   
   
½ h  h B 
B 
A 
A 
IEC   211 4/12  
 
Key 
A container  
B external thermocouple  
 
Figure 102 – Example  of positions of the thermocouples  
 
 
Key 
A adhesive  
B thermocouple wires 0,3  mm diameter to IEC 60584 -1 Type K (chrome alumel)  
C handle arrangement permitting a contact force of 4  N  1 N 
D polycarbonate tube: inside diameter 3  mm, outside diameter 5  mm 
E tinned copper disc: 5  mm diameter, 0,5  mm thick with a flat contact face  
Figure 103 – Probe for measuring surface temperatures  
 
 
IEC 
A 
B 
E 
D 
 C SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
23 
  Annexes  
The annexes of Part 1 are applicable except as follows.  
 
Annex  A  
(informative)  
 
Routine tests  
 
A.101  Pressure test  
The water container is subjected to a pressure test using a fluid.  
When a liquid is used, the pressure is  
– for closed water heaters , 0,7  MPa for those having a rated pressure  not greater than 
0,6 MPa, and 1,1 times rated pressure  for others;  
– for cistern -fed water heaters  and low-pressure water heaters , 1,1 times rated pressure ; 
– for open -outlet water heaters , 0,05 MPa;  
– for cistern -type water heaters , 0,03 MPa.  
Whe n gas is used, these pressures may be reduced but are to be sufficient to reveal leakage.  
Leakage of the fluid is not to occur during the test.  
 
  SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
24 
  Annex R  
(normative)  
 
Software evaluation  
 
R.2.2.5  Modification : 
For programmable electronic circuits  with fun ctions requiring software incorporating measures 
to control the fault/error conditions specified in Table R.1 or Table R.2, detection of a fault/error 
shall occur before compliance with Clause 19 and 24.102.1  is impaired.  
R.2.2.9  Modification : 
The software  and safety -related hardware under its control shall be initialized and shall 
terminate before compliance with Clause 19 and 24.102.1  is impaired.  
 
  SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
25 
  Annex  AA  
(normative)  
 
Additional requirement f or immersion heater  units intended  
for the installation in heat exchange closed water heaters  
 
The following requirements of this standard are for immersion heater  units intended for the 
installation in a heat exchange closed water heater . Other subclauses of this standard not 
mentioned in this annex are applicable .  Where “water heater ” is written, the requirement applies 
for “immersion heater  units” of this annex.  
NOTE  Water storage tanks without an integrated heat exchanger can be retrofitted with an immersion heater unit 
if the retrofitting is allowed  by th e manufacturer of the container . In this case , the manufacturer  needs  to specify the 
acceptable immersion heater  units in the instruction for installa tion of the water storage tank.  
AA.3  Terms and d efinitions  
AA.3.1.9  Replacement:  
normal operation  
operation of the immersion heater  unit after installation in accordance with the instructions in 
the smallest tank specified, the tank being thermally insulated and filled with water  
NOTE 101  Accessible parts of the immersion heater  unit are not thermally insulated.  
AA.3. 201 
immersion heater  unit 
appliance consisting of heating element and controls in a single unit to control the temperature 
in both normal and abnormal conditions and i ntended to be retrofitted to a  heat exchange closed 
water heater  
AA.5  General conditions for the tests  
AA.5.2  Addition:  
Additional  immersion heater  units may be required for the tests of Clause 19 and 22.102.  
AA.5.3  Addition:  
The test is to be carried out in a water tank according to the instructions of the manufacturer of 
the immer sion heater  unit.  
NOTE  Several tests for different mounting positions (vertically from the top or bottom, horizontally) can be required.  
AA.7  Marking and instructions  
AA.7.1  Replacement:  
Immersion heater  units for multiple supply shall be marked with their rated power input  for 
each supply circuit.  
Immersion heater units  shall be marked with the rated pressure.  The rated pressure shall not 
be lower than 0,6 MPa.  SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
26 
  AA.7.12.1  Replacement:  
The installation instructi on shall include the following:  
– type, the volume or volume range , and dimensions of the tank in which the immersion heater 
unit can be installed;  
– the positioning of the immersion heater  unit within the tank;  
– a statement that the installer must check that there is water in the tank before the immersion 
heater  unit is switched on the first time;  
– that a pressure -relief device is to be installed in the installation, unless it is not already part 
of the water tank installation;  
– the type and properties of the pr essure -relief device and how to install it;  
– that a discharge pipe connected to the pressure relief device shall be installed with a steady 
downward inclination in a frost -free environment.  
The instructions for immersion heater  units for water tanks with an incorporated heat 
exchanger shall include instructions for the installation of thermal controls  and their 
temperature setting in order to prevent the thermal cut -out from operating due to the heat of 
the heat exchanger.  
AA.19  Abnormal operation  
AA.19.1  Addition:  
For immersion heater  units, the tests of 19.2 and 19.3 are applicable.  
AA.19.13  Addition:  
During the test , the immersion heate r unit  shall not show any leakage.  
AA.22  Construction  
AA.22.47  Replacement:  
The immersion heater  units shall withstand the water pressure occurring in normal use.  
Compliance is checked by the following: The immersion heater  units are exposed to a water 
pressure which is twice as high as the rated pressure.  
The pressure is raised to the specified value at a  rate of 0,13 MPa/s and maintained at this 
value for 5 min.  
No water is allowed to leak and no permanent deformation of the parts of the immersion heater 
unit intended to withstand the water pressure is allowed to an extent which would impair 
conformity to  this standard.  
AA.22.101  Replacement:  
The rated pressure  of immersion heater  units intended to be exposed directly to the water 
main  shall be at least 0,6 MPa.  
AA.22.111  Replacement:  SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
27 
  Void.  
AA.22.11 2 Immersion heater  units shall be supplied with a seal or similar means to ensure 
that there is no leakage from the tank after installation.  
Compliance is checked by inspection during the test of Clause 11.  
AA.22.11 3 The immersion heater unit shall not be able to be removed from the tank without 
the aid of a tool . 
Compliance is checked by inspection.  
The cover of the compartment containing the supply terminals shall be prevented from rotating 
by more than 180° with respect to the fixed part of the immersion heater  unit. 
Compliance  is checked by inspection.  
AA.24  Components  
AA.24.102  Replacement:  
The thermal cut -out shall operate before the water temperature exceeds 99  °C and the water 
temperature shall not exceed the opening temperature of the thermal cut -out by more than 20 
K. 
Compliance is checked by the following test.  
The operating temperature of the thermal cut -out is measured with a thermo element that is 
attached to the sensor element or arranged in its close vicinity.  
If the tank is in a horizontal position , the water tem perature is measured at the most 
unfavourable position by a thermocouple positioned 50 mm below the upper inner surface of 
the container.  
The immersion heater unit is operated at 1 ,15 times its rated power input with the thermostat 
short -circuited but under  normal operation conditions  and with the output valve of the tank 
closed.  
The test is continued until the thermal cut -out operates.  
 SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
28 
  Annex  BB : List of National modifications  
The text of the international Standard IEC 60335 -2-21:201 8 was approved by Saudi Sta ndards, 
Metrology and Quality Organization as a Saudi Standard with agreed national modification as 
indicated below:  
Addition  / Modification  Clause  NO 
Addition " new paragraph "  
The insulation resistance between live parts and the casing of the water 
heater, when measured at normal room temperature with a voltage of 
500 V d.c , shall not be less than 2 mega ohms.  16  Leakage current 
and electric 
strength  
 1 
    22.6   Addition " After 1st paragraph "  
The casing shall have mechanical and corrosion -resistant properties, 
under the conditions of normal use,  ( not inferior to those of 0.8 mm (as 
a nominal thickness) galvanized steel sheet or of steel sheet of a 
nominal thickness not less than 0.6 mm coated by a thermal layer 
coating of a thick ness not less than 0.05 mm.)  
 
     22.20   Addition " new paragraph "  
Thermal insulation material  shall be of foam type (i.e. C.F.C free 
Polyurethane or its equivalent) and shall be high heat - resistant, non -
conductive, non -flammable, non -absorbent, fire -resistant, non -corrosive 
and vermin growth -resistant. It shall not deteriorate in service or become 
depressed and have uninsulated voids during transportation or cause 
corrosion of any part of the water heater with which it is in contact.  
The thermal insul ation shall be so placed and contained that its 
efficiency is maintained, contact with wiring terminations or temperature 
controls is prevented, and attack by vermin is deterred.  
 
     22.103   Addition "  After 1st paragraph "  
For increasing the safety, the closed storage water heaters shall be 
provided with one of the following two means :  
 Additional pressure relief device installed at the top of the container 
separated from the openings for water connections and shall prevent the 
pressure in the contain er from exceeding the rated pressure by more than 
20 N/cm2. 
 A temperature and pressure relief valve “T & P valve”, installed at the top 
of the container, or with its centre line in the upper 15 cm of the side. This 
valve shall be installed separated from the openings for water connections.  
The temperature and pressure relief valve shall prevent the water 
temperature from exceeding  
99 ˚C, and shall prevent the pressure in the container from exceeding 
the rated pressure by more than 20 N/cm2. The T & P valve  shall be 
connected with a suitable drainage tubing.  22  Construction  2 SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
29 
   
NOTE  The temperature and pressure relief valve shall be tested according to annex 
AD. 
 
     
 22.107  Addition "  After 1st paragraph "  
Each heating element of the water heater shall be provided with a 
thermostat for control of water temperature, it shall have no setting 
higher than 77 ˚C and shall be equipped with a stop to prevent its 
adjustment beyond maximum setting.  
Thermostat shall be such that the temperature of the water at the outlet 
pipe will n ot exceed 85 PoPC.  
 
 
Add the following new sub -clause  
22.112    Pilot lamp  
The water heater that have bottom water connection shall be provided 
with a pilot lamp which shall be connected in parallel with the heatin g 
unit, to indicate the cutting -in and cutting -out of the electric current in 
the heating unit.  
 
 
Add the following new sub -clause  
22.113    Thermometer  
The water heater that have bottom water connection shall be provided 
with a thermometer having  a suitable scale for indicating the water 
temperature level within the container.  
 
Add the following new sub -clause   
 
22.114  Container For the Storage - Electric Water Heaters  
1- Container shall be made either :  
 of copper with a thickness of not less than 1.0 mm and of purity not 
less than 99.85%, the impurities other than zinc shall not exceed 1%, 
provided that the phosphor contents shall not exceed 0.04%, or 
 of steel sheets with a nominal thickness of not less than 1.5 mm, to 
be internally coated , after its fabrication and welding,  
with either of the following corrosion -resistant materials:  SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
30 
  a) Enamel coating (Porcelain) at a temperature not less than 800 oC, 
provided that the internal enamel layer shall be with a thickness of not less 
than 0.15 mm.  
 
b) 1.5 mm Galvanized steel sheets , the galvanized layer of which shall not be 
less than 270 gm/m2 (for both sides) , subject to the manufacture has to take 
the n ecessary measures in order to cover the welded areas ( from inside and 
outside) with an equivalent corrosion - resistant layer .  
 
2- Both ends of cylindrical containers shall be domed outwards unless 
the design and gauge  of the bottom are sufficient to ensure equal 
mechanical strength when domed  inwards.  
 
 
3- Cathodic protection each steel container shall be provided with at 
least one magnesium anode having a mass of magnesium of not less 
than 200 g per square meter  of container area. The anode, which sh all 
be capable of being replaced, shall be electrically connected to the 
container.  
 
The mass of the magnesium anode may be less than 200 g per square 
meter  of container area, if the manufacturer provided evidence that the 
suggested mass is adequate to pro tect the container for not less than 2 
years.  
The water heater shall withstand the water pressure occurring in normal 
use. There shall be no leak of water, and the container shall not show 
any permanent deformation which affects safety after subjecting it to a 
pressure of twice the rated pressure.  
Remove :  
DISCLAIMER  
This Consolidated version is not an official IEC Standard and has been 
prepared for user convenience. Only the current versions of the 
standard and its amendment(s) are to be considered the official 
documents.  FOREWORD  3 
 
 
 SASO STANDARD                                        SASO/FDS/IEC 60335 -2-21:2020 
 
31 
  Bibliography  
The bibliography of Part 1 is applicable except as follows.  
Addition:  
IEC 60335 -2-15, Household and similar electrical appliances – Safety – Part 2 -15: Particular 
requirements for appliances  for heating liquids  
IEC 60335 -2-35, Household and similar electrical appliances – Safety – Part 2 -35: Particular 
requirements for instantaneous water heaters  
IEC 60335 -2-75, Household and similar electrical appliances – Safety – Part 2 -75: Particular 
requ irements for commercial dispensing appliances and vending machines  
 
___________