IEC 60335-2-73:2024 CMV
Household and similar electrical appliances - Safety - Part 2-73: Particular requirements for fixed immersion heaters
- Standard No.
- IEC 60335-2-73:2024 CMV
- Release Date
- 2024
- Published By
- International Electrotechnical Commission (IEC) IX / IEC
- Latest
- IEC 60335-2-73:2024 CMV
- Introduction
Analysis of the Core Content of IEC 60335-2-73:2024
The third edition of IEC 60335-2-73, published by the International Electrotechnical Commission (IEC) in March 2024, comprehensively revised the safety requirements for stationary electric immersion heaters. As an important part of the IEC 60335 series, this standard specifically specifies the safety performance requirements for stationary electric heaters for household and similar purposes.
Scope of Application and Important Definitions
This standard applies to single-phase appliances with a rated voltage not exceeding 250 V and other appliances with a rated voltage of 480 V (including DC-powered appliances), which are stationary electric immersion heaters designed to be installed in a water tank open to the atmosphere and to heat water to a temperature below the boiling point.
It is worth noting that immersion heaters with a rated input power of up to 25kW are also included in the scope of this standard as an alternative heat source to central heating boilers. This expands the application boundaries of traditional household heaters and covers a wider range of commercial and light industrial application scenarios.
Equipment type Rated voltage Power range Application environment Single-phase fixed heaters ≤250V ≤25kW Household and similar purposes Multi-phase fixed heaters ≤480V Commercial and Light Industrial DC-Powered Heaters Corresponding DC Voltage ≤25kW Special Applications Major Technical Changes
Compared to the second edition (2002), this third edition of the standard has undergone three major technical changes:
Text Alignment Update: The standard text has been fully aligned with the sixth edition of IEC 60335-1:2020, ensuring consistency with general requirements. This alignment is reflected not only in clause numbering but also in the harmonization of test methods and safety concepts.
Conversion of Notes to Normative Text: Some notes have been converted to normative text, particularly Clause 1: Scope and Clause 19.2: Abnormal Operation. This change strengthens the mandatory nature of these requirements and provides manufacturers with a clearer design basis. New External Accessible Surface Temperature Requirements: Added external accessible surface temperature limits to Article 11, the heating clause, with a new Table 101 specifying the maximum temperature rise limits for specific external accessible surfaces under normal operating conditions. Articles 8-17 of the standard detail electrical safety requirements, including key indicators such as protection of live parts, power input and current, leakage current, and electrical strength. In particular, Article 13 requires leakage current and electrical strength testing at operating temperature to simulate actual operating conditions. Articles 20-23 of the standard provide specific requirements for the stability, mechanical hazard protection, mechanical strength, and structural design of fixed immersion heaters. These requirements emphasize the structural integrity of the heater during installation and operation to prevent safety incidents caused by mechanical failure.
Thermal Safety Performance
Article 11 Heating Test Requirements is one of the key points of this revision. The newly added Table 101 clarifies the maximum temperature rise limits of various material surfaces:
Surface material Maximum temperature rise (K) Test conditions Measurement method Metal surface 60 Normal operation Figure 101 probe Glass and ceramic surface 65 Normal operation Figure 101 probe Plastic surface 75 Normal operation Figure 101 probe Test methods and acceptance criteria
Clause 5 of the standard stipulates the general conditions for the test and requires that all tests should be carried out under the most unfavorable conditions. For fixed immersion heaters, this includes taking into account factors such as different installation locations, water quality conditions and supply voltage fluctuations.
Article 19 Abnormal Operation Test simulates fault conditions that may occur in actual use, such as dry burning, abnormal supply voltage, control component failure, etc., to verify the safety performance of the heater under these conditions.
Standard Implementation Schedule and Transition Arrangements
According to the instructions in the preface of the standard, national committees should note that equipment manufacturers and testing agencies may need a transition period to produce products and equip equipment for new or revised tests in accordance with the new requirements. The committee recommends that the content of Amendment 2 be adopted at the national level no earlier than 12 months and no later than 36 months after the date of publication.
This arrangement provides manufacturers with sufficient time to adjust product designs, update test equipment and prepare for certification to ensure a smooth transition to the new standard requirements.
Coordination with Other Standards
This standard explicitly excludes the applicability of certain other types of heating equipment, including: liquid heating appliances (IEC 60335-2-15), storage water heaters (IEC 60335-2-21), instant water heaters (IEC 60335-2-35), aquarium heaters (IEC 60335-2-55), portable immersion heaters (IEC 60335-2-74), and engine preheaters for motor vehicles and buses.
This clear demarcation avoids confusion regarding the standard's scope of application and provides specific safety regulations for different types of heating equipment.
Conformity Assessment and Certification Requirements
Manufacturers should be aware that appliances that meet the requirements of this standard are not necessarily considered to meet the standard's safety principles. If, during inspection and testing, other features are found that compromise the level of safety covered by these requirements, they may still be judged to be non-compliant with the standard.
This requires manufacturers to not only meet the explicit provisions of the standard, but also to understand the safety concept behind the standard to ensure that the overall safety performance of the product meets the expected level.
Technology Development Trends and Future Outlook
With the development of smart home and Internet of Things technologies, fixed immersion heaters are moving towards intelligence and efficiency. This standard provides a safety foundation for the application of these new technologies, but at the same time, attention should also be paid to the new security challenges that may be brought about by emerging technologies.
Future revisions to the standard may further focus on security issues in new areas such as energy efficiency requirements, network security, and wireless control, providing technical support for the healthy development of the industry.
Implementation Recommendations and Best Practices
For manufacturers, it is recommended to take the following measures to ensure compliance with the new standard requirements:
1. Conduct gap analysis as early as possible to identify the differences between existing products and the new requirements
2. Update design documents and test plans, especially focusing on the newly added surface temperature requirements
3. Maintain close communication with certification bodies to ensure consistency in test methods and acceptance criteria
4. Establish a continuous compliance monitoring mechanism to ensure consistency and reliability in the production process
For test laboratories, it is necessary to update test equipment and procedures, especially to equip them with surface temperature measurement probes that meet the requirements of Figure 101, and train test personnel to master the new test methods.
IEC 60335-2-73:2024 CMV Referenced Document
- IEC 60335-1 Household and similar electrical appliances - Safety - Part 1: General requirements CONSOLIDATED VERSION*， 2025-10-01 Update
- IEC 60584-1 Thermocouples - Part 1: Ed. 3.0: EMF specifications and tolerances
IEC 60335-2-73:2024 CMV history
- 2024 IEC 60335-2-73:2024 EXV-CMV Household and similar electrical appliances - Safety - Part 2-73: Particular requirements for fixed immersion heaters
- 2009 IEC 60335-2-73:2009 Household and similar electrical appliances - Safety - Part 2-73: Particular requirements for fixed immersion heaters
- 2009 IEC 60335-2-73:2002/AMD2:2009 AMENDMENT 2 Household and similar electrical appliances – Safety – Part 2-73: Particular requirements for fixed immersion heaters (Edition 2.0)
- 2006 IEC 60335-2-73:2006 Household and similar electrical appliances - Safety - Part 2-73: Particular requirements for fixed immersion heaters
- 2006 IEC 60335-2-73:2002/AMD1:2006 Household and similar electrical appliances - Safety - Part 2-73: Particular requirements for fixed immersion heaters
- 2005 IEC 60335-2-73:2005 Household and similar electrical appliances - Safety - Part 2-73: Particular requirements for fixed immersion heaters
- 2002 IEC 60335-2-73:2002 Household and similar electrical appliances – Safety – Part 2-73: Particular requirements for fixed immersion heaters (Edition 2.0)
- 2002 IEC 60335-2-73/AMD1:2002 Household and similar electrical appliances – Safety – Part 2-73: Particular requirements for fixed immersion heaters (Edition 2.0; Amendment 1: 01/2006)
- 1994 IEC 60335-2-73:1994 Safety of household and similar electrical appliances - Part 2: Particular requirements for fixed immersion heaters
