IEC 60335-2-35:2012+A1:2016+A2:2020 deals with the safety of electric instantaneous water heaters for household and similar purposes and intended for heating water below boiling temperature, their rated voltage being not more than 250 V for single-phase appliances and 480 V for other appliances. Instantaneous water heaters incorporating bare heating elements are within the scope of this standard.

Appliances not intended for normal household use but that 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. 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.

This fifth edition cancels and replaces the fourth edition published in 2002, including its Amendment 1 (2006) and its Amendment 2 (2009). The principal changes in this edition as compared with the fourth edition of IEC 60335-2-31 are as follows:

• Converted notes to normative text (7.12, 7.102, 8.1.5, 22.104, and 22.109.3);
• Deleted notes in 19.13, 22.109, and A.101;
• Added Annex R and 22.108 for appliances with programmable electronic circuits and added requirements for water heaters (22.50, 22.51).

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 months from the date of publication. This publication is to be read in conjunction with IEC 60335-1:2010. This consolidated version consists of the fifth edition (2012), its amendment 1 (2016) and its amendment 2 (2020).