IEC 60335-2-55:2021 is available as IEC 60335-2-55:2021 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.

IEC 60335-2-55:2021 deals with the safety of electric appliances for use with aquariums and garden ponds for household and similar purposes, their rated voltage being not more than 250 V, including direct current (DC) supplied appliances and battery-operated appliances.
Examples of appliances that this standard is applicable to are
- aerators;
- aquarium heaters;
- automatic food dispensers;
- sludge-suction appliances.
Appliances not intended for normal household use but that nevertheless can be a source of danger to the public, such as appliances intended to be used by laymen in shops and in light industry and 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.
Attention is drawn to the fact that
- for appliances intended to be used in vehicles or on board ships or aircraft, additional requirements can 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.
This standard does not apply to
- pumps (IEC 60335-2-41);
- other portable immersion heaters (IEC 60335-2-74);
- luminaires for aquariums and garden ponds (IEC 60598-2-18);
- appliances intended for outdoor use having a rated power input exceeding 100 W;
- appliances intended exclusively for professional use;
- appliances intended to be used in locations where special conditions prevail, such as the presence of a corrosive or explosive atmosphere (dust, vapour or gas).
This fourth edition cancels and replaces the third edition published in 2002 and Amendment 1:2008. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
a) the text has been aligned with IEC 60335-1:2020;
b) some notes have been converted to normative text or deleted (Clause 1, 5.2, 19.101, 21.1, 21.102, 22.101);
c) updated the depth of immersion symbol (7.1, 7.6, 7.12);
d) limits on the temperature rise of external accessible surfaces have been introduced (Clause 11).
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.