IEC 60335-2-51:2019 is available as IEC 60335-2-51:2019 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.

IEC 60335-2-51:2019 deals with the safety of electric stationary circulation pumps for household and similar purposes intended for use in heating systems or in service water systems, their rated voltage being not more than 250 V for single-phase appliances and 480 V for other appliances. The hydraulic and electrical parts of the pump can be in the same enclosure, so that the water flows through the motor and serves as a coolant, or they can be separated. 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.
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 for circulating liquids other than water;
– pumps, other than circulation pumps (IEC 60335-2-41);
– circulation pumps intended exclusively for industrial purposes;
– circulation pumps 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, Amendment 1:2008 and Amendment 2:2011. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
– some instructions are no longer required (7.12);
– converted some notes to normative text (7.12.1, 11.3, 11.8);
– new instructions for installation of thermal insulation (7.12.1);
– the leakage current value is modified (Clause A.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 edition (2010) of that standard.