IEC 60335-2-51:2002+A1:2008+A2:2011 deals with the safety of electric stationary circulation pumps intended for use in heating systems or in service water systems, having a rated power input not exceeding 300 W, their rated voltage being not more than 250 V for single-phase and 480 V for other appliances. Hydraulic and electric parts of the pump may be in the same enclosure, so that the water serves as a coolant, or they maybe seperate. 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 for locations where special conditions prevail, such as the presence of a corrosive or explosive atmosphere (dust, vapor, or gas).

This publication is to be read in conjunction with IEC 60335-1:2010.

This consolidated version consists of the third edition (2002), its amendment 1 (2008) and its amendment 2 (2011). Therefore, no need to order amendments in addition to this publication.