IEC 61439-1:2009 lays down the definitions and states the service conditions, construction requirements, technical characteristics and verification requirements for low-voltage switchgear and controlgear assemblies.

This standard applies to low-voltage switchgear and controlgear assemblies (ASSEMBLIES) only when required by the relevant ASSEMBLY standard. This first edition of IEC 61439-1 standard cancels and replaces the fourth edition of IEC 60439-1:1999. Significant technical changes with respect to the last edition of IEC 60439-. IEC 61439-1 is a pure "general rules" standard to be referred to by subsidiary product parts of the IEC 61439 series.

The product standard replacing IEC 60439-1 is IEC 61439-2, the discrimination between type-tested assemblies (TTA) and partially type-tested assemblies (PTTA) is eliminated by the verification approach.

Three different but equivalent types of verification of requirements are introduced:
* verification by testing,
* verification by calculation/measurement, or
* verification by satisfying design rules.

The requirements regarding temperature rise have been clarified:
 * The rated diversity factor (RDF) is covered in more detail.
 * Requirements from the standard for empty enclosures for assemblies (IEC 62208) have been incorporated.
 * The whole structure of the standard is aligned with its new function as "general rules" standard.

However, when a dated reference to IEC 60439-1 is made in another Part of the IEC 60439 series of assembly standards not yet transferred into the new IEC 61439 series, the superseded IEC 60439-1 still applies.

Related British Standard BSEN 61439-1