Posted by messungelectricalengineering on October 16th, 2021

IEC 61439 is the latest standard for low-voltage switchgear and controlgear assemblies. It was launched in 2009 and replaced the earlier IEC 60439, following years of work by an international project group following dissatisfaction with the IEC 60439 series.

The IEC 60439 standards were ambiguous about how to assess compliance of partially type tested assemblies.As a result, manufacturers and testing bodies often treated partially type-tested assemblies differently.

IEC 61439 was drafted with a purpose to harmonise and define all general requirements for low-voltage electrical assemblies, and succeeded in bringing considerable clarityin technical interpretation.


For switchgear definition, we can refer to Wikipedia where it states that \\\"In an electric power system, switchgear is composed of electrical disconnect switches, fuses or circuit breakers used to control, protect and isolate electrical equipment. Switchgear is used both to de-energize equipment to allow work to be done and to clear faults downstream. This type of equipment is directly linked to the reliability of the electricity supply.\\\"

Electrical control gear definition is one or more devices, possibly integrated in a light source, intended to prepare the mains electricity supply for the electric format requiredby one or more specific light sources within boundary conditions set by electric safety and electromagnetic compatibility. It may include transforming the supply and starting voltage, limiting operational and preheating current, preventing cold starting, correcting the power factor and/or reducing radio interference.

Switchgear and control gear as defined by IEC 60947 for electronics applications encompass all electrical components and devices that are used to activate, deactivate, and protect electrical consumers and include switches, contactors, residual current devices, and motor protection switches.

WHAT IS IEC 61439?

IEC 61439 is the international standard for all low-voltage switchgear and control gear assemblies. It describes the design verification for control gear assemblies and the responsibilities of the manufacturer and panel maker.

The IEC 61439 standard applies to enclosuresfor which the rated voltage is under 1000 V AC(at frequencies not exceeding 1000 Hz) or 1500 V DC.The standard seeks to correct the lack of clarity in three significant ways:

·         Clearly defining the respective roles and responsibilities of original manufacturer, assembly manufacturer and specifier.

·         Replacing the concepts of TTA and PTTA with verified assembly.

·         Clarifying and reinforcing tests and their requirements.

In order to conform to the standard, type tests have beenreplaced by a design verification which can be carriedout by the three following equivalent and alternativemethods:

·         Testing

·         Calculation/measurement

·         Design rules

IEC 61439-1defines the general rules for low voltage switchgearassemblies. It gives the definitions and indicates the conditions of use, construction requirements, technical characteristics and verification requirements.

IEC 61439-2 is a product standard which defines the specific requirements (assembly rules).

The new IEC 61439 series of standards thus defines the construction of lowvoltage switchgear assemblies and their inspection more precisely, specifying theresponsibilities of those involved and differentiating between the role of the originalmanufacturer and that of the assembly manufacturer (panel builder). 


The standard mentions many parts but each part cannot be used individually:


The new IEC 61439-1 clearly identifies the various parties involved in specifying and manufacturing equipment and assemblies, along with their responsibilities, as follows:

The Specifier identifies the needs and constraints for design, installation, operation and upgrading of the complete system. This party also checks that requirements have been fully integrated by the assembly manufacturer. The specifier could be the end-user or a design office.

The original manufacturer carries out the original design and associated verification of an assembly system. This party is responsible for the design verifications listed by IEC 61439-2, which governs switchgear and controlgear, including many electrical tests.

The assembly manufacturer (or “panel builder”) is responsible for the completed assembly. This party is responsible for “routine verifications” if the assembly is produced according to the original manufacturer’s requirements. However, any deviation from original manufacturer instructions will force a new, full design verification process. 


Messung designs and manufactures smart electrical panel as per IEC 61439 Standards, customised for diverse applications. It connects various power sources to a single point, with PLC controls for switching the source – and provides unmatched safety for electric power distribution.

Messung’s SPDS (Smart Power Distribution Solution) for villas, bungalows & farmhouses can also serve applications like Hospitals, Hotels & Commercial Complexes.

For more on Messung’s expertise in Electrical Engineering, visit

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Joined: February 27th, 2021
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