Type-testing gives way to verified designs

24Nov

Five years ago, the IEC began to publish the replacement standard for low-voltage switchgear and controlgear assemblies, referred to in the EU as the EN 61439 Series.

On the 1st November 2014, the existing standard for most low-voltage assembly types, EN 60439-1 was eventually replaced with EN 61439-1 and relevant parts, e.g. EN 61439-2 (Power switchgear and controlgear assemblies). Here, Elsteel UK’s Technical Manager, Neil Williams explains some of the implications for Panel Builders and how the company is prepared for the legislation changes.

In the UK, BSI publishes a version of EN 61439-2 to include any specific national requirements. This appears in the form of a National Annex as a ‘BS EN’ published standard. Included within BS EN 61439-2 is National Annex NA, which provides a guide to the internal separation of assemblies detailing the types of construction relating to specific forms of separation.

Demonstrating compliance

Previously with BS EN 60439-1, manufacturers were able to refer to ‘Type-Tested Arrangements’ (Assembly designs subjected to eight particular tests, e.g. temperature-rise limits) and declare any new design as ‘Partially Type-tested Arrangement’ if sufficient reference to tested arrangements could be made or verified by extrapolation for example.

In the BS EN 61439 series, this concept and terminology has now been replaced with ‘Design Verification’, which clearly defines how an assembly can be verified using three options; by test (i.e. in the same fashion as a type-test in laboratory conditions), by comparison (referring to an already tested reference design and applying design rules) and by assessment (applying design rules and calculations).

This now provides clarity with regard to verifying a new design, as for each new design a manufacturer intends to supply, it must have applicable design verifications which refer directly to it. In addition to this, ‘Routine Verification’ is now required, this requires checking suitable design verification is available and performing checks against specific design verifications, in addition to the usual testing of wiring, functionality and operational performance.

Manufacturer types

In order to highlight the responsibilities of different types of manufacturer, the standard now defines two different types; the Original Manufacturer – the organisation responsible for the original design and associated verification of an assembly and the Assembly Manufacturer – the organisation responsible for the completed assembly.

It is worth noting that one organisation can in fact assume both definitions, for example if an assembly manufacturer applies a modification to the original design that may have an adverse affect on the performance of the assembly, then that organisation is defined as being both the original and assembly manufacturer.

BS EN 61439-2 Verification Systems

Elsteel UK recognises its position as an Original Manufacturer, responsible for particular Design Verifications. The company has updated internal processes and procedures and developed a Verification System based on BS EN 61439-2, for both Original & Assembly Manufacturers.

Elsteel’s new system allows it to reference tested reference designs to provide analysis of the Design Verification applicable for project-specific designs. The system allows a quick identification of any requirement for new Design Verifications, and where possible provides technical support.

Complemented with an integrated Routine Verification system, the company can assist manufacturers in demonstrating full compliance with the harmonised standard.

In addition, output documentation provides a clear demonstration to third parties that compliance has been achieved, necessary for the Assembly Manufacturer’s EC Declaration of Conformity and application of the CE Mark. Elsteel has also invested in achieving Design Verification for its Techno Module system, incorporating all of the major manufacturers switching devices.