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New standard challenges panel and system builders16 December 2008 A new standard, IEC 61439, governing the safety and performance of electrical panels is published in January 2009 and according to Schneider Electric, its ramifications will challenge panel and systems builders in the UK. However, with this in mind, the company is providing resources to guide and advise on how to painlessly meet the new standards.
The IEC 61439 is in fact urgently needed, for the previous 35-year old IEC 60439 series of standards were lacking in a number of areas. It was a compromise between different national approaches, some of which were stringent, even proscriptive, and others that were subjective. Where consensus could not be achieved, the subject was ignored, or some vague clause was added that could be interpreted to suit the reader’s point of view.
These weak foundations have made it difficult to evolve the standard in line with market needs and pressures. Every assembly manufactured should meet minimum performance and safety criteria, in spite of ever increasing demands to optimise manufacture and reduce costs.
Since Schneider Electric was a significant lobbyist in persuading the IEC to investigate revising the old IEC 60439 standard and subsequently consulted on the new standard, the company’s experts are well versed in how to understand and address its requirements.
Under the previous standards, panels could contain Type Tested Assemblies (TTA) or Part Type Tested Assemblies (PTTA), but since many assemblies within a typical panel are too small to be covered by TTA or PTTA certifications, they fell outside of any standard.
The structure of IEC 61439 will make revision easier, as changes to General Rules will tend to lag their introduction in product-specific Parts. It also means that assemblies cannot be specified or manufactured to IEC 61439-1, since one of the product-specific Parts must be referenced in any assembly specification.
With the ever-increasing pressures of demand for higher network utilisation, assembly design optimisation and more stringent safety, the changes included in the assembly standard IEC 61439-2 are important and overdue. All assemblies that do not have a specific product standard are covered and there is no opportunity to avoid compliance.
In the new standard, the methods of confirming design performance are practical and pragmatic, reflecting the different market needs and ways in which assemblies are produced. Several alternative and equivalent means of verifying a particular characteristic of an assembly are included. These are defined and their use restricted. Where alternatives to type tests are used, a compensatory approach is taken and margins are added to ensure equivalence. Overall, the standard is performance based, but in some instances where design rules are used, it has to be proscriptive.
Finally, Schneider Electric points out that there are certain provisions that can be made to simplify compliance with the new standards - for example, many of the company’s own products, such as its Prisma panels, are inherently certificated compliant.
Schneider Electric has unveiled a new section of its website expressly to deal with the questions raised by IEC 61439. The company has also published a clear and easy to understand guide to the new standards that can be obtained in both printed format and as an Internet download. A series of seminars is being hosted around the UK - starting in Edinburgh on 20 January as part of a broader event called Tackling Energy.
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