ASTA Guidance on Testing to IEC 61439 Series of Standards Intertek Hilton House, Corporation Street, Rugby, Warwickshire CV21 2DN UK
[email protected] +44 (0)1788 578435 www.uk.intertek-etlsemko.com ASTA Guidance on Testing to IEC 61439 Series of Standards Introduction IEC 61439-1 and IEC 61439-2 have now been published. These are parts of a series to replace the IEC 60439 standards. This is a very significant standard for testing of low voltage equipment and the presentation has changed considerably, although much of the testing is very similar. Intertek ASTA was represented on the UK committee during drafting of the standard. Now that the standard is published, we are seeking to offer guidance on understanding and applying the standards to future testing. This Guide is intended to assist manufacturers and laboratories when planning for testing to IEC 61439, particularly for ASTA Certification. There are several other sources of information readily available which provide more general information. Overview of IEC 61439-1 and IEC 61439-2 The Part 1 document sets out general requirements for the scope of equipment to be covered by the series. Further parts will relate to specific types of equipment (see Table below). The requirements are more comprehensive than in IEC 60439, although there are many parallels. One of the most significant differences is the introduction of alternative methods of design verification. This initially appears to reduce the requirements for actual testing. However, this is not the case, as the alternative methods of verification detailed are analogous with the extrapolation and justification as has been common in the industry for relating project-specific equipment to the supporting ASTA Certificates for tested equipment. The introduction of these methods within the standard should enable more transparent and consistent substantiations of designs to be offered for specific projects. The verification tests described in IEC 61439 confirm the reference design from which subsequent configurations may be verified by the alternative methods described. IEC 61439 also covers common questions such as: manufacture at alternative premises and substitution of alternative functional components. IEC 61439-2 is the first of the product-specific parts to be published and replaces IEC 60439-1. It introduces a new term: power switchgear and controlgear assembly (PSC-ASSEMBLY), which is likely to become the usual way of referring to such equipment. The terms ‘type-tested assembly’ (TTA) and ‘partially type-tested assembly’ (PTTA) from IEC 60439 are no longer used. www.uk.intertek-etlsemko.com 1 ASTA Guidance on Testing to IEC 61439 Series of Standards Comparison of IEC 61439 and IEC 60439 series: New standard IEC 61439-1 IEC 61439-2 IEC 61439-3 IEC 61439-4 IEC 61439-5 Title General rules Power switchgear and controlgear assemblies Distribution boards Assemblies for construction sites Assemblies for power distribution in public networks Busbar trunking systems Previous standard IEC 60439-1 IEC 60439-1 IEC 60439-3 IEC 60439-4 IEC 60439-5 IEC 61439-6 IEC 60439-2 Type Testing and Verification by Testing The industry has become very familiar with the term: Type Testing. This is used in IEC 60439 standards and in the title of many ASTA Certificates. IEC 61439 uses the term Verification tests, but acknowledges these are equivalent to type tests (clause 3.9.2). The title of ASTA Certificates will change to align with the new terminology. It should be noted that IEC 61439-1 covers general rules, hence testing and Certificates will be to subsequent parts. IEC 61439-1 Annex D lists the design verifications to be performed, including verification by testing. This is a similar collection of tests as the type tests described in IEC 60439-1 (clause 8.1.1). Appendix 1 of this document provides a table showing the tests of IEC 61439 and relating these to the type tests of IEC 60439. The requirements of most of the tests are similar and most testing to IEC 60439 may fulfil the requirements of IEC 61439. The most significant difference is for the temperature rise testing. IEC 61439-1 introduces three possible methods of performing temperature rise testing. These are described more fully below, however, the first point to emphasise is the need for the manufacturer to specify which method is to be used (consultation with the laboratory and ASTA can be provided to help with this decision). The cost of temperature rise testing will almost certainly be higher than for testing to IEC 60439, as there are likely to be more actual tests required. www.uk.intertek-etlsemko.com 2 ASTA Guidance on Testing to IEC 61439 Series of Standards Complete compliance In the same way that type testing did not cover all of the requirements described for the design and construction of assemblies to IEC 60439, the verification tests of IEC 61439 do not cover all requirements of the standard. For confirmation of complete compliance, additional inspections and assessments will be required. Marking is one area where the new standard has additional requirements and manufacturers should ensure that their equipment complies with these. Consideration of verification tests 1) Materials properties, lifting, impact and marking These tests were not included in IEC 60439-1 type testing. They include corrosion resistance, properties of insulating materials, resistance to heat, resistance to UV radiation, lifting, mechanical impact and marking. Laboratories will need to confirm they either have the capability inhouse or have an approved provider available to complete the testing. Degree of protection Virtually unchanged from IEC 60439. Clearance and creepage distances Virtually unchanged from IEC 60439. Impulse test may be used instead of measurement for confirming clearances. Protection against shock, protective circuit Virtually unchanged from IEC 60439. 2) 3) 4) 5,6,7) Incorporation of devices, internal circuits, terminals No verification tests specified. 8) Dielectric properties Virtually unchanged from IEC 60439 except that impulse test is now mandatory. Temperature rise Considerable changes to test arrangements – see later section. Short circuit withstand strength Tests similar to those of IEC 60439-1 but with some clarifications of arrangements. Testing of neutral bars may not be required (if rated 60% of main bar rating + similar construction). 3 9) 10) www.uk.intertek-etlsemko.com ASTA Guidance on Testing to IEC 61439 Series of Standards 11) 12) EMC Unchanged from IEC 60439 Mechanical operation Similar to IEC 60439 but number of operations increased from 50 to 200 Temperature rise testing IEC 61439 describes three possibilities for the methods for temperature rise testing (clause 10.10.2.1). These are as follows: a) b) c) Considering individual functional units, the main and distribution busbars and the assembly collectively. Considering individual functional units separately and the complete assembly including the main and distribution busbars Considering individual functional units and the main and distribution busbars separately as well as the complete assembly. The standard requires the manufacturer to specify the method required. A significant change is the introduction of the rated current of a circuit. This is proven in each of the methods above and provides the rating for each outgoing functional unit, irrespective of the rating of devices incorporated within it. Identification of “critical functional units” is required for subsequent verification by design rules for similar equipment. Conclusion IEC 61439 is a very important, new standard. The application and testing has changed from the familiar IEC 60439, and we expect that all users, including ourselves, will require a familiarisation period before feeling as comfortable with it as with IEC 60439. Therefore, we encourage feedback from clients, laboratories and anyone else who has an interest (e.g. specifiers). We will seek to respond to specific questions as well as gather feedback to forward to the committee responsible for the standard. Please send any questions or comments to:
[email protected] www.uk.intertek-etlsemko.com 4 ASTA Guidance on Testing to IEC 61439 Series of Standards Questions? What should we do to ensure compliance with IEC 61439 standards? ASTA Comment: 1) Buy a copy of the appropriate parts of the standards. These can be obtained from IEC web store (http://webstore.iec.ch/). 2) Read the standards, together with any guidance material available. 3) Discuss any requirements for verification by testing with preferred ASTA Test Laboratory alternatively directly with ASTA. Appendix 1 of this Guide could be used to clarify testing requirements. 4) Use Annex C of the standard to clarify specification of assemblies with customers and for verification purposes. Can equipment still be tested to IEC 60439 standards? ASTA Comment: We would recommend that all new test work on equipment for which the appropriate parts of IEC 61439 standards are published should be made to the new standard. Testing can be done to the superseded standards if specifically requested by clients. Can ASTA issue new certificates to confirm compliance with IEC 61439 based on previous testing to IEC 60439? ASTA Comment: This may be possible, depending on which of the type tests were made. Each application will be considered separately. Can a manufacturer specify selected verification tests instead of all of them? ASTA Comment: Yes, the ASTA Certificate would specify precisely the tests done and ratings confirmed. www.uk.intertek-etlsemko.com 5 ASTA Guidance on Testing to IEC 61439 Series of Standards Appendix 1: The table below includes all of the tests described in IEC 61439-1 with comparison to the type tests described in clause 8.1.1 of IEC 60439-1. Prior testing to IEC 60439 may (or may not) fulfil the requirements for the comparable test of IEC 61439. ASTA can advise on request. No. Characteristic to be verified 1 Strength of material and parts Resistance to corrosion Properties of insulating materials Thermal stability Resistance of insulating materials to normal heat Resistance to abnormal heat and fire due to internal electric effects Resistance to ultra-violet (UV) radiation Lifting Mechanical impact Marking Degree of protection of enclosures Clearances and creepage distances Protection against electric shock and integrity of protective circuits: Effective continuity between the exposed conductive parts of the assembly and the protective circuit Effectiveness of the assembly for external faults Dielectric properties: Power-frequency withstand voltage Impulse withstand voltage Temperature rise limits Short-circuit withstand strength Electromagnetic compatibility (EMC) Mechanical operation Clause/ Sub clause 10.2 10.2.2 10.2.3 10.2.3.1 10.2.3.2 10.2.3.3 10.2.4 10.2.5 10.2.6 10.2.7 10.3 10.4 10.5 10.5.2 10.5.3 10.9 10.9.2 10.9.3 10.1 10.11 10.12 10.13 Comparable type test from 60439-1 n/a 2 3 4 8.2.7 8.2.5 8.2.4 8 8.2.2 9 10 11 12 8.2.1 8.2.3 8.2.8 + Annex H 8.2.6 For more information on specific testing and certification information, please contact Intertek at +44 (0)1788 578435, email
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