Conformity Magazine - March 2008 - (Page 16)

c. d. e. Have technical documentation available for inspection; Be supplied with specified User Information; Have a signed EC Declaration of Conformity. • The likely proximity to sensitive equipment that the product’s emissions could interfere with; • The likely EM threats that could interfere with the product, plus the degradation of functional performance that the user will accept when the product is interfered with. Secondly, it should create EMC specifications for the product and design it accordingly despite component tolerances and variations in assembly and installation. Thirdly, it will verify its EMC design against the EMC specifications. “Verification” techniques include, but are not limited to, EMC testing. For products with many configurations and/or operational modes, the amount of verification work required can be reduced by identifying the “worst case” combinations of configuration and operational mode – the ones that would cause the highest emissions or are the most susceptible to interference. The “Standards” Route to Conformity Like the original EMC Directive, 2004/108/EC has two “routes to conformity.” One is for the product to pass all of the relevant harmonised EMC test standards [7], and is identical to the “self-declaration to standards” route under the original EMC Directive. The Directive states: “The correct application of all the relevant harmonised standards whose references have been published in The Official Journal of the European Union shall be equivalent to the carrying out of the EMC assessment.” In other words, if you test to all the relevant standards, you do not need to follow the good EMC engineering process outlined above. But I do not recommend this, because the standards only cover a subset of the EM phenomena and ranges of frequencies, modulations and waveshapes that occur in the real world. For example, none of the immunity standards cover the close proximity of cellphones, or test at frequencies above 1GHz. Simply complying with the standards might not ensure compliance with the Protection Requirements (see The Protection Requirements, above) in real-life operation. Article 6 of 2004/108/EC includes paragraphs that deal specifically with this possibility, although they would provide little comfort to a manufacturer who has had his products banned from the EU because of real-life interference issues. So when following the “standards” route I recommend performing a full EMC assessment, applying all relevant harmonised standards, and then doing whatever else it takes to verify conformity to the Protection Requirements. The “correct application” of a standard means that the manufacturer has done enough work to have sufficient The above must be complete before CE marking and supply of the apparatus in the EU. Constructing systems only from items that are CE-marked, and assuming that this takes care of the EMC compliance of the overall system or installation, is often called “the CE + CE = CE approach.” It was very widely used under the original EMC Directive, but there has never been any legal or technical justification for this approach. It is easy to show that it should not be relied upon, and now the EC Guide to 2004/108/EC warns against using it. The Protection Requirements The Protection Requirements (Clause 1 of Annex I) state the essential legal requirements for conformity of products to 2004/108/EC, in simple terms that lawyers should be able to understand: “Equipment shall be so designed and manufactured, having regard to the state of the art, as to ensure that: (a) The electromagnetic disturbance generated does not exceed the level above which radio and telecommunication equipment or other equipment cannot operate as intended; (b) It has a level of immunity to the electromagnetic disturbance to be expected in its intended use which allows it to operate without unacceptable degradation of its intended use.” These are essentially the same as in the original EMC Directive – except for the new “having regard to the state of the art” requirement. This could have significant implications; for example, product models that complied in 2009 might not comply if supplied in 2011 because their users” EM environment(s) had changed. Conformity Assessment The EMC Assessment Process Conformity assessment is specified in Annex II of 2004/108/ EC, and requires an “EMC assessment” that results in “technical documentation” that demonstrates that the product complies with the Protection Requirements, for all of the operational modes of the product, in all of its intended configurations. An EMC Assessment should firstly assess the EM environment(s) normally expected at the user(s) location(s) [6], taking into account: 1 Conformity marCh 2008

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Conformity Magazine - March 2008 NewsBreaks Editor's Note Adelstein Renominated to the FCC Industry Canada Publishes FAQs On RF Fields FDA Gives Its Scientific Capabilities Poor Marks FDA Offers Guidance On its Product Review Process FDA Publishes Updates to List of Recognized Standards FDA Warns of Patient Risk From Electric Dental Handpieces Complying with the EMC Directive, Second Edition ESD Open Forum Emerging Issues in Standards - Korean "RoHS": Not Like RoHS at All The iNARTE Informer Challenges in Testing - Field-Induced Charged Device Model: What Really Happens Design Fundamentals - EMI Shielding Technologies for Consumer Electronics Equipment Focus On...Compliance Software Buyer's Guide Additional Standards Published for the EU's ATEX Directive Additional Standards for the EU's Medical Devices Directive Also Published China to Require Bar Codes to Enhance Product Safety CPSC Releases 2007 Self-Assessment CPSC Actions in News IEC Standards Update UL Standards Update Product Reviews Telcordia Standards Update From Our "You Can't Make This Stuff Up" Department Looking Back: Items from Past Issues of Conformity Advertisers

Conformity Magazine - March 2008

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