Euro EMC fudge

Euro EMC fudge
IT equipment that fails EMC tests could get into Europe via relaxation of standard. Steve Bush The door to Europe could be opened for IT equipment that fails existing EMC standards. This is the concern of the European Power Supply Manufacturers Association (EPSMA) if proposed changes to the forthcoming mains harmonic distortion EMC directive go ahead. The standard exists to improve the quality of the mains supply by reducing harmonic distortion. However, testing ambiguities within it have caused it to be reviewed, opening it up to lobbying pressure. “If the vote – which closes in March – is in favour of the relaxed limits, manufacturers of large computer systems… will have successfully gained exclusion from the tight limits which power supply manufacturers have been developing new products to meet,” said the EPSMA is a statement. The standard, the EN61000-3-2, covers the harmonics injected into the mains by equipment. Several industry insiders, all wishing to be unnamed, point the finger at large US computer makers who have ignored European legislation and now realise that the European market will soon be closed to their non-conforming products. In particular, the EPSMA is worried about proposed changes to Class F which covers professional IT products consuming more than 600W. The existence of Class F, the latest of the six classes, is already a weak link in the proposed standard. “Many things with a processor could be declared professional IT equipment. Justification could be found for including simulation, medical and telecoms equipment into it,” said EPSMA spokesman Steve Allen who is also the UK’s managing director of Melcher. “Relaxation of Class F could become a get-out which lets manufacturers of large equipment avoid the cost of cleaning up their power supplies,” said Allen. But Class F is not the only problem with EN61000-3-2. Class B, to which most desktop PCs belong, is also causing concern. “The specification is so complicated that it is difficult to get repeatable measurements,” said Dave Imerson, Secretary of the EMCTLA, the industry body representing many of the UK’s approved test houses.


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