I have read most replies to your question and i agree. You referred to the correct standards and THE GUIDE (you may find it on our site http://www.cetest.nl ).
There are some pitfalls however. The manufacturers of CPU boards need emission testing in a enclosure of their choice. We actually succeeded a board with heavy emission problems to pass Class B requirements, by selecting a PC enclosure of a reputable brand (and that we knew was EMC tight). My customer was warned that he should recommend his customers this special brand of PC's to keep ce-compliance. This is too often overlooked ( voluntarily) . This means that if the product (now ce-marked) is sold to a PC assembly company (NO-NAME Ltd) that might use any kind of enclosure to make it's NO-NAME brand of PC's, this customer of you might encounter serious problems getting compliant. A few UK based manufacturers said CE+CE=CE and got caught !!! You dont't want this do you ? So you should select an average enclosure of a questionable brand, and/or leave the cover open during testing. Here the open chassis test shows some value. Legally you are wrong too. A ce-marked board that creates interference in another enclosure then it was tested in, bears it's ce-mark against the "ESSENTIAL REQUIREMENTS" of the EMC-directive, although it passed Class B of EN 55022. Remember, appliance of standards alone gives only presumption of conformity, not proof. Due Diligence is required when ce-marking. Regards, Gert Gremmen Ing. == Ce-test, Qualified testing == Consultants in EMC, Electrical safety and Telecommunication Compliance tests for European standards and ce-marking Member of NEC/IEC voting committee for EMC. Our Web presence: http://www.cetest.nl List of current harmonized standards http://www.cetest.nl/emc-harm.htm 15 great tips for the EMC-designer http://www.cetest.nl/features01.htm -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: dinsdag 24 augustus 1999 22:44 To: [email protected] Subject: CE Marking requirements Well group, if you care to help out another American confused by the specific requirements for Europe, I would appreciate it. I seem to be getting varying stories from different test houses as to what is required for one of our products. These are big enough players that pitting one against another is not something I want to undertake at this point. We currently manufacture a motherboard which is sold both by itself and with a chassis which includes power supply, hard drive and floppy. We are currently going through our internal EMC validation to ensure that we meet both FCC Class B and EN 55022 Class B levels. Our experience on previous products has been if we clear emissions, we haven't had problems in other areas, but we'll be testing to EN 55024 of immunity, as well. The issue arises when we discuss testing of the system versus testing of the motherboard alone. Within the US, the FCC regulations permit an additional 6dB margin for "open chassis" measurement, so long as those frequencies fall back within the class B levels with the cover on. This does not appear to be a problem for our product. We have been told by different parties that for Europe, (a) there is no requirement to test "open chassis" and that we can CE mark the board as compliant as long as we have shown that it can meet the class B levels within a chassis of our choosing and (b) we are still required to perform "open chassis" tests, however, there is no 6dB margin and the board will have to meet the EN 50022 class B levels with the cover off. We're having a little more difficulty making things work using the (b) approach. I am specifically concerned about staying far enough below the levels that we're not going to potentially pass today and fail 6 months from now due to a slight drift in tolerances of components, test equipment or test engineers' dispositions. I have the texts of the EMC directive, as well as the test requirements specified in the above documents and I'm happy to wade through them if you can point me in the right direction. I will be heading that direction in the next day or two if I don't receive a response. I'm hoping, however, that someone in the group can shave a few hours of exceptionally captivating reading from my life by pointing me in the right direction. Regards, Michael Garretson Compliance Engineer RadiSys Corporation --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators). --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators).
