I read in !emc-pstc that Scott Lemon <sle...@caspiannetworks.com> wrote (in <3be064c5.e48c3...@caspiannetworks.com>) about 'Radiated Emissions EUT Config', on Wed, 31 Oct 2001: >I am in search of opinions regarding the acceptable EUT configuration >for radiated emissions testing. If a system is comprised of one or more >independent shelf-level products (e.g. one shelf in a rack or several >racks full), at what level is it acceptable to test? Assume that the >system can be sold as one independent fully functional "shelf" or as >numerous interconnected shelves (interconnection just increasing >"system" capacity). For example, one shelf could be sold and deployed, >then 6 months later another shelf added (cabled up to the first), and so >on, etc. > >1. Would it be acceptable to test at the "shelf" level? >2. If not, where is the line drawn? Two? Ten? > >In a typical CO you may see racks and racks of the same equipment >shelves/chassis - chances are, they were not all tested together - where >is it reasonable to stop? FCC (ref. ANSI C63.4)/EN300386/GR1089 have >some guidance, differing slightly, but not clear. Any and all >opinions/experiences from the group are welcome.
Adopt a 'real world' approach. If the separate products could be simply placed side-by-side or stacked on a table or shelf, instead of being mounted in a rack, you do not need to measure the rack as a whole. See IEC/EN61000-3-2, which says this explicitly. In Europe, the question should not arise, because since each product can be marketed separately, each requires to conform to applicable standards and to be CE marked. Assembly into a rack could be carried out by anyone - an installer or end-user - and clearly to then require re-testing would be unrealistic. The only snag is that if the **manufacturer** assembles the products into a rack, **and then markets the rack as a single article of commerce, i.e. at an inclusive price**, then it is classed as a system under the EMC Directive and DOES need to conform as a whole to the applicable standards, unless the product standard says differently, as CISPR15/EN55015 does for dimmers. Large assemblies and aggregations are almost always more or less 'site- specific' and are thus 'installations' under the EMC Directive. Installations need no a priori testing but the installation must be in accordance with the product manufacturers' instructions, including the correct use of appropriate cables. Installations are assessed for EMC only in case of complaint (of either excessive emission or inadequate immunity). -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Eat mink and be dreary! ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: pstc_ad...@garretson.org Dave Heald davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
