EUROPEAN EMC STANDARDS The European version of the CISPR immunity standard for multimedia

2017-12-08

EUROPEAN EMC STANDARDS The European version of the CISPR immunity standard for multimedia equipment has now been published; the UK's version is BS EN 55035:2017. According to the standard's European foreword' it covers the essential immunity requirements of the EMC Directive 2014/30/EU for products other than broadcast receivers; and, for broadcast receivers, it covers the essential requirements of the Radio Equipment Directive (RED) 2014/53/EU. This coverage is conditional on publication of the standard in the Official Journal (OJ) of the EU. The good news is that a new list was published last month for the RED (Radio Equipment Directive), and it lists EN 55035, so presumption of conformity' with the EMC immunity requirements of this Directive exists. However, OJ publication of lists of standards for the EMC Directive has stalled for a number of bureaucratic reasons, including a legal argument about statistical assessment of conformity'. Many EMC standards refer to a method of assessing compliance of mass-produced products in which a sample of products is tested, and a probability of compliance of a larger group of products is derived by the theory of statistics. Commonly the 80:80 rule' is used and compliance is deemed to exist if there is 80% confidence that 80% of the products comply. Fortunately, EN 55035 does not mention statistical assessment. Nevertheless, at the time of writing this report, it has not been listed in the OJ for the EMC Directive. And, the latest (2015) edition of the corresponding emission standard (EN 55032) is not listed either. Fraught discussion continues between the European standards bodies ETSI and CENELEC (including their committees and experts) about standards to support the RED. Because of the great increase in the use of radio technology, the number of product types covered by the RED is extremely large, and a correspondingly large number of standards appears to be needed. Argument continues about whether ETSI standards can cross-refer to CENELEC standards or vice versa. However the situation for EN 55032 and EN 55035 seems clear: both will (in due course for EN 55032) refer to both the RED and the EMC Directives. INTERNATIONAL STANDARDS DEVELOPMENT The CISPR working groups (now reconstituted as Maintenance Teams') responsible for CISPR 32 and CISPR 35 are expected to meet in Italy at the end of February 2018. Work is continuing on a number of amendments to the emission standard, and this meeting will probably output a number of committee drafts for voting by National Standards bodies. The standardisation of the RF termination impedance of mains cables in radiated emission tests will also be discussed at this round of meetings in Italy. In other international EMC standards committees discussion continues on extending the upper and lower frequency bounds of EMC standards. Upward extension will require new measurement methods to be developed. Downward extension, below 150 kHz, is driven by (among other things) inductive power transfer (particularly to electric vehicles) and emissions from DC power connections (especially from DC to DC converters connected to solar panels).

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