Selection and Erection – Equipment
D 4
EMC and prevention of mutual detrimental influences
D 4.1
Introduction The Wiring Regulations have for a number of years included basic regulations for electromagnetic compatibility (EMC), regulations about separating system voltages and also regulations about the rather cumbersome title of ‘preventing mutual detrimental influences’. These topics are all discussed in this section as many of the recommendations overlap. BS 7671: 2008 has a number of regulations to take note of as follows:
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Section 528 – proximity to other cables, equipment. Part 515 EMC.
Let’s first look at proximity; Regulation 528.2 requires that ELV and LV circuits shall not be in the same containment unless insulated for the highest voltage present. This applies to cables on cable tray as well as within conduit, trunking and ducting. Of course, this insulation requirement is not required where compartments physically separate the cables.
D 4.2
EMC directive and BS 7671 Previously, the EMC directive did not specifically mention installations, but the recent revision to the directive now states installations are not exempt from the legislation. This section provides brief guidance on complying with the EMC directive and EMC requirements of BS 7671: 2008. The directive and official guidance indicates that best practice is followed, and cites HD 60384, the European harmonization document upon which BS 7671: 2008 is based. Regulation 515.3 states that equipment shall be chosen with suitable immunity and emission levels. The EMC directive Regulations and various guidance documents can be found on the DTI website, and this also provides links for supporting informative EMC documents as well as a link to the EU Commission website. All main documents and guides on these sites were, at the time of writing, free of charge. So, what is the impact and what advice can be provided to installation designers and installers? Three key points of action are required:
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