Hi Richard,
Thanks for your detailed response. However, Annex ZB (6.1.2.1) only pertains to insulation that is solid or forms part of a semiconductor component, to Y2 capacitors and to Y3 capacitors with conditions. Is the reference to solid insulation meant to include printed wiring boards? If not, then basic insulation for a secondary circuit is all that's required now. So, basically (please excuse the pun), the only missing part of the TNV-SELV insulation equation would be the working voltage across the barrier. Is this a fair assessment? Best regards, Ron Pickard [email protected] [email protected] m To: [email protected] cc: [email protected] 01/07/2004 01:34 Subject: Re: EN60950-1,TNV to Earth Insulation PM Ron, When you look at "in some countries" notes in IEC standards you will see that they have all disappeared when it comes to CENELEC standards (unless the publishing organisation hasn't done its job correctly). The reason for this is because European deviations are relocated to Annex ZB or Annex ZC and all non-European deviations are just stripped out all together. Annex ZB contain what is known as "Special National Conditions". As the term implies, they are applicable in some countries only (i.e. not across the whole of Europe - such things are called "Common Modifications") and they result from characteristic (e.g. the local environment) or practice (commonly building wiring regulations / national electric codes) that cannot be changed even over a long period. Look here and this is where you will find the deviations for Finland, Norway and Sweden that relate to clause 6.1.2.1. Annex ZC contain what is known as "A-deviations". Typically these stem >from national laws. You will see that there is a Note that states that "it is the view of the Commission of the European Communities ... that compliance with A-deviations is no longer mandatory and that the free movement of products complying with such a standard should not be restricted except under the safeguard procedure provided for in the relevant Directive". Of course, if a company chooses to ignore these deviations and is prosecuted for failure to comply with some national law or other, the opinion of the European Commission may be moot. But what of Annex ZA? That is just a list of standards that have been Normatively referred to (they must be met, where they are specifically called up) where the references to international publications have been replaced by their relevant European counterparts. Now to your specific question... Is supplementary insulation for a primary circuit still required in order to comply with clause 6.1.2.1? Short Answer, NO. Detailed Answer, See Annex ZB (Page 252 if you have BS EN 60950-1). Best regards, Richard Hughes Safety Answers Ltd www.safetyanswers.ltd.uk Ron Pickard wrote: > > To all those knowledgeable with the 60950 series of safety standards, > > I've just been able to receive my copy of EN60950-1 (I've had IEC > 60950-1 for some time now). Upon > leafing thru EN60950-1, I noticed something missing that was in notes > 1 & 2 of clause 6.1.2.1 of > IEC60950 3rd Ed. That being, the requirement for supplementary > insulation for a primary circuit for > Norway and Sweden from TNV to earth. And looking into IEC60950-1, the > note in clause 6.1.2.1 states > "In Finland, Norway and Sweden, there are additional requirements for > the insulation." > Unfortunately, I've looked in clauses 2.3, 2.9, 2.10 and 6.1, but > cannot find these additional > requirements (even the CB Bulletin appears to provide only solid > insulation requirements for > 6.1.2.1). And to make this matter a bit more obtuse, both notes in > clause 6.1.2.1 has been deleted > from EN60950-1 according to Annex NA. > > So.... I have to ask, is supplementary insulation for a primary > circuit still required here? If so, > where is the requirement actually stated? Or, is supplementary > insulation for a secondary circuit, > or even basic insulation, now acceptable for Norway and Sweden? > > Or, have I overlooked something? I'm trying get thru the cobwebs back > to daylight and I'm hoping > that you will help me and maybe others with the same question(s). > > I look forward to your replies. Please advise. > > Best regards, > > Ron Pickard > [email protected] > > > > > ------------------------------------------- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > Visit our web site at: http://www.ieee-pses.org/ > > To cancel your subscription, send mail to: > [email protected] > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Ron Pickard: [email protected] > Dave Heald: [email protected] > > For policy questions, send mail to: > Richard Nute: [email protected] > Jim Bacher: [email protected] > > All emc-pstc postings are archived and searchable on the web at: > http://www.ieeecommunities.org/emc-pstc > This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
