As mentioned by Carl, V-0 is more stringent requirement than V-1. Where is confusion?
Best regards, Boštjan From: John Woodgate <[email protected]> Sent: Thursday, May 7, 2020 12:06 AM To: [email protected] Subject: Re: [PSES] 62368-1 Section 6.4.8 Flammability Confusion Can you please share the format of your 'document and worded' exercise? I might be able to get at lease a small part of IEC interested in it. Best wishes John Woodgate OOO-Own Opinions Only www.woodjohn.uk<http://www.woodjohn.uk> Rayleigh, Essex UK MAY THE VIRUS NOT BE WITH YOU On 2020-05-06 20:40, John E Allen wrote: IMHO & TBH. I encountered such inconsistencies in IEC standards too many times - which was why I "dissected" several standards (notably 60950, 60204 and 61010-1), rigourously followed the various cross-references, and then documented and worded them in a form that would allow your ("average" in safety compliance issues but otherwise very competent!) development engineers to understand and then meet the requirements of the standards in question. Great pity that the IEC tech committees never seem to do the thing - but, if they did then their standards and Technical Report formats would be far more easily and clearly understood by everyone! John E Allen W.London, UK. From: John Woodgate <[email protected]><mailto:[email protected]> Sent: 06 May 2020 19:45 To: [email protected]<mailto:[email protected]> Subject: Re: [PSES] 62368-1 Section 6.4.8 Flammability Confusion This is the sort of thing that can easily happen in a huge document. It is extremely difficult, especially where there is a chain of forward and back cross references, and text pushed off from its primary context to multiple annexes, to ensure internal consistency. Best wishes John Woodgate OOO-Own Opinions Only www.woodjohn.uk<http://www.woodjohn.uk> Rayleigh, Essex UK MAY THE VIRUS NOT BE WITH YOU On 2020-05-06 18:35, Carl Newton wrote: I'm wondering if any list members can explain the rationale behind 62368-1, in sections 6.4.8.2.2 and 6.8.8.4. I'm looking at the 2014 edition. Clause 6.4.6, Control of fire spread in a PS3 circuit, states that, "Fire spread in PS3 circuits shall be controlled by applying all of the following supplementary safeguards:". In that clause it includes, "by providing a fire enclosure as specified in 6.4.8." Clause 6.4.8.2.2, Requirements for a fire enclosure, states "For circuits where the available power does not exceed 4 000 W (see 6.4.1), a fire enclosure shall comply with the requirements of Clause S.1." That clause then goes on to say that V-1 is acceptable.... Clause (6.4.8.4) is addressing "Separation of a PIS from a fire enclosure and a fire barrier" and is only requiring the application of the S.2 flame test, which I believe is less demanding in that only a 60 s flame is applied rather than three steps up to 120 s for the S.1 test method. Clause 6.4.8.4 then goes on to state that a V-0 material is excluded from the requirement. So unless I'm mistaken, this clause 6.4.8.4 (which addresses separation) is requiring a lesser flame requirement than S.1, yet goes on to exclude V-0, but not V-1. I don't see the rationale. I must be missing something here. The most fundamental question in my mind here is why does 6.8.8.4 allow the S.2 test method? Thanks, Carl - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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To post a message to the list, send your e-mail to <[email protected]<mailto:[email protected]>> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe)<http://www.ieee-pses.org/list.html> List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]<mailto:[email protected]>> Mike Cantwell <[email protected]<mailto:[email protected]>> For policy questions, send mail to: Jim Bacher <[email protected]<mailto:[email protected]>> David Heald <[email protected]<mailto:[email protected]>> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]<mailto:[email protected]>> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe)<http://www.ieee-pses.org/list.html> List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]<mailto:[email protected]>> Mike Cantwell <[email protected]<mailto:[email protected]>> For policy questions, send mail to: Jim Bacher <[email protected]<mailto:[email protected]>> David Heald <[email protected]<mailto:[email protected]>> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
