For the power supplies that are certified by UL under category code QQGQ2, UL does have a standardized table format on their online cert directory that includes a code they call the Output Category. The intent is to identify those supplies that have been evaluated for SELV output, or other types of output. More information can be found in the guide card for that category:
http://database.ul.com/cgi-bin/XYV/template/LISEXT/1FRAME/showpage.html?name=QQGQ2.GuideInfo&ccnshorttitle=Power+Supplies,+Information+Technology+Equipment+Including+Electrical+Business+Equipment+-+Component&objid=1073787375&cfgid=1073741824&version=versionless&parent_id=1073787374&sequence=1 On Tue, Jan 20, 2015 at 10:17 AM, Brian Oconnell <oconne...@tamuracorp.com> wrote: > Mr. Nute’s response is significant and is worthy of re-emphasis. > > > > And Mr. Woodgate answered this same question to Mr. Nyffenegger previously: > > > > " The power supply as a whole cannot claim that unless ALL its outputs > > meet the SELV requirements. But it does meet the requirements for safety > > isolation, so those outputs that meet the voltage requirements are SELV." > > > > SELV, TNVx, LPS, LCC, etc are *specific ratings* that would be indicated > in the Conditions of Acceptability in both the test certification document > required to bear a CAB’s logo and the respective CB report. And as many > power supplies are *components, *the report will be necessarily > incomplete; and only the assessment in the end-use construction can provide > a complete report. > > > > Per Mr. Nute, other than simple flyback converters, most component SMPS > are too complex to be evaluated by other than an assessment directed by the > original manufacturer (in last 15 years, have encountered only three agency > engineers capable of a complete and independent assessment of SMPS). There > is never any logical reason to assume a ‘certified’ component power supply > will meet any specific ratings unless stated in a CAB’s report. > > > > Brian > > > > -----Original Message----- > From: Richard Nute [mailto:ri...@ieee.org] > Sent: Monday, January 19, 2015 12:55 PM > To: EMC-PSTC@LISTSERV.IEEE.ORG > Subject: Re: [PSES] SELV rated power supplies > > > > Hi Dave: > > > > EN60950-1 is not equal to SELV. > > > > Certifications and reports do not necessarily > > indicate outputs are SELV, although careful > > reading of the test results can conclude that the > > outputs are SELV or not. > > > > Not all outputs of EN60950-1 power supplies are > > SELV and need not be. The power supplies are > > nevertheless EN60950-1 power supplies. > > > > The requirement for SELV is whether or not the > > circuit is accessible. Accessible circuits must > > be SELV. > > > > To perform a single-fault test, one must > > understand how the circuits operate, and what > > faults could cause the output to possibly exceed > > SELV limits. In today's power supply topology, > > such circuit analysis is not necessarily > > straight-forward. > > > > Your statement > > > > "Therefore my contention is it cannot be assumed > > that a power supply listed as EN 60950-1 compliant > > on a manufacturer's data sheet is also SELV > > compliant unless explicitly stated so or proven in > > the test report results." > > > > is correct. > > > > Best regards, > > Rich > - > ---------------------------------------------------------------- > > 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 < > emc-p...@ieee.org> > > 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 <sdoug...@ieee.org> > Mike Cantwell <mcantw...@ieee.org> > > For policy questions, send mail to: > Jim Bacher <j.bac...@ieee.org> > David Heald <dhe...@gmail.com> > -- Scott Aldous Compliance Engineer Google 650-253-1994 scottald...@google.com - ---------------------------------------------------------------- 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 <emc-p...@ieee.org> 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 <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
