My employer designs and manufactures, among other things, component power supplies for medical, IT, instrument, industrial, and other weird stuff.
Unlike other safety-critical components such as X/Y caps, VDRs, switches, connectors, etc; there are no 'accepted' safety standards for component power supplies. No need to tell me about IEC61204, UL1310, UL1012, IEC61558, etc; as these are 'boutique' standards. Each major product safety standard has some specific requirements for power sources - of which most requirements overlap. Other than an indicated conformity to Articles 600 or 725 of NEC, it is very unusual to be able to drop in a component power supply from different sources even when the ratings are identical. Until there is an industry-standard component power supply product safety standard that has been harmonized by all national codes, and is cited in the Big Four (60950/60065/60335/60601), there will be no drop-in replacements without re-test with an alternate construction amendment to your CB report. Final note - I have recent experience where a CPS with a 60601 report, and tested for patient contact, was installed in ITE. The box could no longer pass all safety requirements for a C.O. device. This has been discussed in previous PSES threads - a medical power supply is not necessarily 'safe' in a consumer or ITE box. Brian > -----Original Message----- > From: [email protected] [mailto:[email protected]]On Behalf Of Amund > Westin > Sent: Wednesday, September 15, 2010 12:19 AM > To: [email protected] > Subject: SV: [PSES] IEC 60950-1 vs IEC 60601-1 > > The end product is an ITE (DVB) and in the previous models, > we have made use > of an open frame AC/DC power supply unit. This PSU had CB certificate > according to IEC60950-1. Then we went to a third party body > for testing the > complete unit according to IEC60950-1. Since we had a CB > certificate, the > scope of work for testing the ITE was limited a lot, since > no testing / > examination on the PSU itself was necessary. > > Now, we want to change PSU to another open frame AC/DC power > supply unit. > This PSU has a CB cert acc to IEC 60601-1, while the end > product still shall > conform according to IEC60950-1. > > Since the new PSU shall be placed inside the ITE, some > safety test and > evaluations must be done. > But we would also assume that a 601-1 PSU should be more > "safe" than an > 950-1 PSU, seen from an application point of view. > > We accept that some safety testing must be done on the end > product. But we > find it a bit strange if the introduction of this medical > PSU involves more > testing than if we had made use of a 950-1 PSU. > > #Amund > > > -----Opprinnelig melding----- > Fra: Brian O'Connell [mailto:[email protected]] > Sendt: 14. september 2010 18:56 > Til: [email protected] > Emne: Re: [PSES] IEC 60950-1 vs IEC 60601-1 > > WARNING - Fractious dichotomous isochroous nondeterministic > reply follows. > > I am not certain of Mr. Westin's use of "PSU". IEC60950-1 > has no definition > for the phrase 'power supply unit', and contextual meaning is not > consistent. IEC60601-1 uses the phrase 'power supply unit' only when > referring to a separate external power source. > > For a COMPONENT power supply, where the final determination > is the end-use > installation - the 'PSU' CB report can use a TRF based on > almost any product > safety standard that would scope a 'PSU'. > > For a power supply that has been assessed as an end-product, neither > standard provides complete coverage for the requirements of > the other for > many uses, and for some uses either standard could provide > coverage for a > superset of the requirements. Anyone wanna see a De Morgan > reduction of that > logic ? > > The coming (????) of the UL/EN/IEC62368-1 standard may > provide an unintended > formal method to 'bridge' various requirements for component > power supplies. > > Most I.T. CB reports for component power supplies require > the repeat of some > Type Tests in the end-use installation. So for a medical > 'PSU', the pudding > would not get cooked until it was subject to tests in your I.T. box. > Conversely, the 3d edition of 60601-1 specifically addresses > the use of I.T. > component power supplies for some medical equipment. > > The CB report could be considered valid; or not. > Additional tests could be required; or not. > > Non-related Note: the '#' at the signature threw some > interesting errors for > my auto-mail program - thanks for the programmatic work-out. > > Brian > > > -----Original Message----- > > From: [email protected] [mailto:[email protected]]On > Behalf Of Amund > > Westin > > Sent: Tuesday, September 14, 2010 1:05 AM > > To: [email protected] > > Subject: IEC 60950-1 vs IEC 60601-1 > > > > Is it possible to make use of a CB certificated (IEC > > 60601-1) PSU, into a > > ITE which shall be approved according to IEC60950-1? > > > > Well, I assume that's OK, but should we expect additional > > tests on the PSU / > > ITE since it's not CB acc to IEC60950-1? > > > > Thanks. > > #Amund - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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