To export to Euroupe you need to conform to EN60950 (for IT equipment), this has the same 60V or 42Vp-p limits, the creepage and clearance distances are also set out in this standard. See :- http://www.ce-mag.com/ce-mag.com/archive/01/03/ProductSafety.html for an overview. It is relatively straight foward to get approvals for US and Europe, Japan is a slightly trickier matter as the SELV limits we discovered were lower. Regards John steve weir wrote: >Steve, yes I know of a company that did not pay attention to the more >stringent European standards and failed to maintain adequate creep >clearance on their -48V feeds, and that forced an expensive redesign of >entire chassis. > >Regards, > > >Steve >At 10:46 AM 10/19/2004 -0700, Salkow, Steven wrote: > > >>Hey Steve >>If your making your equipment for export to Europe you will need to meet >>the requiremnets of IPC. >>See http://dc.ipc.org/resources/tools.htm >> Clearance Distance >>The shortest distance (through air) separating two live conductors or >>circuit components. See Creepage Distance. >> >> Creepage Distance >>The shortest distance between two conductors (typically, one primary, >>one secondary). >> >>On this site find: >>This program is intended to serve as a guide to the manipulation of data >>that supports the concepts and methodology for developing surface mount >>land patterns that are identified in IPC-SM-782, "Surface Mount Design >>and Land Pattern Standard". >> >>Steve Salkow >>Lockheed Martin >>3200 Zanker Road >>San Jose, CA 95134 >>(408) 473-4058 (san Jose) >>(408) 742-4162 (Sunnyvale) >>steven.salkow@xxxxxxxx >>salkow@xxxxxxxxxxxx >>(925) 462-1075 Home >>(925-) 487-5946 Cell >>(408) 468-7271 Numeric Pager >> >> >> >>-----Original Message----- >>From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] >>On Behalf Of Murphy Jack-MGI2488 >>Sent: Tuesday, October 19, 2004 10:30 AM >>To: 'weirsp@xxxxxxxxxx'; tcuratolo@xxxxxxxx; si-list@xxxxxxxxxxxxx >>Subject: [SI-LIST] Re: 48V power distribution >> >> >>Steve, >> >>The low voltage safety limit is actually >60Vdc or >42.4Vpeak. Under >>those limits the circuit is considered SELV and spacings do not apply. >>For centralized DC power inputs, UL requires a 500Vac (707Vdc) hipot >>test between 48Vdc/RET and chassis to verify isolation. We make CO-type >>equipment powered via a -48Vdc centralized DC power source and we use >>UL60950-1 for Product Safety. >> >>A 48Vdc battery power system has a float up to 60Vdc which is still >>under the SELV limit. >> >>The National Electric Code has DC power source limitations (voltage vs >>current) that they classify Class 2 or 3. I'll admit that I'm not very >>familiar with the NEC. >> >>Jack Murphy >>SR Compliance Engineer >>Motorola BCS >> >>-----Original Message----- >>From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] >>On Behalf Of steve weir >>Sent: Tuesday, October 19, 2004 1:06 PM >>To: tcuratolo@xxxxxxxx; si-list@xxxxxxxxxxxxx >>Subject: [SI-LIST] Re: 48V power distribution >> >> >>Tom, the biggest issue is that 48V exceeds the 42V low-voltage safety >>limit >>and so requires substantially greater clearances. A 24V system is under >> >>that limit and does not face the same problem. 48V also changes the >>dynamics of available semiconductors. 12V systems and to a certain >>extent, >>24V systems can leverage the super low on resistance and low capacitance >> >>FETs and diodes. The last issue is one of magnetics and practical >>form-factors. Given you work for Vicor, you should be pretty familiar >>with >>those and how taller primary to output ratios aggravate same. >> >>Regards, >> >> >>Steve >>At 02:04 PM 10/19/2004 +0000, tompegbel wrote: >> >> >> >>>Is there a good resource/document for addressing the concerns in >>>bussing 48V power in a multilayer board? The recently popular 12V or >>>lower intermediate bus approach has limitations as voltages get lower >>>and current gets higher. There appears to be new approaches of using a >>> >>> >>>higher bus voltage (24V or 48V) for distribution since this was >>>explored in the 80's with the advent of distributed power and now more >>>recently with VoIP type designs. Any assistance appreciated >>> >>> >>> >>>------------------------------------------------------------------ >>>To unsubscribe from si-list: >>>si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field >>> >>>or to administer your membership from a web page, go to: >>>//www.freelists.org/webpage/si-list >>> >>>For help: >>>si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field >>> >>>List FAQ wiki page is located at: >>> http://si-list.org/wiki/wiki.pl?Si-List_FAQ >>> >>>List technical documents are available at: >>> http://www.si-list.org >>> >>>List archives are viewable at: >>> //www.freelists.org/archives/si-list >>>or at our remote archives: >>> http://groups.yahoo.com/group/si-list/messages >>>Old (prior to June 6, 2001) list archives are viewable at: >>> http://www.qsl.net/wb6tpu >>> >>> >>> >>------------------------------------------------------------------ >>To unsubscribe from si-list: >>si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field >> >>or to administer your membership from a web page, go to: >>//www.freelists.org/webpage/si-list >> >>For help: >>si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field >> >>List FAQ wiki page is located at: >> http://si-list.org/wiki/wiki.pl?Si-List_FAQ >> >>List technical documents are available at: >> http://www.si-list.org >> >>List archives are viewable at: >> //www.freelists.org/archives/si-list >>or at our remote archives: >> http://groups.yahoo.com/group/si-list/messages >>Old (prior to June 6, 2001) list archives are viewable at: >> http://www.qsl.net/wb6tpu >> >>------------------------------------------------------------------ >>To unsubscribe from si-list: >>si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field >> >>or to administer your membership from a web page, go to: >>//www.freelists.org/webpage/si-list >> >>For help: >>si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field >> >>List FAQ wiki page is located at: >> http://si-list.org/wiki/wiki.pl?Si-List_FAQ >> >>List technical documents are available at: >> http://www.si-list.org >> >>List archives are viewable at: >> //www.freelists.org/archives/si-list >>or at our remote archives: >> http://groups.yahoo.com/group/si-list/messages >>Old (prior to June 6, 2001) list archives are viewable at: >> http://www.qsl.net/wb6tpu >> >> >> > > >------------------------------------------------------------------ >To unsubscribe from si-list: >si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field > >or to administer your membership from a web page, go to: >//www.freelists.org/webpage/si-list > >For help: >si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field > >List FAQ wiki page is located at: > http://si-list.org/wiki/wiki.pl?Si-List_FAQ > >List technical documents are available at: > http://www.si-list.org > >List archives are viewable at: > //www.freelists.org/archives/si-list >or at our remote archives: > http://groups.yahoo.com/group/si-list/messages >Old (prior to June 6, 2001) list archives are viewable at: > http://www.qsl.net/wb6tpu > > > > > ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu