Dear Ken, Brian, Thank you for your reply. I know requirement of CSA No. 04 and all shelfs are compliant to this requirement since US/CAN ND required short-trace test. However new standard has a bit different requirement and I would like to find rationale for 25A protective current rating. Why this solution is not acceptable any more.
I really need to be sure before I made a non-compliant report to the customer. Best regards, Bostjan > On 27. jun. 2016, at 18.36, Brian O'Connell <oconne...@tamuracorp.com> wrote: > > And an additional note that the CSA No. 0.4 test done at 40A. > > Brian > > > From: IBM Ken [mailto:ibm...@gmail.com] > Sent: Monday, June 27, 2016 8:33 AM > To: EMC-PSTC@LISTSERV.IEEE.ORG > Subject: Re: [PSES] earthing through PCB traces > > PS: UL/CSA 60950 always required a limited short circuit test from CSA C22.2 > No. 0.4 for "protective bonding conductors and their terminals of > non-standard constructions, such as printed wiring protective traces" as a D1 > deviation, so if these products were sold in North America they should > already be compliant somehow. > > -Ken > > On Mon, Jun 27, 2016 at 11:09 AM, IBM Ken <ibm...@gmail.com> wrote: > Hi Bostjan! > It looks like 5.6.4.1 gives you four choices: > > (1) Minimum conductor sizes in G.5 > > or (if, presumably, you don't meet the minimum conductor sizes in G.5) > > (2) Meet 5.6.6 (test). If (and only if) the protective current rating is > >25A you also have to meet Table 31 (in general, the requirements of Table 31 > are easier to meet than Table G.5.) > My assumption is that if the protective current rating is <=25A you do not > have to meet Table 31 but you still have to meet the test of 5.6.6 > > Or (if, again, you don't meet the minimum conductor sizes in G.5) > > (3) Meet 5.6.6 (Test). If the protective current rating is <=25A you can > either meet table 31 - or - Perform limited short circuit test from Annex R > > (4) For components only, protective bonding conductors must be not smaller > than the supply conductors > > My interpretation would be that if you have equipment with protective > conductor rating >25A which can't meet (4) or (1), you have to pass the 5.6.6 > test and the conductors must also meet Table 31. Therefore, it seems that > constructions with protective current rating >25A are prohibited from using > PCB traces for bonding. On the other hand, Table 31 just says "Minimum > protective bonding conductor size of copper conductors". What if the PCB > trace cross-sectional area is greater than or equal to the cross-sectional > area stated in table 31? Meeting Table 31 on PCB traces would result in very > wide traces but it doesn't seem to be prohibited the way 62368 is worded. > > -Ken > > > On Mon, Jun 27, 2016 at 9:03 AM, Boštjan Glavič <bostjan.gla...@siq.si> wrote: > Dear Experts, > > I need your opinion about requirements of IEC 62368-1 standard. Standard > requires special limited short-circuit test on earthed accessible parts that > are earthed through PCB traces. However this test is only applicable if > protective current rating is below 25A according to clause 5.6.4.1. > > What about the products with protective current rating above 25A? Standard > does not say that such constructions are not allowed, just does not specify > requirements. > > Many telecom power shelfs, composed of hot-pluggable power supplies and > backplane are using PCB traces for earthing of the power supply enclosure. It > is normal to have protective current rating above 25A in this case. How to > deal with this situation? All power supply shelfs already have IEC 60950-1 > certificate. > > Thank you for your opinion. > > Best regards, > Bostjan Glavic > SIQ > > - > ---------------------------------------------------------------- > 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> - ---------------------------------------------------------------- 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>
