Many thanks Rich. I thought it would be 3,000 Vrms. That would be 4,243 Vdc! That is a far cry from what our procedure says now. These numbers are in line with what's in our CB reports as well. Oh well, what's another ECO among friends 😊
Regards, Mike > On Aug 6, 2014, at 5:41 PM, "Richard Nute" <ri...@ieee.org> wrote: > > > > Hi Mike: > > > For a peak working voltage of 340 (240 rms), the routine test > (Table 5B) is 3000 V rms for 1 second between mains and ground. > (You do not have a peak working voltage exceeding 420 so Table > 5B Part 2 does not apply.) > > If you apply Table 5C, you must determine required withstand > voltage according to G.4 and G.2. You will likely end up with > the required withstand voltage equal to the mains transient > voltage, Table G.1, 2500 V peak. > > According to Table 5C, if the required withstand voltage is > 2500 V peak, the test voltage for reinforced insulation is > 5000 V peak (3536 rms). This voltage can be reduced by 10% > to 4500 V peak (3182 rms). > > So, you have a choice of 3000 V rms or 3182 V rms for 1 second. > > > Best regards, > Rich > > > > >> On 8/6/2014 1:09 PM, Mike Cantwell wrote: >> This seemed to me to be a simple question, but it's turned out to be one >> with different answers from the experts, so I'm confused. Reading section >> 5.2.2 of 60950-1, seems to say that an ITE product (computer server >> specifically) that is Overvoltage Category II can use table 5B to determine >> the test voltage, which is listed at 3,000 Vrms for reinforced insulation >> for an ac mains of 240 Vrms (340 Vpk). I understand that the working voltage >> in the power supply can exceed this value and many of our CB reports >> definitely show this, but the test voltage remains at 3,000 Vrms regardless. >> >> Further along in section 5.2.2, it says that for routine tests, the duration >> of the electric strength test can be dropped to 1 second and the test >> voltage of Table 5C (different table) can be reduced by 10%. But this table >> seems to imply that I can reduce the 3,000 V to a test voltage of 2,700 Vrms. >> >> Now table 5B (Part 2), for 340 V, the test voltage is 2,328 Vrms. If I >> reduce this voltage by 10%, the test voltage is 2,095 Vrms. If I want to do >> a DC hipot, the test voltage would becomes 2,963 Vdc. >> >> I have been given numbers everywhere from 1500 V to 3000 V, and I'd like to >> know what the proper test level should be. Is a different test level >> determined for every power supply based on working voltage for routine >> tests? or can one test level be determined and used for all hipot testing. >> >> As an EMC guy, the range I've been given by the safety folks is only 6 dB >> different and quite within the measurement uncertainty :) but something >> tells me that the safety folks will have a better number for the test levels >> and know the proper way it is derived. >> >> I would like to set the hipot testers to a single value if at all possible. >> Any help would be greatly appreciated on what the test level should be for a >> routine hipot on a computer. > - ---------------------------------------------------------------- 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 <emcp...@radiusnorth.net> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
