Hi Ryan, Clarification at the end of 5.4.2.2 (before the tables) indicates that which table you use is dependent on the frequency of the associated circuit. The implication is that you could have some circuits use Table 10 and some circuits use Table 11. It seems appropriate to use Table 11 for the power supply working voltage. The key question here is whether temporary overvoltages associated with AC mains circuits have a frequency > 30 kHz or not and so also should use Table 11, or if Table 10 should be used.
FWIW, here <https://code-authorities.ul.com/wp-content/uploads/sites/40/2015/02/UL_WP_Final_Effects-of-High-Frequency-Voltage-Stress-on-Air-Insulation-and-Solid-Insulation_v4_HR.pdf> is a paper from UL from 2010 (so before IEC 62368-1 3rd Edition was published) that has an example based on the IEC 60664 series standards. You will notice that the example calculates clearances to withstand transient overvoltages separately from the clearances to withstand periodic voltages, taking the highest of the two as the final requirement. Though it doesn't address temporary overvoltages specifically, the example is interesting. On Tue, Jul 25, 2023 at 3:39 PM Ryan Jazz <rjayasin...@yamahaguitargroup.com> wrote: > Dear Members, > > Hope you can help me understand the requirement for the clearance needed > between the bottom PCB of power supply to metal chassis. > > Looking up UL 62368-1 Third Edition, and using the ‘Voltage up to an > including peak’ of *2000 V* for overvoltage category II Table 10 for *<30 > kHz*. > > I see the clearance is 1,27 mm. > > Going over to Table 11 *>30* kHz this clearance value jumps to 13,2 mm. > > Am I doing this correctly? Or should I be using the ‘working voltage’ of > the power supply, Primary to Earthed Dead Metal 392 Vpk, Primary to > Secondary 520 Vpk. > > 100-240 Vac, 100 W, *90 kHz* switching frequency, AC power supply with a > 2x3 inch footprint. > > End product is, overvoltage category II, pollution degree 2, material > group III. > > Indoor audio music processor, Class 1. > > All guidance would be appreciated. > > If this 13,2 mm value is indeed correct, I may need to use an insulator > under the power supply. > > Any recommendations for a UL rated insulator type? > > Thank you, > > Ryan Jazz > > Ryan Jayasinghe > > Regulatory Compliance Engineer > > rjayasin...@line6.com > > > > "After silence, that which best expresses the inexpressible, is music" - > Aldous Huxley > > > > LINE6 > > 26580 Agoura Road > > Calabasas CA 91302 > > 818.575.3711 <(818)%20575-3711> > > line6.com > > ampeg.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 All > emc-pstc postings are archived and searchable on the web at: > https://www.mail-archive.com/emc-pstc@listserv.ieee.org/ > > Website: https://ewh.ieee.org/soc/pses/ > Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to > unsubscribe) <https://ewh.ieee.org/soc/pses/list.html> > List rules: https://ewh.ieee.org/soc/pses/listrules.html > > For help, send mail to the list administrators: > Mike Sherman at: msherma...@comcast.net > Rick Linford at: linf...@ieee.org > > For policy questions, send mail to: > Jim Bacher at: j.bac...@ieee.org > ------------------------------ > > To unsubscribe from the EMC-PSTC list, click the following link: > https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1 > -- Scott Aldous | Regulatory Compliance Manager | scottald...@google.com | 650-253-1994 - ---------------------------------------------------------------- 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: https://www.mail-archive.com/emc-pstc@listserv.ieee.org/ Website: https://ewh.ieee.org/soc/pses/ Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to unsubscribe) List rules: https://ewh.ieee.org/soc/pses/listrules.html For help, send mail to the list administrators: Mike Sherman at: msherma...@comcast.net Rick Linford at: linf...@ieee.org For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> _________________________________________________ To unsubscribe from the EMC-PSTC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1
