Doug, The standard must assume the RF circuits are even more energy-limited than secondary circuits is my best guess. If so, it doesn't say that anywhere I could find. It takes voltage, but also energy to create an ionizing path. Regards, Brian Gregory 720-450-4933
---------- Original Message ---------- From: Doug Powell <doug...@gmail.com> To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: [PSES] IEC 61010-1 Table K.17 Date: Fri, 7 Aug 2015 16:47:28 -0600 All, I am evaluating spacings for an RF product that operates at 13.56 MHz and can produce maximum voltages of 5,000 Vrms (7,070 Vpk). If I do an interpolation of using Table 6 (Mains 230 V, OV Cat II, indexing on 5,000 Vrms), I get a minimum clearance requirement of 14.9 mm. When I do the same calculation on Table K.17 (column 3, indexing on 7,070 Vpk), I get 12.7 mm. Now I understand the effects of high frequency voltage stress causing air molecules to become more energetic and therefore more likely to break down at lower voltages. So why in this case does IEC 61010-1 Table K.17 result in lower clearance values than Table 6? Somehow, this just seems wrong. Please note that in the case of high frequencies paragraph K.3.1 indicates I am to skip over section K.3.2 with the D1 + F × (D2 – D1) calculations. Thanks a bunch! Doug Douglas E Powell doug...@gmail.com http://www.linkedin.com/in/dougp01 - ---------------------------------------------------------------- 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>
