Re: [PSES] HV relay

[Doug Powell]

BOštjan In the past when I've had to deal with this, I explained to the safety inspector that internal spacings (clearance and creepage) are not applicable. Nearly all IEC based standards use IEC 60644-1 as the basis of their spacings determination. Since there is no atmosphere inside a vacuum relay, things like pollution degree do not apply, additionally you can invoke the Paschen's Law for voltage standoff capability, which is very high for a deep vacuum.  I have achieved 30 kV with just few millimeters. Of course, nearly all vacuum HV relays use shaped electrodes for homogenous e-field control.   That said, normal spacings concern still apply to the exterior surfaces of the relay.  Since most of these are made of glass-like materials or ceramics you can claim CTI I for the material class.   Best fo luck, doug -- Douglas E Powell doug...@gmail.com https://www.linkedin.com/in/dougp01  Currently working from my Android phone From: bostjan.gla...@siq.si Sent: November 25, 2019 8:22 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Reply-to: bostjan.gla...@siq.si Subject: [PSES] HV relay Dear experts,   Is anyone familiar with requirements for HV relay in vacuum? Are clearances and creepage distances between contacts applicable for such relay?   Thank you for your support.   Best regards, BOštjan - ---------------------------------------------------------------- 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>