Thanks to Adam for all the references. They address very thin solid insulations. But they confirm that dielectric strength is not a constant for very small distances, and they do not have an answer as to why.
My concern is verifying clearances in safety standards. I’ve attached curves of three standards clearance requirements (logarithmic scale for volts per millimeter). The solid curves represent the clearances in standards and are close to power curves (dotted lines). The equations are for a best-fit power curve. The solid green curve is from an old standard and depicts actual withstand measurements. I suspect the electric strength curves are related to the reason for Paschen’s finding that gases do not break down at low voltages. My objective is to predict clearance dimensions without tables. Best regards, Rich - ---------------------------------------------------------------- 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 [email protected] All emc-pstc postings are archived and searchable on the web at: https://www.mail-archive.com/[email protected]/ 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: [email protected] Rick Linford at: [email protected] For policy questions, send mail to: Jim Bacher: <[email protected]> _________________________________________________ To unsubscribe from the EMC-PSTC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1
