1. It's always better to have a defined term. In this context IEC 60664-1 defines electrical breakdown as "failure of insulation under electric stress when the discharge completely bridges the insulation, thus reducing the voltage between the electrodes almost to zero" 2. Doug, as far as I can tell from your previous message, you have not clearly defined the effect to which you have referred a few times. Is the effect a permanent failure of solid insulation causing a subsequent hipot test to fail?
At my last employer before retirement, we always asked the question, "what is the problem we're trying solve ?" If there wasn't an obvious or definable problem, we moved on to more pressing matters so to avoid fixing what is not broken. Ralph From: Richard Nute <[email protected]> Sent: February 28, 2025 1:54 PM To: [email protected] Subject: Re: [PSES] major safety issue possibly affecting 20% of the electronic devices in use Hi Doug: I think that we hold different definitions for "breakdown." In safety, "breakdown" signifies 1. failure of solid insulation (in ohms) to withstand the test voltage (for one minute), or 2. an arc through air insulation at a voltage less than the test voltage. In both cases, a hi-pot tester would trip, regardless of current setting. The failure of solid insulation can be verified by an ohmmeter (which, if good, would be near the upper limit of the ohmmeter). Your measurements do not appear to comprise a safety-related breakdown. The question I have is: What is the ohmmeter measurement before and after the pulse test? Well. we don't know the "before" measurement. But, an "after" measurement should indicate whether or not damage to solid insulation has occurred (resistance is less than 5 megohms - say). Or, a leakage current test. Another question: Why did you choose to do the pulse test with the equipment under test not powered on? Best regards, Rich From: doug emcesd.com <[email protected] <mailto:[email protected]> > Sent: Thursday, February 27, 2025 6:30 PM To: [email protected] <mailto:[email protected]> ; [email protected] <mailto:[email protected]> Subject: Re: [PSES] major safety issue possibly affecting 20% of the electronic devices in use Thanks for the information. But in this case breakdown is occurring and the question is if it can be problematic. Doug Smith Sent from my iPhone IPhone: 408-858-4528 Office: 702-570-6108 Email: [email protected] <mailto:[email protected]> Website: http://dsmith.org _____ _____ 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] <mailto:[email protected]> All emc-pstc postings are archived and searchable on the web at: https://www.mail-archive.com/[email protected]/ <https://www.mail-archive.com/[email protected]/%20> Website: https://ewh.ieee.org/soc/pses/ <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://pses.ieee.org/wp-content/uploads/2024/12/EM-PSTC-List-Rules.pdf For help, send mail to the list administrators: Mike Sherman at: [email protected] <mailto:[email protected]> Rick Linford at: [email protected] <mailto:[email protected]> For policy questions, send mail to: Jim Bacher at: [email protected] <mailto:[email protected]> _____ To unsubscribe from the EMC-PSTC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC <https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1> &A=1 - ---------------------------------------------------------------- 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://pses.ieee.org/wp-content/uploads/2024/12/EM-PSTC-List-Rules.pdf 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
