Hi I had a similar situation. We ended using the alternative test method, with just extending the time between discharges. As per IEC 61000-42 Section 7.4.2.1:
Therefore as an alternative, the following options may be used: • the time interval between successive discharges shall be extended to the time necessary to allow natural decay of the charge from the EUT; Sincerely, Dieter Paasche Senior Product Developer, Electrical CHRISTIE 809 Wellington Street North Kitchener, ON N2G 4Y7 Phone: 519-744-8005 ext.7211 www.christiedigital.com<http://www.christiedigital.com/> This e-mail message (including attachments, if any) is confidential. Any unauthorized use, distribution or disclosure is prohibited. If you have received this e-mail message in error, please notify the sender by reply e-mail or telephone and delete it and any attachments from your computer system and records. From: DEREK WALTON <000000734758d943-dmarc-requ...@ieee.org> Sent: Thursday, March 12, 2020 1:31 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] ESD - Floating metal knob, otherwise grounded equipment Oh Boy Elliott, you’ll get a few answers here, lol. My 10 cents is that when you are not discharging each time you are adding more and more charge to the isolated control, that eventually will snap over At that point you are discharging quite a significantly higher level of chart than an individual event. I would not call that a realistic “ compliance” test. OTOH, if it’s possible that may happen in the real world with an operator continually adding charge as they use your EUT, you may want to find a way of adding some way to bleed charge over a few seconds. Interesting problem, lets see what others say, Sincerely, Derek LFResearch and SSCLabs.com<https://nam03.safelinks.protection.outlook.com/?url=http%3A%2F%2Fssclabs.com%2F&data=01%7C01%7CDieter.Paasche%40christiedigital.com%7C87b43028e46b44b73cfc08d7c6aa41c9%7Cdf46f062ad2c407688e6c675c789a0d8%7C1&sdata=4XzbEqYHDMuBVctnJ7sALzrBEmoy%2B3W8dTZQ8Vz13xc%3D&reserved=0> On Mar 12, 2020, at 10:53 AM, Elliott Martinson <elliott.martin...@subzero.com<mailto:elliott.martin...@subzero.com>> wrote: Hi Everybody, We’re having some disagreements regarding the 61000-4-2 standard. In the section “ungrounded equipment”, it states that ungrounded equipment or part(s) of equipment shall have the charge removed in between ESD pulses in order to not over-test. We have a product that only fails pre-compliance when repeated ESD pulses are applied to a floating metal knob without removing the charge in between (eventually there is a second discharge between the knob and the enclosure). The product as a whole is “grounded equipment”. Since the issue only happens when the charge isn’t removed in between pulses, is this a pass or a fail? Thanks, Elliott Martinson Controls Engineer Sub-Zero/Wolf elliott.martin...@subzero.com<mailto:elliott.martin...@subzero.com> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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