Hello James, depending on the product safety standard and the certification scheme, a certification to the applicable IEC component standard (e.g. IEC 61051-2) may not be mandatory. In many cases, IEC product safety standards do not reference a varistor component standard like IEC 61051-2 explicitly, but rather have a general requirement like "Components shall comply with applicable component standards." While UL product safety standards are typically very strict, that only recognized components are accepted that comply with the applicable UL component standard, the IECEE CB scheme also allows components that are either tested as part of the application, or are certified according to a non-IEC standard. Please check OD-2039 "Acceptance of components within the IECEE CB Scheme and component acceptance matrix" (https://www.iecee.org/dyn/www/f?p=107:558:::::P558_DOCUMENT_FILE_ID:3146744), specifically clause 5.1.2.4, that allows components to be accepted at the discretion of the receiving Certification Body, even if an IEC standard is applicable (e.g. IEC 61051-2), but has been certified according to a non-IEC standard (e.g. UL 1449). So you should check early with your Certification Body whether they accept UL component certificates in lieu of IEC component certificates.
Kind regards, Bernd Von: James Pawson (U3C) <[email protected]> Gesendet: Dienstag, 26. September 2023 09:29 An: [email protected] Betreff: Re: [PSES] EN 62368-1:2020 - MOVs - contradiction? [EXTERNAL E-MAIL] This email originated from outside of the organization. Do not click links or open attachments unless you recognize the sender. Thanks Joe, we shall do a bit more digging. The response we had from one of the manufacturers was "UL 1449. That's it." All the best James James Pawson Managing Director & EMC Problem Solver Unit 3 Compliance Ltd EMC : Environmental & Vibration : Electrical Safety : CE & UKCA : Consultancy www.unit3compliance.co.uk<http://www.unit3compliance.co.uk/> | [email protected]<mailto:[email protected]> +44(0)1274 911747 | +44(0)7811 139957 2 Wellington Business Park, New Lane, Bradford, BD4 8AL Registered in England and Wales # 10574298 Office hours: Every morning my full attention is on consultancy, testing, and troubleshooting activities for our customers' projects. I'm contactable between 1300h to 1730h from Monday to Friday. For inquiries, bookings, and testing updates please send us an email on [email protected]<mailto:[email protected]> or call 01274 911747. Our lead times for testing and consultancy are typically 4-5 weeks. From: Joe Randolph <[email protected]<mailto:[email protected]>> Sent: Monday, September 25, 2023 5:58 PM To: 'James Pawson (U3C)' <[email protected]<mailto:[email protected]>>; [email protected]<mailto:[email protected]> Subject: RE: [PSES] EN 62368-1:2020 - MOVs - contradiction? Hi James: This finding surprised me, since MOVs are routinely used internationally for surge protection on the AC mains input to power supplies. Is that the application you have in mind? Typically, MOVs have multiple approvals. So, having a UL approval does not necessarily mean that the same part has no other international approvals. To find the complete list of approvals, it is sometimes necessary to do a deep dive into the "Agency Approvals" list that is typically provided on a sub-page for the web site listing. A quick check of the Littelfuse site shows the C-III series having VDE approval to IEC 61051-2, although this MOV does not have the thermal fuse function that is very useful for compliance with Annex G.8 of 62368-1. The Littelfuse TMOV series is an MOV that contains a thermal fuse, which makes it very useful for complying with Annex G.8. This series also has VDE approval to IEC 61051-2. I hope this helps. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 (USA) [email protected]<mailto:[email protected]> http://www.randolph-telecom.com<http://www.randolph-telecom.com/> From: James Pawson (U3C) [mailto:[email protected]] Sent: Monday, September 25, 2023 4:55 AM To: [email protected]<mailto:[email protected]> Subject: Re: [PSES] EN 62368-1:2020 - MOVs - contradiction? Hello Joe, Thanks for the feedback and the article link, much appreciated. We are seeing a lot of varistors from large manufacturers (Wurth, Bourns, Littelfuse) declaring compliance to UL1449 rather than the IEC standards. This makes recommending parts to our customers a bit harder. If you or anyone else knows of a comparison between UL 1449 and the IEC standards then please let me know as we would like to understand more. All the best James James Pawson Managing Director & EMC Problem Solver Unit 3 Compliance Ltd EMC : Environmental & Vibration : Electrical Safety : CE & UKCA : Consultancy www.unit3compliance.co.uk<http://www.unit3compliance.co.uk/> | [email protected]<mailto:[email protected]> +44(0)1274 911747 | +44(0)7811 139957 2 Wellington Business Park, New Lane, Bradford, BD4 8AL Registered in England and Wales # 10574298 Office hours: Every morning my full attention is on consultancy, testing, and troubleshooting activities for our customers' projects. I'm contactable between 1300h to 1730h from Monday to Friday. For inquiries, bookings, and testing updates please send us an email on [email protected]<mailto:[email protected]> or call 01274 911747. Our lead times for testing and consultancy are typically 4-5 weeks. From: Joe Randolph <[email protected]<mailto:[email protected]>> Sent: Friday, September 22, 2023 7:47 PM To: 'James Pawson (U3C)' <[email protected]<mailto:[email protected]>>; [email protected]<mailto:[email protected]> Subject: RE: [PSES] EN 62368-1:2020 - MOVs - contradiction? Hi James: Yes, I think you have arrived at the correct interpretation. The committee was simply trying to reduce the scope of Annex G.8 in order to avoid re-stating requirements that already appear in other IEC standards. Otherwise, Annex G.8 would have been much longer than just three pages. Annex G.8 provides the option to comply completely with either of two IEC standards, or, alternatively, just specified parts of either one. In practice, I think it would be hard to find a commercial MOV that does not comply fully with one of the two listed IEC standards. So, it may not be necessary to resort to testing to a specific subset of the requirements in either IEC standard. However, the committee wanted manufacturers to have that option. By the way, if you expect to be delving more deeply into the requirements in Annex G.8, in 2018 I wrote an article in InCompliance Magazine that attempts to clarify what the requirements are intended to cover and the rationale behind them. Here is a link to the article: New Requirements for MOVs used for Surge Protection on AC Mains Ports (randolph-telecom.com)<https://randolph-telecom.com/wp-content/uploads/2021/03/New-requirements-for-MOVs-Randolph-October-2018_MOD-6015.pdf> Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 (USA) [email protected]<mailto:[email protected]> http://www.randolph-telecom.com<http://www.randolph-telecom.com/> From: James Pawson (U3C) [mailto:[email protected]] Sent: Friday, September 22, 2023 5:16 AM To: [email protected]<mailto:[email protected]> Subject: Re: [PSES] EN 62368-1:2020 - MOVs - contradiction? Hello me again, Whilst the wording of the standard is not entirely clear, after a bit of head scratching my interpretation is: EN 62368-1:2020 * 5.5.7: MOVs must comply with G.8 (not necessarily with the IEC standard) * G.8.1: comply with either * IEC 61051-2, or * IEC 61643-331:2017, or * The parts of IEC 61051-2 or IEC 61643-331:2017 that are listed in this G.8.1 for the following tests (i.e. the bit that says "taking into account all of the following") * Climate rating * Continuous voltage * Combination pulse * Needle flame (there are plenty more tests in the MOV standards that are NOT called up) Essentially: Comply with IEC standards or do the relevant tests from the IEC standards All the best James From: James Pawson (U3C) <[email protected]<mailto:[email protected]>> Sent: Friday, September 22, 2023 9:30 AM To: [email protected]<mailto:[email protected]> Subject: [PSES] EN 62368-1:2020 - MOVs - contradiction? Hello all, Not sure if this is an amusing contradiction or I'm missing something? See green highlight below. All the best James EN 62368-1:2020 5.5.7 SPDs Where a varistor is used between a mains circuit at ES3 voltage and protective earthing: - the earth connection shall comply with 5.6.7; and - the varistor shall comply with Clause G.8. Where a varistor is used between line and neutral or between lines, it shall comply with Clause G.8. Where an SPD is used between the mains and protective earthing, it shall consist of a varistor and a GDT connected in series, where the following applies: - the varistor shall comply with Clause G.8; - the GDT shall comply with: · the electric strength test of 5.4.9.1 for basic insulation; and · the external clearance and creepage distance requirements of 5.4.2 and 5.4.3 respectively for basic insulation. NOTE 1 Some examples of SPDs are MOVs, varistors and GDTs. A varistor is sometimes referred to as a VDR or a metal oxide varistor (MOV). NOTE 2 It is not a requirement of this document that surge suppressors comply with any particular component standard. However, attention is drawn to the IEC 61643 series of standards, in particular: - IEC 61643-21<https://www.evs.ee/en/evs-en-61643-21-2002-a2-2013> (surge suppressors in telecommunications application) - IEC 61643-311<https://www.evs.ee/en/evs-en-61643-311-2013> (gas discharge tubes) - IEC 61643-321<https://www.evs.ee/en/evs-en-61643-321-2003> (avalanche breakdown diodes) - IEC 61643-331<https://www.evs.ee/en/evs-en-iec-61643-331-2020> (metal oxide varistors) - IEC 61643-341<https://www.evs.ee/en/evs-en-iec-61643-341-2020> (thyristor surge suppressors TSS). And yet... G.8 Varistors G.8.1 General A varistor shall comply with IEC 61051-2 or IEC 61643-331:2017, whether a fire enclosure is provided or not, taking into account all of the following: James Pawson Managing Director & EMC Problem Solver Unit 3 Compliance Ltd EMC : Environmental & Vibration : Electrical Safety : CE & UKCA : Consultancy www.unit3compliance.co.uk<http://www.unit3compliance.co.uk/> | [email protected]<mailto:[email protected]> +44(0)1274 911747 | +44(0)7811 139957 2 Wellington Business Park, New Lane, Bradford, BD4 8AL Registered in England and Wales # 10574298 Office hours: Every morning my full attention is on consultancy, testing, and troubleshooting activities for our customers' projects. I'm contactable between 1300h to 1730h from Monday to Friday. For inquiries, bookings, and testing updates please send us an email on [email protected]<mailto:[email protected]> or call 01274 911747. Our lead times for testing and consultancy are typically 4-5 weeks. ________________________________ 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 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/ Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to unsubscribe)<https://ewh.ieee.org/soc/pses/list.html> List rules: https://ewh.ieee.org/soc/pses/listrules.html 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&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 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/ Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to unsubscribe)<https://ewh.ieee.org/soc/pses/list.html> List rules: https://ewh.ieee.org/soc/pses/listrules.html 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&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 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/ Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to unsubscribe)<https://ewh.ieee.org/soc/pses/list.html> List rules: https://ewh.ieee.org/soc/pses/listrules.html 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&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 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)<https://ewh.ieee.org/soc/pses/list.html> List rules: https://ewh.ieee.org/soc/pses/listrules.html 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&A=1 ________________________________ WILO SE Wilopark 1, 44263 Dortmund Amtsgericht Dortmund, HRB 21356 www.wilo.com Vorstand/Executive Board: Oliver Hermes (President & CEO), Dr. Patrick Niehr, Georg Weber, Mathias Weyers Aufsichtsratsvorsitzender/Chairman of the Supervisory Board: Lars Roßner Dieses Dokument ist vertraulich zu behandeln. Die Weitergabe sowie Vervielfaeltigung, Verwertung und Mitteilung seines Inhalts ist nur mit unserer ausdruecklichen Genehmigung gestattet. Alle Rechte vorbehalten, insbesondere fuer den Fall der Schutzrechtsanmeldung. This document has to be treated confidentially. Its contents are not to be passed on, duplicated, exploited or disclosed without our expressed permission. All rights reserved, especially the right to apply for protective rights. Datenschutz ist uns wichtig! Daher gehen wir sorgsam mit Ihren Daten um. Näheres finden Sie in unseren Datenschutzhinweisen<https://wilo.com/de/de/Wilo-Deutschland/Datenschutzhinweise.html>. Sollten Sie keinen Kontakt mehr mit uns wünschen, wenden Sie sich bitte an [email protected]<mailto:[email protected]>. Data Protection is important to us! Therefore we handle your data carefully. Please find the details in our Note on Data Protection<https://wilo.com/de/de/Note-on-data-protection.html>. If you do not wish to stay in touch with us anymore, please write to [email protected]<mailto:[email protected]>. - ---------------------------------------------------------------- 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
