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/> | ja...@unit3compliance.co.uk <mailto:ja...@unit3compliance.co.uk> +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 <mailto:he...@unit3compliance.co.uk> he...@unit3compliance.co.uk or call 01274 911747. Our lead times for testing and consultancy are typically 4-5 weeks. From: Joe Randolph <j...@randolph-telecom.com> Sent: Monday, September 25, 2023 5:58 PM To: 'James Pawson (U3C)' <ja...@unit3compliance.co.uk>; EMC-PSTC@LISTSERV.IEEE.ORG 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) j...@randolph-telecom.com <mailto:j...@randolph-telecom.com> http://www.randolph-telecom.com From: James Pawson (U3C) [mailto:ja...@unit3compliance.co.uk] Sent: Monday, September 25, 2023 4:55 AM To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 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/> | ja...@unit3compliance.co.uk <mailto:ja...@unit3compliance.co.uk> +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 <mailto:he...@unit3compliance.co.uk> he...@unit3compliance.co.uk or call 01274 911747. Our lead times for testing and consultancy are typically 4-5 weeks. From: Joe Randolph <j...@randolph-telecom.com <mailto:j...@randolph-telecom.com> > Sent: Friday, September 22, 2023 7:47 PM To: 'James Pawson (U3C)' <ja...@unit3compliance.co.uk <mailto:ja...@unit3compliance.co.uk> >; EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 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: <https://randolph-telecom.com/wp-content/uploads/2021/03/New-requirements-fo r-MOVs-Randolph-October-2018_MOD-6015.pdf> New Requirements for MOVs used for Surge Protection on AC Mains Ports (randolph-telecom.com) Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 (USA) j...@randolph-telecom.com <mailto:j...@randolph-telecom.com> http://www.randolph-telecom.com <http://www.randolph-telecom.com/> From: James Pawson (U3C) [mailto:ja...@unit3compliance.co.uk] Sent: Friday, September 22, 2023 5:16 AM To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 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) <ja...@unit3compliance.co.uk <mailto:ja...@unit3compliance.co.uk> > Sent: Friday, September 22, 2023 9:30 AM To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 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 <https://www.evs.ee/en/evs-en-61643-21-2002-a2-2013> 61643-21 (surge suppressors in telecommunications application) - IEC <https://www.evs.ee/en/evs-en-61643-311-2013> 61643-311 (gas discharge tubes) - IEC <https://www.evs.ee/en/evs-en-61643-321-2003> 61643-321 (avalanche breakdown diodes) - IEC <https://www.evs.ee/en/evs-en-iec-61643-331-2020> 61643-331 (metal oxide varistors) - IEC <https://www.evs.ee/en/evs-en-iec-61643-341-2020> 61643-341 (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 <http://www.unit3compliance.co.uk/> www.unit3compliance.co.uk | <mailto:ja...@unit3compliance.co.uk> ja...@unit3compliance.co.uk +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 <mailto:he...@unit3compliance.co.uk> he...@unit3compliance.co.uk 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. 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