Unfortunately, our standards require us to assign a “class” to every product (subject to the standard). Such product assignment (identification) has nothing to do with the safety of the product.
Consider a mains wall outlet. What class is it? We can plug in a Class I or Class II product. In unshuttered mains outlets, you can touch the contact holes. Only clearance (air insulation) between you and live parts. Clearly, the holes are Class II construction. Yet the outlet has a ground/earth terminal behind one of the holes for connection of a Class I product. Fortunately, mains outlets are not subject to Class I or Class II construction identification. And now, some outlets include USB power terminals. USB is Class III. As I said before, most Class I products include Class II construction that is unrecognized by our safety standards. Best regards, Rich From: John Woodgate <[email protected]> Sent: Tuesday, May 20, 2025 11:12 AM To: [email protected] Subject: Re: [PSES] Safety - Class I or Class II That's right, but at one time, IEC 62368-1 said, effectively, that the mere presence of a PE contact at the inlet made the product Class I, but I hope it no longer says, or implies, that. On 2025-05-20 18:46, Ralph McDiarmid wrote: Assuming it can be shown through test and inspection using criteria from the applicable standard(s), it’s Class II. The PE conductor has no safety function in the example you provide. From: [email protected] <mailto:[email protected]> <mailto:[email protected]> <[email protected]> Sent: May 19, 2025 4:06 AM To: [email protected] <mailto:[email protected]> Subject: [PSES] Safety - Class I or Class II A product is designed as a Class II product. But the product has a protective earth (PE) terminal connection. This PE-connection has no further connection on the PCB. It exists only so the electricians have a place to connect the PE wire, which always are present in the AC cable. Is such a product a Class II or does the PE connection, make it Class I? BR Amund - ---------------------------------------------------------------- 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
