In order for a power supply to meet SELV requirements it must pass all of the tests in the EN60950-1 standard for SELV which means component failure testing among other things, not simply isolation testing. Meanwell power supplies that I have researched have been SELV. Meanwell has been very responsive if you contact technical support and will provide the lab reports showing the power supply passed the relevant SELV clauses in the standard.
If the power supply is UL approved the UL certificate available on the UL web site may indicate whether or not it's SELV as well as power supply class and other basic ratings. -Dave -----Original Message----- From: Piotr Galka [mailto:piotr.ga...@micromade.pl] Sent: Wednesday, November 22, 2017 12:51 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: [PSES] Safe powering 12V doorlock Dear safety experts, Help me to make me sure that it is save to use the following power supply: http://www.meanwell.com/webapp/product/search.aspx?prod=DRC-40 to power 12V doorlock with not earthed 12V supply. I think that from practical point of view it is save but how it looks formally. This supply is TUV EN60950-1 approved, and input to output is tested with 3kVAC. There is no info if output is SELV or ELV. Before asking them if their output is SELV I'd like to know if it has to be SELV, or if from info I have I can find it is SELV. I wont to use this case to learn myself more about safety. Why I'm not sure. 1. I suppose that 12 doorlock manufacturer can use only functional isolation betwean 12V and its metal casing as he can assume (I think) that he gets safe voltage. If I'm wrong with it let me know. 2. Then as doorlock metal casing can be touched by user than 12V have to be SELV circuit I think. 3. I'm not sure if the 12V output from this supply is SELV - is it enough to test the isolation with 3kV. In EN 60950-1:2006 5.2.2 I understand that if output is not grounded or there is no protective screen than table 5C should be used. I assume not earthing 12V. I don't know if there is protective screen inside but as I can imagine such supply there have to be feedback and it is probably opto feedback - so can there be metal screen betwean LED and opto element and opto will work? I'm not sure if I understand well what is screen in accordance with 2.6.1 e). From Annex G I understand that for Overvoltage Category II transient voltage (Europe) will be 2k5V and from table 5C I have 5kV test needed. So 3kV written in datasheet looks being not enough. All till now I have written assuming the Overvoltage Category II. But reading Annex Z I'm not sure if access control system, as permanently installed, is integral building wiring or not. It seems me more like a fuse panel then permanently connected electric cooker. If category III then I end with 8kV testing - much more than 3kV. It is TUV approved and under Applications the producer lists Access Systems so powering doorlock should be save. If it is true - where is my mistake. Best Regards Piotr Galka - ---------------------------------------------------------------- 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 <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com> - ---------------------------------------------------------------- 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 <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
