Dear Boštjan:
You said: Input voltage above 60Vdc can be treated as TNV-2 circuit and according to the standard, it is enough to have basic insulation input to output, however, fault condition tests still need to be conducted. So basic + supplementary is not always required if input is >60VDC. A TNV-2 circuit can be up to 71 volts peak or 120 volts d.c., but it cannot be accessible (to an ordinary person) or connected to a SELV circuit. The separation requirements between TNV-2 and SELV/accessible parts is basic insulation and, if necessary, fault tests. If a dc/dc converter generates greater than SELV in its operation but less than 71 volts peak or 120 volts d.c., I suppose the circuit can be classed as TNV-2, although this seems strange to me. Same for 71 volts peak or 120 volts d.c supply circuit to the converter. (If the output remains SELV during and after a fault test of basic insulation, the test proves that the basic insulation is not necessary; this is a flaw in the standard.) Best regards, Rich - ---------------------------------------------------------------- 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>
