Hi Vincent:
You asked: 2) Why is there no uniform values for SELV? Example: SELV is defined as voltage not exceeds 25Vrms and 30Vrms for IEC 60601-1 and IEC 60950-1 respectively. SELV is not a voltage but a scheme for protection against electric shock. I think you are asking why aren’t TOUCH VOLTAGES uniform among standards? Touch voltage is defined in IEC TS 61201. For ac, touch voltage varies from 15 volts to 55 volts and depends on contact area and moisture of the contact. Touch voltages are derived from IEC TS 60479-series and are calculated from the body impedance and the current. 30 volts is for dry contact, 1 cm2. 25 volts is for wet contact, 1 cm2. In a medical environment, wet contact may be expected. 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 <[email protected]> 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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
