Here is an answer for the whole community. Best regards,
Dave Osborn PM-CMS Philips Medical Systems PMS-158 3178 +1 978 659 3178 fax +1 978 685 5624 [email protected] To <[email protected]> "Jon Griver" <[email protected]> "Mike Schmidt" cc <[email protected] Dave Osborn/ANR/MS/PHILIPS@PHILIPS > Subject FW: 60601-1 and patient leakage 10/11/2005 01:46 PM current Classification Please respond to <[email protected] > Dear Doug, As Secretary of IEC/SC 62D (Subcommittee that published 60601-2-38) and as the former convener of the hospital bed working group, I would like to provide some insights on your question about measuring leakage currents for hospital beds. Your question regarding note 3 suggests that you've misunderstood the note or that your bed is extremely unusual in how it connects to the mains. Note 3 addresses equipment that is permanently installed. This means that the connection to mains and protective earth are "hard wired" into the institution's mains voltage and protective earth (and protective earth) distribution system (not connected by a standard power cord). The bed would have to be connected to mains and protective earth such that a tool would be required to disconnect the bed to qualify under Note 3. I have never seen such an arrangement for a hospital bed. The requirement of clause 52.5.4 (interruption of protective earth) of 60601-1 is performed for all equipment connected to the mains through a plug/outlet. Patient leakage currents (under the single fault condition of interruption of protective earth and normal condition) are measured from all applied parts (in essence the surface & siderails of the bed) to earth. Enclosure leakage is measured from the rest of the bed to earth. Patient auxiliary current is measured between parts of the applied part. Where the applied part or enclosure are made of plastic or other non-conductive materials, those parts are covered by foil and leakage is measured from the foil. 60601-2-38 does not modify the leakage current measurement requirements of the general standard (other than identifying what is considered the applied part), so the same requirements apply for beds that apply for any other medical electrical equipment. If in fact your bed is hard wired into the hospital mains and protective earth distribution system, the higher limits for earth leakage current (leakage current flowing through the protective earth conductor for the whole device) would apply. I hope this proves helpful. Feel free to contact me if you have further questions. If you do not have a copy of the 60601-2-38, I strongly suggest you acquire one because there are many requirements that do go beyond the requirements of the general standard. Best regards, Mike Schmidt Strategic Device Compliance Services www.devicecompliance.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/listserv/request/user-guide.html 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] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
