Conflict of interest note - my employer makes medical component power supplies.
There is more to the 'Listing' vs 'Recognized Component' - the UL website explains this for some CCNs. They also talk about this in various PAGs. There are also issues with how to asses a Listed power source to 60601-1-2. An "external" power source, if exposed to the user or to most operating environments, may have to be LISTED for its intended end use. The equipment risk assessment for end-use equipment may present some problems if you just plug its report into your report. Brian From: emc-p...@ieee.org [mailto:emc-p...@ieee.org]On Behalf Of Bryce Stammerjohan Sent: Monday, November 02, 2009 2:00 PM To: emc-p...@ieee.org Subject: RE: [PSES] Medical Grade Brick Power Supplies not Listed? Carl, Yes, it is confirmed. Med grade supplies are Recognized only and are covered under UL Category QQHM2 (the "2" indicating a U.S. Component, as opposed to a Canadian standard component, but a component nonetheless). ITE power supplies can be covered under QQGQ (Listed) or QQGQ2 (Recognized Component), primarily. The Listing of ITE brick supplies was a concession to the massive ITE product mfrs. lobby; it allows them to buy supplies that have been tested further, and thus relieves them of some compliance testing requirements of their products. I would guess that the med device world does not have that much clout with supply mfrs. Given the variable leakage limits for different types of med devices (B, BF, CF), UL probably would not allow Listing of power supplies. Truth be told, the difference in testing of a medical device if it had a Listed supply vs. a Recognized supply is probably minimal for most cases. OOO - Own opinions only, not any current or former employers' Bryce Stammerjohan | Research & Development Engineer Thoratec Corporation | 6035 Stoneridge Drive, Pleasanton, CA 94588 From: Carl Newton [mailto:emcl...@gmail.com] Sent: Monday, November 02, 2009 12:20 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: [PSES] Medical Grade Brick Power Supplies not Listed? Dear List Members, I'm new to medical safety compliance and I've been told that medical grade external (brick) ac/dc converters can only be R/C and not Listed. I've done some brief searches in the UL database and elsewhere and that does appear to be the case at a glance. Would one of you with experience with this issue please confirm or deny? It's my understanding that the two issues for medical grade are low leakage current and high electric strength. I don't understand why the medical grade brick can't be Listed. Thanks in advance, Carl - 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.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <emcp...@socal.rr.com> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
