Hi Don,
Further to what Joe has stated below, according to IEC 60950-1 an ethernet interface circuit is generally characterized as an SELV circuit, but must also be considered a TNV-1 circuit if it is subject to overvoltages (atmospheric conditions). You might also want to read through CENELEC CLC/TR 62102 (replaced ETSI EG 201212) entitled “Electrical safety - Classification of interfaces for equipment to be connected to information and communications technology networks” if you haven’t done do already. I don’t believe there is a hard and firm LPS requirement for power supplies in general nor do I believe that unique LPS certifications are even available. The LPS qualification is usually formally evaluated as part of formal safety approval testing to IEC 60950-1 for instance, which is also noted in that safety report. The LPS marking on the power supply is a result of that. Although with that said, LPS may more likely be more of a customer requirement rather than regulatory, whereby there should be an adequate selection of LPS and non-LPS PoE invertors. LPS selection should depend on a customer’s specific requirements and the specific application. IMHO, for a safer installation, LPS PoE injectors should be considered. IHTH. I look forward to your reply. Best regards, Ron Pickard RPQ Consulting Glendale, AZ 85303 +623.512-3451 tel, +623.848-9033 fax [email protected] www.rpqconsulting.com <http://www.rpqconsulting.com/> www.linkedin.com/in/RonPickard ________________________________ From: [email protected] [mailto:[email protected]] On Behalf Of Joe Randolph Sent: Wednesday, March 25, 2009 9:20 PM To: Umbdenstock, Don; [email protected] Subject: Re: PoE injectors On 3/25/2009, Don Umbdenstock wrote: I have perused the IEEE 802.3af explanation on various web sites and examined supplier specs. I came to the conclusion that the injector should be LPS certified and marked as such. However, most of the injectors I have found by web search do not indicate LPS. Does anyone believe that a PoE injector does not require LPS certification? If so, why not? Hi Don: I'm not certain what you mean by "LPS certification," but if you meant to ask if the Ethernet side of the injector should be safety certified as a SELV circuit, I believe the answer is yes. For safety analysis per UL 60950 and other similar versions of IEC 60950, the voltages that appear on an Ethernet cable are generally considered to be SELV, whether or not the circuit has POE provisions. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 (USA) [email protected] http://www.randolph-telecom.com <http://www.randolph-telecom.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 <[email protected]> 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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher <[email protected]> David Heald <[email protected]> - 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.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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher <[email protected]> David Heald <[email protected]>
