Does it matter for the discussion that: 1) Power is not present at the output of the source unless the other side of the cable connects to a PD (powered device) which "signals" to the sourcing equipment it is a PD and to turn it on. If you unplug the PD, the power goes off.
2) The power supply in the sourcing equipment are isolated per IEEE 802.3 (1500Vrms). ? Neven From: "Don Umbdenstock" <djumbdenst...@tycoint.com> To: emc-p...@ieee.org Sent: Wednesday, March 25, 2009 1:42:50 PM GMT -08:00 US/Canada Pacific Subject: RE: PoE injectors Let me share some of my thought process with you. Hazard based consideration and 60950 would suggest that if a power source (injector) can provide more than 15W, then a fire enclosure or other means of fire protection is necessary. Other means to prevent fire when a fire enclosure is not provided includes LPS source, product built with V-1 or better circuit boards, etc. Most injectors provide more than 15W to be able to power more than one device and handle line loss. Thus it would seem intuitive that the PoE injector (or switch) would be LPS. What's the rest of the story that I'm missing? Don 561 912 6440 From: Umbdenstock, Don Sent: Wednesday, March 25, 2009 4:34 PM To: emc-p...@ieee.org Subject: FW: PoE injectors Hi Pat, LPS means "limited power source" per 60950 Clause 2.5; this is the basis of my question. Don 561 912 6440 From: pat.law...@slpower.com [mailto:pat.law...@slpower.com] Sent: Wednesday, March 25, 2009 12:14 PM To: Umbdenstock, Don Cc: emc-p...@ieee.org Subject: Re: PoE injectors Hi Don, What does 'LPS' mean in this context? Pat Lawler EMC Engineer SL Power Electronics Corp. "Umbdenstock, Don" <djumbdenst...@tycoint.com> wrote on 03/25/2009 07:23:54 AM: > 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? > > Regards, > > Don Umbdenstock > Manager Compliance Engineering > > Tyco Safety Products / Sensormatic > 6600 Congress Avenue > Boca Raton, FL 33487 USA > Phone: 561.912.6440 > djumbdenst...@tycoint.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 <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...@ptcnh.net> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.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 <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...@ptcnh.net> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher <j.bac...@ieee.org> David Heald <dhe...@gmail.com>
