Hi Joe,
802.3af indicates the isolation requirement. Does the concept of the defined use of the product to be within a building, not connected to systems outside of the building, exclude the product from the isolation requirement? If the product is defined to be used only within a building, would it be considered in conformance with 802.3af without isolation provisions? Don Umbdenstock 561 912 6440 From: [email protected] [mailto:[email protected]] On Behalf Of Joe Randolph Sent: Friday, September 11, 2009 5:54 PM To: Brian O'Connell; [email protected] Subject: RE: Additional electrical requirements - isolation On 9/11/2009, Brian O'Connell wrote: I do not think that Telecordia and IEEE standards are addressing just the isolation requirements for devices connected to wired ethernet or wifi. There are problems with mains isolation and OV and misc external wiring. Recently looked at a problem for a local school - they thought that they had isolated some battery-operated equipment using wifi through a wireless router, but it was connected to several other devices through a wired RJ connector on the back of the router, that were in turn connected to the 'isolated' wireless device. One of the devices was outside the building and they had people getting "mild" shocks. As I do not have much experience in this area (paging Mr Joe Randolph, please), I would appreciate advice on how/if the requirements of UL60950-1 clause 6.1.1 is intended to affect the construction requirements of this stuff. Hi Brian: If you introduce Telcordia standards into this discussion, things will likely get even more complex than they already are with just IEEE and UL, but we can try. I think some of the confusion that enters into such discussions relates to the fact that standards often use descriptive language for something that is actually a very precise technical term within the context of that standard (and only within the context of that standard). For example, in UL 60950, the term "Telecommunications Network" is written in capital letters to indicate that it is a technical term that is defined elsewhere in the standard. In this case, the definition appears in clause 1.2.13.8. Within the context of UL 60950, a "Telecommunications Network" is one that is intended to connect different buildings and is exposed to outside hazards such as lightning and power cross. Within the context of UL 60950, the conventional IEEE 802.3af Ethernet used for networking within a building is not a "Telecommunications Network." In view of this, clause 6 of UL 60950 does not apply to conventional Ethernet networks. Now, when we go to Telcordia GR-1089, the definition in Appendix D for "Telecommunications Port" says, (paraphrased here) "Paired conductor interfaces....including Ethernet." So, conventional Ethernet is a "Telecommunications Port" in the context of Telcordia GR-1089, but it does not connect to a "Telecommunications Network" in the context of UL 60950. 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]>
