If I am not missing something obvious, the construction answers the question.
Class II construction does not have to depend on a protective earth for protection against shock, so there is no need for the ground pin. Perhaps we have a 'terminology disconnect' - are you referring to an "IT power distribution system", or perhaps a "Class 2 output" ? Note that for connection to an IT power distribution system (which could be either isolated or separated by some impendence from any 'system' earthing), it may not be possible to clearly indicate the earthed conductor to mains, so there are additional requirements for mains disconnect. I have advised designers, for equipment designed to be connected to an IT power distribution system, to not rely on any ground bonding for protection against shock. Additional note - UL listings will sometimes indicate "IT Power Source"; this is NOT referring to an IT power distribution system. luck, Brian > -----Original Message----- > From: emc-p...@ieee.org [mailto:emc-p...@ieee.org]On Behalf Of > Carpentier Kristiaan > Sent: Friday, October 05, 2007 2:18 AM > To: emc-p...@ieee.org > Subject: Class II PSU for IT power systems > > Hi Group, > > Does it make sense to test a Class II wall plug PSU for IT > power systems > as there is no PE pin on such a PSU? > Some CB reports mention that testing for IT power systems is done and > some don't. > > Best regards, > > Kris Carpentier > Regulatory & Approvals - 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 emc-p...@ieee.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: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc ______________________________________________________________________ This e-mail has been scanned by MCI Managed Email Content Service, using Skeptic(tm) technology powered by MessageLabs. For more information on MCI's Managed Email Content Service, visit http://www.mci.com. ______________________________________________________________________
