There are two kinds of arcing. Air will not break down below 327 volts peak or dc (not 420 V). (Paschen's Law.) Below 327 volts, the arc is due to the small contact area during mate or break due to resistive connection and molten metal vaporizing or burning. (Above 327 volts, an arc may be comprised of both kinds.)
Rich > -----Original Message----- > From: Boštjan Glavič [mailto:[email protected]] > Sent: Friday, December 02, 2016 10:46 PM > To: [email protected] > Subject: Re: [PSES] pre-mating of PE in hot-plug > connector > > Thank you Ted. That was actually a concern of the > customer if there is an arcing. Or for example if unit is > broken(damaged basic insulation to PE) and plugged into > the rack. Can it result in hazardous situation? > > One thing also bothers me. In hazard based standard there > is no requirement for distance between tip of the test finger > and bare hazardous part if voltage is below 420V. The air > will not break down because of Paschens law. > > So can I expect the same for module that is plugged into > the rack - no arcing? > > Best regards > Bostjan > > > > > > On 2. dec. 2016, at 22.42, Ted Eckert > <000007cf6ebeab9d-dmarc- > [email protected]<mailto:000007cf6ebeab9d-dmarc- > [email protected]>> wrote: > > I would also recommend considering the anticipated > voltages on the connector. Higher voltages are capable of > arcing across larger air gaps, and they would require > keeping the ground engaged past the point where the air > gap is large enough to suppress arcing. > > Ted Eckert > Microsoft Corporation > > The opinions expressed are my own and do not necessarily > reflect those of my employer. > > From: Richard Nute [mailto:[email protected]] > Sent: Friday, December 2, 2016 10:10 AM > To: [email protected]<mailto:EMC- > [email protected]> > Subject: Re: [PSES] pre-mating of PE in hot-plug > connector > > > The requirement is, as you have quoted, that the PE > connection mate first and break last. There is no > dimensional requirement as such will be a function of the > overall design. > > The requirement must be met when mating planes are not > parallel due to the design and tolerances of the parts. > > Rich > > > > From: Boštjan Glavič [mailto:[email protected]] > Sent: Friday, December 02, 2016 3:45 AM > To: [email protected]<mailto:EMC- > [email protected]> > Subject: [PSES] pre-mating of PE in hot-plug connector > > Dear Experts, > > One customer is designing own connector for hot-plug > application (power supply). Question is how much longer > shall be PE pin than supply pins. Which standard shall be > used for such connector? > > For reference you can see similar connector on below link. > > http://www.harting.com/en/service/catalogues/downl oads- > and-order-connectivity-networks/din-41612-connecto rs/ > > > I have checked UL 1977 and there is no such requirement. > > Somewhere I found a note that applicable standard is IEC > 60603-2 however I am not sure if requirement for > dimension of PE pin is included. > > I am surprised that no such requirement exist in IEC > 60950-1 or IEC 62368-1. They just mention in clause > 2.6.5.4 that PE connection shall make earlier and brake > later than the supply connections. > > Any idea? > > Thank you for your support. > > Best regards, > Bostjan > > > - > -------------------------------------------------- -------------- > > 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]<mailto:emc- > [email protected]>> > > All emc-pstc postings are archived and searchable on the > web at: http://www.ieee-pses.org/emc-pstc.html > > Attachments are not permitted but the IEEE PSES Online > Communities site at http://product-compliance.oc.ieee.org/ > can be used for graphics (in well-used formats), large files, > etc. > > Website: http://www.ieee-pses.org/ > Instructions: http://www.ieee-pses.org/list.html (including > how to unsubscribe)<http://www.ieee-pses.org/list.html> > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > Scott Douglas > <[email protected]<mailto:[email protected]>> > Mike Cantwell > <[email protected]<mailto:[email protected]>> > > For policy questions, send mail to: > Jim Bacher > <[email protected]<mailto:[email protected]>> > David Heald > <[email protected]<mailto:[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]<mailto:emc- > [email protected]>> > > All emc-pstc postings are archived and searchable on the > web at: http://www.ieee-pses.org/emc-pstc.html > > Attachments are not permitted but the IEEE PSES Online > Communities site at http://product-compliance.oc.ieee.org/ > can be used for graphics (in well-used formats), large files, > etc. > > Website: http://www.ieee-pses.org/ > Instructions: http://www.ieee-pses.org/list.html (including > how to unsubscribe)<http://www.ieee-pses.org/list.html> > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > Scott Douglas > <[email protected]<mailto:[email protected]>> > Mike Cantwell > <[email protected]<mailto:[email protected]>> > > For policy questions, send mail to: > Jim Bacher > <[email protected]<mailto:[email protected]>> > David Heald > <[email protected]<mailto:[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]<mailto:emc- > [email protected]>> > > All emc-pstc postings are archived and searchable on the > web at: http://www.ieee-pses.org/emc-pstc.html > > Attachments are not permitted but the IEEE PSES Online > Communities site at http://product-compliance.oc.ieee.org/ > can be used for graphics (in well-used formats), large files, > etc. > > Website: http://www.ieee-pses.org/ > Instructions: http://www.ieee-pses.org/list.html (including > how to unsubscribe)<http://www.ieee-pses.org/list.html> > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > Scott Douglas > <[email protected]<mailto:[email protected]>> > Mike Cantwell > <[email protected]<mailto:[email protected]>> > > For policy questions, send mail to: > Jim Bacher > <[email protected]<mailto:[email protected]>> > David Heald > <[email protected]<mailto:[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.ieee-pses.org/emc-pstc.html > > Attachments are not permitted but the IEEE PSES Online > Communities site at http://product-compliance.oc.ieee.org/ > can be used for graphics (in well-used formats), large files, > etc. > > Website: http://www.ieee-pses.org/ > Instructions: http://www.ieee-pses.org/list.html (including > how to unsubscribe) > 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.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) 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]>
