Hi Craig:
With regard to clearance, air is the insulator. As you go up in altitude, there is less air, so there is less insulation. And lower dielectric strength. So, to get the same amount of air (and the same dielectric strength) between the two conductors, you need more distance (clearance). Creepage is the interface between solid insulation and air insulation. Physically, creepage cannot be less than clearance. Degradation of the solid insulation surface (creepage) is a long-term effect largely due to deposition of foreign matter on the insulation surface. Best regards, Rich On 2/26/2010 04:12, Petrie, Craig D wrote: > Hello, > Can anyone tell me the link between creepage/clearance and altitude? Why > do these values need increased at greater altitudes? > Regards > Craig > *Craig D. Petrie > **Product Safety Engineer > * > - > ---------------------------------------------------------------- > 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:[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] <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.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]>
