Nick, For what it's worth, I took the IEE BS7671 Design course a few years ago. In one exercise, you were quoted by the electrical supplier a prospective short circuit current Ip of 25kA (3 phase) "in the road", and you have to calculate a more realistic value of Ip at the origin of the installation. You calculate Zphase ... divide 400 V by sqrt 3 and Zphase... and the answer was 12.83 kA.
I would guess that you get quoted values of interrupt current from the power utilities, just as you do in North America, and you would expect them to be on the order of tens of kAs. Regards, Don Gies, N.C.E Senior Product Compliance Engineer Lucent Technologies Holmdel, NJ 07733 USA From: Nick Williams [mailto:[email protected]] Sent: Tuesday, October 18, 2005 4:49 AM To: [email protected] Subject: Domestic electrical supply fault currents Can someone point me to a resource which gives typical maximum fault currents available from a domestic electrical supply in the UK? BS 7671 discusses the issue and gives methods for calculation of temperature rise under fault conditions, as well as maximum fault clearing times, but it doesn't appear to give any numbers for the fault currents. I have no feel for what sort of numbers are actually involved although I suspect that it will be in the kA range. Rgds Nick. - 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 [email protected] Instructions: http://listserv.ieee.org/listserv/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] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - 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 [email protected] Instructions: http://listserv.ieee.org/listserv/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] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
