In message <00AEA30D28014979B44664EAB0477931@MmPc21>, dated Sat, 4 Apr 2009, Piotr Galka <[email protected]> writes:
>Consider electric installation with zeroing and not grounding. I'm not >sure how it is in another countries so to be precise grounding is the 3 >wire installation, and zeroing is the 2 wire installation, but with 3 >contact sockets (the grounding pin in each socket is connected with >neutral power cable). >All house buildings older than about 10 years in Poland have zeroing >and not grounding. In most countries, that technique (TN-C-S) is used only if the combined neutral and grounded conductor is grounded at many places, so that if it breaks, load current is distributed among the grounding points and remains at safe values in all conductors. Your point, effectively about SELV being preferred to PELV where the power circuit protection is by fuses, is valid, being the lesser of two evils (increased risk of electric shock, versus increased risk of fire, if segregation is violated). -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk Things can always get better. But that's not the only option. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - 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]>
