In message <[email protected]>, dated Mon, 6 Apr 2009, Brian O'Connell <[email protected]> writes:
>When you refer to "mains circuits", does this mean the 'mains' power >that enters the building, or is the individual distribution >circuit/node being reference ? > >Do you mean that a fuse, for an indvidual appliance, is better for >protection from fire than a breaker ? No, this is a very specific case, of 'power cross' on to thin data cables. If the data cable conductors are ground-referenced (PELV), the cable may overheat because the fault current is not sufficient to clear a fuse or over-current breaker, but is very unlikely to be insufficient to operate a GFCI or RCD. If the data cable conductors are not ground referenced (SELV), then the 'power cross' can remain undetected, probably until someone touches the SELV circuit. -- 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]>
