In message <[email protected]>, dated Wed, 12 Dec 2007, Curt McNamara <[email protected]> writes:
>I admit to not having followed all this -- however I know an engineer >who works on building issues for people. Supposedly the most >significant problem is the neutral bonding to ground inside the house. >If this is done in such a way that significant neutral current flows >through the pipes instead of the wiring then there is significantly >more 60Hz magnetic field. That isn't anything to do with unhappy cows, but IS another example of the care needed when considering current paths. > >The folks most concerned are those with autistic kids, who seem to be >more sensitive to this. That's a fraught field (pun!). Being autistic, they have difficulty in communication, so their 'sensitivity' lacks a reference point. But ipso facto they have less to distract them, so whatever effect the field might have is more noticeable to them. > >The typical fix is to isolate (electrically) the pipes inside the house >from the main (with a piece of plastic pipe). > >If you want any more details please send questions to me and I will >forward to him. In Europe, we use audio-frequency induction-loop systems to assist the hearing of partially-deaf people. The mains-frequency fields set up by split neutral current paths, or separated line and neutral cable runs, can be a major problem, But gain, no cows involved! > >As to personal experience, as a teenager I used to work on TV antennas >and found the voltage present at the terminal of a receive antenna on a >roof was surprisingly strong. Typically I couldn't keep my fingers on >it and needed insulation. It is possible this was related to weather >conditions. The Earth's DC electric field is around 300 V/m under normal weather conditions, so you experience is not unexpected. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk For very important information, please turn over. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - 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/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
