Ah yes, -sparking, sizzling wire fences... About 40 yrs ago I spent a few summers visiting with an uncle and family on his Iowa farm. He had a small electrified pen with hogs in it. My cousin would dare me to take a blade of grass and loop it around the wire to see how much jolt I could take before letting go. The loop usually burnt through before I reached threshold, unless I ignorantly used a wide blade of buffalo grass...
One heavily dewed morning, we were heading for the car to go to town and another cousin, Kerry Sue (who lived on the farm), excitedly ran toward the car (to occupy the shotgun position) that was parked adjacent to the hog pen. She slipped on the wet weeds. Her body slid under the electrified wires, wrapping her long hair around the lowest conductor. We stood around and laughed as she yelled and convulsed from the pulses. You could actually see tiny arcs in her hair. -maybe that's why to this day she is so docile... Most of these chargers are rated by the miles of wire they can energize, up to 20 miles worth! I seem to remember versions that were battery powered and only a few that were line powered. Determining safety requirements for these is why we get the big bucks...<grin> Happy Labor Day Holiday (USA), Kyle ----- Original Message ----- From: "Pettit, Ghery" <ghery.pet...@intel.com> To: "'John Allen'" <ja014d7...@blueyonder.co.uk>; "Ablewisp - Compliance Consultants" <s...@ablewisp.com>; "Emc-Pstc" <emc-p...@majordomo.ieee.org> Sent: Thursday, August 29, 2002 4:01 PM Subject: RE: Electric Fence Controllers > > Reminds me of when my son (now 25) was very young. We were visiting > relatives in California who used electric fences to keep the cattle where > they belonged. We were sitting around talking when my son came into the > house with eyes as big as saucers to report that "the fence shook me!". It > took a moment for us to realize what had happened, and then the poor kid had > to listen to us all crack up. He grabbed the wire between pulses, then got > the treatment. He's been very careful around electric fences ever since. > And these fencers were used on multiple thousand foot runs of wire. You > could find the shorts to vegetation by walking the fence and listening for > the arc. > > Ghery Pettit > > -----Original Message----- > From: John Allen [mailto:ja014d7...@blueyonder.co.uk] > Sent: Thursday, August 29, 2002 1:51 PM > To: Ablewisp - Compliance Consultants; Emc-Pstc > Subject: Re: Electric Fence Controllers > > > > Hi Folks > > I once (about 12 years ago) had the dubious priviledge of being the Comittee > Secretary for the UK BSI standards committee dealing with these beasts at > British & International levels! > > This question was never asked (that was probably before my time!) but it was > my impression that these had fallen into the "too difficult" category and > the Commission at the time of the Directive (1972/73)ducked the issue to > ensure that it got agreed and that all the more common items got dealt > with.. > > There certainly was (and probably still is - which is why the situation in > the Directive does not appear to have changed) a considerable difference of > opinion between various countries as their safety and what the voltage and > particular pulse tim/energy limits should apply. > > Effectively, countries with small fields (like many in Europe) wanted low > power units which probably were safe enough for general use, and possibly > could have been kept within the LVD by some form of energy limitation kluge. > However, countries with "big" - or "very big" (like Australia and New > Zealand, etc.) - fields wanted units with lots more energy to avoid the > deterent effect being substantially reduced by contact with conductive > vegetation, etc. > > In the end (after I left BSI) I believe that some units were finally covered > under Part 2 Sections of IEC 60335 - but I personally doubt that they are > the high power versions. > > Does'nt really explain the situation fully but might give you some idea of > what was/is behind the exclusion - and do'nt forget that there are other > exclusions as well. > > Regards > > John Allen > > ----- Original Message ----- > From: "Ablewisp - Compliance Consultants" <s...@ablewisp.com> > To: "Emc-Pstc" <emc-p...@majordomo.ieee.org> > Sent: Thursday, August 29, 2002 4:11 PM > Subject: Electric Fence Controllers > > > > > > Hi > > I've been asked why electric fence controllers are "outside the scope" of > > the LVD. > > I don't know much about them and assume its because they generate voltages > > exceeding the LVD upper limit. > > Is my assumption correct? > > > > Many thanks > > > > Stuart Miller > > > > ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
