All, There is no such thing as the "Bovine/Equine Equipotential Directive". However, all this talk about "Stray Voltage" is very much on the minds of farmers. I replied to Gert offline on this subject because I thought nobody else had any interest. But the list of serious and not-so-serious replies has proven otherwise.
I grew up on a farm and still spend time with my brothers and uncles on our farms at night and on weekends. I can tell you that newer cattle barn installations are being designed with the equipotential principle very much in mind. Some of the design features that I have heard of are: 1. Ground rods spaced about every ten feet around the barn to ensure that return currents flowing to the utility company don't "flow through" the facility and set up potentials. 2. Burying a grounding mesh in the concrete on which the cows stand and bonding this to the water pipes, metal stantions, milking equipment and any other metal objects that the cows' upper bodies could contact. 3. Isolating the entire farm's electrical system from the utility company using a spark gap. 4. Installing a voltage monitor on the ground and neutral lines in the facility which will inject charge on one or the other in order to keep them balanced. I'm sure that there are other design methods being used for facilities, I just don't know about them. When it comes to equipment, I would assume that the leakage current (especially of milking machines and other direct contact devices) would need to be specified. How would any of you like an electrically leaky device attached to your mammary glands? Udderly painful! (couldn't resist the pun) I was interested to see if any standards turned up, but I haven't really seen any. The only thing I could recommend was Cornell University's College of Animal Science. >From my weekday engineer/weekend farmer point of view, I think that some farms do have a "stray voltage" problem, while others are being told to spend their hard earned money on expensive fixes that maybe aren't necessary. (Sound like compliance to anyone?) However, farming is very competitive (consumers can buy a half pint of milk for $0.50 (of which, a farmer gets about $0.06), while a serving sized bottle of water can cost $0.65) which leads me to wonder how the farmers can put water through a cow and get less money for it at the udder end. As such, anything that influences the cow's ability to produce, even minute amounts of stray voltage, is taken into consideration. Hope I haven't slung too much bull. Have a nice day!! > -----Original Message----- > From: Price, Ed [SMTP:ed.pr...@cubic.com] > Sent: Thursday, November 16, 2000 9:40 AM > To: 'Art Michael'; CE-test - Ing. Gert Gremmen - ce-marking and more... > Cc: Emc-Pstc@Ieee. Org > Subject: RE: safe voltage limits for cattle ( cows horses etc) > > > > > > > -----Original Message----- > From: Art Michael [mailto:amich...@connix.com] > Sent: Tuesday, November 14, 2000 9:03 PM > To: CE-test - Ing. Gert Gremmen - ce-marking and more... > Cc: Emc-Pstc@Ieee. Org > Subject: Re: safe voltage limits for cattle ( cows horses etc) > > > > Hello Gert, > > After watching the responses to your query for the last few days, and the > good humour offered too, I decided to see what I could find on the > subject. > > If you go to either of my two favorite search tools <www.raging.com> or > <www.google.com> and input the term > > stray voltage AND cows > > you will get a number of very good hits at the top of the pile of links > they locate. (Don't use any quote marks surrounding the term) > > A quick read of a few of the papers indicates that cows are sensitive to > very low voltages (well below 30V) and very small currents. And, although > I didn't note any standards, per se, I did note a number of > recommendations. Apparently this is a well-known and long-studied area of > interest. > > Regards, Art Michael > > Int'l Product Safety News > A.E. Michael, Editor > 166 Congdon St. East > P.O. Box 1561 > Middletown CT 06457 U.S.A. > > Phone : (860) 344-1651 > Fax : (860) 346-9066 > Email : i...@connix.com > Website: http://www.safetylink.com > ISSN : 1040-7529 > > -------------------------------------------------------------------------- > -- > --- > > Ah, then there must be a Bovine / Equine Equipotential Directive. > > > Ed Price > ed.pr...@cubic.com > Electromagnetic Compatibility Lab > Cubic Defense Systems > San Diego, CA. USA > 858-505-2780 (Voice) > 858-505-1583 (Fax) > Military & Avionics EMC Services Is Our Specialty > Shake-Bake-Shock - Metrology - Reliability Analysis > > ------------------------------------------- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > 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: > Jim Bacher: jim_bac...@mail.monarch.com > Michael Garretson: pstc_ad...@garretson.org > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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