Hi,
You'd be best off talking to an electrician qualified and experienced in agricultural installations, maybe a local farmer or stable owner could recommend one.
If they say a 30mA 30 millisecond RCD is good enough protection for a supply for use with horses, then it most probably is...
cheers, Pete.
xena explained on 04/07/2007 :
It does if the voltage is enough to overcome the resistance of your body. The highest resistance is normally that of your skin. Try the 12v on your tongue - on second thoughts perhaps not. Try the 12v via a couple of pins in your skin.
The voltage has to be enough to overcome your body resistance...
..and the current enough and for a long enough period to do damage.
It can, but it depends upon the individual, the exposure conditions, the current path through the body and of course the length of time of exposure to the current.
The worst possible route for the current is in one arm and out the other, via the heart - hence the good working practise of working with your spare hand in your pocket body covered and well insulated dry shoes. The worst you can then suffer is a belt across your hand.
An old party trick I used to do was to allow the 30Kv spark from a colour CRT TV, to arc across to my finger tip. Very high voltage, but very little actual current - due to my normaly dry skin I don't usually feel much.
Even the 10mA RCD's are not certain to prevent death and or injury, but they do limit the time of exposure to a very short time period. They are a delicate balance between protection and nuisance tripping due to normal circuit leakage currents.
Do let us know how she gets on, will you?
fred used his keyboard to write :
You will find a citation somewhere in the URL copied in my sig. Sorry I don't remember the actual page, but it was based upon valid research done upon the subject of such risks.
The current flow in amps depends on two things - the voltage and resistance. V The formula is I (amps) = - R So if you increase the voltage or reduce the resistance the current increases.
The electric fence will have a large value resistor in series with it to limit the maximum current to a safe value.
Your skin when dry has quite a high resistance. Try putting the terminals of a PP3 (9 volt) battery across your tounge. You'll feel that. ;-)
Got ya, thanks :)
Never heard of that, but makes sense. One of the horses in the same field as mine many years ago was killed by lightning. Apparently it hit his ear, went through his heart and to ground through his shod feet. Poor boy :(
Thanks for explaining.
easy
You could simply use 5 diodes in series to drop the 13v to 8v. Basic
1N4001 diodes would do fine. Cost a few p each.NT
Interesting idea, never heard of those before, but a few on ebay for next to nothing. The camera's actually up and running now, using an old car voltage adaptor, and some fancy wiring. However, it's enlightening to see other potential solutions as it may well help the next time I want to do something clever with a 12v supply!
Voltage droppers. Potential solutions. Shouldn't meet much resistance in the current form.
It's probably a bit short notice for a horsey that's about to give birth any minute though...
(Xena) - any news yet?
We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "xena" saying something like:
Not just that, there've been many cattle killed by nearby strikes when the ground potential between their front legs was enough to cause a current to flow, stopping the heart. I'd assume horses would be similarly sensitive.
No, nothing yet. Horses are notoriously difficult to predict though, so whilst she has all the signs of dropping it at any minute, she could still hold onto it for another week or even two if she wants/needs to - hence the need for the cctv. For instance, she might want to wait until the weather is a little better. With the amount of stuff that can go wrong with a foaling though, and the often catastrophic results, I have much more peace of mind now :) Was fantastic being able to watch them last night from the comfort of my bed!!
I really appreciate all the help you people have given me, not just with this topic, but the others I've put up before, like best way to illuminate the shelter, putting a ceiling fan up (though the weather made that unnecessary in the end!) so I'll let you know when she drops it and stick a pic link up :)
In article , Harry Bloomfield writes
That's a bit lazy isnt it :-?
The request for cite was the politest possible suggestion that bollocks was being spake.
Wikipedia's summary is pretty much as I understand it:
100-300mA ventricular fibrillation. Can be fatal.
Human fatality at 1mA seems extremely unlikely but yes I did read the microshock link:
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