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Electric fence current- joule ratings for pigs

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Vraj

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Hi,

I am working on project of electric fencing.
The main focus is pigs.

I found voltage should be 3kv+
But what about the charge and joule rating?

If ratings are 3kv and 0.5 joule then it will deliver 0.1mA current for second?

What frequency will be good?

And there should be feedback to stop electricity for some time after first shock?

Mostly animals touches fence with nose. should I take care of it and reduce voltage - joule?


Thanks
 

Hi,

I´d say the most important is that the electric shock doesn´t harm humans, children, elder people. But for sure it should not harm the animals, too.
But they should recieve a clearly noticable electical shock.

3kV is not the problem as long as the energy is limited.

It just generates a short pulse. It may not last for 1s.....and 0.1mA is not noticable.

Frequency: I assume there are regulations. But there must be at least enough time to react on the pulse and move away from the wire.
I´d start with one pulse per second --> 1Hz

You may limit the current....but besides this I think there is no additional feedback necessary.

Klaus
 
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    Vraj

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A momentary pulse does the job (based on my limited experience with electrified fences). Compare it to automotive ignitions. The spark is unpleasant but not lethal. It is brief yet impossible to ignore. However you don't need such high voltage. You don't need a spark.

- - - Updated - - -

As for frequency, I agree one pulse per second is good. A pulse itself might last 1/100 second or 1/1000 sec.
 
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    Vraj

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Most of the chargers I've seen have a joule rating. But there are different opinions of the value of the joule rating as it pertains to the effectiveness of the fence charger. Most sights say that the joule rating is dependent on how many feet or miles of wire your energizing. Opinions vary from 3 to 10 miles of wire per joule. Low impedance type chargers can tolerate a small amount of grass or weeds touching the wires.
High impedance types had long duration pulses that would burn the weeds off, but they also started fires. Not sure if you can buy this type anymore.
When I was a kid I would help a friend of mine tend to his parents hogs. Let me tell you from experience that they are a royal pain in the ass. If they want what's on the other side of that fence bad enough they will go through it. They would also root the mud up next to the fence until it touched the wire. If you didn't catch it quick enough they would figure out the line was shorted and they would make the great escape.It's like they new exactly what they were doing.
 
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    Vraj

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Amperes from the fence should stay below a safe level. Probably 100 uA. If you maintain high voltage through animal or human, it can push over 1 mA through its body, with risk of inducing a heart attack. Therefore consider installing a detector which alerts you to a current drain. Perhaps also reduce voltage until you press a reset button.
 

Hi,

I don't think that reducing current to 100uA is a good idea.
If you touch the wire the pulse will hardly be noticable - if ever.

I assume the pulsed current needs to be much higher. In a magnitude that surely harms human when applied contionously or with higher frequency.
But limiting the energy and keeping pulse frequency very low (at about 1Hz) makes it safe.

Klaus
 

You can refer to IEC 60335-2-76 for electric fence safety limits. Key parameters are

- repetition rate <= 1 Hz
- impulse duration with nominal 500 ohm load <= 10 ms
- impulse energy <= 5 J for energy limited energizers

There's also a current limit line for current limited energizers, allowing up to 1 A for 10 ms pulse duration and even more below 4 ms.
 
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    Vraj

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