Maximum Voltage for Electric Fences

Hi nambiathiri,

The max voltage covered by IEC EN61011 1993 is 250V,so I guess this is the max allowed. The energy per belt is limited to 5 or 6 joules dependent on country of use.

Ouch!

The standard covers fences intended for livestock containment,and you would probably need to purchase on line to see the full standard.

I think the criteria are based on a maximum shock to that from from a RCD protected 230v AC supply.

If you trawl a search engine for electric fence manufacturers you may find them quoting bits of the standard and the criteria complied with.

When RCD first appeared I tried to get the manufacturers reps to demonstrate how safe they were,but had no takers.I dont think I've ever had a belt from a RCD protected supply,certainly my body has never tripped one.

Has anyone had a belt which tripped an RCD ? Could you share your experience with us? Im too old an eng to try it and thats my excuse.

Del the cat if youre rubbernecking this how about it,you must have some lives left.

I had a few belts from them on my grandmother farm but never trip any thing that I know of. They sure ain't fun to walk into in the dark. The system they had pulsed the current. I wish they would have put lights on it though. Real pain to see in the dark. After a while I learn to take one of the farm dogs. They new real well where the line was and would stoop to go under drawing their tail down between their legs.

Yes I have, I tripped out our training lab by touching a mains input pin while teaching a class of our engineers on switched mode power supply repair.....

It did hurt for a split second, but absolutely no damage of any sort except to my pride.

The biggest problem was finding it to reset!! Took 15 minutes.....it took all the mains sockets off and the lighting too!!!

I recently had three installed for the three phases coming into my house.....

Better be careful about the numbers here folks. While the IEC may cover 230 volt units, that refers to input volts. (Sorry, I don't have a copy of that standard). The actual voltage on the fence will be a lot less. For shock hazard, a number of standards limit leakage current to 0.5 mA, but up to 5 mA in some cases. I don't know the fatal current, but Google can help with that. Considering a human body is just a large resistor, we should be able to calculate the max tolerable voltage. Consider that a 12 volt car battery is no shock hazard, but grabbing 120 volts is definitely painful. A telephone ringing circuit is 50 volts I believe and gives a painful jolt. So, I would venture to say that fences would be in that range.

The farm had a back up battery for power failure it was only 6 volts.

Youre right,again, it probably refers to input volts.

I had a sudden flashback remembering repairing a fence pulser which had a test unit with a scale in kV. and the pulser having an automotive ignition coil as its pulse output device.

Googling I found this DEFRA pdf which specifies that voltages above 10,000 should not be used ! This spec also gives the joule requirements for various animals.

www.defra.gov.uk/wildlife-countryside/vertrebrates/reports/Electric-fencing-manual.pdf

Right then,back to your and others inrush/magnetising explanations.

I guess things have changed, when I was a kid you could hear the fence pulser clicking, maybe about twice a second. Often a transformer was replaced with a car coil as farmers made do rather than order the replacement part, but that power certainly would not cover the distances mentioned above, things are on a different scale in the US or AUS. etc.! The older units depended on raw high volts to cover the distances, with an old battery as the source is unlikely to kill. It makes sense to use the mains frequency & supply (220/230V~ or 110V~ depending where one is in the world) but then it would be current limited and it seem from previous contributor with practical knowledge up to 10kV.

I know from working with the Electricity Suppliers on earth leaks I was surprised to learn & a farmer will probably have knowledge of this, one has to be careful with four legged animals as a power shock that a human would survive will kill them, it is depending on the voltage gradient from back legs to front [or v/v] If a cow rubs up against a electricity pole with a small earth leak and her rear legs in a muddy puddle >50 or 60 V differential with enough energy will be its last pleasure.

Thje fence charger I use is the largest one that TSC sells.

It has an imput voltage of 120 V and a maximum output voltage of 10,000 V - - - the tester I have rarely goes over about 8,500 V on clear dry days and if it goes below 2,000 V I have an alert that will let me know so I can check and clear it. It is also rated to charge 150 miles of fence ( I only have about 5 miles of fence) and it is rated at 12 Joules - -- In the literature it will not harm even small animals but it will really get your attention if you get into it.

This fence charger is strong enough that I've had cars go thru the fence and the cattle stay in as they will not go near where it was.

As a youngster I used to cut asparagrass in the mornings before school. The farmer I worked for had a bull in a small pasture next to the field I worked. I came one morning to find the bull astraddle of the electric fence. Every time the jolt went through he let out a bellow. I shut off the fence and led this once fierce animal quite calmly back into the coral. I have often wondered if he was any good as a bull after that.

I just installed the smallest fence charger i could buy at tractor supply for a boxer dog that used to climb the chain link fence. to go roam the hood

after the first time he put his paws on the wire he never gets close to that fence

that scared me so i called manufacture and they assured me that my Little fencer put out 1000 v pulsed and that it was harmless even there largest fencer putting out over 20k was safe for animals no amps just volt to carry the distance of a few miles or so

Hi

In SA voltage is 220V input, and 10 000 out/on fence. Battery backup is 12V 7Ah. Delivers a hell of a shock.