Electric Fence = Multimeter Death?

As a kid my neighbor kids and I were always running around in the woods etc at night. Especially in the summertime! One night, without realizing how close to the fence line I was……. I pee’d on the electric fence…..
With a small (1/4 ac urban) back yard, there was a problem keeping a particular dog inside. I rigged a fence charger from a GM "Hi Energy" ignition coil (~40 KV), a one megohm resistor (brown, black, blue), and a "chopper", an archaic device from the days of tube type automotive radios. Basicly an insulated "high current" oscillator. It didn't help much with the Lab, but definately kept prowlers (both 2 and 4 legged) on the outside. She got a litter through a chain link fence. That would have been a sight to see. . . I don't know what breed the sire was, but the puppies looked more like black bears than dogs.

The high resistance kept current flow to a "survivable" minimum, but enough to get something's attention. The Lab was about as bullheaded a dog I have ever dealt with. We tried an electric collar and buried cable where she was getting out. She found that with a running start, she could get past the wire and then the shock went off. But had a problem when she got hungry. She was a long time back, but a real problem to keep confined.

I had considered a microwave transformer, and a "neon" sign excitation transformer. Neither one had the high voltage I wanted. Plus they ran at 60 Hertz, I wanted a really high frequency. I don't know what the frequency of the chopper was, I suspect around 5 KHz. Used a battery charger for power and a "flyback" supresser (capacitor/condenser) for the coil. Flyback would have ruined the rectifier in the charger in just a few pulses. Nothing was insulated well, just mounted on a dry wooden shelf above reaching level in the barn.

The idea about using a fluorescent tube at length is very good. A fluorescent tube is just an arc tube with powder to fluoresce when excited. The arc is essentially a short circuit so must have a current limiter. That's what the ballast in a light fixture does. In magnetic ballasts, the impedence of a coil provides that resistance. In the more modern "electronic" ballasts, a circuit provides the same effect. To use for fences or neon signs, or some other stuff, some sort of external current limiter (usually resistance) needs to be applied. My brother tells about a "LORAN" station in the South Pacific where the techs would get on the roof of the transmitter building and hold mock sword fights with 8 foot fluorescent tubes. Scared the "pooh" out of the locals but kept them well away from the station.

To use a multi-meter on anything over 1000 volts (1 KV) is a guaranteed death sentence for a digital meter. I have a very old Simpson 260 (Series 5) that has a 5,000 volt range. It was used for 2300 volt motors in an old mill. But even that is nowhere near enough for a good fence charger.

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As a kid my neighbor kids and I were always running around in the woods etc at night. Especially in the summertime! One night, without realizing how close to the fence line I was……. I pee’d on the electric fence…..
I remember a friend hit a fence while preparing for a major transaction. It wasn't pretty.
 
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