A shocking question

In my neighborhood, the only deterent to rampaging deer that seems to work is an electric fence. High voltage low current, pulsing potential of about 5000 volts, one contact is the wire and the other contact is burried in the ground to complete the circuit. Last night I noticed that one insulator had broken off of a tree and the wire was shorting out to a piece of metal in the ground. I turned off the power switch and put the insulator back on the tree, as I touched the wire, I got a pretty good jolt. Since the power was off, it seems that there must have been a charge build up in the groung near the tree. It had just rained and I would think the improved conductivity would have drained off any built up charge. Any other thoughts?

Dave

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Reply to
DavesVideo
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If you have an electric fence of any size, you need to get a pole mounted grounding clamp so that you can ground the wires before you work on them.

Reply to
John Gilmer

That sounds like a good idea, for the future, but I'm still puzzled as to what happned. In the past I have been able to touch the wire once the power is disconnected. However, in this case the ground apparently acted as a big capacator. Since it was very wet, I would think that any charge would disipate quickly. I touched the wire less than a minute after disconnecting the power source.

Dave

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Reply to
DavesVideo

in article snipped-for-privacy@mb-m22.aol.com, DavesVideo at snipped-for-privacy@aol.com wrote on 9/16/03 12:41 PM:

The conductivity of the ground is too high to leave a significant charge.

There may have been a capacitor in the electronic unit that stored charge. Even more likely, if charge for a pulse were stored on a capactor, after turning the electronics soaked charge became free again. Titanate capacitors often exhibit such behavior becaused of capacitive hysteresis.

Bill

Reply to
Repeating Decimal

On 16 Sep 2003 19:41:02 GMT, snipped-for-privacy@aol.com (DavesVideo) Gave us:

Nope. One gets a capacitor from very dry conditions between the two nodes. Regardless of how wet the ground is or was, the only way for charge to have been stored is for that HVPS to have no bleeder, which is very unlikely, or for the hot wire to be so well isolated that it stored a capacitive charge... also unlikely by the way. Such systems leak HV charge off fairly quickly. Anyway, the key is good isolation of the hot wire, not the grounded side.

Reply to
DarkMatter

Is there any possibility the fence was picking up induced current from something like nearby power wires? I don't have any idea if there could be enough induced voltage to shock someone. One farmer trick is to use an extra electric fence post to lean against the fence while repairs are made. Put the post between the fencer and the needed repair. I've seen guys fix fence without unhooking the fencer but I never trusted this trick. I've never heard of anyone getting shocked with the fencer turned off. Is there something wrong with the fencer? For what it's worth solar and battery powered fencers are available fairly cheap.

Dean

Reply to
Dean Hoffman

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