Static Shock

[ban-all-sheds]

Talking of being on the receiving end - think how careful you'd have to be getting out of the car if you were a naturist....

 

[securespark]

My father and uncle did what your fella is doing, Ban.

Except they did it on an electric fence.....

Oooooooooooooooooooooooooooh!!

 

[AdamW]

An electric fence is a great demonstration of why the insulation test needs to be performed on installations. Why?

Well, as a child I was out in a rural area of France. This French kid insisted that I grab the fence (he thought he was being clever). However, being a clever sort I thought "Aha, he thinks I don't know about electric fences. I'll foil him!". So I wrapped my big heavy jumper around my hand, then grabbed the wire thinking the jumper would insulate me. WRONG! The shock wasn't so bad as the one he got off it (left a mark on him) but it was still enough to be unpleasant.

So, if anyone ever says "Why should I bother having a rewire?! I don't care what your megger says, the cables are fine!", just take them into the country, wrap a jumper round their hand and get them to grab a fence. Don't kidnap them to do it, mind.

 

[kendor]

So, if anyone ever says "Why should I bother having a rewire?! I don't care what your megger says, the cables are fine!", just take them into the country, wrap a jumper round their hand and get them to grab a fence. Don't kidnap them to do it, mind.

Or mention that their wiring could be slowly smouldering away somewhere in the house right this minute just waiting to cause a huge fire and have they ever noticed a burning smell anywhere? that'll get them wondering as to whether it was last sundays roast or their electrics

 

[TexMex]

Some years ago, while on a camping holiday with a mate, we had been out drinking at a local pub. We decided to take a short cut across a field to get back to the tent. My mate just casually swung his leg over the fence and then proceded to bounce up and down on it in agony before finally falling off on the wrong side.

Noticing a bull strolling towards us (probably attracted by all the noise) he then went through the whole thing again to get out again. His agony lasted hours, whereas it took days for me to get over the laughing fits.

 

[securespark]

You cruel s*d!!

 

[AdamW]

I wonder how many people each year are hospitalised after peeing on electric fences? Someone must have worked it out!

I dunno how many people here have been shocked by fences, but it is a weird feeling. You feel a very slight tingle, and think "wassat?". Then just as you realise your mistake it just belts you. I have been told this is because they are pulsed, presumably to reduce energy consumption and also to stop people being paralysed holding on to it!

 

[ban-all-sheds]

Or a learning thing?

Animals are the main target - maybe the idea is that after a few "tingle....

" sequences the creatures learn to move away from the fence as soon as they feel the initial tingle?

 

[phil_ballard]

How do elec fences work? Do I recall someone telling me they're low-voltage DC, or have I made that up?

 

[dingbat]

I dunno how many people here have been shocked by fences..

There's a shocking fence across the road... bright pink it is, eeurgh!

 

[plugwash]

iirc they give very brief high impedence (ie they can't drive much current) high voltage pulses

the main aim is to stop animals passing without needing a very tough expensive fence

 

[securespark]

Sometimes run off a car battery

 

[kai]

Ahh...This post brings those memories of my schooldays back - when I received a static shock, caused by my school jumper rubbing against the nylon inside of my blazer, generating a high voltage, that gave me a shock whenever I touched a metal handrail or door handle etc.

 

[AdamW]

How do elec fences work? Do I recall someone telling me they're low-voltage DC, or have I made that up?

I'm not sure, but thinking about it, AC would be easier to drive over the length of the fence. Would have to be quite a high voltage to give you a shock (but then I suppose mains voltage is classed as "low voltage" )

Next time any of you see a Van de Graff generator being demonstrated (perhaps taking kids to look at secondary schools, I dunno), here is a trick my old physics teacher used to do. Grab a board marker (or a metal rod), hold it in your hand then jab the person touching the generator with it. You have to do it with a metal object, if you do it with your finger then it sparks you too!

 

[ban-all-sheds]

Next time any of you see a Van de Graff generator being demonstrated (perhaps taking kids to look at secondary schools, I dunno), here is a trick my old physics teacher used to do. Grab a board marker (or a metal rod), hold it in your hand then jab the person touching the generator with it. You have to do it with a metal object, if you do it with your finger then it sparks you too!

I wonder if the memory of an interesting demonstration that my old physics teacher once gave has faded. He foolishly left a piece of apparatus on his bench at the front of the room when he was called out for an urgent phone call.

When he returned 10 minutes later there was no outward sign that the apparatus had been running whilst he was away

"Right", he said, as he reached out with both hands to grasp the gleaming metal sphere, "the Van de Graaf generator....."