"Adam Russell" wrote in message ...
"Snooze" wrote in message
. com...
Don't let your kids wear wool socks on a low humidity day...imagine what
would happen if they discovered they can shuffle around the house and zap
each other with a few thousand volts. A typical static electricity shock
is
about 2000 - 4000 volts.

Of course a amperage involved is so low, that aside from the surprise, no
damage is done. Ever taken a weak 9v battery and tapped it against your
tongue? A fresh battery hurts a little, but a weak one gives a little
tingling sensation.

A consumer grade electric fence is harmless, it will give a mild shock,
but
nothing dangerous. I couldn't find the specifications online, so
guestimating, if an electric fence transformer draws 120v A/C @ 1 amp, the
output would be 4000 v A/C at .03 amp.

That's just a mild shocker, pretty safe..if it was D/C on the otherhand is
a
different story.

You dont know much about electricity it appears. Static electricity is
completely different from transformer electricity. When you get a shock
from static electricity it is 2-4k for only an extreme fraction of a second.
I dont remember how short exactly (1ms comes to mind), but it is the brevity
that saves you. As it swiftly runs out of electrons the voltage falls to
zero.

Somehow I doubt it's the brevity that makes static electricity
harmless. I've played around with battery-powered circuits that work
by delivering pulses of electricity to the subject when the current
through a circuit containing an inductor is interrupted (for example,
the gag lighters that shock people work this way). Whatever current
is flowing through the inductor gets sent through the subject for a
short period of time. It's relatively safe because the peak amperage
is controlled. If you hook up a resistor in series with the subject,
the maximum current doesn't change, but the pulses get shorter. When
you do this, the pain falls off, but the response from your muscles
doesn't change as much. Eventually, especially if the contact area
between the electrodes and the skin is large, you can produce
involuntary muscle contractions with little or no pain.

Given that the heart is a muscle, I would think that a few seconds of
current would be better than a few milliseconds if the goal was to
produce pain without rendering any permanent harm. I could be wrong,
but if I had to guess, I'd say the reason static electricity isn't
harmful is because most of the voltage is across the air gap, not
across your body. Also, the charge is entirely on your skin, and most
is probably very close to the spot where you're about to touch
something, so practically no current is going through your heart.

Power out of your wall does not fall off. At all. That 120v will
deliver 1mA or 15A depending on the resistance of what you are powering and
only limited by your circuit breaker or fuse. If you were to put a penny in
the fusebox it could deliver 1000's of amps with no problem except that the
wires would get hot. So putting it through a transformer will not reduce
the amperage available to any safe amount. 4000v will kill you, and it
matters not whether it is DC or AC.

Surely it couldn't be very difficult to have a device of some sort in
the circuit to control the maximum current. At the very least,
couldn't he just put an appropriate fuse in the circuit, if there
wasn't one already?

Now as to the matter of electric fences, when I was a child my grandpa told
me to stay away from the electric fence surrounding the cow field. He said
it would kick me like a sledgehammer. He could have been pulling my leg,
but I imagine that anything meant to coerce a cow would hurt a human. OTOH,
a raccoon is not a cow. The question is open whether you could make a fence
with enough jolt to keep out racoons but not enough to hurt 3 year olds. I
personally doubt it.

There's almost one order of magnitude between the current needed to
cause pain and the current that's large enough to be dangerous. The
fact that the area of contact with the wire is small, and a three-year
old is larger than a racoon, ought to make the range of safety even
broader.