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'[EE:] curious Live wire experiment'
2004\02\21@060349 by Omega Software

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Hello,

I've always been curious to know if one can get an electric shock by JUST touching the 230V Live wire (not the Neutral).

A lot of people keep telling me it's impossible, yet I can measure some AC voltage between me and the Live wire with my multimeter (pity it cannot measure AC current).

Since the AC voltage was something like very few volts, and my body's resistance quite high (at least at those voltages), I decided to try an experiment, knowing anyway that the "automatic emergency switch" (Ground Surge Protection? how is it called?) would have saved me from eventual annoying problems.

I had a green led I wasn't too fond of, so I've put one pin (the anode, although I doubt that it matters) to the Live wire, and left the cathode unconnected. I turned on the switch.. and then finally put a finger on the cathode, thinking the LED may have started to emit some light.
Instead, I heard a loud pop and saw a shiny spark.. while the current in the house immediately went away (the automatic emergency switch (lifesaver? Ground Surge Protection?) acted).
The LED wasn't damaged (!), but the pin tied to the Live 230V line was burned and damaged, so much that it was nearly cut.
I'd have some questions about the above experiment:

1) Being I insulated from earth, why did the current (and so much of) pass anyway? Was I the plate of a "capacitor" to earth? If so, how big? And what was the other plate, every thing surrounding me, maybe?

2) How much current may have passed through me, if the automatic emergency switch didn't stop it?

3) Why the LED still works perfectly, while one of its pins is so much damaged?

Thanks,
Andrea

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2004\02\21@080754 by Alexander JJ Rice

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On Sat, 21 Feb 2004 12:01:58 +0100, Omega Software <spam_OUTomegasoftwareTakeThisOuTspamTISCALI.IT> wrote:

> Hello,
>
> I've always been curious to know if one can get an electric shock by
> JUST touching the 230V Live wire (not the Neutral).

In theory, no, you won't get an electric shock just from touching the live wire - assuming you are insulated from your surroundings so that your body can 'float' to the higher potential of the mains you should be fine.

> A lot of people keep telling me it's impossible, yet I can measure some
> AC voltage between me and the Live wire with my multimeter (pity it
> cannot measure AC current).

That is because unless you are standing on an insulator like a big plastic milk crate, you are connected to ground by whatever is touching the floor. Conductve additives are now added to the soles of most shoes. The above experiment is dangerous - would you trust your life to a £6.99 piece of equipment, if the resistors in the multimeter were to flash over, you woudl get a serious electric shock.

> Since the AC voltage was something like very few volts,

Um... 240/110 volts, that is more than enough to push a current of several amps through you. 20ma will usually kill you.

 and my body's
> resistance quite high (at least at those voltages),

no it isn't - sure you may have a resistance of a few Mohms at loww currents, but during an elctric shock from the mains the current penetrates the skin, vapourising it and destroying the cells, the bulk resistance of your body is quite low once this has happened, typically a few hundred ohms. You are basically a big bucket of salty water just waiting to get zapped.

I decided to try an
> experiment, knowing anyway that the "automatic emergency switch" (Ground
> Surge Protection? how is it called?) would have saved me from eventual
> annoying problems.

What, annoying problems... like death. This is a rediculous attitude - a bit like - my local hospital has a good ER, why don't i go tightrope walk across a motorway: the hospital will save me from 'annoying problems'

>
> I had a green led I wasn't too fond of, so I've put one pin (the anode,
> although I doubt that it matters) to the Live wire, and left the cathode
> unconnected. I turned on the switch.. and then finally put a finger on
> the cathode, thinking the LED may have started to emit some light.

Don't do this, you will rapidy remove yourself from the gene pool.


{Quote hidden}

At 50/60Hz the current flowing due to the 20pF or so of distributed capacitance is negligible. The reason current was flowing to earth is beacause you were probaly not insulated from earth.

> 2) How much current may have passed through me, if the automatic
> emergency switch didn't stop it?

Enough to stop your heart, enough to give you 3rd degree burns over parts of your body.

> 3) Why the LED still works perfectly, while one of its pins is so much
> damaged?

what i suspect actually happened is thaf you touched the led and jogged it into touching the neutral or the earth, if enough current had flowed through you that you saw sparks you wouldn't have been able to type your e-mail - theres no cybercafe in whatever from of afterlife you believe in.

>
> Thanks,
> Andrea

Please don't do stupid stuff like this again, if you inist on doing it, make sure you have a parent/supervisor/friend who is trained in CPR to recusitate you and take you to hospital in the likely eventuality that you get a serious electric shock.

Reagrds

Alexander Rice

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2004\02\21@084352 by Jake Anderson

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(Topic Tag odd, outlook (not express) didnt used to muck with them)
this is simmilar in many respects to faraday flying the kite in the
thunderstorm
and no i dont mean electrically

people working on high tension lines will sometimes opperate on them live
they generally wear a suit woven with metal fibers running through it and
opperate from a helicopter.
even then when they connect the helicopter to the line they throw a spark
about 20cm long.

This is a *really* silly experiment to do.

most people who are electrocuted get zapped touching just one wire and

{Original Message removed}

2004\02\21@095940 by Omega Software

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At 02.20 22/02/2004 +1300, you wrote:
>> Where is Olin now we need him?
>> Ill let the non-Olin supporters answer this one
>> PS moved to OT Please keep it there
>
>Entirely valid to have this under EE IMHO.
>Others may hopefully learn the appropriate lessons.
>
>Basically - this is not a good experiment to do.
>Death is a possibility.
>Earth leak breakers help reduce the number of people who die. You cannot
>be certain that an ELCB will always stop you dying.

But how can current pass from just one wire? Is it a capacitive effect?

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2004\02\21@095942 by Omega Software

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At 13.10 21/02/2004 +0000, you wrote:
>On Sat, 21 Feb 2004 12:01:58 +0100, Omega Software <.....omegasoftwareKILLspamspam@spam@TISCALI.IT> wrote:
>
>>Hello,
>>
>>I've always been curious to know if one can get an electric shock by JUST touching the 230V Live wire (not the Neutral).
>
>In theory, no, you won't get an electric shock just from touching the live wire - assuming you are insulated from your surroundings so that your body can 'float' to the higher potential of the mains you should be fine.
>
>>A lot of people keep telling me it's impossible, yet I can measure some AC voltage between me and the Live wire with my multimeter (pity it cannot measure AC current).
>
>That is because unless you are standing on an insulator like a big plastic milk crate, you are connected to ground by whatever is touching the floor.

Isn't the floor's ceramics an excellent insulator?


{Quote hidden}

PS: I think the plug is defective.. the same happened again by just mechanical effect (pressing a bit on it).
Damn.. it must be defective, that's why the big spark and all.




>Reagrds
>
>Alexander Rice
>
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2004\02\21@105245 by Scott Dattalo

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On Sat, 21 Feb 2004, Omega Software wrote:

> But how can current pass from just one wire? Is it a capacitive effect?

Assuming that you weren't touching some other conducting surface, then yes
it is a capacitive effect. At Synaptics (where I work), we use ~10pF for
the human body free-space capacitive coupling. Our TouchPads measure the
capacitive coupling between a finger and the surface of the TouchPad
sensor. This is roughly 1pF (and our ASIC can resolve this down to 10's of
femtofarads!). In your case, you could approximate the LED as a wire and
your body as a two-plate capacitor; one plate tied to the LED and the
other to free space. Using that approximation, you can then estimate how
much energy your "body-capacitance" can store.

Now, as the grounded LED approaches the wire, there is another capacitive
coupling there as well. In this case, it's the capacitance between the
wire and the LED. As the LED approaches, there will be some point at which
the air-dielectric of this capacitance will break down. That distance will
depend on many factors such as the peak voltages, air humidity, and the
geometry of the conductors. A sharp point like the lead of the LED will
cause the air to break down at a larger distance than a flat conductor
(like your finger). Once the air-dielectric breaks down, the live wire
will begin to charge your body capacitance. So the arc that you saw was
most probably the current flowing from the live wire to charge your 10 pF
body. You probably immediately pulled back, at which point your body
discharged into the surroundings!

I hope you weren't at home when you did this because you're not supposed
to do these at home! :)

Scott

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2004\02\21@122115 by Michael Johnston

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 This reminds me of a stunt this guy I met in tech school Father did. He
had built a DVM from a kit and took it home to show his folks. His father
took the dvm and showed it to his friends and plugged it into the AC at home
in the Ohms mode and it melted the probes. melt and blew the main fuse. They
guys father got away with his life. Be ware of AC Power lines!!!
Michael Johnston
{Original Message removed}

2004\02\21@124531 by Alexander JJ Rice

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On Sat, 21 Feb 2004 07:51:26 -0800, Scott Dattalo <scottspamKILLspamDATTALO.COM>
wrote:

> On Sat, 21 Feb 2004, Omega Software wrote:
>
>> But how can current pass from just one wire? Is it a capacitive effect?
>
> Assuming that you weren't touching some other conducting surface, then
> yes
> it is a capacitive effect. At Synaptics (where I work), we use ~10pF for
> the human body free-space capacitive coupling. Our TouchPads measure the
> capacitive coupling between a finger and the surface of the TouchPad
> sensor. This is roughly 1pF (and our ASIC can resolve this down to 10's

Assuming the distributed capacitance of a human body is around 20pF then
your capacitative reactance at 50Hz is about 1.5G Ohms. This means that if
you are isolated in free space around 16uA will flow at the point where
you are touching the mains. This is well within safe limits, probaly too
little to even feel it. However, if you are stood on ,say, a nice big
ground plane with some nice high K floor tiles between you and the ground
plane i am sure your capacitance to ground could be much bigger with the
correspondingly larger current flow.

As regards floor tiles being insulators, you really shouldn't count on it.

If you want to play with sparks why not build a mans of doing it safely,
check out http://www.coe.ufrj.br/~acmq/electrostatic.html if you look
carefully you will one of my machines listed there.

Regards

Alex Rice

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2004\02\21@131647 by James Nick Sears

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Be careful, Andrea.  I think the rule with high voltages and the human body
is that there ultimately is no rule and that anything can happen.

I interned at a recording studio when I was in college for EE and the
engineer/owner, who is a very intelligent guy with a lot of self-taught
electrical knowledge told me, contrary to what intuition may first tell you,
that in countries where the mains carry 240V @ 50Hz the percentage of shocks
that result in death are actually LESS than here in America where we use
120V @ 60Hz.  The reason is, he explained, that 60Hz is close to a frequency
that regulates heartbeat (or is a frequency that is more likely to perturb
said signal).  Even though more current flows with a 240V shock, it is less
likely to stop the heart and cause death.

This indicates that there is a more delicate issue at play than how many
amps of current we are conducting or how many volts we apply across the
body.

When I was in my early teens, my uncle gave me an old mechanical timer (the
sort that you would use to turn a light on and off while you are away) that
didn't work.  I knew virtually nothing about electricity but I cracked it
open and wanted to see if I could see anything obviously wrong.  I didn't
see anything but I couldn't tell whether or not the gears that drove the
timer were turning very slowly or not at all.  So being the brilliant young
pup that I was I decided to try to catch one of my fingernails on one of the
gear teeth to see if I could feel any motion.  Well, I'm not sure what I
touched but it was very live.  I got the most intense shock that I have had
thus far in my life.  Luckily I wasn't in a position where I grabbed the
power source but it still took me a moment to get my hand pulled away and I
was shocked to the point where my arm felt strange for awhile afterward,
etc.  I unplugged the timer and said the hell with it.

But, before learning of the 50Hz/60Hz issue, I took this experience as
evidence that while getting shocked isn't fun, as long as you aren't in the
horrible situation where you are latched onto the high voltage by
involuntary muscle tension, you'll be ok with a brief shock.  This was also
furthered by the fact that I had a different uncle who was working with an
old power tool (before plastic insulated tools) that connected him to 120VAC
for a considerable time (he was working alone and the shock caused his
muscles to tense around the tool so he couldn't let go and it was I think
maybe a minute or more before my grandfather came upon him writhing on the
floor) and he was OK, although IIRC he did go to the hospital over it.

However, after hearing the 50Hz/60Hz effect, I believe (whether it is
commonly accepted or not) that even a few cycles of 120VAC could be the end
of a person under the wrong circumstances.  Probabilistically I would say
that the odds of getting killed by a 100ms 120V/60Hz shock are obviously
much lower than those of the same shock applied for 10s or a minute.
BUT...I believe (and for my own saftey intend to continue to believe) that a
significant factor in that probability distribution is one that is in itself
for all intents and purposes random - the frequency/phase difference between
your relevant internal signals and the AC frequency.  That is to say that
even a very brief shock with just the wrong timing could be the end of a
person, even after he/she has sustained a much larger and otherwise
identical shock due to subtle differences in the way that the 50 or 60Hz
interacts with your body's signals.

I am the first to admit that I have no hard evidence to back up this theory,
but for my purposes I don't need any.  Passing significant current through
your body is a bad idea, even if you've done it a million times before with
no problems.

Think of your body as a PIC with incomprehensible value.  In the datasheet
it says not to connect it to mains voltage.  We've all had parts that
exceeded their datasheet performance.  But we also know that this behavior
is not guaranteed and that at any moment while the part is operating out of
spec, a puff of smoke could be just around the corner.  Be glad that you
probably can sustain the occasional shock without death, but don't roll the
dice any more than you have to.  There is very little to gain and everything
to lose.

Be careful, babe. :)

Nick


PS:  If you have to play with mains voltages, I have learned from
electricians that if there is ANY doubt as to the potential of the part in
question, ALWAYS test with the back of your hand before grabbing hold of
them so that if it is hot you will pull away rather than grab hold when your
muscles involuntarily tense.  But you are still rolling the dice, just
stacking the odds toward your favor.


{Original Message removed}

2004\02\21@135919 by Patrick J

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I have touched the live wire (240VAC) and I am still here and I didnt feel
a thing because there was no, or close to zero, current.
Tho I was really carefull not to be grounded...

BTW: its something u really shoudnt be testing at home kidz!


> How can current flow by touching JUST the Live wire?
>
> This is my original question no one yet answered to, after many replies.
> My idea is of some capacitive effect (my body with the planet, which I
> suppose is at earth potential, although with a big virtual serie
resistor)..
> I can't imagine anything else.

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2004\02\21@141958 by Pietro Cecchi

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Andrea!
I think you can claim a prize for that: they give a prize to the few ones who survive to experiments like this... :)


 {Original Message removed}

2004\02\21@145938 by James Nick Sears

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And those that don't survive may be eligible for a Darwin Award.


----- Original Message -----
From: "Pietro Cecchi" <.....pietrocecchiKILLspamspam.....INWIND.IT>
To: <EraseMEPICLISTspam_OUTspamTakeThisOuTMITVMA.MIT.EDU>
Sent: Saturday, February 21, 2004 1:18 PM
Subject: Re: [EE:] curious Live wire experiment


Andrea!
I think you can claim a prize for that: they give a prize to the few ones
who survive to experiments like this... :)


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2004\02\21@153305 by Jim Franklin

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I remember being told to always test something (if you absolutely have to)
with your left hand behind your back. The chances of the current running
down through your heart are less likely if you get zapped with your right
hand.

I must personally admit to a bit of "brain in neutral" when I was at
college. This was around 1980, I had an old instrument panel power supply
controlling my CB radio. +12v 20A or so (IIRC). I touched the side and got a
"mains" shock. I then proceded to touch all around the case to see if it was
all "live", needless to say it was. I thought afterwards how stupid this was
as the power supply was in a metal case ... DUH!

But back to the 240/110v issue, I have probably had more than my fair share
of electric shocks for various reasons and I'm still alive - actually there
must be a mental condition for this - I actually like the feeling <gulp>,
but then I blame my mother :)

Does anyone recall the episode of ER where there was a student doctor who
was having an asthma attack and was given injection overdose (x10 dose) of
something. He started to have a heart misfunction of some sort
(irregularity) and started to bang his own chest. The permanent doctor
spotted this and said

"ok we are going to have to shock him", remember he was awake at this time.
"Do, you want some valium" : to the "patient"
"No, just shock me, quick"
"charging 150, clear"
ZAP
"Valium, pleeeease"
"again, Clear"
ZAP
"ok, he's back with us."

Now THAT was a funny scene, I wonder how close to reality that was?

Jim




{Original Message removed}

2004\02\21@153720 by Roland

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......
>Assuming the distributed capacitance of a human body is around 20pF then
>your capacitative reactance at 50Hz is about 1.5G Ohms. This means that if
>you are isolated in free space around 16uA will flow at the point where
>you are touching the mains. This is well within safe limits, probaly too
...


not true, or not likely, since the case where anything would really happen
is if the wire is touched when the mains is at the peak, so, worst case,
it's 311V (peak) into 20pF, instantaneous.

Regards                                    \o
Roland                                      l>
                                          < \

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2004\02\21@161153 by Roland

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I was told; If you must test something by touching, always use the back of
your hand(either?), because the reflex tendency will be to grasp, and so
you'll pull away rather than take a good grip!

And my best; when I was a kid I got an old valve scope, bust, and had it on
my desk, cover off. After sitting on the bed for a while mulling on how to
fix it, I leant forward and grabbed the corner of the scope to pull myself
up. Right where the mains switch was! Well there was a flash, a puff of
smoke and I had two neat holes burnt into my index finger. Was sore for days.

At 08:32 PM 21/02/04 +0000, you wrote:
{Quote hidden}

Regards
Roland Jollivet


JeM Electric cc
PO Box 1460
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2004\02\21@163853 by Jim Franklin

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I seem to remember someone telling me it was worse when the mains power was
D.C.
your involuntary muscle spasm would be in one direction, i.e. ON to the
power.
With A.C. the spasms are ON/OFF, more of a chance to "unhook" yourself from
the relevant parts.



{Original Message removed}

2004\02\21@171424 by Bob Ammerman

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Remember that although you may not have an 'ohmic' or conductive path to
ground, you are likely to be capacitively coupled to ground. When measuring
the voltage from yourself to the 230V line with a high impendence voltmeter
you may see a small voltage. This is because you have created an AC voltage
divider with several elements: the voltmeter (1 or 10M ohm typical
impedance), you (? ohms) and the capacitive coupling between you and ground
(? ohms at 60hz).

Now, assuming for the sake of concrete numbers:

Rmeter = 1Mohm
Ryou = 0ohm    (worst case - highest current)
Rcap = 19Mohm
V = 240V

Then your meter would show a voltage of :
    1M/(1M+19M)*240V = 12V

Oh, and the current would be
   240V / 20Mohm = 12 microamps (should be quite safe)

Now, you can test this theory be placing a 1M resistor in parallel with the
voltmeter. Now the voltage read on the meter should be:

   500K/(500K+19M)*240V = 6.15V

And this time the current is

Now, as far as your burning the LED lead: in order to get enough current to
do that, you must have accidentally connected with a real ground somewhere,
I would think. Please describe in more detail the physical arrangement of
your experiment.

Bob Ammerman
RAm Systems

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2004\02\21@184952 by Jake Anderson

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i think the 50/60hz thing is why americans do that whole pounding on the
chest thing before starting CPR.
meant to restart the heart so i hear if it gets stunned by 60hz.
take it with several kilos of salt i think

{Original Message removed}

2004\02\21@185824 by Jake Anderson

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-----Original Message-----
From: pic microcontroller discussion list
[@spam@PICLISTKILLspamspamMITVMA.MIT.EDU]On Behalf Of Jake Anderson
Sent: Sunday, February 22, 2004 10:45 AM
To: KILLspamPICLISTKILLspamspamMITVMA.MIT.EDU
Subject: Re: ] curious Live wire experiment


you have feet no?
they are touching the ground
current will flow from active to ground

-----Original Message-----
From: pic microcontroller discussion list
[RemoveMEPICLISTTakeThisOuTspamMITVMA.MIT.EDU]On Behalf Of Omega Software
Sent: Sunday, February 22, 2004 12:44 AM
To: spamBeGonePICLISTspamBeGonespamMITVMA.MIT.EDU
Subject: Re: ] curious Live wire experiment


At 00.34 22/02/2004 +1100, you wrote:
{Quote hidden}

But I didn't touch ground at all, how come that current flowed anyway?
I knew that ground is at the same potential of the Neutral wire.

How can current flow by touching JUST the Live wire?

This is my original question no one yet answered to, after many replies.
My idea is of some capacitive effect (my body with the planet, which I
suppose is at earth potential, although with a big virtual serie resistor)..
I can't imagine anything else.


{Quote hidden}

the
{Quote hidden}

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2004\02\21@185825 by Omega Software

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At 17.11 21/02/2004 -0500, you wrote:
{Quote hidden}

That mains plug is faulty.. weird, because it's a new one.

The whole experiment is invalid because of this.. but better so, it was
scare if it was a capacitive effect, considering how big that spark has
been.

I replaced the plug, but didn't want to retry the experiment anyway.

I learnt that it's better not to make such experiments.. you never know
what can go wrong.

Thank you all for all the good advice and for the excellent technical
discussion. Now I know much more than I did before.. my love for electronics
got bigger, and my love for live and health as well. ;)

On the other hand, could anybody give a deep technical explanation of
capacitors (I mean the electronic components)?
Do nucleis' protons play any active role/effect in capacitors? Or it's
all only about electrons (but then again, aren't electrons attracted by
atoms that lack some of their electrons and thus the nucleis' protons
attract external electrons)?


>
>Bob Ammerman
>RAm Systems
>
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2004\02\21@194224 by William Chops Westfield

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On Saturday, Feb 21, 2004, at 15:58 US/Pacific, Jake Anderson wrote:

>
> you have feet no?
> they are touching the ground
> current will flow from active to ground
>
Well, no.  At least, not according to the expensive ESD grounding
monitor in the labs at work.  And those labs have intentionally
conductive and grounded floor tiles...

BillW

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2004\02\22@044904 by Howard Winter

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Jim,

On Sat, 21 Feb 2004 20:32:37 -0000, Jim Franklin wrote:

{Quote hidden}

I haven't seen that one, but I once asked my sister-in-law, who is a neurosurgeon, whether a defibrillator
hurts - she said: "Well we only do it to people who are dead!"  I think she meant that since they would die
without it, it doesn't matter...

Cheers,

Howard Winter
St.Albans, England

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2004\02\22@125740 by James Newton, Host

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source= http://www.piclist.com/piclist/2004/02/21/060349a.txt?

Omega Software  says:
> I had a green led I wasn't too fond of, so I've put one pin
> (the anode, although I doubt that it matters) to the Live
> wire, and left the cathode unconnected. I turned on the
> switch.. and then finally put a finger on the cathode,
> thinking the LED may have started to emit some light.
> Instead, I heard a loud pop and saw a shiny spark.. while the
> current in the house immediately went away (the automatic
> emergency switch (lifesaver? Ground Surge Protection?)
> acted). The LED wasn't damaged (!), but the pin tied to the
> Live 230V line was burned and damaged, so much that it was
> nearly cut. I'd have some questions about the above
> experiment:


Having just removed a valued member from the list for calling another member
an idiot, I will stop short of that. Sigh, life has a way of testing one
right after one passes judgment on another... But I don't think that calling
you names would help in any case. You are displaying a part of the hacker
ethic that I admire: Obsessive curiosity.

Andrea, please, listen. Do NOT do this sort of thing again. I personally
know two people who have killed themselves mucking about with live AC. And
they got it from 110 rather than 220.

Here are some ideas for protecting yourself if you must continue:

a. Measure things with a high voltage meter in both AC and DC modes rather
than measuring with your body. You did this in the first place and I don't
understand why you continued after you observed a voltage.

b. Turn off the power at the source, AND CHECK IT, before you release any
wire from its mount, and remount it before turning on the power. Loose wires
move.

c. Do not trust any safety device to actually work. Ground Fault systems can
fail, and are, at times, installed incorrectly.

d. NEVER work with any power electronics without another person in the area
who knows where the off switch is located. But don't depend on this to save
you... you can be dead in less time and you will probably not be able to
speak...

e. Your body will do strange things when shocked. I know that it is possible
that when you touched that wire, your body could have been thrown not away,
but towards the wire. Please don't ask how I know this! Usually, if you grab
a live wire, your hand will be held closed (in a death grip) around the
wire. Also, one of the people who I know who died from a shock was killed,
not by the shock, but because he was so disoriented after the shock that he
brained himself on a block wall.


That's all I can think of... any other safety with high voltage ideas?

And just to end things on a light note:
A woman came home to find her husband in the kitchen, shaking frantically
with what looked like a wire running from his waist towards the electric
kettle. Intending to jolt him away from the deadly current she whacked him
with a handy plank of wood by the back door, breaking his arm in two places.
Until that moment he had been happily listening to his Walkman.

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2004\02\22@154620 by Peter L. Peres

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>is if the wire is touched when the mains is at the peak, so, worst case,
>it's 311V (peak) into 20pF, instantaneous.

The initial charge current is 0.2A at worst (using 1.5 kohm model). It is
a very short pulse but you can feel if something is live (ac) by running
the back of your hand against (just barely touching) it even if you are
fully insulated. You will feel a specific tingling sensation. I suppose
that tiny arcs repeatedly excite the muscles on the back of the hand when
you do this. At 311V an arc should form at 0.1-0.3mm separation in air.
The tingling cannot be felt when touching the object firmly. Maybe the
tiny discharges could be heard in an AM radio placed nearby, tuned between
stations.

Peter

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2004\02\22@164550 by John N. Power

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> From:         Omega Software[SMTP:EraseMEomegasoftwarespamTISCALI.IT]
> Sent:         Saturday, February 21, 2004 8:32 AM
> To:   RemoveMEPICLISTEraseMEspamEraseMEMITVMA.MIT.EDU
> Subject:      Re: [EE:] curious Live wire experiment

>>
> >Basically - this is not a good experiment to do.
> >Death is a possibility.
> >Earth leak breakers help reduce the number of people who die. You cannot
> >be certain that an ELCB will always stop you dying.

> But how can current pass from just one wire? Is it a capacitive effect?

The current (February 2004) issue of Nuts & Volts magazine has an article
which addresses this capacitive effect. According to the author, a retired
Bell Labs scientist and former professor at Rutgers University (now
retired), you can "harvest" electricity from the air. Use an insulated 15 foot
piece of wire as an antenna, and connect it to one AC input of a bridge
rectifier which has its other AC input grounded. Use a ground which is
not associated with the power line, in order to make the test convincing.
Put a 1000 uF capacitor on the output of the bridge. After an hour of
charging, the capacitor will accumulate enough charge to flash an LED
(according to the article). With a 10 or 20:1 step-up transformer, the
voltage will be enough to flash a neon bulb. Obviously this has to be
done inside a house or other building with wiring in the walls.

John Power

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2004\02\22@171904 by Steve Smith

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This reminds me of some work I did in a 400Kv substation ! It was
possible to draw an arc from any metal object with the end of your
finger about half a mm long and it tingled. (capacitive pickup 400Kv to
me) the volts were about 30 ft up in the air on the top of the main
circuit breakers and cause serious deafness when they trip (6 breaks per
phase air blast circuit breaker) used for turning off power stations as
I remember and then all the hair on back of your neck stands on end

Steve....

{Original Message removed}

2004\02\23@075115 by Mark Jordan

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On 22 Feb 2004 at 16:43, John N. Power wrote:

> Use an insulated 15 foot
> piece of wire as an antenna, and connect it to one AC input of a bridge
> rectifier which has its other AC input grounded. Use a ground which is
> not associated with the power line, in order to make the test convincing.
> Put a 1000 uF capacitor on the output of the bridge. After an hour of
> charging, the capacitor will accumulate enough charge to flash an LED
> (according to the article).

       I have did that experiment.  It worked.  Got ~4V each hour.
       The capacitor charged to 30V after a day...

       Mark Jordan, PY3SS

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2004\02\23@160048 by John N. Power

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> From:         Mark Jordan[SMTP:RemoveMEmarkspam_OUTspamKILLspamCPOVO.NET]
> Sent:         Monday, February 23, 2004 7:45 AM
> To:   RemoveMEPICLISTTakeThisOuTspamspamMITVMA.MIT.EDU
> Subject:      Re: [EE:] curious Live wire experiment

> On 22 Feb 2004 at 16:43, John N. Power wrote:

>> Use an insulated 15 foot
>> piece of wire as an antenna, and connect it to one AC input of a bridge
>> rectifier which has its other AC input grounded. Use a ground which is
>> not associated with the power line, in order to make the test convincing.
>> Put a 1000 uF capacitor on the output of the bridge. After an hour of
>> charging, the capacitor will accumulate enough charge to flash an LED
>> (according to the article).

>        I have did that experiment.  It worked.  Got ~4V each hour.
>        The capacitor charged to 30V after a day...

>        Mark Jordan, PY3SS

That is the same result presented in the article: 4 volts after 1 hour.

John Power

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2004\02\23@161709 by Omega Software

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At 09.45 23/02/2004 -0300, you wrote:
>On 22 Feb 2004 at 16:43, John N. Power wrote:
>
>> Use an insulated 15 foot
>> piece of wire as an antenna, and connect it to one AC input of a bridge
>> rectifier which has its other AC input grounded. Use a ground which is
>> not associated with the power line, in order to make the test convincing.
>> Put a 1000 uF capacitor on the output of the bridge. After an hour of
>> charging, the capacitor will accumulate enough charge to flash an LED
>> (according to the article).
>
>        I have did that experiment.  It worked.  Got ~4V each hour.
>        The capacitor charged to 30V after a day...

Couldn't this energy be coming from local radios emissions, etc..?

The device after all is more or less a "wide band", non-tuned radio receiver.

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2004\02\23@170118 by John N. Power

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{Quote hidden}

The power bridges which are typically used for these experiments are not
rated for RF. Also, the energy levels involved just can't be explained this
way. A voltage developed from broadcast radio signals would level off at
the peak output voltage from the antenna. There is no way that this will
be 4 or 30 volts; if the source voltage is 120 volts from power lines, on
the other hand, these voltages are feasible.

John Power

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2004\02\23@172826 by Mark Jordan

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On 23 Feb 2004 at 22:04, Omega Software wrote:

> At 09.45 23/02/2004 -0300, you wrote:
> >On 22 Feb 2004 at 16:43, John N. Power wrote:
> >
> >> Use an insulated 15 foot
> >> piece of wire as an antenna, and connect it to one AC input of a bridge
> >> rectifier which has its other AC input grounded. Use a ground which is
> >> not associated with the power line, in order to make the test convincing.
> >> Put a 1000 uF capacitor on the output of the bridge. After an hour of
> >> charging, the capacitor will accumulate enough charge to flash an LED
> >> (according to the article).
> >
> >        I have did that experiment.  It worked.  Got ~4V each hour.
> >        The capacitor charged to 30V after a day...
>
> Couldn't this energy be coming from local radios emissions, etc..?
>
> The device after all is more or less a "wide band", non-tuned radio receiver.
>

       I have used a bridge of 1N4148 diodes. The wire was a vertical
one, some 10m high.
       The voltage doesn't rise to 30V if the wire is horizontal at
some 3m high.
       In case you have a 50m high tower available, you can connect
a wire on the top of it and get some real juice at the ground level.
I mean some kVolts.

       Mark Jordan, PY3SS

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2004\02\23@173033 by Richard.Prosser

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Does this mean that with 230V mains around I can get ~8V?

Must give it a try

RP



The power bridges which are typically used for these experiments are not
rated for RF. Also, the energy levels involved just can't be explained this
way. A voltage developed from broadcast radio signals would level off at
the peak output voltage from the antenna. There is no way that this will
be 4 or 30 volts; if the source voltage is 120 volts from power lines, on
the other hand, these voltages are feasible.

John Power

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2004\02\23@212312 by William Chops Westfield

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On Monday, Feb 23, 2004, at 12:51 US/Pacific, John N. Power wrote:

>>> se an insulated 15 foot
>>> piece of wire as an antenna, and connect it to one AC input of a
>>> bridge
>>> rectifier which has its other AC input grounded. Use a ground which
>>> is
>>> not associated with the power line, in order to make the test
>>> convincing.
>>> Put a 1000 uF capacitor on the output of the bridge. After an hour of
>>> charging, the capacitor will accumulate enough charge to flash an LED
>>> (according to the article).
>>>
Much longer wires (ie lofted by a balloon) have been used to extract
energy from the natural electrical fields around the earth, driving
things like electrostatic motors (running at very high voltages and
miniscule current.)  I would have thought there would have been more
recent work in converting "static" electricity to more conventional
forms (ie useful for running semiconductors), but I don't recall ever
seeing anything along those lines...

BillW

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2004\02\24@080357 by Alan B. Pearce

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>>        I have did that experiment.  It worked.  Got ~4V each hour.
>>        The capacitor charged to 30V after a day...
>
>Couldn't this energy be coming from local radios emissions, etc..?

Saw a picture recently where someone had taken a whole bunch of fluorescent
tubes, and stuck them on end in the ground under a power line. The photo was
taken at dusk with each tube having a surreal glow at the top end nearest
the power line.

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