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'[OT:] More stupid electrical tricks...'
2004\03\04@132302 by Robert Ussery

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Hi all.
I just thought I'd relate a pitiful yet funny incident that I just
experienced.
Yesterday, I was debugging a circuit hooked up to my computer and powered
from a 7AH 12V battery. I was happily plugging along, when I reached across
the desk for my drink. Suddenly, I got a shooting pain in my wrist followed
by some pretty severe heat. I dropped my drink and hopped around yelping for
a couple of minutes before I finally realized what happened.

What happened? In reaching for my drink, I accidentally bridged the contacts
of the battery with my metal watchband... I now have a watchband with welded
links, a couple of small burns on my wrist, and a very paranoid attitude
about batteries.

How many of you have experienced this same phenomena? Please say you've done
the same thing so I'll stop feeling like such a moron...

BTW, the watch still works! Timex - keeps a lickin' and keeps on tickin'! I
was able to snap the links apart and wear it again after it cooled down. No
real damage, except for a few stylish burn marks. Needless to say, as soon
as I start using my 12V battery, the watch comes off. :O))

Stay safe out there, you guys (& gal or two)!

- Robert

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2004\03\04@144126 by Bob Barr

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On Thu, 4 Mar 2004 11:21:28 -0700, Robert Ussery wrote:

<snip>
>
>How many of you have experienced this same phenomena? Please say you've done
>the same thing so I'll stop feeling like such a moron...
>
>BTW, the watch still works! Timex - keeps a lickin' and keeps on tickin'! I
>was able to snap the links apart and wear it again after it cooled down. No
>real damage, except for a few stylish burn marks. Needless to say, as soon
>as I start using my 12V battery, the watch comes off. :O))
>

I did that *once* while working on my car.

A quick grab for a falling DMM put my watchband across the positive
battery terminal and, IIRC, the transmission cooling line. Ever since
that day, I've disconnected the ground connection to the battery
whenever I can while working on my car. If I can't disconnect the
ground because I'm working on the electrical system, the watch goes in
my pocket.


Regards, Bob


BTW, mine was a Timex and it kept working too.

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2004\03\04@144127 by Howard Winter

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Robert,

On Thu, 4 Mar 2004 11:21:28 -0700, Robert Ussery wrote:

>...<
> In reaching for my drink, I accidentally bridged the contacts
> of the battery with my metal watchband... I now have a watchband with welded
> links, a couple of small burns on my wrist, and a very paranoid attitude
> about batteries.
>
> How many of you have experienced this same phenomena?

I haven't myself - and one of the things I was taught early-on in working on cars was that you take off all
metalwear, jewellery and watches, before you go anywhere near the battery - Lead-acid batteries can produce a
*lot* of current!

But I heard a big strong Irishman scream once - he was working on his own car in the garage I worked in, and
was taking the battery off.  He managed to get the spanner and his gold wedding ring to short across the
battery terminals, and the ring immediately got *really* hot!  And it was a tight fit and he couldn't get it
off... he rushed about and found a bucket of water and plunged his hand in, but he still had to go to hospital
to have the ring removed and the injury treated.

I did once do a really stupid thing though - I had a piece of telephone wire (one strand from inside an
extension cable) and I "flashed" it across a newly-charged car battery.  I don't know why I did it, but the
wire *vapourised*!  There was about an inch length left welded to one terminal, but the rest of it just ceased
to exist... I won't do *that* again!

Cheers,

Howard Winter
St.Albans, England

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2004\03\04@153737 by Robert Rolf

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Howard Winter wrote:
> I did once do a really stupid thing though - I had a piece of telephone wire (one strand from inside an
> extension cable) and I "flashed" it across a newly-charged car battery.  I don't know why I did it, but the
> wire *vapourised*!  There was about an inch length left welded to one terminal, but the rest of it just ceased
> to exist... I won't do *that* again!

I did something simlar, but with a length of PVC insulated #14.
I was just imitating my dad, who used to 'brush' the bare end of the wire
across a post to see if the battery had a good charge. Unfortunately
I didn't just 'brush' it, and had a red hot snake of near molten copper to
yank on to break off the welded contact. And what a stench....
Lesson learned.

Robert

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2004\03\04@154321 by steve

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> What happened? In reaching for my drink, I accidentally bridged the
> contacts of the battery with my metal watchband...

> How many of you have experienced this same phenomena? Please say
> you've done the same thing so I'll stop feeling like such a moron...

I haven't done these myself but I have seen two good lessons in that
respect.

1) I watched someone take a ring spanner, put it on the positive terminal
and turn it until it hit the engine block. When it sparked, he jumped and then
went to grab the spanner which was still connected and now glowing a dull
orange. Lesson -Disconnect the ground wire first.

2) Someone with a metal watch strap managed to get them across the
terminals of the remote starter solenoid. The good news was  that they
didn't weld themselves together so he just got the watchstrap burn on his
wrist. The bad news was that the car was in gear and it promptly jumped
forward and parked on his foot. Lesson - Stay away from some people.

Steve

==========================================
Steve Baldwin                          Electronic Product Design
TLA Microsystems Ltd             Microcontroller Specialists
PO Box 15-680, New Lynn                http://www.tla.co.nz
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2004\03\04@155400 by Spehro Pefhany
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At 01:29 PM 3/4/2004 -0700, you wrote:


>I did something simlar, but with a length of PVC insulated #14.
>I was just imitating my dad, who used to 'brush' the bare end of the wire
>across a post to see if the battery had a good charge. Unfortunately
>I didn't just 'brush' it, and had a red hot snake of near molten copper to
>yank on to break off the welded contact. And what a stench....

Burning PVC is quite toxic, AFAIUI.

Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
.....speffKILLspamspam@spam@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com

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2004\03\04@160436 by Gary Neal

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So, my one friend at work has a remote car starter in his manual 5 speed
Saturn. So at 8:30 this morning we heard the security guy paging
him.  Evidently, while he is in the office his car starter went
bonkers and started the car (car in gear of course) bashed the car in front
of him, stalled out, and then the cycle repeated again and again and
again...  Some days it just doesn't pay to get out of bed...

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2004\03\04@160438 by Russell McMahon

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> What happened? In reaching for my drink, I accidentally bridged the
contacts
> of the battery with my metal watchband... I now have a watchband with
welded
> links, a couple of small burns on my wrist, and a very paranoid attitude
> about batteries.
>
> How many of you have experienced this same phenomena? Please say you've
done
> the same thing so I'll stop feeling like such a moron...

Carrying a number of 2 AH NimH AA cells in one's trouser pocket along with
coins and keys is not recommended :-). Puts mere wrist band shorting to
shame for personal pain and inconvenience. Not learning some things well
means I have done this several times :-)


       RM

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2004\03\04@165628 by Robert Ussery

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>-----Original Message-----
>From: pic microcontroller discussion list [PICLISTspamKILLspamMITVMA.MIT.EDU]
>On Behalf Of Howard Winter
>Sent: Thursday, March 04, 2004 12:40 PM
>To: .....PICLISTKILLspamspam.....MITVMA.MIT.EDU
>Subject: Re: [PICLIST] [OT:] More stupid electrical tricks...


>I haven't myself - and one of the things I was taught early-on in working
>on cars was that you take off all
>metalwear, jewellery and watches, before you go anywhere near the battery -

Ditto for me, whenever I work on my car, but I never really thought of it
with this smaller gel cell. It pays to be aware that even these small
batteries can deliver thousands of amps.

- Robert

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2004\03\04@171534 by John Ferrell

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I consider that a digital camer "hot pocket"! It happens best when you sqat
down to do something...

John Ferrell
http://DixieNC.US

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2004\03\04@191048 by Robert Rolf

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So did he install the remote starter himself?

Any competent installer would have a 'neutral detect' and 'lurch'
switch to detect and prevent this exact situation.

Hope he sued the pants off the installer and forced a recall on
all his other installs.

R


Gary Neal wrote:
>
> So, my one friend at work has a remote car starter in his manual 5 speed
> Saturn. So at 8:30 this morning we heard the security guy paging
> him.  Evidently, while he is in the office his car starter went
> bonkers and started the car (car in gear of course) bashed the car in front
> of him, stalled out, and then the cycle repeated again and again and
> again...  Some days it just doesn't pay to get out of bed...

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2004\03\04@192939 by Lenihan.Eugene

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When I was a young Technician in the Navy I had an electrical experience
that turned one of my hands into a kind of mechanical oscillator.
I was in one of the ship's radio rooms performing sensitivity tests on
receivers.
I had to reach behind the receiver, disconnect the antenna input cable,
connect a signal generator output in it's place, make & record the
measurement, and then restore the antenna connection.  This, of course, was
done for each separate receiver.
Well, unbeknownst to me, some insulation had broken away from the AC power
connection to one of the receivers and the power connection was adjacent to
the antenna connection.
When I reached around behind this receiver to disconnect the antenna, my
hand came in contact with the AC.  I let out a howl, my hand flew back the
few inches of clearance there was, hit the bulkhead behind, bounced off the
bulkhead and hit the AC again, flew back to the bulkhead.......
I was yodelling pretty good there while I my hand & arm were vibrating away
until I pulled my poor abused hand out of there.

That broken insulation was repaired forthwith!


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2004\03\04@202208 by William Jacobs

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Robert Ussery wrote:

So should  your rings and other jewelry
bill

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2004\03\04@225256 by Mike Hord

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For anyone who hasn't seen this one yet...

I used to work in an outdoor summer theatre.  14 wireless microphones
times 2 battery changes a night times 14 shows and 4 rehearsals yields
several hundred half-dead 9v batteries.  I will NEVER understand why it's
possible to daisy-chain them positive to negative to positive ad nauseum,
but it is.  More than 10 requires some reinforcement, and 65 will make an
impressively long bar.

After burning holes in aluminum cans and bursting electrolytic caps got
dull, I started showing it off.  A friend was hefting it, commenting on
all the power stored in this bar of death, when he suddenly went quite
silent.  After much shaking and jumping, he managed to throw it a few
feet.  The profanity was amazing.

It turns out he'd capped the ends of the bar, touching the positive
and negative end terminals with the balls of his palms.  It burned pits
into his hands almost a centimeter deep.  I'm still not sure how he
didn't die; all I can figure is that the current went past heart
interruption
straight to cooking tissue.  Also the fact that it was DC certainly helped.

Mike H.
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2004\03\04@230750 by Herbert Graf

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> For anyone who hasn't seen this one yet...
>
> I used to work in an outdoor summer theatre.  14 wireless microphones
> times 2 battery changes a night times 14 shows and 4 rehearsals yields
> several hundred half-dead 9v batteries.  I will NEVER understand why it's
> possible to daisy-chain them positive to negative to positive ad nauseum,
> but it is.  More than 10 requires some reinforcement, and 65 will make an
> impressively long bar.

       Hehe, a friend of mine also worked in a theatre and I scavanged a whole
boatload of industrial 9V batteries after the run. Didn't run out of
batteries for many years! Strung a bunch together to light 120V light bulbs,
very neat. TTYL

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2004\03\04@230751 by Robert Ussery

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>-----Original Message-----
>From: pic microcontroller discussion list [EraseMEPICLISTspam_OUTspamTakeThisOuTMITVMA.MIT.EDU]
>On Behalf Of William Jacobs
>Sent: Thursday, March 04, 2004 6:21 PM
>To: PICLISTspamspam_OUTMITVMA.MIT.EDU
>Subject: Re: [PICLIST] [OT:] More stupid electrical tricks...


>So should  your rings and other jewelry
>bill

??? :O)

Glad to say I don't wear other jewelry... I'm not married so no wedding ring
(heck, I'm still in high school! :O), and I'm not much for hanging big
chains around my neck.
As far as wearing the watch, I just forget I'm wearing it, and my
electronics work is usually really casual (i.e., sit down for a couple of
minutes between getting my homework done, eating, etc. and plug away at it).
Needless to say, this little incident has made me significantly more
cognizant of the dangers of even pretty small batteries. <Grin>

- Robert

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2004\03\04@233731 by William Chops Westfield

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On Thursday, Mar 4, 2004, at 12:52 US/Pacific, Russell McMahon wrote:

>>  Please say you've done the same thing

I've got a couple burns from taking apart Li-Ion battery packs.
Frequently, these are assembled with some sort of flex circuit
board, and one mus be careful, when cutting through the flex, not
to bridge + and - from anywhere with your cutting tool.  You find
out real quick which parts are connected to that section, cause
they ALL get hot real quick...

BillW

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2004\03\04@235017 by Jinx

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> Any competent installer would have a 'neutral detect' and 'lurch'
> switch to detect and prevent this exact situation.

The dangers are appreciated. There are some responsible
installers as illustrated in this local case a few weeks ago

www.nzherald.co.nz/storydisplay.cfm?thesection=news&thesubsection=&st
oryID=3544154

You really don't need something like this to happen at full-term

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2004\03\05@023751 by Vasile Surducan

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On Fri, 5 Mar 2004, Jinx wrote:

> > Any competent installer would have a 'neutral detect' and 'lurch'
> > switch to detect and prevent this exact situation.
>
> The dangers are appreciated.


 At 20 I was a tehnician, working at a plant factory and studing in the
same time. All automations where powered up from a local acid battery
station, having 110V or 220V and almost 220 Ah. It was a huge room where
the elements (30kg) where connected in series. One of the biggest problem
whas the accidental shortcircuit of one of the poles to ground. Why ?
Because if one pole was grounded, another scurtcircuit to ground of
the opposite polarity circuit could produce firing. Of course the
accidental grounding was checked by a supervising meter. In one day I was
searching for such a damn shortcircuit. It was very hot, about 30C inside
and all automations closed in some big metal cases.
With my right shoulder firmly on the metal case (grounded and +110V),
I have touch accidentaly a relay socket with my arm (-110V).

 I can't explain the feeling. But is fresh in my mind after 20 years.
Nothing is the same like a good, no ripple, "infinite output power" DC
shaking !

best,
Vasile

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2004\03\05@095454 by Alan B. Pearce

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I have had various shocks over a number of years from various items, but I
think the worst one was probably when I was doing a callout one night. The
company I worked for serviced microfiche printers and copiers. We took over
the servicing of a couple of machines that we did not normally handle, so we
had to get used to the idiosyncrasies of these.

this particular night I was called out to a problem with exposures on the
duplicate fiche. I ascertained that the exposure tube needed replacing, and
being on my own in the place (apart from an operator in later stages of
pregnancy), was being very careful.

The exposure lamp in this machine is a gas discharge lamp which has about
3kV DC across it, and when it comes time to turn on the light, an additional
AC voltage is turned on to get the lamp above its striking voltage. When
this AC voltage is turned off the lamp goes out as the 3kV is not sufficient
to sustain the arc. To further complicate matters the lamp is in an acrylic
tube which has water flow through it to keep the lamp temperature down to a
point where the film does not burn up.

I proceeded to turn off the power at the mains switch on the machine, at
which point all the pumps went dead, indicators went out etc, and I then
dismantled the lamp housing. Once the lamp assembly was accessible, and free
of the chassis, I manoeuvred the assembly so that the chassis touched each
end of the lamp in turn to discharge any stray volts left behind lurking in
capacitors. Proceed to unbolt things, and then while getting the lamp out
managed to touch the terminals with both hands. The resulting shock caused
me to sit on my backside between the machines. The operator was at this
point standing on an upturned rubbish bin, attending to some DLT tapes in a
tape drive which was an add-on sitting on top of the machine, and she was
quite short, and could not otherwise reach it. She turns around and asks if
I am all right, to which I said yes.

having done this less than elegant manouvour, I went investigating somewhat
more thoroughly, and found that although the main switch I had turned off
removed power from almost everything, it left this DC supply still on. My
attempts at trying to be safe by shorting the voltage to earth were thwarted
as the supply was fully floating from ground, with some 10's of Megohms
resistors each end to the chassis. Hence my attempts at shorting things to
ground still left several 10's megohms load on the supply, and did not
achieve anything. The one thing I did not do was short the two ends of the
lamp together, but this was hard to do as it was a straight lamp with
terminal on the ends, and I could not manoeuvre it to have both ends touch
chassis simultaneously.

Moral of the story is to make sure the machine is fully isolated from the
mains before doing anything remotely dangerous.

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2004\03\05@101615 by Hulatt, Jon

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This really isn't that interesting, so you probably want to skip, but it's a
lesson learned for me...

I live in a rented house. Our freezr packed up, and the landlord came round
to replace it. The old freezer (and fridge) was an integrated type, built in
to a cupboard unit), The new one was a freestanding fridge freezer. So we
had to rip the cupboard out. There was a double-socket built in to the
cupboard, and this needed relocating to the wall. The landlord seemed
somewhat scared at the concept of electricity, so I offered to do it for him
(I used to rewire houses when I was younger). So, I went into the downstairs
toilet where the fuse box is, in a wooded cupboard up high, and flipped off
the power. I proceeded to disconnect the socket, and we ripped the cupboard
out.

Later on that afternoon, when I came to remount the socket on the wall, I'd
bent the wires from the two cables apart (ring main - 2 bits of T+E), and
marked out the holes I needed to drill. Then proceeded to plug in the drill,
and I would have turned the power on  and drilled the holes. I decided to
plug the drill into the socket literally just around the corner (L shaped
kitchen), only 2-3 feet away horizontally. The cd player was plugged into
this socket, and at that point I noticed that the cd player was on. Which
caused me to be somewhat alarmed- I traced it back to the fusebox, and this
socket and the one next to it seems to be an unfused spur, from the
electricity companies side of the fuse box!!!!

I'd just assumed that flipping the switch had isolated the whole house. I'm
lucky that, by chance, the socket I disconnected *was* isolated, otherwise I
mightn't be here now.

Also, distinctly shocked at the wiring for that spur. I've arranged with the
electricity company for them to disconnect my circuit so I can remove the
spur, since it's lethal. At the moment it's taped over, and I refuse to let
anyone use the socket.


Anyway, from now on, I will always be testing any wiring I'm working on to
see if it really is live or not. Even the master breaker is not good enough
for me to assume. One thing I tend to do anyway is to short live to neutral
and earth, before actually touching any copper with my hands, when working
on mains electricity. Although even this isn't great with wire-fuses...
sometimes a fuse can take a number of seconds to blow.

Jon

> -----Original Message-----
> From: Alan B. Pearce [RemoveMEA.B.PearceTakeThisOuTspamRL.AC.UK]
> Sent: 05 March 2004 14:54
> To: spamBeGonePICLISTspamBeGonespamMITVMA.MIT.EDU
> Subject: Re: [OT:] More stupid electrical tricks...
>
>
> I have had various shocks over a number of years from various
>...

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2004\03\05@111747 by THE NELSONS

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30 Years ago I worked in a factory that did custom styrofoam also known
as EPS(expanded poly styrene).  They had what we called the bag room
which had about 10 large bags  8 foot square by 15 foot high ( 2.5M X
2.5M X 5M)  These were used to store the different density pre-expanded
beads in.  The used a black plastic flexible pipe to move the beads from
the bags to the molding machines as needed.  this was done with
compressed air.  when you walked in the room you could feel you hair
stand on end from the STATIC electricity.   The pipes were connected
together with slip couplings that could be taken apart by hand.  They
also had a  heavy wire  that jumped across the coupling. About my third
day there I went to  unhook a coupling and did not make sure the jumper
wire was attached. when the pipes were seperated I heard a big SNAP and
found myself on the floor about 5 feet away wondering what happened.  I
never before realised that static electricity could carry that much of a
charge.  My boss told me later that had happened to most every one there
and some of the carless ones several times.  I have since had very much
respect for static electricity.  Also my TIMEX red led wrist watch iwas
wearing went totaly dead.

Anyone wanting to know the basics of  styrofoam molding  and some of
special circuits I designed can email me off line.  I sometimes think
what I could have done with a PIC chip if they had been around back then.

Bob N

>

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2004\03\05@112951 by Alan B. Pearce

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>About my third day there I went to  unhook a coupling and
>did not make sure the jumper wire was attached. when the
>pipes were seperated I heard a big SNAP and found myself
>on the floor about 5 feet away wondering what happened.

The first company I worked for was involved in developing radio telephone
hardware, mainly HF marine, and branching into VHF radio telephone. There
was a reasonable aerial farm on the roof of the building, all brought inside
onto a patch panel, from where any desk could patch into any aerial. One
evening there was just the boss and I there, about to go home, so with all
the gear turned off everything was real quiet. All we could hear was a
periodic tick ... tick .... tick and went to investigate. We found a BNC
connector on the end of a lead connected to an aerial, but the connector was
not connected to anything at this end, just lying on a bench. It was raining
outside, and the rain static on the aerial was building up sufficient
voltage on the cable coax to make quite a healthy spark between the centre
pin of the connector and the body.

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2004\03\05@122629 by John Ferrell

face picon face
This happens in my shop frequently.I disconnect the antenna & rotor when not
using it and it dangles at about 7 feet off the floor, When it starts
ticking, I shut down computers and prepare for lightning. Yes, the tower is
grounded...

John Ferrell
http://DixieNC.US

> The first company I worked for was involved in developing radio telephone
> hardware, mainly HF marine, and branching into VHF radio telephone. There
> was a reasonable aerial farm on the roof of the building, all brought
inside
> onto a patch panel, from where any desk could patch into any aerial. One
> evening there was just the boss and I there, about to go home, so with all
> the gear turned off everything was real quiet. All we could hear was a
> periodic tick ... tick .... tick and went to investigate. We found a BNC
> connector on the end of a lead connected to an aerial, but the connector
was
> not connected to anything at this end, just lying on a bench. It was
raining
> outside, and the rain static on the aerial was building up sufficient
> voltage on the cable coax to make quite a healthy spark between the centre
> pin of the connector and the body.
>
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2004\03\05@141457 by Alvaro Deibe Diaz

picon face
> This happens in my shop frequently.I disconnect the antenna &
> rotor when not using it and it dangles at about 7 feet off
> the floor, When it starts ticking, I shut down computers and
> prepare for lightning. Yes, the tower is grounded...

> > It was raining outside, and the rain static on the aerial
> > was building up sufficient voltage on the cable coax to
> > make quite a healthy spark between the centre pin of the
> > connector and the body.

Some years ago, I was involved in Control Line Aeromodelling.
We made the kind of planes flying circles (radious of 19 meter)
around the pilot. The plane was linked to the pilot hand with a
pair of 0,4mm diameter iron wire.

One summer evening, while I was flying my plane, the wind grew
up, and begun to rain. Yes, a storm was coming to us fast. Soon
I felt (and saw!) little sparks from the wires to my right hand.
Being the kind of plane without throttle control, I had to wait
till all the fuel was burnt out, flying very low (about 0,5m and
fast (some 80Km/h).

Still alive. But fast-moving long antennas, like the one I was
Grasping, are not good companions in a storm...

:o)

Alvaro Deibe.

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2004\03\05@172921 by Nate Duehr

face
flavicon
face
On Mar 5, 2004, at 10:26 AM, John Ferrell wrote:

> This happens in my shop frequently.I disconnect the antenna & rotor
> when not
> using it and it dangles at about 7 feet off the floor, When it starts
> ticking, I shut down computers and prepare for lightning. Yes, the
> tower is
> grounded...

Mmm... they really should install a copper entrance panel connected to
ground via wide copper strapping and get you some Polyphaser devices to
pass all the cables through.

The tower ground needs to be bonded to the building ground and the
"dangling" cables need to be plugged into a separate grounding block
when they're not in use.   Otherwise they're a fire hazard, most
likely.

A direct strike to the tower will charge it and everything connected to
it to a high enough potential that the electricity will be looking for
ANYTHING that looks like a ground, and the tower's ground can't
instantaneously bleed off all that charge -- the potential of those
cables WILL be high enough for them to find a place to arc over to.
ESPECIALLY if the tower is not bonded to the electrical ground -- that
has to be done correctly also.  (The bummer with this for us RF guys is
of course, that a nicely protected electrical ground system usually
ends up resonant at some darn frequency we want to use.)

Polyphaser's website has some nice engineering information about how to
properly ground a tower "system", not just the tower itself.  After
seeing firsthand what a solid direct hit can do to a residential
dwelling when my dad's house took a direct hit last year, I carefully
think about all paths to ground any lightning that hits any of my
antennas will take... ALL of them.

Nate Duehr, RemoveMEnateTakeThisOuTspamspamnatetech.com

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2004\03\05@174207 by gacrowell

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Funny how you can be extra careful to disconnect the power and still get bit...

When I was a young tech in the Air Force, a grizzled old Master Sgt was showing me how to do the preventive maintenance on a teletype crypto machine.  We carefully turned off the breaker, put a "maintenance in progress" sign on the breaker box, and went to work.  This was a KW-26 as I recall, tubes even.  First job is to drop the front panel and clean a large multi-level rotary switch that had at least 50 wires going to it.  Sarge sprays cleaner on the switch and poof, it bursts into flame.  Its a *teletype* crypto machine, and its still got the teletype loop power connected to it.

So flash 25 years later, and I'm poking around in a PC trying to plug in a card, power is off, and I feel a jolt.  What the heck, and I yank the modular power cord out of the power supply.  Stick my hand back in, and get zapped again.  'bout that time from another room my daughter says the telephone ring sure sounds funny...  I was getting my hand across the adjacent modem card telephone line, just as a ring was coming in.

Gary

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2004\03\05@180318 by Jinx

face picon face
> Anyway, from now on, I will always be testing any wiring I'm working
> on to see if it really is live or not. Even the master breaker is not good
> enough for me to assume

When a friend was moving business premises from a sub-divided
warehouse I went in to remove the strip lighting she'd had installed. Her
main switch was turned off, the fuse pulled and the lights were out. Two
were removed, no problem. Cutting through the wiring to the third vapour-
ised my lovely new and fairly pricey Lindstrom snippers, the bang and
flash right in my face scaring the crap out of me. It turned out that some
(not so) clever dick had wired this particular light to next door's supply.
What shocked, no pun intended, me too was that even then the wires
were still hot. No fuse anywhere had blown

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2004\03\05@190418 by Hopkins

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> Polyphaser's website has some nice engineering information about how to
> properly ground a tower "system", not just the tower itself.  After
> seeing firsthand what a solid direct hit can do to a residential
> dwelling when my dad's house took a direct hit last year, I carefully
> think about all paths to ground any lightning that hits any of my
> antennas will take... ALL of them.

Ok - what is PolyPhasers web site address???????????
*************************************************
Roy Hopkins   :-)

Tauranga
New Zealand
*************************************************

>
> Nate Duehr, spamBeGonenateSTOPspamspamEraseMEnatetech.com



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2004\03\05@190834 by Peter L. Peres

picon face
I'm wearing a plastic watchband and have been for ~16 years. The watch
proper is also plastic. Also no rings, and no chains. I worry a lot about
my spectacles, which have metal frames. And I'd like to say that you were
lucky it was a *low* voltage battery. Bigger ones work better as you can
imagine. Ac too. Even if your body is insulated. I have a friend who
barely escaped from the death-hug of his golden neckchain which decided to
pop out of his shirt while he was bending over a HV smpsu, and another who
was saved by his spectacles from blindness by acid steam exhaust from a
capacitor.  Also there's nothing like working around rf transmitter tank
coils to teach you about the value of *removable* wedding rings and *not*
having any teeth fillings (let alone implants).

Peter

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2004\03\05@191452 by Hopkins

flavicon
face
I worked at a radio transmitter site in a large building - 12 high power HF
transmitters.

One guy was carrying out maintance with all the power off to his transmitter
and I was standing 30 feet away with my back to him when I heard a loaud
crack and saw a bright flash.

The other guy was sitting on his backside 15 feet away with the remains of
his slodering iron in his hand.

On investigation it was found that the earth connection in the iron was
broken and that the tip had become live through the heating coil touching
the tip cover so that when he went to unsolder a point connected to earth he
cause a short circuit.

So it is not just the equipment that can cause a problem as in this case the
tool he was using.

*************************************************
Roy Hopkins   :-)

Tauranga
New Zealand
*************************************************



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2004\03\05@215120 by michael brown

picon face
From: "Robert Ussery"

> of the battery with my metal watchband... I now have a watchband with
welded
> links, a couple of small burns on my wrist, and a very paranoid
attitude
> about batteries.
>
> How many of you have experienced this same phenomena? Please say
you've done
> the same thing so I'll stop feeling like such a moron...

Ask how many have picked up a soldering iron by the hot end and how many
times.  ;-)

I once installed an 8-track tape deck in my car and didn't see any need
to worry about fuses.  Eventually a short developed and the power lead
to the deck immediately turned a nice cherry red causing the plastic
insulation to just drop off the wire.  I got a nice burn when yanking
out the wiring.  Now, I always use fuses.

For amateur radio installations, I usually run power/ground leads all
the way to the battery.  I fuse both leads as close to the battery as
possible.

michael brown

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2004\03\05@221648 by William Chops Westfield

face picon face
On Friday, Mar 5, 2004, at 15:02 US/Pacific, Jinx wrote:
>  Cutting through the wiring to the third vapourised my lovely new and
> fairly pricey Lindstrom snippers, the bang and flash right in my face
> scaring the crap out of me.

Having decided that the mixer was indeed broken, I decided to salvage
what I could (ie the power cord.)  So I unplugged it, grabbed the nice
chefs knife from the knife block, and slice through the cord near the
mixer body.   Too bad the cord I had unplugged was to the food
processor.  Left an impressive notch in the knife blade, made a nice
flash, didn't blow the beaker...

BillW

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2004\03\05@222308 by Anthony Toft

flavicon
face
> to the deck immediately turned a nice cherry red causing the plastic
> insulation to just drop off the wire.  I got a nice burn when yanking
> out the wiring.  Now, I always use fuses.

Reminds me of the time I was testing my tank circuit for the in car mp3
player. I hooked the positive side to the 10 guage (yep the big fat
stuff), and the negative to the ground point using those little
connectors available at radioshack, the ones with the croc clips on both
ends (yep the little skinny ones). It seemed to work with no load, so I
figured it was time to hook the inverter to the circuit (which I did). I
had the girlfriend observe the experiment in the trunk as I turned the
key in the front.

After hastily shutting everything off from the cries of alarm issuing
from the now alarmed observer I return to the scene of the crime to find
the skinny connector vanished, completely, only the clips remained.
There was an impressive cloud of evil smelling gray smoke dissipating in
the evening air and a seriously concerned looking girlfriend asking me
if it was going to "catch fire".

I also had no fuse which I rectified before the final install, and again
the mp3 player outlived the car.


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2004\03\05@225216 by Hopkins

flavicon
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hence the name willian CHOPS westfield lol
----- Original Message -----
From: "William Chops Westfield" <.....westfwspamRemoveMEMAC.COM>
To: <RemoveMEPICLISTspamspamBeGoneMITVMA.MIT.EDU>
Sent: Saturday, March 06, 2004 4:13 PM
Subject: Re: [OT:] More stupid electrical tricks...


{Quote hidden}

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2004\03\05@230706 by Rick C.

flavicon
face
So far I've only heard about accidents pertaining to electricity. Here's a
"trick" we played on a co-worker. We had just built a new workshop and no AC was
to the premises yet. We were in the process of wiring the receptacles. Our
co-worker was always shy and jumpy around electricity and he overheard us
"talking" about the dangers of working around AC mains and assured him no AC
power was anywhere on the lot. He was delegated the job of wiring the
receptacles in the wall boxes.

We ran out and got a 20AH gel cell and jumper cables, and went behind the wall
to the next receptacle in the line making sure he didn't see us. We jumpered to
battery to the power cable and stood by and watched.

Eventually he inadvertantly shorted his pliers across the cable and the sparks
flew. He was sitting crosslegged in front of the outlet and came rolling
backwards away from the wall. We fell on the ground laughing and he chased us
for two blocks before he cooled off but never caught us.

We knew with the long lead length and #12 wire that not much real damage would
occur. Just a bunch of sparks. He was wearing glasses and no rings.

We did a lot of stupid things in our younger years. Probably wouldn't do it
anymore. You never know if someone has a weak heart or could get burned.
Rick

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2004\03\06@015546 by James Newton, Host

face picon face
Oh man... That was a perfect 1, 2 punch. The original story was funny as all
heck and then this wise crack...

My sides are hurting. And the worst part is it reminds me of when my little
boy noticed a power cord by the side of our bed and for some strange reason
decided to cut it with a pair of scissors from the table near by. It was one
of those deals that you see just before it happens and you launch and scream
but it's already too late... Nice big shower of sparks and a notch in the
scissors and...

...a little boy who has a healthy respect for power cords.

I just love that bit about unplugging the wrong cord. Things like that are
one reason why I try to stick to software.


---
James.


{Original Message removed}

2004\03\06@023358 by Jim Tellier

picon face
OK, two more $0.01's :%)


I worked in an electric motor repair shop in Pennsylvania when I was in high
school.. it was a steel-foundry town, so the shop got some BIG motors in for
refurb once in a great while..  I mean *B*I*G* !!!  The one that I got to
help rewind the stator coils was big enough that you could walk into the
frame without bumping your head.. about 7 ft. diam.   I can't recall what
the HP rating was on this beast, (a couple thousand, IIRC), but the shaft
was about a foot in diameter, and it was 3PH 440VAC at something like 400
amps startup current.  They had to have a power service upgrade in the shop
just to be able to test it!  The beast was used for a very large crane; I
wish I could have seen it in use.
Anyway, after having rewound one of the stator coils, my coworker asked me
to make sure it was correctly phased and secure.   I grabbed my regular
"tool of choice" for putzing with coil alignment - the 12" long flat-blade
screwdriver - and proceeded to walk into the motorframe.   As I got about a
foot inside the frame, I felt my arm being pulled upward; natural instinct
was to grab onto the screwdriver so it wouldn't fly out of my hand (I
guess!).   About that instant, I realized that there was a full-voltage test
in progress (Gee, I wish they'd told me!!!).   The field literally picked me
up and caused my screwdriver to jam itself into one of the coils at the
12:00 position, while my left hand flailed around until I made contact with
the face of the coils at the 9:00 position.   OWWWW!!!  I was in a
horizontal position when I felt the zap, and basically ejected from the far
side of the stator... I think about 3 mSec elapsed!  My entire left side
hurt for 2 weeks.  No idea why I wasn't "toast"!   But I decided a career in
motor repair wasn't the ticket for me... so I joined the software brigade!
:^)

Jim-the-lucky!

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2004\03\06@044937 by Steve Smith

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This reminds me of a small fire I once encountered !
I was at one point the owner of a robin reliant (plastic pig stupid 3
wheeled thingy probably only available in uk) I was going out one day
inserted the key turned and the throttle cable caught fire loads o smoke
! Tracing the fault the bond between the chassis and the engine was
rotted away and the point of best conductance was the throttle cable it
caused the discharge of a fire extinguisher and made ell of a mess damm
lucky fiberglass body could have all gone up in smoke !

Steve (no longer owner of plastic pig)

{Original Message removed}

2004\03\06@045559 by Alan B. Pearce

face picon face
> >  Cutting through the wiring to the third vapourised my lovely new and
> > fairly pricey Lindstrom snippers, the bang and flash right in my face
> > scaring the crap out of me.
>
> Having decided that the mixer was indeed broken, I decided to salvage
> what I could (ie the power cord.)  So I unplugged it, grabbed the nice
> chefs knife from the knife block, and slice through the cord near the
> mixer body.   Too bad the cord I had unplugged was to the food
> processor.  Left an impressive notch in the knife blade, made a nice
> flash, didn't blow the beaker...

A jeweller friend of my parents decided to get a new lathe for his workshop,
but being scared of electricity asked dad to wire it into the mains for him.
Dad duly turns up, and it seems the unit id to be some way from the power
point. OK, the way to work out how much lead to use, is to put the plug on
it, plug it in, and run the wire around the wall, then cut it to length, and
wire it into the unit. Bang - flash - much to the consternation of friend
and amusement of my father. It seems that the act of plugging into the wall
produced an automatic reflex to turn the switch on ...

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2004\03\06@051505 by Russell McMahon

face
flavicon
face
> Having decided that the mixer was indeed broken, I decided to salvage
> what I could (ie the power cord.)  So I unplugged it, grabbed the nice
> chefs knife from the knife block, and slice through the cord near the
> mixer body.   Too bad the cord I had unplugged was to the food
> processor.  Left an impressive notch in the knife blade, made a nice
> flash, didn't blow the beaker...

Bracing the bare metal of the (nice largish chrome vanadium) screwdriver on
the edge of the earthed chassis O slid it forward until the tip contacted
the tag-strip lug to which the incoming phase lead was connected*. The
subsequent arc welded the screwdriver tip to the tag and the arc then formed
between screwdriver body and the chassis edge. When enough metal had been
arc eroded from the screwdriver side the arc stopped. The screwdriver was
left welded to the tag and floating at 240 V mains potential.  It
subsequently served me well fro many years, with a nice chunk missing part
way up the blade as a reminder.


       EM

* Then, and to this day, I have no idea why I did what I did as the outcome
should have been obvious.

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2004\03\06@055106 by Mike Hawkshaw

flavicon
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----- Original Message -----
From: "Hulatt, Jon" <spamBeGonejhulattEraseMEspamMONSTEREUROPE.COM>
To: <PICLISTspamBeGonespamMITVMA.MIT.EDU>
Sent: Friday, March 05, 2004 3:06 PM
Subject: Re: [OT:] More stupid electrical tricks...
Scary story snipped.

My dad was a domestic electrician and as a 16 year old I used to help him do
re-wires from time to time. The funniest thing I ever saw (funny after the
event - scary at the time) was when we came to wire up the cooker in this
house. We'd moved the cooker a bit to one side and the fridge a bit to the
other, so he could squeze between them and get to the old cooker cable. He
cut through the cable close to the hole in the floor where it emerged, and
then proceded to push it through the hole in the floor in order to get the
new wire in. Unfortunately, being 6 square mm cable, he had to cut from one
side and then the other, so he had not actually cut through the whole thing
in one go (which is what I always try and do). Also unfortunately, the
cowboy who'd fitted the cooker had wired the thing up from the 30 amp socket
ring main, (which was the only circuit that was live due to us using the
electric drill)

I'll never forget the image of him squirming between too well earthed
appliances with his finger on the end of 240 volts. The air got pretty blue
for a couple of seconds as well, I have to say.

Morale of the story? Trust no one where your life is concerned.

> Also, distinctly shocked at the wiring for that spur. I've arranged with
the
> electricity company for them to disconnect my circuit so I can remove the
> spur, since it's lethal.
Also, Jon, at a rough guess the prospective fault current at your
"intrestingly wired" spur is probably between 2000 and 5000 amps. That's
quite incredible, really, if you consider that one can weld with 10 amps!!
You're definately doing the right thing in getting rid of it.

Keep safe.....Mike.

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2004\03\06@060353 by Jinx

face picon face
> I once installed an 8-track tape deck in my car and didn't see any
> need to worry about fuses.  Eventually a short developed and the
> power lead to the deck immediately turned a nice cherry red

My boss learned the hard way about fuses in cars. His stereo
started popping every 2A fuse he put in. OK, time for lateral
thinking. Forget those wimpy 2A fuses, waste of money those
things. He shoves a 40A headlight fuse in there. Ha ! Now that's
a man's fuse, let's see you pop now. No, no, no. Let's see the
sound-proofing behind the dash catch fire shall we and watch
boss run around like a headless chicken. Hey boss, I think I
know where you went wrong there chief...........

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2004\03\06@061634 by Mike Hawkshaw

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----- Original Message -----
From: "Nate Duehr" <.....nateRemoveMEspamNATETECH.COM>
To: <.....PICLISTSTOPspamspam@spam@MITVMA.MIT.EDU>
Sent: Friday, March 05, 2004 10:27 PM
Subject: Re: [OT:] More stupid electrical tricks...

> A direct strike .........
I've been on one of our sites during a storm, and experienced a few direct
strikes. (This is hardly a domestic evironment, being 550 metres above sea
level with a 220 metre mast - I suppose it's asking for trouble, really)
I've seen solidly earthed electrical trunking flash over to solidly earthed
equipment bays; flashovers inside equipment bays; equipment that has been
blown off walls.....Scary.

On our large medium wave sites, we have a thing called a prematch coil
between the mast (which is the antenna and so is live) and ground. These
things are also called static leaks (direct short to DC and open circuit to
RF) You would think that a coil made of 30 or so turns of 1/2 inch copper
pipe would be quite a mechanically strong thing. We recently had one damaged
by a direct strike, where some of the turns ended up shorted together,
pesumably by the huge magnetic fields set up by the currents involved. We
had to do an emergency repair, and had to use a crow bar to get enough force
to put it right!!

Static leaks are definately the way to go, because they'll always provide
protection even when the antenna is in use.

All the best...Mike.

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2004\03\06@070203 by Alan B. Pearce

face picon face
>On our large medium wave sites, we have a thing called a prematch coil
>between the mast (which is the antenna and so is live) and ground. These
>things are also called static leaks (direct short to DC and open circuit to
>RF) You would think that a coil made of 30 or so turns of 1/2 inch copper
>pipe would be quite a mechanically strong thing. We recently had one
damaged
>by a direct strike, where some of the turns ended up shorted together,
>pesumably by the huge magnetic fields set up by the currents involved. We
>had to do an emergency repair, and had to use a crow bar to get enough
force
>to put it right!!
>
>Static leaks are definitely the way to go, because they'll always provide
>protection even when the antenna is in use.

late in my apprenticeship I had occasion to visit the radio New Zealand MW
transmitter site at Titahi Bay (pronounced as Tee tah Hee), Wellington. This
has a high power transmitter (some hundreds of kilowatts) at around 550kHz,
and a lower power transmitter (about 100kW IIRC) at around 617kHz fed into a
single mast which is a quarter wave at the mid point between the two
frequencies, and a matching/combiner unit made out of big copper tube coils
etc. The mast suffered a lightning strike some months before our visit, and
the techs there regaled us with stories of molten copper balls rolling
around the floor which had resulted from the coils in these matching units
absolutely melting.

Mind you this mast is real ripe for any sort of lightning strike. It is
built on a peninsula with the sea around about 7/8 of the periphery, and the
highest point on it is about 100 - 200 feet. Then the mast is some 600-700
ft high if memory serves me correctly, and sweet all other high stuff for
miles.

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2004\03\06@113443 by Joseph Bobek

flavicon
face
--
 My dad used to tell me a story about a physics teacher he had in
high school.  The teacher was doing the demonstration where you make a
metal ring flow over a electric magnet with AC power.  He then was going
to demonstrate how if he unhooked the power, the metal ring would fall,
but when he unhooked the wires from his source, the coil be came a big
spark plug and sent him to the floor.

JoE

On Sat, 6 Mar 2004, Mike Hawkshaw wrote:

> {Original Message removed}

2004\03\06@131848 by Rafael Fraga

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face
My wife, who was learning to solder some prototype pcbs, had a habit of
laying the solder iron around, burning the table, books, tools, and almost
any other thing near. Once I told her: watch out, you are going to burn the
soldering iron handle one of these days!.  A couple of days later, I did it.
I burned a nice hole in the soldering iron handle, with another one hot tip.
She reminds me it sometimes, as a case of "divine justice"

RF

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2004\03\06@150039 by John Ferrell

face picon face
I would like to tie the gounds to a common building ground, but I cannot
seem to come up with anything that does not seem to contribute to the
problem.

The only way to achieve a straigtline connection between the tower and the
building ground is to go throug the house. That in itself would not pose a
problem, but I am not comfortable with the thought.



John Ferrell
http://DixieNC.US

{Original Message removed}

2004\03\06@154306 by Robert Rolf

picon face
My high school science teacher used to work as a power tech.
He showed us photos of a substation transformer that had been blown
apart, not by the heat, but put the magnetic forces on the
shorted secondary. 3" x 1" copper strapping (windings) that
looked like some giant hand had picked at the turns.
Gave us all a great respect for the forces a little
electromagnetism can generate (the teaching topic of the day).

R

Mike Hawkshaw wrote:
>
> {Original Message removed}

2004\03\07@005117 by James Newton, Host

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Married men should forget any mistakes they make...

...there is no point in two people remembering the same thing.


---
James.


{Original Message removed}

2004\03\07@005325 by michael brown

picon face
From: "Robert Rolf"

> Gave us all a great respect for the forces a little
> electromagnetism can generate (the teaching topic of the day).

If you liked that, you'll love this:
http://www.popsci.com/popsci/science/article/0,12543,490445,00.html

I wouldn't have believed it possible, it's truly an amazing practical
application of theory.  I wish I had the link to the first site that I
saw this on.  That guy used some serious banks of capacitors and could
shrink a US quarter (24.26mm) to be smaller than a dime(17.91mm).  He
was working on doubling the power.

Apparently it makes an incredibly loud noise too when the coil
evaporates.  Combining that with the light show makes it the perfect big
boys toy for entertaining guests at a barbecue.  Don't you all think so
too?  ;-)

michael brown (I used to want a big Tesla coil, but now I'd much rather
have one of these)

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2004\03\07@035047 by Jinx

face picon face
> http://www.popsci.com/popsci/science/article/0,12543,490445,00.html

> shrink a US quarter (24.26mm) to be smaller than a dime(17.91mm)

We have a little thing called inflation that does just the same

(why does inflation make money smaller ;-)) ?)

I clicked his link to a wooden Periodic Table. Classy. Reminded me
of this display. Possibly similar what The Flintstones had for a TV

http://fargo.itp.tsoa.nyu.edu/~danny/mirror.html

Not such a stupid electrical trick though..........pretty clever actually

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2004\03\07@070054 by Jonathan Johnson

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or your ex..........
:-/

-----Original Message-----
From: pic microcontroller discussion list
[PICLISTspam_OUTspam@spam@MITVMA.MIT.EDU]On Behalf Of James Newton, Host
Sent: Sunday, 7 March 2004 4:50 PM
To: spamBeGonePICLIST@spam@spamMITVMA.MIT.EDU
Subject: Re: [OT:] More stupid electrical tricks...


Married men should forget any mistakes they make...

...there is no point in two people remembering the same thing.


---
James.


-----Original Message-----
From: pic microcontroller discussion list [RemoveMEPICLISTEraseMEspamKILLspamMITVMA.MIT.EDU] On
Behalf Of Rafael Fraga
Sent: 2004 Mar 06, Sat 10:20
To: spamBeGonePICLISTspam_OUTspamRemoveMEMITVMA.MIT.EDU
Subject: Re: [OT:] More stupid electrical tricks...

My wife, who was learning to solder some prototype pcbs, had a habit of
laying the solder iron around, burning the table, books, tools, and almost
any other thing near. Once I told her: watch out, you are going to burn the
soldering iron handle one of these days!.  A couple of days later, I did it.
I burned a nice hole in the soldering iron handle, with another one hot tip.
She reminds me it sometimes, as a case of "divine justice"

RF

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2004\03\07@143537 by Richard.Prosser

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face
Yep - used to live about 1km from that mast.
Richard P






Mind you this mast is real ripe for any sort of lightning strike. It is
built on a peninsula with the sea around about 7/8 of the periphery, and
the
highest point on it is about 100 - 200 feet. Then the mast is some 600-700
ft high if memory serves me correctly, and sweet all other high stuff for
miles.

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2004\03\08@161002 by llile

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face
One of the tricks we would play in Electronics 1 class (high school) was
to load up a power strip with little coils of solder across each of the
mains terminals.  Then we would go to the breaker box which was in the
same room, and turn the power back on to the bench (we had previously shut
it off)  By this time most of the students were under their desks.  ka
POW!

"But teacher, I was just resetting a circuit breaker, minding my own
business.  I don't know WHO loaded the power strip up with solder AGAIN,
really I don't "


-- Lawrence Lile
Senior Project Engineer
Toastmaster, Inc.
Division of Salton, Inc.
573-446-5661 voice
573-446-5676 fax




Howard Winter <HDRWspam@spam@H2ORG.DEMON.CO.UK>
Sent by: pic microcontroller discussion list <EraseMEPICLISTRemoveMEspamSTOPspamMITVMA.MIT.EDU>
03/04/2004 01:40 PM
Please respond to pic microcontroller discussion list


       To:     RemoveMEPICLISTKILLspamspamTakeThisOuTMITVMA.MIT.EDU
       cc:
       Subject:        Re: [OT:] More stupid electrical tricks...


Robert,

On Thu, 4 Mar 2004 11:21:28 -0700, Robert Ussery wrote:

>...<
> In reaching for my drink, I accidentally bridged the contacts
> of the battery with my metal watchband... I now have a watchband with
welded
> links, a couple of small burns on my wrist, and a very paranoid attitude
> about batteries.
>
> How many of you have experienced this same phenomena?

I haven't myself - and one of the things I was taught early-on in working
on cars was that you take off all
metalwear, jewellery and watches, before you go anywhere near the battery
- Lead-acid batteries can produce a
*lot* of current!

But I heard a big strong Irishman scream once - he was working on his own
car in the garage I worked in, and
was taking the battery off.  He managed to get the spanner and his gold
wedding ring to short across the
battery terminals, and the ring immediately got *really* hot!  And it was
a tight fit and he couldn't get it
off... he rushed about and found a bucket of water and plunged his hand
in, but he still had to go to hospital
to have the ring removed and the injury treated.

I did once do a really stupid thing though - I had a piece of telephone
wire (one strand from inside an
extension cable) and I "flashed" it across a newly-charged car battery.  I
don't know why I did it, but the
wire *vapourised*!  There was about an inch length left welded to one
terminal, but the rest of it just ceased
to exist... I won't do *that* again!

Cheers,

Howard Winter
St.Albans, England

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2004\03\09@164527 by Mike Hord

picon face
>You cannot beat dropping molten solder between the toes, while wearing
>sandals. You have to wait for it to cool apparently. I know this from
>someone else. I never wear sandals ...
>
>Peter

Even common sense doesn't always work.  I ended up with a glob of solder
and wires between my sock and shoe one day.  I've never removed a shoe
so quickly!  Fortunately the sock took all the damage and I learned a
valuable lesson about being more careful with my soldering iron.

Mike H.

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2004\03\10@053703 by Howard Winter

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flavicon
picon face
On Fri, 5 Mar 2004 02:09:31 -0600, michael brown wrote:

> I once installed an 8-track tape deck in my car and didn't see any need
> to worry about fuses.  Eventually a short developed and the power lead
> to the deck immediately turned a nice cherry red causing the plastic
> insulation to just drop off the wire.  I got a nice burn when yanking
> out the wiring.  Now, I always use fuses.

I once built myself a car, using bits of old ones, and a body shell (from a Ford Corsair 2000E - this was a
long time ago!) that had been in an accident, which I bought and had had repaired.  The battery tray (part of
the bodywork) was unusable, so I removed its remains and mounted the battery in the boot ("trunk") as all good
rally-cars had in those days.  A big hefty cable ran through the car to a disconnect switch in easy reach of
the driver and then on to the starter-solenoid which acted as the main power distribution point.  All went
well for some time, but one evening as I was walking away from the car I happened to glance back - no idea why
- and had a strange feeling about the way the inside of the car looked.  I walked back to see flames licking
up from the front of the rear seat!  I opened the door, and saw that the bottom edge of the seat had worn
through the battery cable insulation and was now shorting it to the the body...  the heat had set the seat on
fire.

I opened the boot rapidly and unbolted the battery lead (I had used nuts with built-in tommy-bars so I could
do this without tools) grabbed a container of water (I thought), rushed round and threw engine-oil on the
fire... Oops!  Went back and got water, put out the fire and dragged the seat-base out of the car.  It could
so easily have been the end for that car, if I hadn't looked back and noticed something that tweaked my
interest (I hadn't seen the flames at that point).

I ran that car for another couple of years after that, but without a rear seat  :-)

Lessons learned:  Don't run cables between things that can abrade them, always have quick-disconnect
connectors on batteries (I had reasonably-quick ones in this case, luckily), and always carry a
fire-extinguisher!

Cheers,

Howard Winter
St.Albans, England

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