Hi all,

Anyone got any high-current/low-voltage horror stories they'd care to
share? You know; where your messin' about with a car battery or
something like that and forget to take your watch off or whatever.

p.
--

"What is now proved was once only imagin'd." - William Blake, 1793.

Hmmmmmmmmm......there was this time a few decades back a solder blob
caused a B-C short in the linear for my CB - Man, do the ceramic caps sure
fly off those MRF454's :-o

--
Gregg t3h g33k
"Ratings are for transistors....tubes have guidelines"
http://geek.scorpiorising.ca

The place was Hong Kong.

It was around Xmas, 1945.

I was alone in the lab.

Working on a set of airborne radar equipment strewn around the workbench.

The scanner was not rotating, just pointing out of the open window, past a
Royal Navy cruiser moored in the harbour about a mile away and onwards to
Victoria City with the island's mountainous peaks in the background. All
displayed strong echos on the PPI on its 10-mile range.

As indicated on the PPI there was something intermittent.

I suspected a poor coaxial cable connection.

Familiarity breeds contempt.

Forgetting the equipment was still switched on I unscrewed one of the many
coaxial connectors and Pye plugs.

To clear out any foreign bodies I inserted the tip of by my right forefinger
into the vacant socket.

Now that particular socket was power output from the modulator unit on its
way to the transmitter unit. The transmitter was a 50 Kilowatt magnetron
which required unpteen thousand volts, pulsed at several hundred times
persecond with a one microsecond pulse width.

How long I lay on the floor I do not know. Probably only a few seconds.

I trembled all over which passed off after a few minutes. Apart from a white
burn on the afore-mentioned fingertip the after-effects were
sychological - it took several days to pluck up courage just to re-enter
the lab when I had difficulty looking in the direction of the offending plug
and socket.
---
Reg, G4FGQ

Sorry, I answered the wrong question. Hope you found it interesting.

=============================

"Reg Edwards" wrote -

The place was Hong Kong.

It was around Xmas, 1945.

I was alone in the lab.

Working on a set of airborne radar equipment strewn around the workbench.

The scanner was not rotating, just pointing out of the open window, past a
Royal Navy cruiser moored in the harbour about a mile away and onwards to
Victoria City with the island's mountainous peaks in the background. All
displayed strong echos on the PPI on its 10-mile range.

As indicated on the PPI there was something intermittent.

I suspected a poor coaxial cable connection.

Familiarity breeds contempt.

Forgetting the equipment was still switched on I unscrewed one of the many
coaxial connectors and Pye plugs.

To clear out any foreign bodies I inserted the tip of by my right
forefinger
into the vacant socket.

Now that particular socket was power output from the modulator unit on its
way to the transmitter unit. The transmitter was a 50 Kilowatt magnetron
which required unpteen thousand volts, pulsed at several hundred times
persecond with a one microsecond pulse width.

How long I lay on the floor I do not know. Probably only a few seconds.

I trembled all over which passed off after a few minutes. Apart from a
white
burn on the afore-mentioned fingertip the after-effects were
psychological - it took several days to pluck up courage just to
re-enter
the lab when I had difficulty looking in the direction of the offending
plug
and socket.
---
Reg, G4FGQ

The place was the same lab in Hong Kong.

There was a chinese lady who came in each day to sweep the floor and remove
the EF50 valves, etc, which had been replaced because of low cathode
emission.

It was my habit to point the radar scanner into the room, stand in the beam
and quickly put put a neon lamp into my mouth. The lamp always lit up
brightly.

Whenever I did this the lady used to run out of the room terrified at the
magic sight.

Just the sort of trick a 21-year-old RAF radar mechanic would play.

Being in the Far East, the anti-radar defence rumour, spread by the Germans,
that exposure to radar beams caused sterilisation to radar mechanics had not
reached me.

Anyway, as my wife at intervals some years later allowed me to think, I
eventually became the father of 5 children.
---
Reg

On Mon, 16 Aug 2004 00:37:32 +0000 (UTC), "Reg Edwards"
wrote:

Being in the Far East, the anti-radar defence rumour, spread by the Germans,
that exposure to radar beams caused sterilisation to radar mechanics had not
reached me.

Anyway, as my wife at intervals some years later allowed me to think, I
eventually became the father of 5 children.

Perhaps you shoulda stood a bit closer to the waveguides, Reg. You'd
have been rich by now without all those kids. Plus you might even have
grown an extra brain. ;-)
--

"What is now proved was once only imagin'd." - William Blake, 1793.

The time was 1952 or 1953. I had a roving job. Indeed I've nearly always
had a roving job. You meet people.

The place was Gretna Green, just a few hundred yards from the well-known
black-smith's forge and its famous marriage-ceremony anvil.

I was working with a colleage in a normally unstaffed telephone repeater
station. The job was capacitance-rebalancing of the multi-pair trunk carrier
cables which ran through the place.

The test leads were very flexible twin-screened cables which kept getting in
the way of the portable test equipment, on a collapsible table, and the two
operators. Difficult to read the dB meters.

So to ease the accommodation problem the test cables were tossed up and over
a pair of substantial bars, up near the ceiling, which could have been part
of the station's equipment racks.

Unfortunately, the insulation over the screening braid was worn at one point
and the bars turned out to be the main copper 50-volt bus-bars from the
battery room. Work continued in silence until suddenly there was a loud
bang, like a cannon shot.

The main fuse from the station's batteries had blown. The station stopped
working. England was disconnected from Scotland at a time when the Cold War
had started.

There was a glass-fronted fusebox containing a lot of cardboard-cased fuses.
The idea was for fuses which had blown to indicate themselves by charred
cardboard. But none were indicated although spare fuses were available. One
catastophy after another. But in any case neither my colleage or I was
familiar with station maintenance procedures.

We had visions of severe disciplinery action being taken. And I had brought
with me a set of fishing rods. Indeed, I had obtained after much arguing
temporary exclusive membership of Gretna Green fishing club at the then
extortionate fee of 2 shillings and sixpence.

But then our luck changed. 10 minutes later the local maintenance man walked
in. Purely by chance he had come in to make himself a cup of tea (facilities
were available) whereas he should have been doing something else in the
English town of Carlisle, 12 miles away. We were of senior rank. He fixed
the fuse and we never heard any more about the serious incident.

In the evenings I went fishing for trout by bright moonlight while my
colleage, a much older fellow than I, took my wife (who had come to join me
for a week) to the local Gretna cinema. He bought her icecream in the back
row. And I made friends with the female cook at the hotel and had trout and
butter for the first course at breakfast.

The next few jobs took me further into the wilds of Bonnie Scotland where
there was nothing to do except to gamble and play cards in the evenings. I
always lost. Even to the extent of losing my ex-army camp bed and having to
sleep on the hard wooden blocks of the repeater station floor. Myxamatosis
raged amongst the poor Scottish rabbit population.

It is only relatively recently, in my old age, have I returned to such happy
days. I have just opened a bottle of Sierra Valley, Californian white wine
for a night-cap. Diplomatic relations are now back to normal. I expect no
more irritable invitations to tea parties in Boston.
----
Yours, Reg, G4FGQ

My brother, circa 1965, was working on a six volt Chevrolet.

His ring got between the battery terminal and ground. (Don't ask me
how.)

He ended up with a destroyed ring and a finger with a very painful burn
around it.

No permanent damage but come to think about it he's a little weird even
today. Hmmm.... but isn't everybody weird but you and me and I sometimes
wonder about...

================

This is really not low voltage high current but an event that sticks in
my mind as potentially fatal.

I had a female student in one of my community college electronics class.
The electronic bench where she was working had a 8 foot strip of outlets
on one of the typical 1970s surface mount plug strips. She had plugged
in some instrument but in retrospect she hadn't pushed the plug in
completely, leaving a small amount of the metal of the plug exposed.

Around her waist she had a silver colored metal belt with a hanging end
with a washer shaped end on it. It looked to me like a dog collar.

She bent over the bench to adjust something and the metal end of her belt
went across the metal prongs of the plug.

RESULT = lots of sparks, a loud scream, a partially melted end to the
belt and a much wiser and more careful student. (And a very relieved
instructor, thankful that it hit BOTH prongs and not just one while she
was holding touching a grounded instrument case.

Yes, we then moved all the plug strips on the benches where they were
mounted to the bottom edge of the bench and removed them from other
benches where there were adequate outlets on the plug strip on the front
of the shelf along the back of the bench.

Paul Burridge wrote:

Hi all,

Anyone got any high-current/low-voltage horror stories they'd care to
share? You know; where your messin' about with a car battery or
something like that and forget to take your watch off or whatever.

p.
--

"What is now proved was once only imagin'd." - William Blake, 1793.

--
Address is NOT monitored due to SPAM volume from newsgroups. DO NOT
REPLY to post directly.

On Sun, 15 Aug 2004 15:12:54 GMT, DO NOT REPLY to this ADDRESS hath writ:
My brother, circa 1965, was working on a six volt Chevrolet.

His ring got between the battery terminal and ground. (Don't ask me
how.)

He ended up with a destroyed ring and a finger with a very painful burn
around it.

No permanent damage but come to think about it he's a little weird even
today. Hmmm.... but isn't everybody weird but you and me and I sometimes
wonder about...

My dad (the first W3DHJ) told me an almost identical story.

It was in the late 20's. He was working on _his_ dad's Ford utility
truck. (Grandpa owned a dairy in Big Bear, Calif.) Six volts here, too.
The truck was parked in the driveway -- just outside the garage.
When my dad caught his ring between the positive terminal and the truck
frame, my Grandpa picked him up bodily -- ran him over to the rain barrel
at the corner of the garage -- and stuffed my dad's entire left arm (and
much of his upper torso) into the barrel.

( *The worst* thing you could do in a situation like that is try to _pull_
the ring off.)

My dad was a 90-day wonder in WW II. He then spent 25+ years in the U.S.
Army Corps of Engineers (we traveled the planet....) Most of his
duty assignments were as (Deputy) Post Engineer -- with the added
responsibity as Post Safety Officer. I always knew him to be
evangelically anal about safety. I'm sure that incident with the old
Ford truck had a wee bit to do with it.

73
Jonesy
--
| Marvin L Jones | jonz | W3DHJ | linux
| Gunnison, Colorado | @ | Jonesy | OS/2 __
| 7,703' -- 2,345m | config.com | DM68mn SK

Paul Burridge wrote:
Hi all,

Anyone got any high-current/low-voltage horror stories they'd care to
share? You know; where your messin' about with a car battery or
something like that and forget to take your watch off or whatever.

p.
Well there was this guy changing batteries on a golf cart.
Had 6 very large 6 volt storage batteries wired in series.
He was using a ratchet wrench to remove the battery contact
clamps and while detaching the most postive end first (!)
the ratchet handle touched the frame of the golf cart.

Ever see a Sears ratchet glowing WHITE HOT?