On Dec 6, 2:18*pm, Bruce wrote:
Bob Martin wrote:
in 1119577 20101205 084818 Bruce wrote:

On the question of voltage, a relative of mine was killed by an
electric shock from a 12 volt car battery. *He had no underlying
health condition. *:-(

I can believe that. *The worst shock I had was from 28 volts in an RAF
servicing bay (and I've had quite a few from the mains).

It was raining heavily. *His car wouldn't start and he flattened the
battery. *He told his wife he was going to put the battery on charge.
He had opened the bonnet and removed the battery clamp. *No-one knows
exactly what happened next but it is assumed that he had wet hands and
was electrocuted from the battery terminals.

He could have cut himself, the skin has a high resistance, but if it
is broken and a live conductor at any voltage touches the tissue
beneath, then lethal currents, it only takes a fraction of an amp, can
flow. There have been a number of deaths from this cause.

alexander.keys1 wrote:
On Dec 6, 2:18 pm, Bruce wrote:
Bob Martin wrote:
in 1119577 20101205 084818 Bruce wrote:
On the question of voltage, a relative of mine was killed by an
electric shock from a 12 volt car battery. He had no underlying
health condition. :-(
I can believe that. The worst shock I had was from 28 volts in an RAF
servicing bay (and I've had quite a few from the mains).
It was raining heavily. His car wouldn't start and he flattened the
battery. He told his wife he was going to put the battery on charge.
He had opened the bonnet and removed the battery clamp. No-one knows
exactly what happened next but it is assumed that he had wet hands and
was electrocuted from the battery terminals.

He could have cut himself, the skin has a high resistance, but if it
is broken and a live conductor at any voltage touches the tissue
beneath, then lethal currents, it only takes a fraction of an amp, can
flow. There have been a number of deaths from this cause.
I got the belt of my life breaking a circuit from my toy train
transformer to an electric motor in my Meccano set.

Wasn't till ten years later I learnt about inductive flyback voltages.
Easy to get 250v+ out of breaking an inductive circuit carrying current
from a 12v source,. That's what a car coil is anyway. starts at 12v,
break it, primary goes to -300 to -400v and secondary goes to 25KV or
more if the spark gap don't short it.

IF the starter was stalled and on and someone disconnected the battery,
then easily a very big current 400+ volt spike for a few milliseconds.

Normally not enough to kill, but with a hearty condition..?

In article , lid says...

alexander.keys1 wrote:
On Dec 6, 2:18 pm, Bruce wrote:
Bob Martin wrote:
in 1119577 20101205 084818 Bruce wrote:
On the question of voltage, a relative of mine was killed by an
electric shock from a 12 volt car battery. He had no underlying
health condition. :-(
I can believe that. The worst shock I had was from 28 volts in an RAF
servicing bay (and I've had quite a few from the mains).
It was raining heavily. His car wouldn't start and he flattened the
battery. He told his wife he was going to put the battery on charge.
He had opened the bonnet and removed the battery clamp. No-one knows
exactly what happened next but it is assumed that he had wet hands and
was electrocuted from the battery terminals.

He could have cut himself, the skin has a high resistance, but if it
is broken and a live conductor at any voltage touches the tissue
beneath, then lethal currents, it only takes a fraction of an amp, can
flow. There have been a number of deaths from this cause.
I got the belt of my life breaking a circuit from my toy train
transformer to an electric motor in my Meccano set.

Wasn't till ten years later I learnt about inductive flyback voltages.
Easy to get 250v+ out of breaking an inductive circuit carrying current
from a 12v source,. That's what a car coil is anyway. starts at 12v,
break it, primary goes to -300 to -400v and secondary goes to 25KV or
more if the spark gap don't short it.

IF the starter was stalled and on and someone disconnected the battery,
then easily a very big current 400+ volt spike for a few milliseconds.

Normally not enough to kill, but with a hearty condition..?

We are told that there was no underlying health condition.

Within reason, the body can withstand some very high voltages - the killer is current.

The EHT on monochrome TVs, for example, was from about 10 to 16kV but from a high
impedance source, so you got a belt and cursed, but that was all there was to it.

The introduction of colour with its power hungry shadowmask tubes was a differnt matter
entirely as not only was the voltage much higher, at 25kV, but it was generated by a
relatively low impedance source. It's surprising how safety conscious one becomes
overnight when you realise you are now dealing with something that is lethal ...

Going back to your Meccano motor, I had a Trix construction set from which I built bells
and buzzers. One project in the manual modified a buzzer by adding two wires connected to
metal 'handles' to turn it into an electric shock machine ...!

--

Terry

On Dec 6, 9:45*pm, Terry Casey wrote:
In article , says...





alexander.keys1 wrote:
On Dec 6, 2:18 pm, Bruce wrote:
Bob Martin wrote:
in 1119577 20101205 084818 Bruce wrote:
On the question of voltage, a relative of mine was killed by an
electric shock from a 12 volt car battery. *He had no underlying
health condition. *:-(
I can believe that. *The worst shock I had was from 28 volts in an RAF
servicing bay (and I've had quite a few from the mains).
It was raining heavily. *His car wouldn't start and he flattened the
battery. *He told his wife he was going to put the battery on charge.
He had opened the bonnet and removed the battery clamp. *No-one knows
exactly what happened next but it is assumed that he had wet hands and
was electrocuted from the battery terminals.

He could have cut himself, the skin has a high resistance, but if it
is broken and a live conductor at any voltage touches the tissue
beneath, then lethal currents, it only takes a fraction of an amp, can
flow. There have been a number of deaths from this cause.
I got the belt of my life breaking a circuit from my toy train
transformer to an electric motor in my Meccano set.

Wasn't till ten years later I learnt about inductive flyback voltages.
Easy to get 250v+ out of breaking an inductive circuit carrying current
from a 12v source,. That's what a car coil is anyway. starts at 12v,
break it, primary goes to -300 to -400v and secondary goes to 25KV or
more if the spark gap don't short it.

IF the starter was stalled and on and someone disconnected the battery,
then easily a very big current 400+ volt spike for a few milliseconds.

Normally not enough to kill, but with a hearty condition..?

We are told that there was no underlying health condition.

Within reason, the body can withstand some very high voltages - the killer is current.

The EHT on monochrome TVs, for example, was from about 10 to 16kV but from a high
impedance source, so you got a belt and cursed, but that was all there was to it.

The introduction of colour with its power hungry shadowmask tubes was a differnt matter
entirely as not only was the voltage much higher, at 25kV, but it was generated by a
relatively low impedance source. It's surprising how safety conscious one becomes
overnight when you realise you are now dealing with something that is lethal ...

Going back to your Meccano motor, I had a Trix construction set from which I built bells
and buzzers. One project in the manual modified a buzzer by adding two wires connected to
metal 'handles' to turn it into an electric shock machine ...!

Funny how things have changed, that sort of thing was normal but now
quite unacceptable.


NT

On Dec 6, 11:13*pm, Owain wrote:

I'm sure I vaguely remember a Boys Own Make a Van De Graaf generator
from an old LP record and some tinfoil.

Or was it a leyden jar?

Could have been a Wimshurst Machine? (also require a couple of Leydon
Jars). On list of 'one day' projects...

jon N

On 06/12/10 22:00, Tabby wrote:
On Dec 6, 9:45 pm, Terry wrote:
In , says...





alexander.keys1 wrote:
On Dec 6, 2:18 pm, wrote:
Bob wrote:
in 1119577 20101205 084818 wrote:
On the question of voltage, a relative of mine was killed by an
electric shock from a 12 volt car battery. He had no underlying
health condition. :-(
I can believe that. The worst shock I had was from 28 volts in an RAF
servicing bay (and I've had quite a few from the mains).
It was raining heavily. His car wouldn't start and he flattened the
battery. He told his wife he was going to put the battery on charge.
He had opened the bonnet and removed the battery clamp. No-one knows
exactly what happened next but it is assumed that he had wet hands and
was electrocuted from the battery terminals.

He could have cut himself, the skin has a high resistance, but if it
is broken and a live conductor at any voltage touches the tissue
beneath, then lethal currents, it only takes a fraction of an amp, can
flow. There have been a number of deaths from this cause.
I got the belt of my life breaking a circuit from my toy train
transformer to an electric motor in my Meccano set.

Wasn't till ten years later I learnt about inductive flyback voltages.
Easy to get 250v+ out of breaking an inductive circuit carrying current
from a 12v source,. That's what a car coil is anyway. starts at 12v,
break it, primary goes to -300 to -400v and secondary goes to 25KV or
more if the spark gap don't short it.

IF the starter was stalled and on and someone disconnected the battery,
then easily a very big current 400+ volt spike for a few milliseconds.

Normally not enough to kill, but with a hearty condition..?

We are told that there was no underlying health condition.

Within reason, the body can withstand some very high voltages - the killer is current.

The EHT on monochrome TVs, for example, was from about 10 to 16kV but from a high
impedance source, so you got a belt and cursed, but that was all there was to it.

The introduction of colour with its power hungry shadowmask tubes was a differnt matter
entirely as not only was the voltage much higher, at 25kV, but it was generated by a
relatively low impedance source. It's surprising how safety conscious one becomes
overnight when you realise you are now dealing with something that is lethal ...

Going back to your Meccano motor, I had a Trix construction set from which I built bells
and buzzers. One project in the manual modified a buzzer by adding two wires connected to
metal 'handles' to turn it into an electric shock machine ...!

Funny how things have changed, that sort of thing was normal but now
quite unacceptable.

Not sure if this delivers real shocks or just vibrates...

http://www.argos.co.uk/static/Produc...SHOCK+GAME.htm

You can certainly get real shocks with Slendertone type things though.

Cheers,

Colin.

On Mon, 06 Dec 2010 21:45:14 +0000, Terry Casey wrote:
The introduction of colour with its power hungry shadowmask tubes was a
differnt matter entirely as not only was the voltage much higher, at
25kV, but it was generated by a relatively low impedance source. It's
surprising how safety conscious one becomes overnight when you realise
you are now dealing with something that is lethal ...

I've only had one shock from a colour TV, and it bloody hurt. Certainly
not something I'd care to repeat. Mains shocks tickle in comparison :-)

cheers

Jules

In message , Jules Richardson
writes
On Mon, 06 Dec 2010 21:45:14 +0000, Terry Casey wrote:
The introduction of colour with its power hungry shadowmask tubes was a
differnt matter entirely as not only was the voltage much higher, at
25kV, but it was generated by a relatively low impedance source. It's
surprising how safety conscious one becomes overnight when you realise
you are now dealing with something that is lethal ...

I've only had one shock from a colour TV, and it bloody hurt. Certainly
not something I'd care to repeat. Mains shocks tickle in comparison :-)

My last mains "tickle" sent me 6' across a room, from a standing start,
into a wall. Not sure what hurt the most, the shock or hitting the
wall.
Or possibly it was the embarrassment of being an idiot?



--
Bill

"Jules Richardson" wrote in message
...
On Mon, 06 Dec 2010 21:45:14 +0000, Terry Casey wrote:
The introduction of colour with its power hungry shadowmask tubes was a
differnt matter entirely as not only was the voltage much higher, at
25kV, but it was generated by a relatively low impedance source. It's
surprising how safety conscious one becomes overnight when you realise
you are now dealing with something that is lethal ...

I've only had one shock from a colour TV, and it bloody hurt. Certainly
not something I'd care to repeat. Mains shocks tickle in comparison :-)

cheers

I had a 440v shock once, working out of hours testing a boiler control
panel, crouching down holding the flame sensor (a bloody good earth) near a
candle to simulate ignition, overbalanced and grabbed the nearest thing, a
440v switch (which I couldn't release). Things went black and I apparently
fell backwards dragging the switch out of my hand. Once is enough.

On Dec 6, 9:02*pm, "Colonel Edmund J. Burke"
wrote:

On Dec 6, 2:18 pm, Bruce wrote:

On the question of voltage, a relative of mine was killed by an
electric shock from a 12 volt car battery. He had no underlying
health condition. :-(

His underlying condition was being English. *His death was just Mother
Nature taking out the trash.

Your underlying condition meanwhile is one of incurable ****wittery of
the totally immersive kind (the immersion involving your cranium and
your rectum).

brass monkey wrote:
"Jules Richardson" wrote in message
...
On Mon, 06 Dec 2010 21:45:14 +0000, Terry Casey wrote:
The introduction of colour with its power hungry shadowmask tubes was a
differnt matter entirely as not only was the voltage much higher, at
25kV, but it was generated by a relatively low impedance source. It's
surprising how safety conscious one becomes overnight when you realise
you are now dealing with something that is lethal ...
I've only had one shock from a colour TV, and it bloody hurt. Certainly
not something I'd care to repeat. Mains shocks tickle in comparison :-)

cheers

I had a 440v shock once, working out of hours testing a boiler control
panel, crouching down holding the flame sensor (a bloody good earth) near a
candle to simulate ignition, overbalanced and grabbed the nearest thing, a
440v switch (which I couldn't release). Things went black and I apparently
fell backwards dragging the switch out of my hand. Once is enough.


You were lucky,.

The 600V DC on the third rail is enough to seriously burn and often
kills outright.

A 12v supply and an inductor with wet hands and an arcing contact is
quite enough to generate several seconds of 400vAC. Starter motors draw
a few hundred amps on starting..

In article ,
The Natural Philosopher wrote:
A 12v supply and an inductor with wet hands and an arcing contact is
quite enough to generate several seconds of 400vAC. Starter motors draw
a few hundred amps on starting..

It would require some 'skill' to disconnect the battery while the starter
was turning...

This story will turn out to be the usual urban myth. Where they've left
out the faulty mains battery charger he was connecting - or whatever.

--
*Wrinkled was not one of the things I wanted to be when I grew up

Dave Plowman London SW
To e-mail, change noise into sound.

On 06/12/2010 21:45, Terry Casey wrote:
In , lid says...

alexander.keys1 wrote:
On Dec 6, 2:18 pm, wrote:
Bob wrote:
in 1119577 20101205 084818 wrote:
On the question of voltage, a relative of mine was killed by an
electric shock from a 12 volt car battery. He had no underlying
health condition. :-(
I can believe that. The worst shock I had was from 28 volts in an RAF
servicing bay (and I've had quite a few from the mains).
It was raining heavily. His car wouldn't start and he flattened the
battery. He told his wife he was going to put the battery on charge.
He had opened the bonnet and removed the battery clamp. No-one knows
exactly what happened next but it is assumed that he had wet hands and
was electrocuted from the battery terminals.

He could have cut himself, the skin has a high resistance, but if it
is broken and a live conductor at any voltage touches the tissue
beneath, then lethal currents, it only takes a fraction of an amp, can
flow. There have been a number of deaths from this cause.
I got the belt of my life breaking a circuit from my toy train
transformer to an electric motor in my Meccano set.

Wasn't till ten years later I learnt about inductive flyback voltages.
Easy to get 250v+ out of breaking an inductive circuit carrying current
from a 12v source,. That's what a car coil is anyway. starts at 12v,
break it, primary goes to -300 to -400v and secondary goes to 25KV or
more if the spark gap don't short it.

IF the starter was stalled and on and someone disconnected the battery,
then easily a very big current 400+ volt spike for a few milliseconds.

Normally not enough to kill, but with a hearty condition..?

We are told that there was no underlying health condition.

Within reason, the body can withstand some very high voltages - the killer is current.

The EHT on monochrome TVs, for example, was from about 10 to 16kV but from a high
impedance source, so you got a belt and cursed, but that was all there was to it.

The introduction of colour with its power hungry shadowmask tubes was a differnt matter
entirely as not only was the voltage much higher, at 25kV, but it was generated by a
relatively low impedance source. It's surprising how safety conscious one becomes
overnight when you realise you are now dealing with something that is lethal ...

Going back to your Meccano motor, I had a Trix construction set from which I built bells
and buzzers. One project in the manual modified a buzzer by adding two wires connected to
metal 'handles' to turn it into an electric shock machine ...!


I remember there being an electric shock machine outside the lower tram
station on the Great Orme in Llandudno. I think it took pennies and
there was a fixed brass handle, a rotating one, and a meter, and I
suppose the idea was to see how high a voltage one could stand.

Regarding shocks from batteries, I recently heard of some chaps who
claim to have been told on a Balfour Beatty site induction that the use
of battery operated tools is not permitted if there is a drop of rain in
the sky- it sounds a bitt OTT and of course they may have misunderstood...

j

Dave Plowman (News) wrote:
In article ,
The Natural Philosopher wrote:
A 12v supply and an inductor with wet hands and an arcing contact is
quite enough to generate several seconds of 400vAC. Starter motors draw
a few hundred amps on starting..

It would require some 'skill' to disconnect the battery while the starter
was turning...


Not really. You are playing with what you suspect is a dodgy terminal.
You yell to someone in the drivers seat..'try that' and give the
terminal a wiggle and momentarily break it and get 400v between the
hand on the live terminal and the chassis which your other hand is
grasping as you lean into the engine compartment.

You have set up the perfect conditions for a cardiac arrest. One hand to
the other, both firmly in contact with the applied voltage. Both
gripping hard, and probably sweaty.


This story will turn out to be the usual urban myth. Where they've left
out the faulty mains battery charger he was connecting - or whatever.

I would say its almost certainly true. The inductance in a starter motor
is massive as are the currents. The flyback pulse would be very energy
rich. It PROBABLY would do a lot of damage in a modern car. And there
may well be snubber networks these days, but an old car...yes.

In article ,
The Natural Philosopher wrote:
It would require some 'skill' to disconnect the battery while the starter
was turning...


Not really. You are playing with what you suspect is a dodgy terminal.
You yell to someone in the drivers seat..'try that' and give the
terminal a wiggle and momentarily break it and get 400v between the
hand on the live terminal and the chassis which your other hand is
grasping as you lean into the engine compartment.

You might. Others would have more sense. High current flow is likely to
burn your hand if nothing else.

You have set up the perfect conditions for a cardiac arrest. One hand to
the other, both firmly in contact with the applied voltage. Both
gripping hard, and probably sweaty.

Have you no self preservation tendencies?

This story will turn out to be the usual urban myth. Where they've left
out the faulty mains battery charger he was connecting - or whatever.

I would say its almost certainly true. The inductance in a starter motor
is massive as are the currents. The flyback pulse would be very energy
rich. It PROBABLY would do a lot of damage in a modern car. And there
may well be snubber networks these days, but an old car...yes.

So where is the evidence of a 'helper'? 'No-one knows what happened' would
be the clue.

--
*No hand signals. Driver on Viagra*

Dave Plowman London SW
To e-mail, change noise into sound.

On Dec 7, 2:00*am, The Natural Philosopher
wrote:

The 600V DC on the third rail is enough to seriously burn and often
kills outright.

It has often bemused me that the sides of the tracks aren't littered
with dead cats and urban foxes (not to mention moles on the line).
Does anyone know why?

Having said that, I was once standing on a platform when a fox walked
its length to the footbridge where it crossed over and proceeded down
the opposite platform. Perhaps their mummies tell them.

Chris

On Tue, 07 Dec 2010 09:28:51 +0000, Djornsk wrote:

Regarding shocks from batteries, I recently heard of some chaps who
claim to have been told on a Balfour Beatty site induction that the use
of battery operated tools is not permitted if there is a drop of rain in
the sky- it sounds a bitt OTT and of course they may have misunderstood...

j

One of my drills tells me to remove the battery before changing the bit -
yeah, sure!
Then there was "unplug from the mains" on a packet of sheets of abrasive
paper (prolly meant the sander), but could I find the lead?
--
Peter.
The gods will stay away
whilst religions hold sway

wrote:
On Dec 7, 2:00 am, The Natural Philosopher
wrote:
The 600V DC on the third rail is enough to seriously burn and often
kills outright.

It has often bemused me that the sides of the tracks aren't littered
with dead cats and urban foxes (not to mention moles on the line).
Does anyone know why?


they are.

Found most of my cat on a line.

Mind you it looked as though it had actually been caught in a gin trap,
then tossed there to look like a train accident.

A cat will get blown way off line by a train hit.

Having said that, I was once standing on a platform when a fox walked
its length to the footbridge where it crossed over and proceeded down
the opposite platform. Perhaps their mummies tell them.


Their ears tell them. Rails sing.
Chris

PeterC wrote:

One of my drills tells me to remove the battery before changing the bit -
yeah, sure!

Corporate lawyers worried you might squeeze the trigger as you grab the bit
and sue them for the lacerations.

--
Mike Clarke

On Dec 7, 6:06*pm, The Natural Philosopher
wrote:

. . . .Rails sing.

Do they sell many records?

1501 wrote:
On Dec 7, 6:06 pm, The Natural Philosopher
wrote:
. . . .Rails sing.

Do they sell many records?

Lots. But no one buys them.

On Dec 7, 6:27*pm, Mike Clarke wrote:
PeterC wrote:
One of my drills tells me to remove the battery before changing the bit -
yeah, sure!

Don't the batteries just pull out on these things? I've always used
mains drills myself, as the battery ones don't always have enough
'oomph', and I always pull the plug before changing the bit. Common
sense really with any kind of machinery, serious injuries can result
from contact with moving parts under power.


Corporate lawyers worried you might squeeze the trigger as you grab the bit
and sue them for the lacerations.

--
Mike Clarke

In message , Colonel
Edmund J. Burke writes
Your underlying condition meanwhile is one of incurable ****wittery of
the totally immersive kind (the immersion involving your cranium and
your rectum).


You are a specialist in the latter, I hear.
LOL

I'm surprised you can hear anything with your head so far up your ass.
(That's what the words in brackets (the curvy things) mean...)
--
Kenny

On Tue, 7 Dec 2010 12:36:15 -0800 (PST), alexander.keys1 wrote:

On Dec 7, 6:27*pm, Mike Clarke wrote:
PeterC wrote:
One of my drills tells me to remove the battery before changing the bit -
yeah, sure!

Don't the batteries just pull out on these things? I've always used
mains drills myself, as the battery ones don't always have enough
'oomph', and I always pull the plug before changing the bit. Common
sense really with any kind of machinery, serious injuries can result
from contact with moving parts under power.

Agreed, but there are times when that would be more risky: down and up a
ladder seems more risk than just being careful.
I do unplug if there's something big to use - holesaw etc. - but an ordinary
drill bit is easy to avoid.

Corporate lawyers worried you might squeeze the trigger as you grab the bit
and sue them for the lacerations.

--
Mike Clarke


--
Peter.
The gods will stay away
whilst religions hold sway

On Tue, 7 Dec 2010 10:51:12 -0800 (PST), 1501 wrote:

On Dec 7, 6:06*pm, The Natural Philosopher
wrote:

. . . .Rails sing.

Do they sell many records?

Only to line-dancers.
--
Peter.
The gods will stay away
whilst religions hold sway

In article , says...

On 06/12/2010 21:45, Terry Casey wrote:
In , lid says...


Going back to your Meccano motor, I had a Trix construction set from which I built bells
and buzzers. One project in the manual modified a buzzer by adding two wires connected to
metal 'handles' to turn it into an electric shock machine ...!


I remember there being an electric shock machine outside the lower tram
station on the Great Orme in Llandudno. I think it took pennies and
there was a fixed brass handle, a rotating one, and a meter, and I
suppose the idea was to see how high a voltage one could stand.


They were quite common in penny arcades years ago, alongside the cranes, fortune telling
machines and laughing policemen ...

Made a change from flicking ball bearings around at high speed behind a sheet of glass,
though ...

--

Terry

Bill wrote:
My last mains "tickle" sent me 6' across a room, from a standing start,
into a wall. *Not sure what hurt the most, the shock or hitting the
wall.

My last real shock was when somebody decided to phone
me just as I was holding the spade terminals under the
connector screws. 50V 20mA is enough to hurt.

JGH

On Wed, 8 Dec 2010 09:42:04 -0800 (PST), jgharston wrote:

My last real shock was when somebody decided to phone me just as I was
holding the spade terminals under the connector screws. 50V 20mA is
enough to hurt.

Ringing is a little more than that, 80v AC 25Hz.

The 50v DC on a line can make you jump if you forget the block you
are connecting the CNR or music lines to also has a DEL and it's
peeing with rain...

--
Cheers
Dave.

In message , PeterC
writes
On Tue, 7 Dec 2010 10:51:12 -0800 (PST), 1501 wrote:

On Dec 7, 6:06*pm, The Natural Philosopher
wrote:

. . . .Rails sing.

Do they sell many records?

Only to line-dancers.

How many tracks?


--
geoff

On Wed, 8 Dec 2010 23:27:26 +0000, geoff wrote:

In message , PeterC
writes
On Tue, 7 Dec 2010 10:51:12 -0800 (PST), 1501 wrote:

On Dec 7, 6:06*pm, The Natural Philosopher
wrote:

. . . .Rails sing.

Do they sell many records?

Only to line-dancers.

How many tracks?

One.
--
Peter.
The gods will stay away
whilst religions hold sway