Many have had a 'belt' from domestic 240Volt wiring through bad luck,
bad judgment or plain stupidity .
Whilst a shock from 240V CAN kill how often does that actually happen
and how many just get thrown across the room into a foetal position
whimpering and crying until the arm unknots and the tingling feeling
goes away.

soup wrote

Many have had a 'belt' from domestic 240Volt wiring
through bad luck, bad judgment or plain stupidity .

Whilst a shock from 240V CAN kill how often does that actually happen

Not very often at all, essentially because you really
need the current to go from one hand across the
chest to the other to kill you most of the time.

and how many just get thrown across the room into a foetal position

Never.

whimpering and crying until the arm unknots

Never knots.

and the tingling feeling goes away.

On Mon, 29 Mar 2021 23:32:04 +0100, soup wrote:

Many have had a 'belt' from domestic 240Volt wiring through bad luck,
bad judgment or plain stupidity .
Whilst a shock from 240V CAN kill how often does that actually happen
and how many just get thrown across the room into a foetal position
whimpering and crying until the arm unknots and the tingling feeling
goes away.

I was sitting on a quarry tiled kitchen floor connecting up a cooker. My
understanding was the the supply was isolated, that quickly got revised
when I tried to strip off the insulation of a live 10mm2 feed with
uninsulated side cutters.

Well the key is where you take the shock. It only takes a surprisingly small
current across the chest to kill you merely by stopping your heart, that is
why the one hand in your pocket advice is so useful.
Lots of us have had shocks, mine were usually thru the fingers of the same
hand when delving inside a working piece of valve gear that had series fed
heaters across the mains.
Yes you get some expletives but not much else. The buzzing bruised feeling
soon passes.

Remember in the past some dodgy practitioners thought shocks were actually
therapeutic, How they did not manage to kill most of their patients is
amazing. I'm also sure as kids we all made electric shock machines All you
needed was a small mains transformer a battery and something like a
mechanical buzzer. You wired the buzzer and secondary in series with the
battery and a switch, and asked your victim to hold the ends of the
primary.
I guess current was quite low, but when bridge rectifiers and small high
voltage capacitors came along you could end up with something really
dangerous. What we used to do was charge up a capacitor and leave it on a
young ladies seat and watch what happened when she picked it up, Ahem, Well
it was fun at the time...
Brian

--

This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"soup" wrote in message
...
Many have had a 'belt' from domestic 240Volt wiring through bad luck, bad
judgment or plain stupidity .
Whilst a shock from 240V CAN kill how often does that actually happen
and how many just get thrown across the room into a foetal position
whimpering and crying until the arm unknots and the tingling feeling goes
away.

On Tue, 30 Mar 2021 08:04:22 +0100, Brian Gaff \(Sofa\) wrote:

Well the key is where you take the shock. It only takes a surprisingly
small current across the chest to kill you merely by stopping your
heart, that is why the one hand in your pocket advice is so useful.
Lots of us have had shocks, mine were usually thru the fingers of the
same
hand when delving inside a working piece of valve gear that had series
fed heaters across the mains.
Yes you get some expletives but not much else. The buzzing bruised
feeling
soon passes.

Remember in the past some dodgy practitioners thought shocks were
actually therapeutic, How they did not manage to kill most of their
patients is amazing. I'm also sure as kids we all made electric shock
machines All you needed was a small mains transformer a battery and
something like a mechanical buzzer. You wired the buzzer and secondary
in series with the battery and a switch, and asked your victim to hold
the ends of the primary.
I guess current was quite low, but when bridge rectifiers and small
high
voltage capacitors came along you could end up with something really
dangerous. What we used to do was charge up a capacitor and leave it on
a young ladies seat and watch what happened when she picked it up, Ahem,
Well it was fun at the time...
Brian

The radio room at Lyons where I did my apprenticeship had two door handles
that had to be operated simultaneously to gain entry.

Yes that would certainly do it. I am very sensitive to that electrostatic
buzz you get when you touch double insulated gear that is still live, so am
very wary. Luckily these days I do not attempt to wire up mains gear as I
cannot see the colours of wires any more.
As an aside there are a couple of forms of shock you do not want, unless you
have masochistic tendencies.1. On some navel ships the supply is 440 volts
at 300Hz.

No matter where you catch that kind of shock it bleedin well hurts and
often you seemingly cannot let go. To be avoided at all costs.
2 RF burning. When I was still young I got a burn across my palm from a ham
radio aerial in my garden. . It first started to feel like an itch then
pure pain, I let go very quick but not fast enough to stop a burn that took
some weeks to heal properly. So effectively microwaving your palm is not
advisable!

People get shocks all the time of course, but mostly its what we call
static, caused by the imbalance of ions plus and negative that can occur
merely with friction between materials, whether they be clothing carpets
seating or for air rushing down a vacuum cleaner pipe. I did when I was
younger 'borrow' a high impedance voltage probe and some people could get
charged up with over 20,000 volts in just a few seconds. Luckily its got no
current behind it on discharge so the worst you get is a crack a spark, and
a tiny pin point burn on your finger.
Talking of real life sad cases though, the daughter of an MP had just had a
new kitchen fitted and was trying to get something out of a cupboard and
touched a securing screw with one hand while steadying herself on the
washing machine with the other. She was killed instantly and the kitchen
fitter was convicted of involuntary manslaughter. He had basically joined a
number of wires up inside a wall cavity, and not filled in the hole merely
screwed the cabinet over the top, One of the screws in the back had just
caught a live wire and was thus live and the washing machine was earthed.
The report did not go into too many details, but apparently she was alone
her heart stopped and she fell off her kickstep and hit her head on some
appliance.

Brian



--

This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"jon" wrote in message ...
On Mon, 29 Mar 2021 23:32:04 +0100, soup wrote:

Many have had a 'belt' from domestic 240Volt wiring through bad luck,
bad judgment or plain stupidity .
Whilst a shock from 240V CAN kill how often does that actually happen
and how many just get thrown across the room into a foetal position
whimpering and crying until the arm unknots and the tingling feeling
goes away.

I was sitting on a quarry tiled kitchen floor connecting up a cooker. My
understanding was the the supply was isolated, that quickly got revised
when I tried to strip off the insulation of a live 10mm2 feed with
uninsulated side cutters.

On Tue, 30 Mar 2021 08:39:22 +0100, Brian Gaff \(Sofa\) wrote:

Yes that would certainly do it. I am very sensitive to that
electrostatic buzz you get when you touch double insulated gear that is
still live, so am very wary. Luckily these days I do not attempt to wire
up mains gear as I cannot see the colours of wires any more.
As an aside there are a couple of forms of shock you do not want, unless
you have masochistic tendencies.1. On some navel ships the supply is 440
volts at 300Hz.

No matter where you catch that kind of shock it bleedin well hurts and
often you seemingly cannot let go. To be avoided at all costs.
2 RF burning. When I was still young I got a burn across my palm from a
ham
radio aerial in my garden. . It first started to feel like an itch then
pure pain, I let go very quick but not fast enough to stop a burn that
took some weeks to heal properly. So effectively microwaving your palm
is not advisable!

People get shocks all the time of course, but mostly its what we call
static, caused by the imbalance of ions plus and negative that can occur
merely with friction between materials, whether they be clothing carpets
seating or for air rushing down a vacuum cleaner pipe. I did when I was
younger 'borrow' a high impedance voltage probe and some people could
get charged up with over 20,000 volts in just a few seconds. Luckily its
got no current behind it on discharge so the worst you get is a crack a
spark, and a tiny pin point burn on your finger.
Talking of real life sad cases though, the daughter of an MP had just
had a
new kitchen fitted and was trying to get something out of a cupboard
and touched a securing screw with one hand while steadying herself on
the washing machine with the other. She was killed instantly and the
kitchen fitter was convicted of involuntary manslaughter. He had
basically joined a number of wires up inside a wall cavity, and not
filled in the hole merely screwed the cabinet over the top, One of the
screws in the back had just caught a live wire and was thus live and the
washing machine was earthed. The report did not go into too many
details, but apparently she was alone her heart stopped and she fell off
her kickstep and hit her head on some appliance.

Brian

At International Aeradio Ltd., there was a guy who had hundreds of RF
burns to his head where he had gone into transmitting cages to adjust
something over the years.

On 29/03/2021 23:32, soup wrote:
Many have had a 'belt' from domestic 240Volt wiring through bad luck,
bad judgment or plain stupidity .
Â* Whilst a shock from 240V CAN kill how often does that actually happen
and how many just get thrown across the room into a foetal position
whimpering and crying until the arm unknots and the tingling feeling
goes away.

Been there done that - once!
When I was about 8 years old I had a crystal set and thought I needed a
longer aerial on it to get better reception. Had seen pylons with wires
on them supplying electricity so thought that would be a lovely aerial!.
Went to mains socket in bedroom with metal meccano screwdiver in one
hand, bare wire to plug into socket in other. Pushed down the earth
shutter with screwdriver and inserted bare wire into now open shuttered
pin. I now know the difference between live and neutral! Seriously
thought I was going to die. Been extreemly cautious ever since and never
had another belt from the mains!

On 29/03/2021 23:32, soup wrote:
Many have had a 'belt' from domestic 240Volt wiring through bad luck,
bad judgment or plain stupidity .
Â*Whilst a shock from 240V CAN kill how often does that actually happen
and how many just get thrown across the room into a foetal position
whimpering and crying until the arm unknots and the tingling feeling
goes away.

I looked into this a few years ago when I drew the short straw and had
to conduct some staff training about electrical safety.

Very approximately, 30 people per year die in the UK from electric
shock. Nearly all of those are from digging up cables or contacting
overhead cables. In other words, very few from the domestic mains.

Figures for the number of indirect deaths - eg falling off the ladder
due to a shock - were not available, or at least not easily, and I
didn't care that much anyway. The small, innovative company had just
been bought by GE and I wasn't hanging about to be tapped in a world of
online training courses and wearing Kevlar gloves to use a scalpel.

--
Cheers
Clive

On 29/03/2021 23:32, soup wrote:
Many have had a 'belt' from domestic 240Volt wiring through bad luck,
bad judgment or plain stupidity .
Â*Whilst a shock from 240V CAN kill how often does that actually happen
and how many just get thrown across the room into a foetal position
whimpering and crying until the arm unknots and the tingling feeling
goes away.

I doubt anyone has statistics on the latter - and I'd doubt their
reliability if they require people to own up to the whimpering bit

But deaths are few. Used to run at about 15 a year in England where the
/underlying/ cause of death was electric current. And bulk of those
were not in the home (and so include ones where more than 240v involved).

There are of course serious injuries on top of the deaths. But changes
to BS 7671 seem to be made without assessments of costs and benefits.
Too much flavour of "no price is too high..." for my liking.

--
Robin
reply-to address is (intended to be) valid

soup explained :
Many have had a 'belt' from domestic 240Volt wiring through bad luck, bad
judgment or plain stupidity .
Whilst a shock from 240V CAN kill how often does that actually happen and
how many just get thrown across the room into a foetal position whimpering
and crying until the arm unknots and the tingling feeling goes away.

I've had many shocks, it usually doesn't much bother me, except for
once when I genuiningly was thrown across a room, a flooded banking
hall.

I was the key holder. It was raining heavily, I was wet through as I
walked in, alone. Carpet soaked, several feet of water in the basement,
water dripping from the ceiling, several dehumidifier and fans in use,
for safety all individually powered via RCD's - all set up by me. I had
written a large notice, which I placed at the RCD's, saying everything
had to be powered via an RCD - no exceptions.

Unknown to me, an unskilled trainee had been there the previous day and
one of the dehumidifier (industrial sized, metal cased) was tripping
its RCD, the stupid bugger wrongly assumed the RCD was at fault,
ignored the notice and bypassed it. The dehumidifier casing was
actually live, putting everyone at risk who went in the banking hall.

The company denied any responsibility, refused to investigate,
basically called me a liar. I had gone in alone, there were no
witnesses, luckily I only had a few bruises - so easy for them to deny
it happened.

You can do your best to make things fool proof, but somebody is bound
to invent an even bigger fool.

On Tue, 30 Mar 2021 09:44:21 +1100, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:


Not

LOL

Never.

LOL

Never

LOL

Sick idiot!

--
Kerr-Mudd,John addressing the auto-contradicting senile cretin:
"Auto-contradictor Rod is back! (in the KF)"
MID:

Brian Gaff (Sofa) laid this down on his screen :
Well the key is where you take the shock. It only takes a surprisingly small
current across the chest to kill you merely by stopping your heart, that is
why the one hand in your pocket advice is so useful.

Across the chest is the worst possible type of shock, almost as bad is
from the hand and down through the body to the wet feet.

They do still use a type of electric shock machine. They sometimes call
them 'TENS' commonly available with a type sold on TV ads. (Think
cricketer). Idea is the controlled electric shocks, trigger local
muscles, which also helps stimulate circulation and maybe use up fat in
the body.

On 30/03/2021 09:47, Harry Bloomfield wrote:
Brian Gaff (Sofa) laid this down on his screen :
Well the key is where you take the shock. It only takes a surprisingly
small current across the chest to kill you merely by stopping your
heart, that is why the one hand in your pocket advice is so useful.

Across the chest is the worst possible type of shock, almost as bad is
from the hand and down through the body to the wet feet.

They do still use a type of electric shock machine. They sometimes call
them 'TENS' commonly available with a type sold on TV ads. (Think
cricketer). Idea is the controlled electric shocks, trigger local
muscles, which also helps stimulate circulation and maybe use up fat in
the body.

I think that is on the low frequency setting (around 3 Hz, but variable
on many) - pulses that cause the muscles to contract. On the high
frequency setting (150Hz), the muscles don't have time to react, but the
nerves become numbed, relieving pain.

Electrocution isn't always a dodgy therapy. The NHS still use
electroconvulsive therapy (ECT) for severe depression if there's no
other practicable option.


On 30/03/2021 08:04, Brian Gaff (Sofa) wrote:
Well the key is where you take the shock. It only takes a surprisingly small
current across the chest to kill you merely by stopping your heart, that is
why the one hand in your pocket advice is so useful.
Lots of us have had shocks, mine were usually thru the fingers of the same
hand when delving inside a working piece of valve gear that had series fed
heaters across the mains.
Yes you get some expletives but not much else. The buzzing bruised feeling
soon passes.

Remember in the past some dodgy practitioners thought shocks were actually
therapeutic, How they did not manage to kill most of their patients is
amazing. I'm also sure as kids we all made electric shock machines All you
needed was a small mains transformer a battery and something like a
mechanical buzzer. You wired the buzzer and secondary in series with the
battery and a switch, and asked your victim to hold the ends of the
primary.
I guess current was quite low, but when bridge rectifiers and small high
voltage capacitors came along you could end up with something really
dangerous. What we used to do was charge up a capacitor and leave it on a
young ladies seat and watch what happened when she picked it up, Ahem, Well
it was fun at the time...
Brian



--
Robin
reply-to address is (intended to be) valid

On 2021-03-30, Jethro_uk wrote:

On Mon, 29 Mar 2021 23:32:04 +0100, soup wrote:

Many have had a 'belt' from domestic 240Volt wiring through bad luck,
bad judgment or plain stupidity .
Whilst a shock from 240V CAN kill how often does that actually happen
and how many just get thrown across the room into a foetal position
whimpering and crying until the arm unknots and the tingling feeling
goes away.

Well didn't an MPs daughter die of a 240V shock in a domestic incident ?

And Keith Relf formerly of the Yardbirds was killed in an electrocution
at his home (so presumably 240V).

When I was at Uni a lecturer mentioned checking out a neighbours cooker
that was "buzzy" when you touched it. He found there was no earth and
600V potential between it and the sink ...

OK, you've got my curiosity --- how do you get a 600 V difference
inside one house?

On 29/03/2021 23:32, soup wrote:
Many have had a 'belt' from domestic 240Volt wiring through bad luck,
bad judgment or plain stupidity .
Whilst a shock from 240V CAN kill how often does that actually happen
and how many just get thrown across the room into a foetal position
whimpering and crying until the arm unknots and the tingling feeling
goes away.

As a very young child I got a nasty jolt from putting my fingers in a
lamp bayonet socket. I didn't do that again! But the worst shock was
when, as a young teenager into hobby electronics, I was making a small
valve-based transmitter. I was holding the HV DC +ve lead (about 350V)
and went to move the large smoothing electrolytic the -ve was soldered
to. I didn't know that the -ve and metal case were often connected. My
hand clamped around the electro so that I could not release it, but very
fortunately my biceps muscle also contracted and I involuntarily threw
the electro across the room, thus breaking the connection. It was one
hell of a shock, and I was very lucky the connection had been broken.

--

Jeff

Adam Funk pretended :
OK, you've got my curiosity --- how do you get a 600 V difference
inside one house?

+1

On 30/03/2021 10:21, Harry Bloomfield wrote:
Adam Funk pretended :
OK, you've got my curiosity --- how do you get a 600 V difference
inside one house?

+1

Ah, but was the sink earthed? ;-)

PA

On 30/03/2021 11:08, R D S wrote:
On 30/03/2021 09:35, Harry Bloomfield wrote:

I'm more careful generally as I age
so incidents are tailing off.


Or your skin impedance is rising... ;-)

PA

On 30/03/2021 09:35, Harry Bloomfield wrote:

I've had many shocks, it usually doesn't much bother me, except for once
when I genuiningly was thrown across a room, a flooded banking hall.

I've had more than I care to admit. I'm more careful generally as I age
so incidents are tailing off.

The worse was when I had something in my hand (a water solenoid), some
dickhead (most likely me) had connected live to earth so I powered it to
test it was working and couldn't let go. Very unpleasant that one.

On 30/03/2021 05:18, jon wrote:
On Mon, 29 Mar 2021 23:32:04 +0100, soup wrote:

Many have had a 'belt' from domestic 240Volt wiring through bad luck,
bad judgment or plain stupidity .
Whilst a shock from 240V CAN kill how often does that actually happen
and how many just get thrown across the room into a foetal position
whimpering and crying until the arm unknots and the tingling feeling
goes away.

I was sitting on a quarry tiled kitchen floor connecting up a cooker. My
understanding was the the supply was isolated, that quickly got revised
when I tried to strip off the insulation of a live 10mm2 feed with
uninsulated side cutters.

Last time it happened to me I was sitting on te floor trying to work out
why a brand new desk lamp didn't work. I had been through several cycles
of 'switch off at the wall, take apart, change rebuild, switch on at the
wall, test. and at one point I must have forgotten the 'switch off at wall'

I think it was hand to hand but one wasn't grasping anything just touching


--
"And if the blind lead the blind, both shall fall into the ditch".

Gospel of St. Mathew 15:14

On 30/03/2021 10:38, Jethro_uk wrote:
On Tue, 30 Mar 2021 10:16:43 +0100, Jeff Layman wrote:

On 29/03/2021 23:32, soup wrote:
Many have had a 'belt' from domestic 240Volt wiring through bad luck,
bad judgment or plain stupidity .
Whilst a shock from 240V CAN kill how often does that actually
happen
and how many just get thrown across the room into a foetal position
whimpering and crying until the arm unknots and the tingling feeling
goes away.

As a very young child I got a nasty jolt from putting my fingers in a
lamp bayonet socket. I didn't do that again! But the worst shock was
when, as a young teenager into hobby electronics, I was making a small
valve-based transmitter. I was holding the HV DC +ve lead (about 350V)
and went to move the large smoothing electrolytic the -ve was soldered
to. I didn't know that the -ve and metal case were often connected. My
hand clamped around the electro so that I could not release it, but very
fortunately my biceps muscle also contracted and I involuntarily threw
the electro across the room, thus breaking the connection. It was one
hell of a shock, and I was very lucky the connection had been broken.

ISTR being told that you should test an exposed wire (????) with the back
of your hand so that any muscle reaction will not cause you to grab hold
of it.

I'd rather test it with a neon screwdriver.

--
Max Demian

On Tue, 30 Mar 2021 09:47:36 +0100, Harry Bloomfield, Esq. wrote:

They do still use a type of electric shock machine. They sometimes call
them 'TENS' commonly available with a type sold on TV ads. (Think
cricketer). Idea is the controlled electric shocks, trigger local
muscles,
which also helps stimulate circulation and maybe use up fat in the body.

TENS was really produced for blocking nerves with a high freqenecy signal.

However, mine is adjustable to very low frequencies, and I use mine at
fairly high intensity, at 2Hz, to cause a tight muscle to flex
repeatedly. I was put on it by a nurse at the pain clinic, and it's
pretty well fixed the problem after doctors gave up (following X-ray and
MRI...)


--
My posts are my copyright and if @diy_forums or Home Owners' Hub
wish to copy them they can pay me £1 a message.
Use the BIG mirror service in the UK: http://www.mirrorservice.org
*lightning surge protection* - a w_tom conductor

It happens that Peter Able formulated :
Or your skin impedance is rising... ;-)

Even as a youngster, I was able to put my finger in a live BC lamp
socket, without too much bother, providing the rest of my body was
insulated.

Max Demian pretended :
I'd rather test it with a neon screwdriver.

Frowned upon, but I would use a volt-stick, after proving it was
working.

Jethro_uk wrote:

Keith Relf formerly of the Yardbirds was killed in an electrocution
at his home

Dodgy guitar/amp wiring is traditional, isn't it?

https://www.ranker.com/list/musicians-electrocuted-on-stage/jessica-defino

though I don't think jessica knows what electrocuted means

On 30/03/2021 10:06, Adam Funk wrote:
On 2021-03-30, Jethro_uk wrote:

On Mon, 29 Mar 2021 23:32:04 +0100, soup wrote:

Many have had a 'belt' from domestic 240Volt wiring through bad luck,
bad judgment or plain stupidity .
Whilst a shock from 240V CAN kill how often does that actually happen
and how many just get thrown across the room into a foetal position
whimpering and crying until the arm unknots and the tingling feeling
goes away.

Well didn't an MPs daughter die of a 240V shock in a domestic incident ?

And Keith Relf formerly of the Yardbirds was killed in an electrocution
at his home (so presumably 240V).

When I was at Uni a lecturer mentioned checking out a neighbours cooker
that was "buzzy" when you touched it. He found there was no earth and
600V potential between it and the sink ...

OK, you've got my curiosity --- how do you get a 600 V difference
inside one house?

More than one phase (not in most houses, but definitely in some);
transformers; charged capacitors.

In my case an induced supply - I have a cable connecting my boiler (in
the kitchen) to a control box (in a bedroom). It is one continuous run,
no connections en-route and there are no other connections to the
boiler. It runs alongside other mains cables and if I isolate it at the
control box end, that cable and the boiler electrics float at around 90V
- which may not be in phase with other, nearby supplies.

Similarly, I had an out of use UHF aerial splitter under the floor, that
always floated high enough to give you a good belt, despite the cables
being connected to nothing else!

"Brian Gaff (Sofa)" wrote in message
...
Yes that would certainly do it. I am very sensitive to that electrostatic
Talking of real life sad cases though, the daughter of an MP had just had
a new kitchen fitted and was trying to get something out of a cupboard
and touched a securing screw with one hand while steadying herself on the
washing machine with the other. She was killed instantly and the kitchen
fitter was convicted of involuntary manslaughter. He had basically joined
a number of wires up inside a wall cavity, and not filled in the hole
merely screwed the cabinet over the top, One of the screws in the back had
just caught a live wire and was thus live and the washing machine was
earthed. The report did not go into too many details, but apparently she
was alone her heart stopped and she fell off her kickstep and hit her head
on some appliance.

That's nasty. And such a stupid mistake for the electrician to make.

Earthed appliances can be more trouble that they are worth if you happen to
touch an appliance that is live.

I got a nasty jolt when I unplugged a TV aerial cable from a USB DVB tuner
connected to my PC. I had the metal aerial plug in one hand and was holding
the earthed case of the PC with the other hand. As soon as the plug was no
longer in contact with the earthed PC, I got about 100 V across me. Probably
very low current, but it was enough to hurt for a few minutes afterwards.
Another leg of the TV aerial was plugged into my TV (which was off but
plugged in) and from there audio and SCART cables went to a VCR, an
OnDigital box and my hifi. One of those was evidently to blame. Having
disconnected everything in turn, with a voltmeter across the aerial plug and
mains earth, I narrowed it down to the TV. It was putting out about 300 V as
measured with a high-resistance voltmeter which went down to about 100 V
when I put a human-sized resistor (I measured my across-the-chest resistance
as about 200 K ohms) in parallel to simulate me touching aerial and earth.
So there was a large internal resistance, but not large enough to prevent a
noticeable jolt.

After that I rigged up a wire from mains earth to the aerial amplifier's
screen connection, to make sure everything was earthed. All it needed was
one earthed appliance (the PC) and everything was OK, which is why I'd never
noticed the problem before, but as soon as that earthed connection was
removed, everything was "semi-live". Sod's Law: everything else was
double-insulated and so not earthed. Probably to avoid hum loops as much as
to avoid needing a three-pin mains lead.


I've only had a "proper" mains shock twice in my life. Once when I made the
elementary mistake of working on a tape recorder that was turned off (so
everything downstream of the mains switch was safe), forgetting that the
input terminals to the switch were live... This was in the old days of a
fuse box that only contained (wire) fuses, with no earth-leakage RCD. I
still have two marks on my finger where it touched the soldered switch pins
for the live and neutral feed: it looks like a snake bite ;-)


The second time was equally silly. I was changing a lot of GU10 light
fittings which had Philips Hue bulbs in them - the type of bulb is
important, because these can be turned off with the mains still live (there
is a switch inside the bulb which is controlled by a phone app). Each time I
did a few more fittings, I turned off the wall switch and also the circuit
breaker for the lighting circuit. Except for one set, when I made the stupid
mistake of thinking that the bulbs were not lit, therefore the power was off
at least at the wall switch. Wrong! On that occasion the house was protected
with an RCD, which did its job and tripped very quickly: I know that because
it also killed the table lamp that I was using for illumination while the
ceiling lights were supposedly off.

The second shock was much less sever that the first one, probably because of
the RCD, so I didn't have to pull my hand away.

"Brian Gaff (Sofa)" wrote in message
...
Well the key is where you take the shock. It only takes a surprisingly
small current across the chest to kill you merely by stopping your heart,
that is why the one hand in your pocket advice is so useful.
Lots of us have had shocks, mine were usually thru the fingers of the
same hand when delving inside a working piece of valve gear that had
series fed heaters across the mains.

Ah, the perils of series-fed Christmas tree lights or valve heaters. When
all are working, you get the regulation 6 V across each one, but if one
fails and you remove it, there is near-enough the full mains voltage at the
socket (since the body resistance is so much greater than the filament
resistances).

Yes you get some expletives but not much else. The buzzing bruised feeling
soon passes.

With my two mains shocks it took about 48 hours before the residual tingling
had gone.

On 29/03/2021 23:32, soup wrote:
Many have had a 'belt' from domestic 240Volt wiring through bad luck,
bad judgment or plain stupidity .

One of my friends at university was unlucky enough to grab onto a Jesus
lead in the lab with a plug at each end. He was holding a live plug.
Third degree burns in the time it took someone to knock off the mains.

A previous (and terminally stupid) research student had made it - too
lazy to open up the four way strip and wire it up properly.

I have lost count of the number of hedge trimmer and lawn mower Jesus
leads I have reconfigured after noticing neighbours with it the wrong
way around. Usually just after they have cut through the cable again.

Â*Whilst a shock from 240V CAN kill how often does that actually happen
and how many just get thrown across the room into a foetal position
whimpering and crying until the arm unknots and the tingling feeling
goes away.

The funniest one for me was a US service engineer training on our kit in
the UK. They have a tendency to lick fingers and touch live to see if
its hot which on US 100v mains you can get away with. UK mains threw him
hard against a wall and he turned ashen grey. First aid was
administering warm sweet tea and a stern warning never to do that again.

When you do fire training in smoke you are taught to walk with your arms
in front, elbows out and palms facing inwards to your chest. That way if
you do touch a live wire muscle reflex pulls your hand away from it.

The tendency is for anyone untrained to flail their hands about in the
smoke feeling for things palms open and outwards. Do that and touch live
and the contracting muscles will grab onto it for you. Not good!

--
Regards,
Martin Brown

"Jethro_uk" wrote in message
...
On Tue, 30 Mar 2021 12:04:37 +0100, Andy Burns wrote:

Jethro_uk wrote:

Keith Relf formerly of the Yardbirds was killed in an electrocution at
his home

Dodgy guitar/amp wiring is traditional, isn't it?

https://www.ranker.com/list/musician...stage/jessica-
defino

though I don't think jessica knows what electrocuted means

The English language really does need another word to mean "received a
serious *but non-fatal* electric shock". Maybe we should avoid being King
Canutes, and accept that people will use "electrocuted" for the non-fatal
meaning, and devise a new wording such as "electrocuted to death".

When I was rehearsing and playing live I made damn sure I had an RCD trip
on my amplifier. Back in the mid 80s no one knew why.

I don't remember RCD devices (plug and socket) being around in the 1980s. I
can remember mains spike filters, but not RCD. That shows how little
prominence they had 40 years ago.

When did the fitting of RCDs on new house installations become part of
building regs? My first house, built in 1985, didn't have one - and
surprisingly it had wire fuses rather than MCB current-operated trip
switches. So evidently mandatory RCDs was after that. My second house, built
in 2000, had RCD and MCBs. As usual, only one RCD for the whole house,
rather than one per ring main, so a faulty appliance (or a finger on a live
terminal) took out the whole house, not just one ring.

"Martin Brown" wrote in message
...
I have lost count of the number of hedge trimmer and lawn mower Jesus
leads I have reconfigured after noticing neighbours with it the wrong way
around. Usually just after they have cut through the cable again.

My grandpa had an electric mower with a plug/socket between the short lead
on the mower and the long lead. Both the same cable, so probably the lead
had been supplied with the mower. It was the rectangular connector with
three pins in line.
https://www.cef.co.uk/catalogue/prod...onnector-black
When it's connected up, the plug and socket ends are almost
indistinguishable.

I borrowed it one day, and while I was mowing the lead got tangled up, so I
unplugged the lead at the connector on the mower - and was faced with three
live pins on the long line.

Someone, probably the manufacturer, had wired plug and socket the wrong way
round. I unplugged the lead at the wall and rewired the connectors the
correct way round - and kept quiet about it to avoid embarrassing my grandpa
just in case he had been the one who had wired it like that (but I don't
think it was his fault).

In article ,
Andy Burns wrote:
Jethro_uk wrote:

Keith Relf formerly of the Yardbirds was killed in an electrocution
at his home

Dodgy guitar/amp wiring is traditional, isn't it?

I know a musician was killed at Surrey University some years ago when he
grabbed hold of a microphone stand. That's why all stage sockets in
Guildford now need RCds.

https://www.ranker.com/list/musicians-electrocuted-on-stage/jessica-defino

though I don't think jessica knows what electrocuted means

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

On Mon, 29 Mar 2021 23:32:04 +0100, soup wrote:

Many have had a 'belt' from domestic 240Volt wiring through bad luck,
bad judgment or plain stupidity .
Whilst a shock from 240V CAN kill how often does that actually happen
and how many just get thrown across the room into a foetal position
whimpering and crying until the arm unknots and the tingling feeling
goes away.

About 50 years ago a work colleague was trying to connect an early
consumer tape recorder to a telephone handset plugge into an old
fashioned GPO telephone switchboard to see if he could record
conversations. When I moved a switch on the board I unwittingly put
40v into his tongue, which he was using to hold the connecting wires
in place. He gave up with his experiment.

On 30/03/2021 13:00, NY wrote:
"Brian Gaff (Sofa)" wrote in message
...
Well the key is where you take the shock. It only takes a surprisingly
small current across the chest to kill you merely by stopping your
heart, that is why the one hand in your pocket advice is so useful.
Lots of us have had shocks, mine were* usually thru the fingers of the
same hand when delving inside a working piece of valve gear that had
series fed heaters across the mains.

Ah, the perils of series-fed Christmas tree lights or valve heaters.
When all are working, you get the regulation 6 V across each one, but if
one fails and you remove it, there is near-enough the full mains voltage
at the socket (since the body resistance is so much greater than the
filament resistances).

There used to be a toy museum in Cockermouth. In one cabinet was an
early, electric, model railway. That had a controller that plugged into
a light fitting, with the removed bulb plugged into the top of the
controller, which had a rheostat. As soon as the train derailed, the
tracks would have no load and go to 240V!

Yes you get some expletives but not much else. The buzzing bruised
feeling soon passes.

With my two mains shocks it took about 48 hours before the residual
tingling had gone.

I too got one off a tape recorder - my fault, I did not expect them to
use 240V directly to power the erase head!

I've had a couple from accidentally contacting something that needed to
stay live, while working on something else in the same enclosure. Only
the tape recorder one was a proper belt, leaving me with a painful, but
numb and unresponsive arm, but only for a few minutes.

These days I've obviously improved, so none for quite a few years -
except for my boiler supply/switching, which floats at about 90V when I
disconnect both live and neutral at the supply end of the cable. There
are no other connections to either cable and boiler, so it must be an
induced voltage from parallel cabling.

Now we also have RCBOs on the non-lighting circuits and will be adding
them to the lighting soon.

Yes well I can believe that as well. I visited Brookman's Park back in 1961,
and unlike today, the only thing between us and the high voltages and rf was
a line of stands with a ribbon stretched between them, we were actively
encouraged to use a small neon lamp with a coil attached and see if we
could get it to light, Of course we did, I was 11 at the time. We were told
to keep clear of the transmission lines that ran on about 1M stands from
transmitter building to a small brick building at the base of each aerial
and were allowed to go inside the building of one not in use at the moment
to see the huge coil and clamp of the matching system.
There are people who still live nearby to large transmitters who can hear
the program on such diverse things as the chains on mirrors and their
cookers, Also keeping the rf out of telephones etc is not easy at those
field strengths.
Brian

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"jon" wrote in message ...
On Tue, 30 Mar 2021 08:39:22 +0100, Brian Gaff \(Sofa\) wrote:

Yes that would certainly do it. I am very sensitive to that
electrostatic buzz you get when you touch double insulated gear that is
still live, so am very wary. Luckily these days I do not attempt to wire
up mains gear as I cannot see the colours of wires any more.
As an aside there are a couple of forms of shock you do not want, unless
you have masochistic tendencies.1. On some navel ships the supply is 440
volts at 300Hz.

No matter where you catch that kind of shock it bleedin well hurts and
often you seemingly cannot let go. To be avoided at all costs.
2 RF burning. When I was still young I got a burn across my palm from a
ham
radio aerial in my garden. . It first started to feel like an itch then
pure pain, I let go very quick but not fast enough to stop a burn that
took some weeks to heal properly. So effectively microwaving your palm
is not advisable!

People get shocks all the time of course, but mostly its what we call
static, caused by the imbalance of ions plus and negative that can occur
merely with friction between materials, whether they be clothing carpets
seating or for air rushing down a vacuum cleaner pipe. I did when I was
younger 'borrow' a high impedance voltage probe and some people could
get charged up with over 20,000 volts in just a few seconds. Luckily its
got no current behind it on discharge so the worst you get is a crack a
spark, and a tiny pin point burn on your finger.
Talking of real life sad cases though, the daughter of an MP had just
had a
new kitchen fitted and was trying to get something out of a cupboard
and touched a securing screw with one hand while steadying herself on
the washing machine with the other. She was killed instantly and the
kitchen fitter was convicted of involuntary manslaughter. He had
basically joined a number of wires up inside a wall cavity, and not
filled in the hole merely screwed the cabinet over the top, One of the
screws in the back had just caught a live wire and was thus live and the
washing machine was earthed. The report did not go into too many
details, but apparently she was alone her heart stopped and she fell off
her kickstep and hit her head on some appliance.

Brian

At International Aeradio Ltd., there was a guy who had hundreds of RF
burns to his head where he had gone into transmitting cages to adjust
something over the years.

Yes well, the bodger who fitted the kitchen was not an electrician, it
turned out just a kitchen fitter trying to save time and extra money in that
out of sight out of mind way some people have.
The older TVs of course had the chassis at half mains voltage and the
aerial socket was supposed to contain isolating capacitors, but even those
can get charged up to high voltages and also you can get leaky capacitors
after some time and this practice luckily has now almost stopped, in favour
of the switch mode psu which is then supposedly isolated by its much
smaller transformer working at the higher frequencies. Having said that I
have seen cheap Chinese wall warts actually come apart when you try to pull
them out of a socket leaving live ends of the mains pins bare inside. Not a
good design.
Brian

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"NY" wrote in message
...
"Brian Gaff (Sofa)" wrote in message
...
Yes that would certainly do it. I am very sensitive to that
electrostatic Talking of real life sad cases though, the daughter of an
MP had just had a new kitchen fitted and was trying to get something out
of a cupboard and touched a securing screw with one hand while steadying
herself on the washing machine with the other. She was killed instantly
and the kitchen fitter was convicted of involuntary manslaughter. He had
basically joined a number of wires up inside a wall cavity, and not
filled in the hole merely screwed the cabinet over the top, One of the
screws in the back had just caught a live wire and was thus live and the
washing machine was earthed. The report did not go into too many details,
but apparently she was alone her heart stopped and she fell off her
kickstep and hit her head on some appliance.

That's nasty. And such a stupid mistake for the electrician to make.

Earthed appliances can be more trouble that they are worth if you happen
to touch an appliance that is live.

I got a nasty jolt when I unplugged a TV aerial cable from a USB DVB tuner
connected to my PC. I had the metal aerial plug in one hand and was
holding the earthed case of the PC with the other hand. As soon as the
plug was no longer in contact with the earthed PC, I got about 100 V
across me. Probably very low current, but it was enough to hurt for a few
minutes afterwards. Another leg of the TV aerial was plugged into my TV
(which was off but plugged in) and from there audio and SCART cables went
to a VCR, an OnDigital box and my hifi. One of those was evidently to
blame. Having disconnected everything in turn, with a voltmeter across the
aerial plug and mains earth, I narrowed it down to the TV. It was putting
out about 300 V as measured with a high-resistance voltmeter which went
down to about 100 V when I put a human-sized resistor (I measured my
across-the-chest resistance as about 200 K ohms) in parallel to simulate
me touching aerial and earth. So there was a large internal resistance,
but not large enough to prevent a noticeable jolt.

After that I rigged up a wire from mains earth to the aerial amplifier's
screen connection, to make sure everything was earthed. All it needed was
one earthed appliance (the PC) and everything was OK, which is why I'd
never noticed the problem before, but as soon as that earthed connection
was removed, everything was "semi-live". Sod's Law: everything else was
double-insulated and so not earthed. Probably to avoid hum loops as much
as to avoid needing a three-pin mains lead.


I've only had a "proper" mains shock twice in my life. Once when I made
the elementary mistake of working on a tape recorder that was turned off
(so everything downstream of the mains switch was safe), forgetting that
the input terminals to the switch were live... This was in the old days of
a fuse box that only contained (wire) fuses, with no earth-leakage RCD. I
still have two marks on my finger where it touched the soldered switch
pins for the live and neutral feed: it looks like a snake bite ;-)


The second time was equally silly. I was changing a lot of GU10 light
fittings which had Philips Hue bulbs in them - the type of bulb is
important, because these can be turned off with the mains still live
(there is a switch inside the bulb which is controlled by a phone app).
Each time I did a few more fittings, I turned off the wall switch and also
the circuit breaker for the lighting circuit. Except for one set, when I
made the stupid mistake of thinking that the bulbs were not lit, therefore
the power was off at least at the wall switch. Wrong! On that occasion the
house was protected with an RCD, which did its job and tripped very
quickly: I know that because it also killed the table lamp that I was
using for illumination while the ceiling lights were supposedly off.

The second shock was much less sever that the first one, probably because
of the RCD, so I didn't have to pull my hand away.

On 30/03/2021 15:05, Peter Johnson wrote:
On Mon, 29 Mar 2021 23:32:04 +0100, soup wrote:

Many have had a 'belt' from domestic 240Volt wiring through bad luck,
bad judgment or plain stupidity .
Whilst a shock from 240V CAN kill how often does that actually happen
and how many just get thrown across the room into a foetal position
whimpering and crying until the arm unknots and the tingling feeling
goes away.

About 50 years ago a work colleague was trying to connect an early
consumer tape recorder to a telephone handset plugge into an old
fashioned GPO telephone switchboard to see if he could record
conversations. When I moved a switch on the board I unwittingly put
40v into his tongue, which he was using to hold the connecting wires
in place. He gave up with his experiment.

I got my first serious shock - we had an electric heater that always
'tingled' - from a 12v train transformer used to drive a train set. I
was using it to drive an overhead live rail train I had made out of
Meccano with the super big Meccano electric motor in it.
It wouldn't go - it sat there buzzing so I calculated the overhead rail
needed to be lifted a bit ...so I grabbed the train and lifted the
overhead rail with my other hand..and broke the circuit between motor
and transformer...

YEOWCH!! I hadn't even begun to study electricity and had no idea such a
thing as inductance existed. I thought 12V was 'safe'

I was only about 8 or 9 I think



--
Truth welcomes investigation because truth knows investigation will lead
to converts. It is deception that uses all the other techniques.

One popular one is the ceiling rose syndrome. There is no point in turning
off the light if you discover you need either a new block in the ceiling or
a new bit of pendant wire as we all know there is an unswitched live up
there in that rose and a screwdriver in the wrong hole while up a ladder can
be a very unpleasant surprise, I always after my first encounter with this
situation tripped the cut out on the circuit first.

Brian

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"The Natural Philosopher" wrote in message
...
On 30/03/2021 05:18, jon wrote:
On Mon, 29 Mar 2021 23:32:04 +0100, soup wrote:

Many have had a 'belt' from domestic 240Volt wiring through bad luck,
bad judgment or plain stupidity .
Whilst a shock from 240V CAN kill how often does that actually
happen
and how many just get thrown across the room into a foetal position
whimpering and crying until the arm unknots and the tingling feeling
goes away.

I was sitting on a quarry tiled kitchen floor connecting up a cooker. My
understanding was the the supply was isolated, that quickly got revised
when I tried to strip off the insulation of a live 10mm2 feed with
uninsulated side cutters.

Last time it happened to me I was sitting on te floor trying to work out
why a brand new desk lamp didn't work. I had been through several cycles
of 'switch off at the wall, take apart, change rebuild, switch on at the
wall, test. and at one point I must have forgotten the 'switch off at
wall'

I think it was hand to hand but one wasn't grasping anything just touching


--
"And if the blind lead the blind, both shall fall into the ditch".

Gospel of St. Mathew 15:14