Hi
Nick,
Yes
it is the current that kills but the mistake you are making is using it
basing
your calculations on POWER.
For
a given power halving the voltage will double the
current
240W
@ 240V = 1A
240W
@ 120V = 2A
240W
@ 12V = 20A
When
you receive an electric shock the voltage is applied across the RESISTANCE
of
your body. That is fairly constant and only changes according to the amount
of
moisture in or on the body. That is why water and electricity is often a
fatal
combination.
For
DC it only takes few milliamps to kill you as it causes muscles to contract
and as the current is constant the muscles wont release. For AC it takes
quite
a bit more as the current keep reversing and also has brief periods of
zero.
If
you take as an example, a person with dry skin and a body resistance of
50kohms then
@
240V 240/50000 = 4.8mA
@120V 240/50000 = 2.4mA
@50V 50/50000 = 1mA
@
12V 12/50000 = 0.24mA aka 240uA
I
just tested my body resistance with my multimeter and got a reading of
about
1Mohm with dry fingers, wetting the tips of finger and thumb made the
resistance drop to about 40kohms.
One
of the reasons I never wear rings or watches is because the last thing I
want
is a large lump of metal attaced to my skin to give a much improved contact
area. >From the risk of shock, you can also get severe burns if a piece
of
jewellery comes into contact with live contacts.
The
biggest danger from electric shock is when the current flows from one side
of
the body to the other as it crosses the chest and causes heart
failure.
The
one thing that really confuses me is that electricity can kill a living
person
but.....
....
electricity is used to bring a very recently deceased person back to life
!!!!
Keith
www.diyha.co.uk
www.kat5.tv
Keith
I
thought it was current that killed, not voltage? Static electricity
produces very high voltages.
W=AV, so lowering voltage increases current to provide the same
power to a the tool.
What am I missing in this argument?
Nick