Re: Old Audio Receiver Hum?
From: Bradley1234 (someone_at_yahoo.com)
Date: 01/05/05
- Next message: Max Harding vk3jin: "Re: Looking for Philips 17A schematic"
- Previous message: Kevin R: "Re: FA Ebay UK Oscilloscope Tektronix 465B 100mhz"
- In reply to: harrogate2: "Re: Old Audio Receiver Hum?"
- Next in thread: NSM: "Re: Old Audio Receiver Hum?"
- Reply: NSM: "Re: Old Audio Receiver Hum?"
- Messages sorted by: [ date ] [ thread ]
Date: Wed, 05 Jan 2005 23:05:38 GMT
"harrogate2" <harrogate2@ntlworld.com> wrote in message
news:eJZCd.723$Mw3.523@newsfe6-gui.ntli.net...
>
>
> What a load of crap!
>
> The danger from electricity is NOTHING to do with supply frequency -
> it is all about current. A current of 30mA - that is 0.03A - passing
> through your body across your heart will usually be fatal. 10mA may
> cause problems, but in a healthy person will usually not be fatal.
>
> 120V (to earth) as used in the US is specifically chosen since it is
> rarely high enough to cause 30mA current flow through the body: by the
> same token here in the UK and across most of Europe, 110V (actually
> 55-0-55) is used professionally for power tools etc.
The number of people who believe that normal household current is not
lethal or that powerlines are insulated and do not pose a hazard is
alarming. Electrocutions may result from contact with an object as seemingly
innocuous as a broken light bulb or as lethal as an overhead powerline, and
have affected workers since the first electrical fatality was recorded in
France in 1879 when a stage carpenter was killed by an alternating current
of 250 volts. 2
>
> However our normal mains is 220V in Europe, 240V in the UK (that is to
> earth) and can be fatal. I understand that in the US 240V is available
> across both supply lines but it is actually 120-0-120 and thus much
> less dangerous.
>
>
> --
> Woody
>
> harrogate2 at ntlworld dot com
>
>
My my, you seem to be very educated in this subject if what I said was a
load of (incorrect information.) Can you explain what happens to the heart
to make it stop? Why doesnt a defibrillator, which probably jolts more than
30mA, cause a person to die?
It would be proper for me to quote sources, rather than assume;
When current greater than the 16 mA "let go current" passes through the
forearm, it stimulates involuntary contraction of both flexor and extensor
muscles. When the stronger flexors dominate, victims may be unable to
release the energized object they have grasped as long as the current flows.
If current exceeding 20 mA continues to pass through the chest for an
extended time, death could occur from respiratory paralysis. Currents of 100
mA or more, up to 2 Amps, may cause ventricular fibrillation, probably the
most common cause of death from electric shock. 11 Ventricular
fibrillation is the uneven pumping of the heart due to the uncoordinated,
asynchronous contraction of the ventricular muscle fibers of the heart that
leads quickly to death from lack of oxygen to the brain. Ventricular
fibrillation is terminated by the use of a defibrillator, which provides a
pulse shock to the chest to restore the heart rhythm.
11. Dalziel CF, Lee WR [1968]. Re-evaluation of Lethal Electric Currents.
IEEE Trans. Ind. Gen. Appl. IGA-4:467-476.
http://www.cdc.gov/niosh/pdfs/98-131.pdf
- Next message: Max Harding vk3jin: "Re: Looking for Philips 17A schematic"
- Previous message: Kevin R: "Re: FA Ebay UK Oscilloscope Tektronix 465B 100mhz"
- In reply to: harrogate2: "Re: Old Audio Receiver Hum?"
- Next in thread: NSM: "Re: Old Audio Receiver Hum?"
- Reply: NSM: "Re: Old Audio Receiver Hum?"
- Messages sorted by: [ date ] [ thread ]
Relevant Pages
|
