"K Wind" wrote in message
.. .
Would 1,500VDC with 6mA capability flowing through one arm and out the
other
be considered lethal? At one time, I knew how much current was considered
lethal, but have forgotten.

No. It is actually quite hard to kill yourself with electrical shocks.
There are tons easier and more likely things to die from in everyday life.

60Hz AC is most dangerous in the range of 100 to 300 mA. Current in that
range sometimes causes ventricular fibrillation, whereas currents above that
usually cause the heart to temporarily contract and protect itself. Very
high currents, however, can dissipate lots of power in your organs and cook
them, leading to a painful death if nothing stops the electrocution for
several minutes. High frequency AC (like many kilohertz and beyond) should
be less dangerous since it will be bound by "skin effect" and not penetrate
as far into your chest cavity. DC is considerably safer than 60Hz AC, and
I've read some estimates saying you need 4 times as much current to die from
DC shocks. I don't know if I believe that though; I suspect there are too
few cases to draw significant statistical conclusions. As I understand it
(and I may be wrong here), DC is safer than AC because it doesn't cause
ventricular fibrillation, so death by these shocks occur from organ damage
and falling off ladders and things.

Howard Henry Schlunder




-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 80,000 Newsgroups - 16 Different Servers! =-----

On Sun, 10 Aug 2003 14:25:01 -0400, scharkalvin
wrote:

Some of these stories are hair rasing... and I'm too much of a weenie to
stick my tongue on a 9V battery...

That's how we tested batteries when I was a kid. 'Course there was the
dufus that tried it with a 90v B battery!

I'm sure when he could speak again he could tell you that there was
voltage present.

Happy trails,
Gary (net.yogi.bear)
------------------------------------------------
at the 51st percentile of ursine intelligence

Gary D. Schwartz, Needham, MA, USA
Please reply to: garyDOTschwartzATpoboxDOTcom

On Sun, 10 Aug 2003 14:25:01 -0400, scharkalvin
wrote:

Some of these stories are hair rasing... and I'm too much of a weenie to
stick my tongue on a 9V battery...

That's how we tested batteries when I was a kid. 'Course there was the
dufus that tried it with a 90v B battery!

I'm sure when he could speak again he could tell you that there was
voltage present.

Happy trails,
Gary (net.yogi.bear)
------------------------------------------------
at the 51st percentile of ursine intelligence

Gary D. Schwartz, Needham, MA, USA
Please reply to: garyDOTschwartzATpoboxDOTcom

In article , Gary S.
Idontwantspam@net writes:

On Sun, 10 Aug 2003 13:06:23 +0100, Paul Burridge
wrote:

On 10 Aug 2003 03:22:06 GMT, (Avery Fineman)
wrote:

I really don't know the medical-biological low threashold for direct
cardiac stimulation through an opening in the chest cavity. I don't
care to know. I care to know NOT to futz around with my or anyone
else's body with anything above the "30-30" limits.

As a general safety rule I'm sure you're right. However it does
overlook the fact that different individuals have different tolerance
levels, hence the fatality at 12V (the only recorded one, I believe)
and that Polish electrician who checks for the presence of 230VAC by

It also matters what the surface resistance of your skin is, and how
good a "connection" to the nervous system and heart.

For example, You could put dry fingers on a 9V battery and not feel a
thing, but if you lick your fingers first, get a real tingle. Same
voltage, but the moisture allows current to flow.

Too bad the old "B" batteries aren't common any more. As a 15 year
old (back in the prehistory of mankind) newcomer hobbyist to radio
and electronics, I couldn't feel anything across the snap-on terminals
of a 67 V "B" battery. Curious, I touched my tongue to them.

Z A P ! ! ! !

Stunned, I waited about a half hour to get my tongue unrolled.

Never EVER tried such a totally dumb idea again...

In medicine, the defibrillator paddles are covered with a conductive
gel, and use a precise pulse of voltage and current. In open heart
procedures, lower voltage and current is used, with paddles applied
directly to the heart.

True enough. What is overlooked is that medical instruments,
meters, appliances are all precisely calibrated-adjusted-designed-
to-be-stable-in-their-settings...based on KNOWN INFORMATION to
medical and biological people.

Of course, disrupting the heart rhythm may happen with lower voltage,
especially AC or RF.

Why is being careful such a problem for some?

Bravado and a general feeling of immortality. Especially true for males
and once useful as a survival thing way back in time.

Some actually believe their boast "It can't happen to ME!" :-(

No problem for the morticians...keeps their business going.

The solid-state era was born with a dangerous side-effect: Low supply
voltages. High voltages of 100 to 300 VDC weren't needed with
transistors. Most folks are not able to feel supply voltages under 15
V, DC or AC. As a result they get way too CASUAL about handling
supply rails with the power on. "Familiarity breeds contempt," etc.

When they take that casual attitude towards handling mains supplies
with 115 to 230 VAC input, there's trouble just waiting to happen. It's
like sticking one's hand into a snake basket...the snake may bite or it
may not, depends on the snake...if it bites the bite can be deadly.

Len Anderson
retired and still living in the current reality after 56 years in electric
things

In article , Gary S.
Idontwantspam@net writes:

On Sun, 10 Aug 2003 13:06:23 +0100, Paul Burridge
wrote:

On 10 Aug 2003 03:22:06 GMT, (Avery Fineman)
wrote:

I really don't know the medical-biological low threashold for direct
cardiac stimulation through an opening in the chest cavity. I don't
care to know. I care to know NOT to futz around with my or anyone
else's body with anything above the "30-30" limits.

As a general safety rule I'm sure you're right. However it does
overlook the fact that different individuals have different tolerance
levels, hence the fatality at 12V (the only recorded one, I believe)
and that Polish electrician who checks for the presence of 230VAC by

It also matters what the surface resistance of your skin is, and how
good a "connection" to the nervous system and heart.

For example, You could put dry fingers on a 9V battery and not feel a
thing, but if you lick your fingers first, get a real tingle. Same
voltage, but the moisture allows current to flow.

Too bad the old "B" batteries aren't common any more. As a 15 year
old (back in the prehistory of mankind) newcomer hobbyist to radio
and electronics, I couldn't feel anything across the snap-on terminals
of a 67 V "B" battery. Curious, I touched my tongue to them.

Z A P ! ! ! !

Stunned, I waited about a half hour to get my tongue unrolled.

Never EVER tried such a totally dumb idea again...

In medicine, the defibrillator paddles are covered with a conductive
gel, and use a precise pulse of voltage and current. In open heart
procedures, lower voltage and current is used, with paddles applied
directly to the heart.

True enough. What is overlooked is that medical instruments,
meters, appliances are all precisely calibrated-adjusted-designed-
to-be-stable-in-their-settings...based on KNOWN INFORMATION to
medical and biological people.

Of course, disrupting the heart rhythm may happen with lower voltage,
especially AC or RF.

Why is being careful such a problem for some?

Bravado and a general feeling of immortality. Especially true for males
and once useful as a survival thing way back in time.

Some actually believe their boast "It can't happen to ME!" :-(

No problem for the morticians...keeps their business going.

The solid-state era was born with a dangerous side-effect: Low supply
voltages. High voltages of 100 to 300 VDC weren't needed with
transistors. Most folks are not able to feel supply voltages under 15
V, DC or AC. As a result they get way too CASUAL about handling
supply rails with the power on. "Familiarity breeds contempt," etc.

When they take that casual attitude towards handling mains supplies
with 115 to 230 VAC input, there's trouble just waiting to happen. It's
like sticking one's hand into a snake basket...the snake may bite or it
may not, depends on the snake...if it bites the bite can be deadly.

Len Anderson
retired and still living in the current reality after 56 years in electric
things

In article , "Mike Gilmour"
writes:

Maybe apocryphal but I heard that if you're stupid enough to look into an
open waveguide of an active 10cm marine radar it would cause that eye to
become the equivalent of a hard boiled egg. No need for a 3 minute timer
then?

Back when I was doing electronic instrumentation with an optics group
at Rockwell, my first day in that group brought forth a caution from one
of the optical physicists about lasers: "Do NOT look INTO a laser beam
unless you want that to be the LAST thing you see."

That was with a little 10 milliWatt laser used on their optical table
for initial system calibration.

Good advice I thought...and remembered it.

I'm sure there are some in here who want to gabble about "open wave-
guide" and it "not radiating much because it is open, represents a
discontinuity, and the VSWR is so high there won't be any power
radiated." Which MIGHT happen at any microwave frequency from
L-band bottom (1 GHz) on up past Ku band (24 GHz+). That will
depend on the wavelength of the physical waveguide opening to the
microwave source. The magnetron MAY also refuse to oscillate due
to a high VSWR, flash over and trip its breaker or something to not
operate. Then again it MAY - with equal likelyhood - work just fine
with an opening and radiate FULL power out that open waveguide.
Or something in between full power and no power...a big unknown.

No matter how much anyone likes hardboiled eggs, those belong in
the mouth and not the eye sockets.

Len Anderson
still looking at the world of electric things with cautious eyes

In article , "Mike Gilmour"
writes:

Maybe apocryphal but I heard that if you're stupid enough to look into an
open waveguide of an active 10cm marine radar it would cause that eye to
become the equivalent of a hard boiled egg. No need for a 3 minute timer
then?

Back when I was doing electronic instrumentation with an optics group
at Rockwell, my first day in that group brought forth a caution from one
of the optical physicists about lasers: "Do NOT look INTO a laser beam
unless you want that to be the LAST thing you see."

That was with a little 10 milliWatt laser used on their optical table
for initial system calibration.

Good advice I thought...and remembered it.

I'm sure there are some in here who want to gabble about "open wave-
guide" and it "not radiating much because it is open, represents a
discontinuity, and the VSWR is so high there won't be any power
radiated." Which MIGHT happen at any microwave frequency from
L-band bottom (1 GHz) on up past Ku band (24 GHz+). That will
depend on the wavelength of the physical waveguide opening to the
microwave source. The magnetron MAY also refuse to oscillate due
to a high VSWR, flash over and trip its breaker or something to not
operate. Then again it MAY - with equal likelyhood - work just fine
with an opening and radiate FULL power out that open waveguide.
Or something in between full power and no power...a big unknown.

No matter how much anyone likes hardboiled eggs, those belong in
the mouth and not the eye sockets.

Len Anderson
still looking at the world of electric things with cautious eyes

When I worked as an RO in the Merchant Navy I found I could light my
cigarette by holding on to the overhead copper aerial feeder while
simultaneously keying the transmitter on MW (say 480 or 512 Khz) ....only
when I couldn't find my lighter. Kinda daft in retrospect...and chuckle to
think I eventually won a safety award ;-)

"Gary S." Idontwantspam@net wrote in message
...
On Fri, 8 Aug 2003 16:56:28 -0700, Watson A.Name - 'Watt Sun'
wrote:

In article ,
mentioned...
On Sat, 9 Aug 2003 01:18:38 +1000, "Alex Gibson"
wrote:

I think I may have experienced rf burns some years ago. Is this when
you touch a metal object close to an rf field; it feels thermally
*hot* enough to burn you, but when the field is killed, said object
*instantly* feels normal room temperature again?

No, RF burns is when the skin is actually burnt.

The example above sounds more like inductive heating.

If an ungrounded piece of metal is near an RF energized coil, a
current is induced in it which heats it up. Somewhat similar to a
microwave oven.

Happy trails,
Gary (net.yogi.bear)
------------------------------------------------
at the 51st percentile of ursine intelligence

Gary D. Schwartz, Needham, MA, USA
Please reply to: garyDOTschwartzATpoboxDOTcom

When I worked as an RO in the Merchant Navy I found I could light my
cigarette by holding on to the overhead copper aerial feeder while
simultaneously keying the transmitter on MW (say 480 or 512 Khz) ....only
when I couldn't find my lighter. Kinda daft in retrospect...and chuckle to
think I eventually won a safety award ;-)

"Gary S." Idontwantspam@net wrote in message
...
On Fri, 8 Aug 2003 16:56:28 -0700, Watson A.Name - 'Watt Sun'
wrote:

In article ,
mentioned...
On Sat, 9 Aug 2003 01:18:38 +1000, "Alex Gibson"
wrote:

I think I may have experienced rf burns some years ago. Is this when
you touch a metal object close to an rf field; it feels thermally
*hot* enough to burn you, but when the field is killed, said object
*instantly* feels normal room temperature again?

No, RF burns is when the skin is actually burnt.

The example above sounds more like inductive heating.

If an ungrounded piece of metal is near an RF energized coil, a
current is induced in it which heats it up. Somewhat similar to a
microwave oven.

Happy trails,
Gary (net.yogi.bear)
------------------------------------------------
at the 51st percentile of ursine intelligence

Gary D. Schwartz, Needham, MA, USA
Please reply to: garyDOTschwartzATpoboxDOTcom

Watson A.Name - 'Watt Sun' wrote:

I used to be able to do that with the nickle plated antistatic bags
that parts came in back in 1980. The ohmmeter would measure several
hundred ohms. But nowadays all I can measure is an open. I just
tried it again, measured open even on the 200M range.

Yeah, it's been like that for at least 15 years. Anti-static work mats
aren't conductive either. So what principle do they use?

--
-Reply in group, but if emailing please add two more zeros and delete
the obvious-