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