On 11 Sep 2003 02:03:19 -0700, Winfield Hill
wrote:

Watson A.Name wrote...

http://www.rfcafe.com/references/ele...ctrocution.htm

"Cannot let go" at 13mA? That seems pretty low. Hand to hand,
I suppose. Hmm, is that dc or ac, and if ac at what frequency?

Thanks,
- Win

And what do they think the difference is between "Ventricular
Fibrillation" at 90 mA and "Death" at 100 mA? Other than about 5
minutes, except under the most unusual circumstances?

Possibly more accurate info at
http://www.osha.gov/SLTC/etools/cons...eccurrent.html

http://www.agc-ca.org/services/safety/Sb97-2.htm

http://cpmcnet.columbia.edu/texts/guide/hmg13_0006.html

Low voltage electrocution is most often caused by Ventricular
Fibrillation, described at:

http://sprojects.mmi.mcgill.ca/cardi...brillation.htm

http://www.emedicine.com/emerg/topic633.htm

For the description of the unusual circumstances where Ventricular
Fibrillation may not be fatal:

http://www.utilitysafety.com/archive...rt_a_heart.htm

Unfortunately I can't now seem to find any references which describe
the exact electrical mechanism by which Venticular Fibrillation (VF)
occurs, although it is well understood. Deliberatly induced VF is
used to temporarily stop the heart for surgery, by applying a short,
low current pulse to the nerve which fires the heart (crudely put)
durung the "reset" or "succeptable" part of its cycle - essentially
preventing the recharge of the ion powered synapse, so that it cannot
fire, and without firing, it cannot recharge. I have read that it is
not actually current which is critical, but dI/dt during the reset
period, and since the dI/dt on initial contact can be much greater
than during the subsequent sineusoidal current, initial contact at the
right polarity and timing of the heartbeat can cause death at currents
much lower than those that reliably cause death (per the standard
charts). Note that GFI breakers can take up to 1/10 sec to trip, and
provide no protection from initial contact electrocution!

Furthermore, individual succeptablilty to VF varies widely, and there
are plenty of documented cases of death caused by only a few
milliamps.

Bottom line as I see it is that contact with line voltage is a lot
like Russian Roulet with 1 bullet and a few hundred empty chambers.
Why risk it?

Regards,
Glen