[TriLUG] On Electrocution

[Pete Soper via TriLUG]

Did you happen to read the context of my comment? Twelve volt batteries? 
Heat, fire risk? Think for about an extra 20 seconds before you make 
somebody look like an idiot. I have heart rhythm issues and wear a 
single rubber glove any time I'm dealing with much over 40 volts, 
specifically to limit the current that has a chance to pass through my 
chest. And I think I'm one of the folks in this area who propagated the 
(real, documented) "look at me as I put sharp VOM probes into my fingers 
and kill  myself" story. Sheesh.

-Pete


On 4/23/20 12:06 PM, Brian via TriLUG wrote:
> On 4/18/20 1:55 PM, Pete Soper via TriLUG wrote:
>> Current can be just as dangerous as voltage. 
>
> It's current that kills you.  Voltage is only the "potential" to 
> create current; nothing happens until the electrons start moving. A 
> 12-V car battery can easily melt a large wrench but won't hurt you if 
> you touch the terminals*.  A nine-volt battery with subdermal contact 
> can be fatal.
>
> i.e. be very careful with your high-range ohmmeter if it has 
> insulation-piercing probes!
>
> And since we're on the subject:
>
> First, always be careful with any power source.  But with that said:
>
> DC is relatively safe up to some hundred volts in brief contact with 
> unbroken dry skin.  Dry skin has a relatively high resistance (on the 
> order of 100 kOhms).  Note that for many of us sweaty-palmed types, 
> our skin is actually rarely really "dry." Also, resistance is 
> inversely proportional to contact area, so a larger contact patch 
> means lower resistance.  So, be careful.
>
> Low-frequency high-voltage AC (e.g 60 Hz "house current") is extremely 
> dangerous, as it will capacitively couple right through your body and 
> kill you dead.  So, be careful.
>
> High-frequency high-voltage AC (several thousand Hz, e.g. a tesla 
> coil) is much less dangerous; although it can still capacitively 
> couple through your skin, the "skin effect" will keep current flow 
> around the perimeter of your body, mostly away from your heart. It'll 
> still burn and damage you badly, but most likely in a nonfatal way.  
> So, be careful.
>
> See https://en.wikipedia.org/wiki/Electrical_injury for more gory 
> details.
>
> And be careful!
>
> :-)
>
> -B
>
> * - with dry hands