Chuck Craven wrote:Even the 12v from a power supply or battery charger can do you damage. It’s the current that kills not the voltage
Chuck
Yes, its current, irrespective of voltage that kills. As little as 5mA can induce ventricular fibrillation (a heart attack) after 3 seconds, assuming the current has a path through your heart. Luckily, the human body is a pretty good resistor. If I measure the resistance of my body by holding the leads of a sensitive ohmmeter and I have clean dry hands, I measure a resistance of about 1 million ohms. So at 12v DC how much current would be conducted through my heart if I grab the terminals of a battery?
Ohms Law
E=IR
I=E/R
I=12/1,000,000
I=1.2 x10^-5 or 12 microamps
Roughly 3 orders of magnitude lower than what is considered lethal.
Now lets assume I've been working really hard on my teardrop and my hands are good and sweaty. Now I can measure a resistance of 17,000 ohms.
I=12/17,000
I=7X10^-4 or 700 microamps
Now we're only about one order of magnitude below the lethal level.
Now don't get me wrong here, you have to be carefull working around electricity. Period. But there is a reason that we use 12V batteries for systems like start batteries and power for a teardrop; its a pretty rare circumstance that causes an electrocution death. And as Chuck described, there's a good reason for a fuse in every circuit (see previous post with the oneline diagram) and taking off all your jewelry when working on energized circuits. You might not be electrocuted but how many of us have accidentally touched a wrench across the terminals of their car battery?
Bruce