Why Numbers are Dangerous.

I've always been fascinated how the brain works.

More likely out of frustration when dealing with incompetent instructors.

You know the type: They tell you 37 ways to NOT do something, and one way TO do it...
...when it comes time to use that knowledge, you remember every single one of the 37 ways to NOT do something, and a few of your own, but can't remember the RIGHT way, because you were overloaded on information.

In comes the brainpower, and why you DON'T TEACH SO MUCH TO PEOPLE. Not everyone has a perfect "filter" for such things, will forget 90% of what you said in an hour anyways, and will remember something the way their brain is wired, not the way you taught them.

Example 1:

Dry skin: 120v and 0.0011A. 

Example 2:

GFI trips at 0.0050A

Thesis 1: Grabbing 120VAC will result in 0.0011A current in body with dry skin at the contact point

Thesis 2: GFI receptacles trip at 0.0050A imbalance.

Synthesis: It is OK to touch live 120VAC wiring with dry skin.

WRONG!

An example of why this is NOT the way to teach someone about safety;

People wrongly assume electricity takes the shortest or easiest path to ground. NOT TRUE.

Except for high-frequency examples of WHERE on the conductor the current flow is (i.e., "skinning") and certain experiments Tesla was famous for, under normal conditions, electricity takes ALL paths it can as a return point (or ground) and can be can be calculated accordingly. 

Say there is a set of conductors, size 3 AWG (size of a Sharpie marking pen) and a spot removed on the insulation by a genetically engineered plastic mouse, impervious to electricity, whom has gnawed an area large enough away for you to put your "1000-ohm dry skin palm" on.

Well, its feeding a 5HP motor (about 3700W)  drawing 30 amps at 120 volts. V=I*R, so That's only 4 ohms! Your dry-skin hand is 1000 ohms, so no current will go through you, right? WRONG!

Regardless of the motor,  you are now a new branch circuit. Unless you and the motor will draw enough to trip the breaker or fuse, you'll continue to be an electronic heater/screamer which hasn't been tested by UL;  until the cows come home, whatever that means. Even if the breaker does blow, you're already had enough to ruin your organs, fry your heart or brain, probably even the family Joules.

So, I guess I have issues with people thinking they know about electricity because they "learned it in school".

Well, teachers were STILL teaching that Neptune didn't have rings and water vapor was visible when I was in school. A guy from the Electric Company told us in Driver's Ed class that if a power line falls on our car, we're "OK" because the tires insulate us. NOT EVEN CLOSE TO TRUE!

We're OK because we're the same voltage (potential) as the car, as the line, as the ground immediately under us. We're OK because we're all the same voltage and therefore no current flow.

MetersFeet

Voltage dissipates radially to ground, assuming all conditions equal.

Volts

       Distance to ground point

So, being in a car with a live 13800-Volt line on it can be fatal just stepping out of the car.

A 4000-5000 volt difference between the car and where your foot touches the ground means you get 4000-5000 Volts. Lets say a path between  your right hand and left foot exist at 2500 Ohms.

V=I*R; 5000=n*2500; 5000=2*2500. You now have two amps going through you.

Two hundred times dead, you are. Not a pretty way to die, nor always instant. Electric chairs are engineered (or were) poorly and often caused unspeakable misery rather than their intended "insta-death" purpose.

I'm far off-topic here, but I'm ranting. If you like weird movies and want to know more about electric chairs, see Mr. Death (1999). Warning: It's a political shocker movie. No pun intended. It covers capital punishment and the Holocaust, so if you're the least bit queasy about either subject, by all means see it anyways and flame my blog with insults.

Just a side note which I will prove soon:

GFI receptacles wont trip even if you shove a fork in one end and your tongue piercing in the other.

There needs to be an imbalance between the L and N side (usually indicating current going to ground and not back to the N; in a 1-phase circuit, a neutral really isnt a neutral; it's a return path).

Good day!