# Electrical Safety[]

```U.S.
PRESIDENTS
VIVE LE
RESISTANCE
ELECTRICAL
SAFETY
30 KV ABOVE
GROUND
“OHM” MY!
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WHO WAS PRESIDENT
WHEN ELECTRICITY
WAS INSTALLED IN THE
WHITE HOUSE?
BENJAMIN HARRISON

What is the
canonical value of
resistance for a
human gripping two
tips of a multimeter?
500 kW
I’m a resistor;
you’re a resistor!
Hooray, we’re all
resistors!
2013 Circuit class resistance (gripping tips of ohmmeter probes with dry skin):
Mean +/- std. dev 1.3 +/- 1 Mohm
Range: 105 kOhms – 3.2 MOhm
Canonical value: 500 kW (a reasonable ‘back of the pocket’ number to carry around)
Franco Colombo on Venice Beach circa 1960

WHAT UNIV. OF
CALIFORNIA PROF
STUDIED THE EFFECTS OF
ELECTRICAL CURRENT
ON ELICITING
INVOLUNTARY MUSCLE
MOVEMENT WHO LATER
INVENTED THE GFCI?
CHARLES
CHARLESDALZIEL
DALZIEL
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“Don't think it's conductive?
Go stand outside in your
bare feet and hold a hot
wire. But before you do
make funeral
arrangements.” -Bill
Marsden

Is the bird shocked?

Why or why not?

Draw the circuit
diagram and explain
Never ever remove it!
Hot wire in
contact
with metal case
due to wear over
time
Can a toaster dropped into a bathtub electrocute you?
Crap….I dropped
my toaster in the
bathtub again
Develop an approximate circuit model a person soaking in a bathtub with an electrical appliance in contact with the water, then…
&quot;I figured if I had the stamina to run four marathons, I
could take the brunt a good-humored 10,000 volt shock.
Not quite.
&quot;The obstacle, the last of a few dozen, was 50 yards from
the finish line. What made it worse: There was a wait. A
line formed so we could watch people run through 50-60
dangling wires that charged with electricity every three
seconds…
&quot;When it was my turn, I took off fast hoping to power my
way through.
&quot;The first shock hurt like hell. If you've ever been shocked
before, you know how it feels. Intense pin-prickling pain is
followed by your extremities involuntarily flailing in all
directions.
&quot;The second shock just about sent me to the ground. Mind
you, we were running over hurdles of dirt through the 20
feet of live cables. I almost made it until the third shock
hit. My legs left the ground and sent the rest of my body
face first into the wet mud.
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http://howelectricityworks.weebly.com/
http://science.nationalgeographic.com/science/photos/heart/
http://www.physics.ohio-state.edu/~p616/safety/fatal_current.html