On Sep 13, 8:51*pm, The Daring Dufas
wrote:
Ralph Mowery wrote:
"E Z Peaces" wrote in message
...
When humidity is low, clothing rubbing against car seats can cause static
shocks when a person touches grounded metal. *If the car manufacturer puts
some megohms between that metal and ground, touching it will drain the
charge painlessly.

Actually the car metal does not have to be grounded. *As the car is a large
mass of metal it will have a differance of potential from the person that
slides across the seat.
PUtting a resistor between the car and ground will do nothing for this
effect.

Years ago some gas trucks would drag a chain to ground the truck. *This was
thought to drain off any static charge the truck would have so the gas would
not *blow up when the hose was used to transfer the gas. *A spark could jump
from the end of the hose to the storage tank.

Fuel trucks still use static dissipation devices.
Instead of chains there are conductive straps
that are less likely to cause a spark when dragged
across metal. The straps are used on cars, trucks
and motor cycles. Sometimes the chains you may see
under a truck could be automatic snow chains. It's
some interesting stuff.

http://www.mizter.com/index.htm

http://www.onspot.com/

Check out #9

http://www.wilsonantenna.com/tsswrt.htm

TDD

Looking at that automatic tire chain sitting so close to the ground
got me to wondering.

If he ran over a piece of tire debris and knocked it loose, that could
cause some serious damage to his truck.

Andy