Jack Painter wrote:
"m II" wrote

CaveDweller wrote:


Of course, I'm interested in the lowest noise possible, but my main
concern is protecting my new baby.


This is a nice, simple solution. I had to go back in time to find it for
you.


http://www.gutenberg.net/cdproject/c...ah/fig006c.png


mike



NO!

That drawing, taken on it's own, will allow a nearby strike to blow your
radio into pieces so fine you can clean up with a duster. Why? Becasue the
electric power ground (house entrance), and cold water ground (a different
entrance than AC service 99% of the time), and that phony knife-switch
"protector" ground rod, are all at different locations and will have
*enormous* electrical potential between them .


I disagree. A big knife switch will have a few INCHES of air gap between
the common and the radio feed. At roughly 20K volts per inch needed to
jump the gap to the disconnected radio, any few volt difference between
grounding potentials is immaterial.

Check the diagram. The radio is **never** connected to the ground rod.
It's only meant to discharge antenna static to ground

Also, this switch is an ISOLATING switch and not meant in any case to
supplant a proper lightning protection set up.


A metal cold water line coming into the house is the PREFERRED code
ground for the house (system) wiring. An artificial electrode like a
ground rod/plate may be used if plastic line is coming in for the water,
but NOT if metal water line is available.

To make you even more paranoid, the electrical code, at least here, says
the ground rod/pipe may NOT have a resistance greater than TEN ohms
between it and ground. Up to ten ohms is code acceptable.

That means on a nominal 120 volt residential circuit, a fault current of
up to TWELVE amps may be flowing at all times and not even trip the
breaker.



mike


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