Re: water pipe RF ground. (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Thu, 30 Aug 2007 14:03:26 -0700
From: Jim Lux <jimlux@xxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: water pipe RF ground. (fwd)

At 06:52 AM 8/30/2007, you wrote:

>---------- Forwarded message ----------
>Date: Wed, 29 Aug 2007 14:47:27 -0400
>From: Scott Bogard <teslas-intern@xxxxxxxxxxx>
>To: tesla@xxxxxxxxxx
>Subject: water pipe RF ground.
>
>Hey guys,
>      Just one quick question, would it be a bad idea to use the cold water
>pipe (feeding into the hot water heater) as an RF ground for TC stuff in my
>apartment?  As far as I know it is copper all the way to the source, but I
>am not entirely sure.
>Scott Bogard.


Bad idea.
a) why put HV RF on the water pipes inside the walls?
b) "as far as I know" is exactly the reason that cold water pipes are 
not legal as a ground electrode in the electrical code any more.

Build yourself a counterpoise/ground screen. Place coil on top of it. 
Connect "cold" end of secondary to screen with short wire.  Make sure 
that anything you deliberately draw arcs to is connected to the screen also.

   Connect screen to "green wire" ground if you like


The idea is to keep the RF currents from the coil somewhere safe and 
not conduct them hither and yon.  Imagine the topload of the TC as 
one plate of a capacitor. The other plate is whatever you connect to 
the bottom of the coil. If that's the water pipe, then RF current 
flows from topload through wall to water pipe and so forth.  Bad news.

If you are operating a bigger coil on the ground, say in a garage or 
driveway, the screen thing still works well.  It provides a low 
impedance path to "earth" by virtue of the fairly large capacitance, 
so if you do have strikes out to things in the vicinity, the RF 
current can still get back to the coil via the ground.

Jim