Presumed RF Interference

Mon Mar 6 15:06:19 UTC 2006

On Mon, Mar 06, 2006 at 09:49:39AM -0500, Steven M. Bellovin wrote:
> 
> On Mon, 06 Mar 2006 21:17:17 +1100
> Matthew Sullivan <matthew at sorbs.net> wrote:
> 
> > (In the 
> > UK where I served my apprenticeship, we were required to provide earth 
> > bonding to the copper plumbing system, additional bonding at every 
> > exposed fitting - this caused a few issues when plumbers first starting 
> > using PVC pipes)... 
> 
> The US National Electrical Code (which has no national force of law;
> it's a model code voluntarily adopted by many jurisdictions) now bars
> grounding to pipes except within (as I recall) six feet of where the
> pipe enters the building, for precisely that reason.

The use in modern times of teflon tape at joints in copper
piping makes them unuseable for earth grounds even near the entry
point to the building. A long (e.g. 2-3 meters) copper stake must be 
driven for a proper earth ground, or else a large copper mesh mat if
the ground is rocky -- unless you are certain that the copper piping
that you want to use extends a significant distance underground and
unbroken.

-w