nanog mailing list archives

Re: Presumed RF Interference


From: ww () styx org
Date: Mon, 6 Mar 2006 10:06:19 -0500


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 () 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


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