nanog mailing list archives
Re: Presumed RF Interference
From: Ian Mason <nanog () ian co uk>
Date: Tue, 7 Mar 2006 13:11:42 +0000
On 6 Mar 2006, at 15:06, ww () styx org wrote:
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 theUK where I served my apprenticeship, we were required to provide earthbonding to the copper plumbing system, additional bonding at everyexposed fitting - this caused a few issues when plumbers first startingusing 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.
The purpose here is not to use the piping *as* a ground, but to ensure that the piping *is* at ground potential. Otherwise, if an electrical failure causes the pipe to reach a dangerous potential then so does the water in it, then so do the hands you're washing in that water. Thus if there's an electrical discontinuity in the piping it is even more important to earth bond any conductive piping/taps etc. that are on the non-earth side of that discontinuity. The same applies too to gas piping except here the principal risk is static, sparks and the subsequent explosion.
Current thread:
- Re: Presumed RF Interference, (continued)
- Re: Presumed RF Interference Peter Dambier (Mar 05)
- Re: Presumed RF Interference David Lesher (Mar 05)
- Re: Presumed RF Interference Steven M. Bellovin (Mar 05)
- RE: Presumed RF Interference Scott Morris (Mar 05)
- Re: Presumed RF Interference Robert Boyle (Mar 05)
- Re: Presumed RF Interference Steven M. Bellovin (Mar 05)
- Re: Presumed RF Interference Peter Dambier (Mar 05)
- Re: Presumed RF Interference Martin Hannigan (Mar 05)
- Re: Presumed RF Interference Matthew Sullivan (Mar 06)
- Re: Presumed RF Interference Steven M. Bellovin (Mar 06)
- Re: Presumed RF Interference ww (Mar 06)
- Re: Presumed RF Interference Ian Mason (Mar 07)
- Re: Presumed RF Interference Andrew C Burnette (Mar 08)
- Re: Presumed RF Interference Randy Bush (Mar 06)
- Re: Presumed RF Interference Peter Dambier (Mar 06)
- Re: Presumed RF Interference Jay Hennigan (Mar 06)
- Re: Presumed RF Interference Iljitsch van Beijnum (Mar 05)