From: null@void.com   
      
   On 7/15/2015 7:26 AM, gfretwell@aol.com wrote:   
   > On Wed, 15 Jul 2015 08:33:29 -0400, "Rich."    
   > wrote:   
   >   
   >>   
   >> "krw"  wrote in message   
   >> news:3pfaqadhkrn6mpj5avo8611g7sv9h7095q@4ax.com...   
   >>> On Tue, 14 Jul 2015 06:15:55 -0400, "J.B. Wood"   
   >>   
   >>> BTW,   
   >>> water pipes are no longer allowed as the building ground (just the   
   >>> opposite, though - they are grounded).   
   >>   
   >> Nope you have it backwards. The water piping, assuming 10 or more feet is in   
   >> direct contact with the Earth, is the main ground. The driven ground rod is   
   >> referred to as the supplemental ground.   
   >   
   > There has been a major shift in the thinking about water pipe. Back   
   > when it was all metal, that was the best electrode you could get. Now   
   > that utilities have transitioned to plastic, not so much. These days   
   > the feed, all the way to the wall of the house, might be blue plastic   
   > with the copper starting at the basement wall.   
   > You still need to size the bonding conductor to water pipe using   
   > 250.66 even though 250.122 might be more appropriate.   
   >   
      
   My oldest NEC, 1968, says:   
   When there is less than 10 ft of metal in contact with the earth "or   
   there is some likelihood of the piping system being disconnected or   
   isolated through the use of nonmetallic piping or insulated  couplings,   
   the piping system shall be supplemented ..."   
      
   That is substantially the same as the current NEC, except a supplemental   
   electrode is now always required because a metal water service pipe may   
   be replaced by plastic in the future.   
      
   Used to be the "supplemental" electrode was ground rod(s), which are   
   often slightly better than nothing. Now often a "concrete encased   
   electrode" (Ufer ground) is required, and that is also the supplemental   
   electrode. That is a good electrode and loss of a metal water pipe   
   doesn't matter so much.   
      
   Far as I know all the water service pipe is Minneapolis - St Paul is   
   metal. Water pipe as an effective earthing electrode is far from dead,   
   and is important here (and elsewhere).   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)