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Fw: Ground current



 
  I assume that what you have then is something that looks like this:
 
  
          power co pig
 
          WWWWWW
          |       |         |
          |       +--------|---------+
          |       |         |          |
          |       |         |         ///  power co ground (at the pig)
          |       |         |         
       breaker panel/fuse box
          |       |         |       
         L1     N       L2
          |       |         |
          |       |         +----
          |       +-------------- other house circuits
          +----------------|----- 
          |       |         |                               ( -------------
          |       |         +--------/  ---------------)||(
          |       |         |                           )||( 
          |       +--------| ---------------------+---)||(  your pig
          |       |         |                       |   )||(
          +------|---------| --------/ ------------|---)||(
          |       |         |                       |       (--------------
          |       |         |                       |
                  |                                +----- pig case
                  |                                 |
                 ///                              ///
 
         neutral tied to house       pig ground
       ground (water pipe, etc.)
 
 Here's what I believe you're seeing:

 What you've done by connecting the neutral to your pig
 and then to ground, is to put your neutral-pig-ground connection in
 parallel with the neutral wire going back to the power company pig and
 their ground. Any current flowing in the neutral because of active loads
 will tend to divide itself (depending on the resistances in each path)
 between the neutral wire  to the PC's pig, the neutral to cold water pie
 ground (which is normal), and your pig's ground. 
 
 For example, if there's a 10A load between L1 and neutral somewhere 
 in the house (and no other load on L2 to balance it out), you'll
 have 10A trying to 'get back' to the PC pig via the neutral. Some
 (hopefully most) of it will return via the neutral wire which should have
 the least resistance. Some will travel via the cold water pipe ground, and
 some will travel via your pig ground. This then is probably the current
 you're measuring in your pigs neutral circuit. I'm not surprised that you
 can't measure the voltage though, because we're dealing with resistances 
 that are (or should be anyway) very small, making the voltage drop very 
 small as well. In fact, if you could measure any significant voltage
 I would say that your ground(s) weren't very good!
 
 However, aside from causing some confusion, connecting the pig to the
 neutral and ground in this way is potentially dangerous and probably a
 violation of the electrical code too. Normally, the only connections
 between the neutral and ground should be at the PC's pig and at your
 service entrance/breaker panel. The neutral should not be tied to ground
 anywhere else!  

 I would suggest that you disconnect the neutral from the
 pig (it isn't needed if you're running the pig line-to-line as shown), and
 also disconnect the pig's CT from the both the case and ground
 as well. By all means leave the pig's case grounded though. Any metallic
 objects that can be grounded  probably should be for safety reasons, but 
 not the neutral or your pig's CT.
 
 Sorry for being long winded and I hope my crummy ASCII graphics are
 decipherable...
 
 - Mike
 
 
 > > all power disconnected
 > > Tolally dead !!!!