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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 !!!!