On Mon, 28 Oct 2013 04:08:32 -0400, "Robert Green"
wrote:

"Nate Nagel" wrote in message
stuff snipped

If you have a voltmeter or test light, measure voltage from a copper
pipe to a good ground (usually the copper pipe *would* be a good ground,
but in this case it is apparently not! Try a grounded receptacle.)

Not sure if that's going to work if the ground is energized. There's also
the problem of phantom voltage readings if he's using a digital meter that
might make the readings meaningless. I've been researching this problem on
the net out of curiousity and there are lots and lots of potential causes.
So many that it's a problem best left to a licensed professional.

The copper supply piping may have once been connected to a ground but a
repair with a plastic union of some sort has isolated a section of the pipe
which is touching something electrical and is now energized. Since there
are so many possibilities, it's time for Fred, the OP, to call in the
cavalry now that we know it's not a simple static shock.

I'm
guessing you'll find there is some. Unplug any appliance that connects
to water line one at a time (clothes washer, refrigerator with ice maker
are the two obvious ones; water softener if you have it, etc.) until you
find the faulty one. Leave that one unplugged until it's fixed.

If you've unplugged everything and you still have voltage on the pipes,
start turning off breakers one by one until it goes away. Then
depending on your skill level you can find the issue or give a pro a
good place to start troubleshooting (and be safe in the meantime.)

I agree that the OP should be tracing the pipes *visually* to locate
possible contact points, clamps with wires leading from them and places
where there might be a plastic union, but it's a serious enough problem to
defer to an electrician that has experience with such issues.

Consider driving some ground rods, and bonding your panel and plumbing
system so this doesn't happen again!

I suspect that's going to be part of the solution a qualified sparky will
recommend. Something's rotten in Denmark, and it could be more than one
problem which makes it really hard for a homeowner to isolate and fix. I
say Fred's exceptionally lucky he detected this problem before he stepped
into what might have been his last shower on Earth. (-:

When I installed my new water softener I had to connect a bonding wire
between the inlet and outlet of the softener too - it was in the
instructions - because the softener meter-head is composite instead of
brass.

The water heater has anti-dialectric bushings too - so a jumper across
the water heater maintains ground continuity there as well.