According to Jeff Wisnia :

Chris Lewis wrote:

Frankly, guys, if I was in shoes on a concrete floor, and just touching
a pipe gave me a tingle, I'd kill the house power _immediately_ and
get everyone out of the house.

Then, I'd get out the voltmeter, and turn on the power again. Then carefully
(touching as little as possible) start measuring voltages between "supposed"
grounds to figure out what's wrong.

I'd do exactly the same thing...For sure!

Good, someone agrees with my paranoia ;-)

And how about those laundry machines? Unless they were both unplugged
from their outlets they should have been grounded too, so something had
to be seriously wrong with the grounding of the electrical system in
that building.

Dryers aren't hooked up to the plumbing. Washers often don't have
electrical conductivity to the plumbing either (the hoses are rubber -
our code requires a bonding strap from case to pipe, but it's often omitted...)

You missed my point there. The OP said he touched *the case* of his new
washer and got bitten. Whoops, you're right. Sorry.

That indicates that the case of the washer wasn't
at ground potential, as it should have been if it was plugged into a
properly grounded outlet, eh?

Basically, I think we all agree that the plumbing isn't grounded properly.

I was more exploring the possibility that the plumbing wasn't grounded,
but the house electrical system is. Getting a tingle off the dryer
frame (or the washer if it's not bonded directly to the pipe) certainly
does suggest that the house ground isn't grounded properly either.

Unless he was leaning against the pipes when he touched the dryer and washer,
and he _thinks_ it was the dryer/washer at fault, when it was really the pipes.

The reason I'm casting about for alternatives is because (a) I'm uncomfortable
with the fact that _two_ failures are needed to explain the symptoms - a buggered
main system ground _and_ a ground fault energizing things and (b) if he's
going to try to diagnose this himself (which I don't really think he should),
he needs to know all the possibilities.

The one (remote) possibility that really concerns me is that he _may_ have
a loose/bad neutral between the panel and the pole.

Why? Well, that _single_ fault would imply that the neutral/ground voltage
would be pulled "away" from dirt potential simply by imbalanced current thru
the two hots. As such, he'd see a moderate tingle voltage on the ground,
anywhere, but that tingle voltage will vary wildly depending on what things
are turned on in the house.

[No, a grounding electrode will _not_ provide enough conductivity to ensure
that the grounding system stayed at dirt potential.]

The only reason I didn't jump to it immediately is that the brighten/dimming
of lights that are also symptomatic of this are usually _immediately_ obvious
and he'd have mentioned it.

Water heaters cases don't necessarily have good electrical connectivity to the
plumbing, because the teflon tape or pipe dope _may_ interrupt the electrical
path. Plastic certainly would. Rusty metal unions might too.

Rvery electric water heater I've worked with has had a ground terminal
on it to which an electrical ground lead from the panel should be
connected. If his wasn't then it wasn't to code.

Right. What I was addressing is that a heater supply ground would not
necessarily help ground the pipes.

The main thing we know is that the pipe isn't grounded. It _may_ or
may _not_ be connected to the electrical system ground. If it is, the
electrical system ground isn't connected to the dirt (or whatever the
other object the OP was touching when they got the tingle).

Any decent building code requires all metal plumbing supply lines to be
conected to earth ground.

Right.

Agreed, I think we both know something's AFU with that building's
wiring, and they ought to get a *good* professional out there to put it
right.

Right.

Forget electrical field strength. You won't feel it at these frequencies
and power levels.

Puhleeze! You can have a DC electric field you know. What do you think
causes that tingling you feel when standing outdoors just before an
electrical storm hits? The charge on those clouds sure ain't AC is it?
And you can have a field in any media that isn't a perfect conductor,
such as water.

Puhleeze! ;-) I thought it so completely absurd that you could get an
tingleable electrostatic field at 240V, I didn't even consider it,
and simply assumed you were referring to electromagnetic/induction
effects. Which are only slightly less absurd at 60Hz and house power
levels than getting a detectable tingle from a 240V DC electrostatic
potential.

Of course electrical storms can cause tingles. But they're not 240V DC
are they? ;-)

All I was saying is that the water in the tank isn't a perfect
conductor. So (if the tank was grounded per the "plastic pipe" thesis)
the majority of the leakage current from a rotted through element would
flow to the grounded metal nearest the break, because the shortest path
through the water will have the least resistance. There would be very
little current flowing through the much longer paths to the inlet and
outlet bushings, and I'd expect the voltage there would be negligable.
Of course if the tank shell *weren't grounded* then the whole tank and
the water in it would probably just follow one half of the line voltage.

It could even follow line voltage, depending on how much stray conductance
to dirt potential there was, where the break was, etc.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.