"roger" wrote in message
...
Not to complicate Adrian's thread.. here's an earthing funny that lay
dormant for many years.
Victorian house - Granny Flat extension added to the rear - all is well
till a graphic artist takes over the flat.
On arrival installs extensive computer system, and at end of day takes a
shower. Two minutes into showering, adjusts the controls a 2nd or 3rd
time - and gets a shock.

Reminds me of the one I had to look at a few months ago - Owner reported
getting a shock from the running water in his bathroom sink. With past
experience of customers I toddled along with the phone number of a good
psychiatrist in my pocket. Went in, turned on tap, put hand in water -
nothing. "Try taking your shoes off" says he. Took off shoes, turned on tap,
put hand in water and nearly landed on my ar*e! Checked usual things - no
fault showing. Stuck meter probe between running water and earth - best part
of 100v. Pulled bullet at meter - still 100v. Pulled meter bullet for flat
upstairs - voltage disappeared. Customer then said that when he first moved
in he used to get a shock off the walls (it was a refurbished old building
converted into upstairs / downstairs flats). Problem turned out to be a nail
through the live tail insulation to the upstairs flat. It had only nicked
the insulation and you couldn't see bare copper but it was obviously enough.
Why the voltage appeared only in the running water is beyond me - the shock
from the walls was presumably down to wet plaster and disappeared as it
dried out.
Richard.