On 28 Jun 2005 03:35:19 -0700,it is alleged that "Fitz"
spake thusly in uk.d-i-y:

I previously had no reason to suspect that the equipment did not work.
Placing the device against the wall of an alcove in his party wall
gives a live indication for the entire wall. Other walls in the same
room do not indicate as live. Testing around a light switch gives
correct behviour.


These detectors, for safety, are very sensitive. Any leakage current
will trigger the 'live' detection. I have had this myself from an
entire wall. What's happening is the wall is probably slightly damp
(being a party wall it's likely solid masonry and thick, thus holding
moisture) and the detector is picking up leakage, probably a minute
and non-dangerous amount of leakage mind you, so not in itself a
hazard, but annoying due to this false indication nonetheless.

As for workarounds the only suggestion I can think of is to turn off
the power, put it in metal detection mode, and see if it finds the
buried (dead) cable around the light switch as metal, then see if you
can find the buried dead cables in the party wall.

HTH

--
Life is like a hot bath. It feels good while you're in it, but the
longer you stay in, the more wrinkled you get.
- Robbert Oustin