"Sasha" wrote in message
oups.com...
I beleive I have the same tester and it only rings when you move close
to electrical box. I tried to scan entire wall with known hot wire
behind itand it didn't give any signal.

Question: The wires within the wall were alive; but you could not get any
indication; right?
Was the test tried when there was current 'flowing through the wires' to
some appliance/device etc. plugged in further down the circuit?
Reason I ask is because I have once or twice been able to detect certain
wiring location (using something that draws quite a few amps, such as a hair
dryer/heat gun etc. = 12amps. 2 115 volts) not something lightweight (such
as 40 watt lamp bulb = 0.3 amps) using a small powerful hand held magnet and
feeling the vibration caused by the significant amount of AC current flowing
through the wires!
In some cases it seemed that even though the two wires carrying current, hot
and neutral, are very close together and their respective magnetic fields
will thereby tend to cancel, there is enough difference between them to
detect in certain cases.