"Brian Gaff (Sofa)" wrote in message
...
Are the old argument on here of whether a neon screwdriver is a blessing
or a curse then...
ISTR being told that you should test an exposed wire (????) with the
back
of your hand so that any muscle reaction will not cause you to grab hold
of it.

I'd rather test it with a neon screwdriver.

The worst safety device is one that cannot be relied on. I bought a
proximity detector (induction) "pen" from B&Q for tracing live wires in
plaster to determine where it is safe to drill or hammer in picture hooks. I
quickly realised that it was worse that useless because it seemed to detect
some wires are great distance (making it vey difficult to determine the
maximum point where the wire lies) or else it failed to detect "known-live"
things like putting it close to a mains socket or a trailing appliance lead.

That went in the bin. It said "test it every time on a known live item
before using for tracing" - but if it fails to detect that known live, it's
useless. Especially if the known live *does* get detected (so you know the
device is working) but it fails to detect a live that you are testing.

A neon, for an exposed wire/terminal, is much more reliable, though you
still need an induction device for finding buried wires.

Should induction devices be able to detect wires which are live but have no
current flowing through them?