Electric / Pipe Detector - Why are they sold?

anotheruser

I bought a Bosch Truvo wire/pipe detector but the electrician said they aren't reliable.

If so, why are they sold?

Mine detected a live twin and earth but when the electrician came and used another one, he said it was dead.

Is there one that IS reliable?

Aylesbury_Duck

Does it matter, as long as they give at least "false positive" readings? Once you know there's something there, you wouldn't necessarily worry whether the pipe was full of water, gas or oil or the cable was live or not, you'd assume they were "live" and work around it. I've used detectors for years and never had a nasty surprise because I've always assumed that what's been detected is something I wouldn't risk drilling/hammering into.

anotheruser

Well, if it's saying there's something there when there isn't, I'd day that's a problem.
Perhaps it works the other way, doesn't detect something when it should?

coffeehound

anotheruser wrote: »

Is there one that IS reliable?

What brand was the electrician using?

spadoosh

I thought most of them where just detecting 'something' as opposed to that something being live or not.

I was under the impression they worked by detecting density changes in the wall. So a stud would be lense dense than the plasterboard which would be picked up as a void or a 'do not hammer here'.

Between a live and dead wire the density isnt going to be that distinguishable so wouldnt work that effectively. It just needs to point out there is something there which isnt great for putting a nail in.