DIY pipe and cable detectors

I've always found an electric drill, mounted with a large drill bit, will unerringly find and penetrate any pipework or live electric cabling running within walls James. Second best I've used is a Black & Decker pipe and live cable detector - borrowed so I can't remember the exact part, but it seemed to do the job.

I think gaining views of a variety of users is a good idea - my own experience also just of one is also one of ‘flakiness’: Someone gave me a Black and Decker for a birthday present, some years ago. It was supposed to be able to locate the position of not just metal, but also things like joists in ceilings and wood in stud walls. I found it completely unreliable at detecting wood, and with cables (e.g clipped to studs or lying across ceiling plasterboard) it would detect live wires up to a couple of inches away, but not dead circuits. Metal pipes OK, but I doubt it would have been able to detect plastic pipes. i ended up throwing it away. The gift was at least 13 years ago, so this may not necessarily apply to any current product by the same company. 

I’ve has a Screwfix own brand one for maybe 10 or 12 years, and it works pretty well. I do still take the precaution of isolating power and water as far as possible, before adopting Tony’s technique, which I must say can be a lot more reliable, especially when looking for plastic pipes now almost universally used by plumbers. 

I’ve used several of these DIY level meters and one cannot trust them.  If the metal / cable is fairly near the surface you’ll usually get a bleep but if they are deeper nothing.  All the ones I’ve tried struggle with older lath and plaster walls or foil backed plasterboard.  All one can do is hope whoever installed the pipe/cable followed best practice or take an educated guess and drill only as deeply as needed.

Cheers guys, I guess I’ll carry on with the tried and trusted hit and hope method...

An electric jigsaw is also rather effective at finding hidden water pipes.....

The indoor "water feature" was quite magnificent. My sprint to the stopcock would have shamed Usain Bolt. My drive to the local hardware store before it closed on Saturday evening, well I'm saying nothing

Willy.

I think these detectors are still useful if you accept their limitations. Of course they will not find plastic! They should reliably locate a live electrical cable, or a copper pipe, in a wall chase, with sufficient accuracy to enable you to drill holes and avoid them. Studs behind plasterboard are fine, too - lath and plaster will be less successful. 

ChrisSU posted:

I think these detectors are still useful if you accept their limitations. Of course they will not find plastic! They should reliably locate a live electrical cable, or a copper pipe, in a wall chase, with sufficient accuracy to enable you to drill holes and avoid them. Studs behind plasterboard are fine, too - lath and plaster will be less successful. 

Possibly excluding plasterboard with foil backing, which is used in some houses