electrical wire detection?

[markjw12]

I have fitted 2 flat screen tv's to walls in my house and would like to fit a 3rd, the problem I have is this; The tv has to go above a electrical wall sockett so I have been out to buy a wire detector but it beeps no matter where I put it on the wall? I have since been out and bought a further 2 detectors and although they are set up correctly they still beep where ever I put them? I know it's not a problem with the wire's as I have just had my garage converted so the wire's are new.Is there another way to find them or is there a set practice for fitting wire's ie; certain hight up & accross?

 

[tonyelectric]

I've always found wire detectors to be useless, they can do exactly what you say and beep regardless.

First take off the socket faceplate and see if the wiring goes up or down, if up in theory it should go straight up, however theory is a wonderful thing.

Map out where the TVs mounting screws are going to be fixed and test drill using a small flat screwdriver pushed and twisted into the plaster (turn off the power whilst you do this), once you have hit brick or block you are fairly safe to drill at that location, if you find plastic capping or outer cable insulation stop at once before you cut into it and relocate.

Another method would be to tentatively chase across directly above the socket but behind the TV location, if you find the wiring directly above chances are its going straight for the rest of its run.

It is time consuming but I have always found this method to work, within reason once you are 50cm from the edge of the socket you are unlikely to find anything, I say unlikely because not too long ago when fitting a coat hook at home I drilled right through a ring running diagonaly down a wall house was built in '72 and thats how some idiot had run the cable.

 

[tonyelectric]

Incidently two reasons for false detection that are common are foil backed plasterboard and walls mae from cinter blocks which were made from waste slag from power stations, foundries etc and contain a lot of iron particles (and in some cases large blobs of welding slag

 

[markjw12]

Thank you for the help it's apreciated, I know the wire goes up attached to the baton then across and down to the next socket and as I want to attach the tv to the baton I want to find out how for up the wire goes and if it's on the side of the baton or the front edge? I will give the screw driver trick you suggest a go,Thanks again for the tip.

 

[ban-all-sheds]

I know the wire goes up attached to the baton then across and down to the next socket

That's wrong, and dangerous. Cables concealed in the wrong locations can get people killed.

• http://www.voltimum.co.uk/files/gb/attachments/niu/l/attachments/c5-43.pdf
  
  
• http://web.archive.org/web/20061110111450/http://www.niceic.org.uk/downloads/concealedcables.pdf
  
  
• IEE article
  
  
• IEE Article on 17th Edition requirements for concealed cables.

Any idea when the wiring was installed, and who the moron was who did it?