Find solution
Is voltage an intensive property?

Why might a voltage meter read positive on an entire main wall?

  • I'm trying to drill into my main wall in property, but everywhere I scan with my voltmeter reads positive for voltage and metal. I've tested the meter on a 'normal' wall with electricity cables I know to exist, so why am I getting a positive reading for the whole wall?

  • Answer:

    Some walls in older buildings are plaster over expanded metal mesh lathe. I've run into that quite a few times in remodelling vintage structures. It will make a metal structure detector go nuts. In more recent commercial structures that were built since the 1960's the framing can be steel studs rather than wood, this will tend to cause a more irregular signal, though. I doubt that foil backed plasterboard would be enough metal to trigger the device. If there is a discreet place you can break through a 2" square of the wall board it might be worth checking to see what is behind it. It is remotely possible if this was an old hospital that the walls could be lead lined -- also most operating rooms and intensive care units were built using metal mesh lath and plaster so they would not explode if anaesthesia gases were ignited. You never know what can be in old walls of converted buildings! Also in a large building conversion you may have old plumbing or abandoned power risers imbedded in the wall, though that would tend to be localized to make stronger signals in some areas. My best guess is metal lathing or steel stud framing.

nutty_gi... at Yahoo! Answers Visit the source

Was this solution helpful to you?

Other answers

I don't think what you are using is a voltmeter, it's a metal detector that it is on a too sensitive setting or is faulty. It's very unlikely that there are cables in places that are not on a vertical or horizontal line with any light switch or socket in the room. But if you want to be certain you need a working metal detector.

tom7railway

A "voltmeter" does not detect wires or studs or anything else behind plaster. It is a specific device for connecting across electrical terminals to measure the voltage on them. I think that because you are confusing voltmeter with "stud detector" and "cable detector" you may also be confusing the device that you're using and its instructions. Finding concealed wiring needs a "cable detector". This is a device that picks up the small electric field which surrounds a "live" wire. The meter (or light) should indicate when you pass the device over a concealed wire in the wall. To help you, it is normal for concealed wires in properly wired UK houses to run vertically up or down from a switch or socket. Finding studs and joists (the wooden supports for a plaster wall and ceiling) needs a "stud detector". This is a device which picks up the edges of wooden beams behind plaster walls and above ceilings. They usually have a light and bleeper to indicate when you pass the detector over an edge. The "stud" is solid between the edges (about 2" apart). You cannot use the same detector for concealed cables and for wooden studs, and you can't use a voltmeter for either. You need the correct detector for each thing that you're looking for - unless you get a combined unit. They cost about £12 each for simple ones.

The Tank

Make sure your test leads are hooked up correctly.

Related Q & A:

Just Added Q & A:

Find solution

For every problem there is a solution! Proved by Solucija.

  • Got an issue and looking for advice?

  • Ask Solucija to search every corner of the Web for help.

  • Get workable solutions and helpful tips in a moment.

Just ask Solucija about an issue you face and immediately get a list of ready solutions, answers and tips from other Internet users. We always provide the most suitable and complete answer to your question at the top, along with a few good alternatives below.