This question already has an answer here:

i'm going to drill into a wall interior and avoid the wires immedietly above the socket and horizontally near it below If I remember my dad told me that wires are normally found travelling vertically above and below the socket. The socket is near the floor should I worry about any horizontally running wires either side?

marked as duplicate by isherwood, ThreePhaseEel, Daniel Griscom, mmathis, Machavity Mar 20 '18 at 23:24

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • How deep do you need to drill? – Harper Mar 16 '18 at 16:52
  • always assume that there are wires where you are drilling – jsotola Mar 16 '18 at 17:10
  • Wires can be run anywhere. In a wall they can come from below, from above, or from another outlet to another outlet horizontally through the wall. I would assume wires are in any direction unless you know for sure. Example, my living room, from panel to light switch from above, back to lights above. From panel to outlets from above, then horizontal across wall to each outlet and to the adjacent wall. Kitchen has random as it was a remodel and has some from above and some horizontal, but the range is from below. Every house will be different. But I would assume horizontal if you have multiple.. – Jeff Cates Mar 16 '18 at 18:28
  • You could make a hole with a knife and then look to see where the wires are. – Yehuda_NYC Mar 16 '18 at 18:28
  • ...outlets in the room on the same circuit, especially on the same wall. || || || EO----EO-------EO----EO Just an example. – Jeff Cates Mar 16 '18 at 18:29

When I had this problem years ago, I resolved it using my own improvised detection method. And it worked 100% accurately.

Before I discuss the method let me to point out about the limitations of the standard gadgets being sold for this type of detection.

  1. Voltage detector: it may detect the hot/live wire but tell you nothing about the neutral/return wire. Normally both hot and neutral are bundled together but this not necessarily be real for all installations. Using this, you may end up drilling into a neutral wire.

  2. Stud finder: works well in detecting ferromagnetic materials such as iron nails or steel screws. Its sensitivity drops sharply when being used to detect buried copper wire. I might be wrong on this but I don't have much confidence on this gadget to detect buried thin copper wires.

My method; Listen to the line frequency of electromagnetic wave emitted by buried wire when it carries a large current.

The gadget:

I improvised an old "walkman" type cassette player by hooking up a one-inch small 1000 turns copper coil to the wires originally connected to the player's tape head. This copper coil actually from a primary of a small power transformer, with its iron core fully removed. This modified player become a sensitive magnetic field detector. Whatever signal picked by the coil can clearly be heard thru earphones connected to the 'walkman'. This gadget picks electromagnetic field of AC current carrying wires from as far as 18 inch distance.

Method: Detect one conductor at a time. I load the circuit in such a way so that current flows only in one conductor at a time. This is done by connect a significantly heavy load such as a 100 watts or 500 watts halogen lamp to the live wire of that socket and get the neutral return for the lamp at another socket some where else.

This ensures my gadget can listen only to the magnetic field around the buried live wire. When the pickup coil is sweeped on the wall, the intensity of the line frequency signal peaks at its closest position. This is how I locate the position of the cable run.

Repeat this for neutral wire by loading the lamp on the neutral wire and get it live feed from some other far socket.

  • Couldn't this procedure could cause damage by generating heat in metallic conduit, metallic boxes, or other metallic loops by generating eddy currents? – Jim Stewart Mar 17 '18 at 1:38
  • 1
    My method not inducing magnetic field into anything instead just pickup magnetic field around the current carrying conductors. – soosai steven Mar 17 '18 at 14:06
  • 1
    @soosaisteven - Your method will fail whenever you try to trace some circuit that happens to feed through a GFCI outlet or breaker. – Michael Karas Mar 17 '18 at 14:40
  • 1
    @Jim Stewart: 100W going one-way thru a metal conduit or j-box for the 15 minutes needed to locate the wires is not going to generate heat that you could feel with your fingertips much less damage anything. – A. I. Breveleri Mar 17 '18 at 16:43
  • 1
    @A.I.Breveleri - Your comment is understood. My point still stands in that the proposed scheme will still fail if a GCFI is involved in the circuit. – Michael Karas Mar 17 '18 at 16:52

Wires 'NORMALLY' travel down into the socket; however if the sockets are daisy chained (and an outlet most likely will be) in other words you will have more than one socket on a circuit; you will have wires traveling horizontally to the next outlet. I said normally - because you never know how those wires were stretched across the space etc.. unless you physically saw them before the dry wall was fastened.

  • You can use a stud finder with a wire detector to determine where wires are (~ $40) - to some extent they work.

  • There are non-contact voltage detectors that might find it for you.

  • Then Of course there is a product advertised on TV that will allow your android or iPhone to see through the wall .. the wires, the pipes and whatever. While not cheap it is probably the best tool you could use.

1: Smartphone-sensor-lets-you-peer-right-through-wall

2: 3d-sensor-walabot-vayyar

  • 1
    I use a stud finder with a power indicator when I don't have my tracer it works quite well not real accurate but by finding the zone it alerts for power the wires are usually in the center of that zone or the detector may show the wire in a 4 inch wide zone the wires are usually 2" from the outside edge. – Ed Beal Mar 16 '18 at 18:51
  • Wear insulating shoes when you drill, and try not to ground yourself anywhere. Even then, drilling into a 120 volt line can get a bit tingly. – Wayfaring Stranger Mar 17 '18 at 2:54
  • @WayfaringStranger Yes it is not good to drill into any AC voltage line because it can get more than a bit tingly it could be deadly. Better Safe then oops. :-) – Ken Mar 18 '18 at 5:07

Not the answer you're looking for? Browse other questions tagged or ask your own question.