Mystery wire

[Trygve Lillefosse]

Hi

I live in an old house where I moved in about a year ago.

In the hallway there is a dual switch, but only the wires from one of
them do any "action", and is connected to the hall light. I expect
that there are wires that are meant for a light in the stairs, but
have not been able to find out where the outlet may be.

Would it be possible to follow the wires with a current detector, when
there are no load in the end, or do I need some kind of metal
detector?

 

[Martin Riddle]

Hi

I live in an old house where I moved in about a year ago.

In the hallway there is a dual switch, but only the wires from one of
them do any "action", and is connected to the hall light. I expect
that there are wires that are meant for a light in the stairs, but
have not been able to find out where the outlet may be.

Would it be possible to follow the wires with a current detector, when
there are no load in the end, or do I need some kind of metal
detector?

You didn't mention if they are still hot.
If they are not hot, then a tone probe may allow you to find them in the walls.

<http://www.homedepot.com/webapp/wcs...nktype=product&storeId=10051&ddkey=THDSiteMap>

You may have to turn the gain to max on the probe to penetrate the walls

Most likely you have one end of a three-way switch .

Cheers

 

[Trygve Lillefosse]

You didn't mention if they are still hot.
If they are not hot, then a tone probe may allow you to find them in the walls.

They are still connected to the mains, but there are no load(lamp or
whatever) at the end.

<http://www.homedepot.com/webapp/wcs...nktype=product&storeId=10051&ddkey=THDSiteMap>
You may have to turn the gain to max on the probe to penetrate the walls
Most likely you have one end of a three-way switch .

I do not quite understand how this gadget work. Do you have any link
that explains the workings?

 

[Trygve Lillefosse]

The little black thing is a tone generator that connects to the wire. The probe
contains an inductive pickup that signals when it picks up the radiated field from
the wire.

The one cited is designed for de-energized wiring. Telephone, network and other
similar wiring. One probably more suited for your application is this:

http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?productId=100087660

This unit is similar to the above one except that it works with live circuits. The
tone generator connects to the live circuit and is powered from it.

None of these work very well when tracing Romex because the two parallel wires act
like a transmission line and thus don't radiate much signal. If you're tracing a
single wire then either should work well.

You probably don't need either of these to find an energized power conductor. All
you need is a capacitive probe feeding a reasonably high gain audio amplifier. I
have a Rat Shack amplified speaker with a fairly high impedance microphone input that
I've used to find hidden wiring. A phono preamp is ideal. The probe can be as
simple as a length of wire or perhaps a plate of metal. It picks up the e-field
radiated by the wire. Simply move the probe over the area and home in on the spot
that produces the most hum.

Think I will try this method. Even though it may mean that I have to
move around my stereo.
Thinking about it - i think I have an old casette/radio stowed away in
the basement.

Now I only need a cheap pair of airline earplugs I can modify, luckily
I'm going away this weekend - I may get a pair. If not, I will have to
search one of my "mystery drawers".

 

[Trygve Lillefosse]

Think I will try this method. Even though it may mean that I have to
move around my stereo.
Thinking about it - i think I have an old casette/radio stowed away in
the basement.

Now I only need a cheap pair of airline earplugs I can modify, luckily
I'm going away this weekend - I may get a pair. If not, I will have to
search one of my "mystery drawers".

Oh well, it turned out that there had been used a dual switch, but
only one of them was connected and in use.

Anyhow, I should now be able to find hidden wires if needed.