OT: Tracking Mains Wires in the Walls

Go to Radio Shack (or similar) and buy a Progressive Electronics "tone & probe"

That's how I found my surround sound speaker wires which were placed and covered by drywall while I was out of town.

...Jim Thompson

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|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

Or go to RatShack and buy one of those little amplifier-speaker boxes and a telephone pickup coil (or a drum-core inductor, or anything with lots of turns.) You'll be able to pick up and hear both the magnetic field and the capacitive coupling from wires in the wall. A dimmer-type load can add a characteristic signature to any one circuit.

That rig is fun for listening to all sorts of magnetic fields.

John

And then swear very loudly as a spike comes through the capacitor, and eats you HP generator.

Klaus, I recently had a problem similar to yours, except that I was trying to locate a circuit that suddenly went dead (no breakers popped). The only way I could think of to find the errant circuit was to bash holes in my walls. Unwilling to do this, I called an electrician. He tried a gizmo called a "circuit tracer". He had no success, but you might want to try one. The solution that worked for the electrician?......He bashed holes in the walls! Sigh... You might have better luck with the circuit tracer than he did. Sorry, I didn't get the brand name. Your local electrical supply house can probably help. Good Luck!

Hello Jim,

IIRC they don't have Radio Shacks in Viking territory. But there is another old trick:

Turn the switch on so the line is connected to the grid. Then take an AM radio, tune it to a vacant frequency at the low end of the AM band and follow the noise. Today's household mains wiring is so polluted from cheap switchers and the like that I was able to find most lines this way. In "quiet" households it helps to turn on some lamps with dimmers, to about half brightness.

Regards, Joerg

[snip]

Surely even "Vikings" has some kind of access to tone tracing equipment ?:-)

...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |

| 1962 | I love to cook with wine. Sometimes I even put it in the food.

You may buy wiring detectors in any "Baumarkt" but don't expect these devices to work reasonably well. You may trace wires in the wall only if there is a load causing a magnetic field and these devices even don't permit to locate the wire precisely (to a few centimeters). I had one such device which had an option to indicate electric field as well, but this is pretty useless because there will be electric fields everywhere around in any electrified household. I saw devices which are used to find phone circuits in the house's distribution by injecting a high frequency modulated circuit, which worked really well, but I doubt that this approach would work with mains wiring, because the mains is too much interconnected (think about the neutral being the same on every mains socket) so that capacitive coupling would make your efforts useless. (IMHO)

Out of practice: Just disconnect the wire you are in doubt about and see what happens (= what doesn't work anymore). If nothing happens, you where probably right to disconnect it! Look for distribution boxes under your wallpaper and you'll find out that it will end up in a distribution box if you follow the direction it went off. (What about the colour of the wire. There appears to be some logic with colours in a decent installation?) Just my 5 cents.

Greetings!

Hello Jim,

They do. But in Europe it was always harder to buy anything electronic locally. With the advent of video games and the slumping interest of teenagers in electronics that didn't improve, just like here. Even our local Radio Shack is history now and rumors have it that a whole slew of them will be shut down.

There are some mail order places over there. Klaus: Check Conrad Electronics for tone tracing gear or kits. Their web site is very frustrating though, IMHO.

Regards, Joerg

In theory, at least where I live, and assuming the wiring was done to code, all wire ends are accessible without making holes in the wall. That is, all splices have to be done in junction boxes, and those can't be plastered or dry-walled over.

So if you turn off power at the main breaker, you may be able to trace wires using a simple continuity check.

regards, Mac

These overpriced gizmos just have a diac in the Tx, and a sensor coil and detector in the Rx. The Tx just zaps a very narrow pulse down the earth . Quite easy to detect cables

martin

Yes - I would need a transient filter to protect the generator :-)

Regards

Klaus

Thanks

I went to the Conrad site and found one I may use. Will be interesting to see how well it works :-)

Thank you all for your help

Klaus

Even if you don't find a suitable detector, and want to do what you proposed, isn't it safer to borrow an inverter and turn off the electricity at your place?

Best,

Hello Klaus,

If you found that on the Conrad site all by yourself and without cussing you might be qualified to work as a detective :-)

Regards, Joerg

No problem at all. Didn't use the tree structure though - a bit confusing. Just used the search function :-)

Regards

Klaus

Hello Klaus,

Well, when I read your first post I keyed in "Kabelsucher" and it gave me hundreds of hits, everything that had the word "Kabel" (for cable) in there. Seems like one more example of how not to design web sites.

Regards, Joerg

Slap together a little buffer amp with a 2N4401/2N4403 pair and a 47R or so isolation resistor on their emitters. :-)

Cheers! Rich

In article , Rich Grise wrote: [....]

No, slap together a buffer using TIP35 and TIP36, then you'll be able to see the solder joints without your glasses.

Oh yeah, and its harder to break.

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kensmith@rahul.net   forging knowledge

And add another couple, to do a multivibrator, so you can lose the sig gen.