Use metal detector as cable tracer...?

[Geir Holmavatn]

Hi,

Say I have a disconnected electrical cable dug into the ground. I need
to trace the cable to find out its route and where it ends.

I wonder if it is possible to inject a signal from a signal generator
between one of this cable's conductors and earth and walk away with a
metal detector to trace the cable.

Has anyone any experience or knowledge on this to share, and if yes, how
deep in the earth will the detector be able to trace the cable?

Thanks for comments on this issue ;-)

regards

Geir

 

[Dave]

Say I have a disconnected electrical cable dug into the ground. I need to
trace the cable to find out its route and where it ends.

I wonder if it is possible to inject a signal from a signal generator
between one of this cable's conductors and earth and walk away with a
metal detector to trace the cable.

Why would a metal conductor be any more "detectable" with a signal on it
than without using a metal detector?

A metal detector won't work worth a damn if there's six inches of material
on top of it. It won't do what you want it to do.

What you want is a commercial cable detector. The good ones have a mode
which detects 60Hz AC (or 50Hz depending on where you live) so you could
just energize the cable and detect it with the detector. If you can't power
it up, there's a mode which uses a transmitter to put an RF signal on the
line which is then detected. I don't know if you can rent them, but any
decent-sized excavation company will have one as will most municipal public
works yards. They all read depths as well, and I've found them good to
deeper than four feet, depending on the ground composition up to 6'.

 

[Bob F]

Hi,

Say I have a disconnected electrical cable dug into the ground. I need to
trace the cable to find out its route and where it ends.

I wonder if it is possible to inject a signal from a signal generator between
one of this cable's conductors and earth and walk away with a metal detector
to trace the cable.

Has anyone any experience or knowledge on this to share, and if yes, how deep
in the earth will the detector be able to trace the cable?

I had some luck using an AM radio and a signal generator that imposed an audio
tone on a RF signal in the AM band in tracking a break in a buried AC line.
(Power off) It gave me a fair idea of the route of the cable, and a hint of the
break location. Adjust the signal and radio volumes for minimum hearable signal
for more accuracy. The other hint I got was by using my DVM to measure voltage
or current from a probe stuck in the ground to a ground reference with the AC
power to the wire turned on. Where a wire has failed, there is a significant
leakage which can be picked up with the meter.