In Need of tone genertor/cable tracer...

[Tim R]

On Saturday, August 28, 2021 at 10:45:55 AM UTC-4, Peter W. wrote:

How far would that read?

Power to my shed is underground, and I need to do some digging to fix some drainage. it would really help to know exactly where the 220 is routed. I suspect it\'s in the 6 to 8 inch deep range, given the slope, hopefully a little deeper some places. .
That is a low-voltage device, not for power lines. Underground cable tracers are very different animals, and substantially more costly. if all you need to do is 6-8\" or so, borrow a decent metal detector and trace that way. You will be within inches - dig out that area by hand. In any case, do call your local One-Call service, it is free and often you have no idea of what may be down there. And they DO have the costly devices.
Peter Wieck
Melrose Park, PA

Sorry to confuse the thread with two different applications.

My thought was that if a signal generator can put a tone on my line, I could shut the breaker in the house, leave the shed dead, put the signal on the shed end, and trace the wire back to the house. It seems like that should work if the wire is 6 inches down, maybe not if it\'s 18. Or maybe those tone generators don\'t work at all underground, I\'ve never tried it. I did borrow a metal detector some years ago but got inconclusive results. Maybe i could rent a better one from a big box or electrical place. I\'m sure the there is no conduit, I hit a wire some years back that looked like UFB, so I know where at least one piece of it is, and it wasn\'t where I expected it.

 

[Phil Allison]

timoth...@gmail.com wrote:
----------------------------------------------------

Sorry to confuse the thread with two different applications.

My thought was that if a signal generator can put a tone on my line, I could shut the breaker in the house, leave the shed dead, put the signal on the shed end, and trace the wire back to the house.

** LOL - that is NOT what tone generators do !!

Their job is to facilitate cable *identification* where multiples exist.

OTOH a buried mains cable reveals it *location * by the magnetic field created by all the damn AC current flowing in it !!



...... Phil

 

[Phil Allison]

timoth...@gmail.com wrote:
----------------------------------------------------

Sorry to confuse the thread with two different applications.

My thought was that if a signal generator can put a tone on my line, I could shut the breaker in the house, leave the shed dead, put the signal on the shed end, and trace the wire back to the house.

** LOL - that is NOT what tone generators do !!

Their job is to facilitate cable *identification* where multiples exist.

OTOH a buried mains cable reveals it *location * by the magnetic field created by all the damn AC current flowing in it !!



...... Phil

 

[Jeff Liebermann]

On Sat, 28 Aug 2021 18:03:03 -0700 (PDT), Phil Allison
<pallison49@gmail.com> wrote:

timoth...@gmail.com wrote:
----------------------------------------------------

Sorry to confuse the thread with two different applications.

My thought was that if a signal generator can put a tone on my line, I could shut the breaker in the house, leave the shed dead, put the signal on the shed end, and trace the wire back to the house.

** LOL - that is NOT what tone generators do !!

Their job is to facilitate cable *identification* where multiples exist.

OTOH a buried mains cable reveals it *location * by the magnetic field created by all the damn AC current flowing in it !!

..... Phil

This might help:
\"Buyers Guide To Cable Locators\"
<https://www.tigersupplies.com/LC/Buyers-Guide-To-Cable-Locators-.aspx>
There are some that work at 60 Hz, but most use higher frequencies.
There\'s just too much interference at 60 Hz. Also, the higher the
frequency, the higher the resolution, which translates in a more
accurately located cable.
\"Successful Locating Depends on Knowing Which Frequency to Use\"
<https://www.utilityproducts.com/tools-supplies/article/16003409/successful-locating-depends-on-knowing-which-frequency-to-use>

More than you probably wanted to know:
\"The theory of buried cable and pipe location\"
<https://www.radiodetection.com/sites/default/files/Theory-Buried-pipe-manual-V10.pdf>

For what it\'s worth, I used an RF signal generator to locate buried
cables. The trick is to build a series resonant RF transformer
(ferrite torroid) for your choice of RF frequency. I picked the 160
meter ham band (1.8 to 2.0Mhz), much to the irritation of the local
ham radio operators. The generator was set to about 70% AM modulation
at 1KHz to produce a detectable tone. The resonant transformer will
pass the RF but not the 60 Hz line frequency, thus insuring that there
is some hope that the RF generator will survive the exercise. It also
provides an ungrounded connection to the power line, which should
prevent some types accidental electrocutions.

The difficult part was designing and building a suitable pickup coil.
I finally resorted to a ferrite rod (loopstick) antenna similar to
what is found in many SW (short wave) receivers.
<https://www.google.com/search?q=loopstick+antenna&tbm=isch>
Such a loopstick antenna a nice deep null in the antenna pattern off
the end of the rod, which makes direction finding possible.

If I were to design a cable locator today, the system would be quite
different. The problem with using only one frequency is that various
types of dirt attenuate different frequencies differently. Instead of
one frequency, I would use a range of frequencies (spread spectrum),
in the hope that at least one frequency will make it through the dirt
(and interference). That\'s how ground penetrating radar works.
<https://ieeexplore.ieee.org/abstract/document/9381259>

The last time I had to locate some underground wiring, I was lazy and
used an acoustic method. I made a low frequency \"buzzer\" that ran
from compressed air. I shoved the air hose as far up the PVC conduit
as possible and turned on the buzzer. With a 1 HP motor, that might
produce 200 watts of audible buzz, which should be audible at ground
level. I used a stethoscope to locate the buried conduit. It wasn\'t
very precise at locating the conduit, but good enough to provide
clearance for a backhoe trencher.

Good luck.

--
Jeff Liebermann jeffl@cruzio.com
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Jeff Liebermann]

On Sat, 28 Aug 2021 18:03:03 -0700 (PDT), Phil Allison
<pallison49@gmail.com> wrote:

timoth...@gmail.com wrote:
----------------------------------------------------

Sorry to confuse the thread with two different applications.

My thought was that if a signal generator can put a tone on my line, I could shut the breaker in the house, leave the shed dead, put the signal on the shed end, and trace the wire back to the house.

** LOL - that is NOT what tone generators do !!

Their job is to facilitate cable *identification* where multiples exist.

OTOH a buried mains cable reveals it *location * by the magnetic field created by all the damn AC current flowing in it !!

..... Phil

This might help:
\"Buyers Guide To Cable Locators\"
<https://www.tigersupplies.com/LC/Buyers-Guide-To-Cable-Locators-.aspx>
There are some that work at 60 Hz, but most use higher frequencies.
There\'s just too much interference at 60 Hz. Also, the higher the
frequency, the higher the resolution, which translates in a more
accurately located cable.
\"Successful Locating Depends on Knowing Which Frequency to Use\"
<https://www.utilityproducts.com/tools-supplies/article/16003409/successful-locating-depends-on-knowing-which-frequency-to-use>

More than you probably wanted to know:
\"The theory of buried cable and pipe location\"
<https://www.radiodetection.com/sites/default/files/Theory-Buried-pipe-manual-V10.pdf>

For what it\'s worth, I used an RF signal generator to locate buried
cables. The trick is to build a series resonant RF transformer
(ferrite torroid) for your choice of RF frequency. I picked the 160
meter ham band (1.8 to 2.0Mhz), much to the irritation of the local
ham radio operators. The generator was set to about 70% AM modulation
at 1KHz to produce a detectable tone. The resonant transformer will
pass the RF but not the 60 Hz line frequency, thus insuring that there
is some hope that the RF generator will survive the exercise. It also
provides an ungrounded connection to the power line, which should
prevent some types accidental electrocutions.

The difficult part was designing and building a suitable pickup coil.
I finally resorted to a ferrite rod (loopstick) antenna similar to
what is found in many SW (short wave) receivers.
<https://www.google.com/search?q=loopstick+antenna&tbm=isch>
Such a loopstick antenna a nice deep null in the antenna pattern off
the end of the rod, which makes direction finding possible.

If I were to design a cable locator today, the system would be quite
different. The problem with using only one frequency is that various
types of dirt attenuate different frequencies differently. Instead of
one frequency, I would use a range of frequencies (spread spectrum),
in the hope that at least one frequency will make it through the dirt
(and interference). That\'s how ground penetrating radar works.
<https://ieeexplore.ieee.org/abstract/document/9381259>

The last time I had to locate some underground wiring, I was lazy and
used an acoustic method. I made a low frequency \"buzzer\" that ran
from compressed air. I shoved the air hose as far up the PVC conduit
as possible and turned on the buzzer. With a 1 HP motor, that might
produce 200 watts of audible buzz, which should be audible at ground
level. I used a stethoscope to locate the buried conduit. It wasn\'t
very precise at locating the conduit, but good enough to provide
clearance for a backhoe trencher.

Good luck.

--
Jeff Liebermann jeffl@cruzio.com
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Bob F]

On 8/26/2021 11:30 AM, three_jeeps wrote:

I need to trace some cables (phone catv, ethernet) throughout a house.
An inexpensive tone generator would work but I don\'t have one. Any recommendations for an inexpensive one? or alternatives? I rigged a 1.5V battery holder with alligator clips to be used in conjunction with a modified LED \'probe\' flashlight which will work. Looking for alternative ideas.
I did make a \'break out box\' for the rj45 and rj11 sockets where needed.
Thanks
j

https://www.harborfreight.com/cable-tracker-94181.html

 

[Bob F]

On 8/26/2021 11:30 AM, three_jeeps wrote:

I need to trace some cables (phone catv, ethernet) throughout a house.
An inexpensive tone generator would work but I don\'t have one. Any recommendations for an inexpensive one? or alternatives? I rigged a 1.5V battery holder with alligator clips to be used in conjunction with a modified LED \'probe\' flashlight which will work. Looking for alternative ideas.
I did make a \'break out box\' for the rj45 and rj11 sockets where needed.
Thanks
j

https://www.harborfreight.com/cable-tracker-94181.html

 

[Peter W.]

> https://www.harborfreight.com/cable-tracker-94181.html

Designed for use with telephone lines, alarm cables, computer cables, intercom lines, speaker wires, and thermostat wiring

Do you NOT read for content, or is it that you cannot read at all?

Apples: Low-voltage signal wire inside a structure - where only one end may be identified - and getting to the other is the exercise, and possibly identifying individual conductors within a cable.
Oranges: Line-voltage wiring buried underground - where both ends are identified, but the pathway is not.

Peter WIeck
Melrose Park, PA

 

[Peter W.]

> https://www.harborfreight.com/cable-tracker-94181.html

Designed for use with telephone lines, alarm cables, computer cables, intercom lines, speaker wires, and thermostat wiring

Do you NOT read for content, or is it that you cannot read at all?

Apples: Low-voltage signal wire inside a structure - where only one end may be identified - and getting to the other is the exercise, and possibly identifying individual conductors within a cable.
Oranges: Line-voltage wiring buried underground - where both ends are identified, but the pathway is not.

Peter WIeck
Melrose Park, PA

 

[Tim R]

I had another idea but will read the links about locating cable first.

 

[three_jeeps]

On Saturday, August 28, 2021 at 9:03:05 PM UTC-4, palli...@gmail.com wrote:

timoth...@gmail.com wrote:
----------------------------------------------------
Sorry to confuse the thread with two different applications.

My thought was that if a signal generator can put a tone on my line, I could shut the breaker in the house, leave the shed dead, put the signal on the shed end, and trace the wire back to the house.
** LOL - that is NOT what tone generators do !!

Their job is to facilitate cable *identification* where multiples exist.

OTOH a buried mains cable reveals it *location * by the magnetic field created by all the damn AC current flowing in it !!



..... Phil

Thanks for pointing out the inaccuracy of my post. My task is one of identification.
I just bought an inexpensive one from one of the references. I\'ll use my flashlight arrangement as a backup.
I did learn something from Jeff about cable locators - TY. Will file that away as I may be doing some of that in the future.

J

 

[three_jeeps]

On Saturday, August 28, 2021 at 9:03:05 PM UTC-4, palli...@gmail.com wrote:

timoth...@gmail.com wrote:
----------------------------------------------------
Sorry to confuse the thread with two different applications.

My thought was that if a signal generator can put a tone on my line, I could shut the breaker in the house, leave the shed dead, put the signal on the shed end, and trace the wire back to the house.
** LOL - that is NOT what tone generators do !!

Their job is to facilitate cable *identification* where multiples exist.

OTOH a buried mains cable reveals it *location * by the magnetic field created by all the damn AC current flowing in it !!



..... Phil

Thanks for pointing out the inaccuracy of my post. My task is one of identification.
I just bought an inexpensive one from one of the references. I\'ll use my flashlight arrangement as a backup.
I did learn something from Jeff about cable locators - TY. Will file that away as I may be doing some of that in the future.

J

 

[three_jeeps]

On Saturday, August 28, 2021 at 9:03:05 PM UTC-4, palli...@gmail.com wrote:

timoth...@gmail.com wrote:
----------------------------------------------------
Sorry to confuse the thread with two different applications.

My thought was that if a signal generator can put a tone on my line, I could shut the breaker in the house, leave the shed dead, put the signal on the shed end, and trace the wire back to the house.
** LOL - that is NOT what tone generators do !!

Their job is to facilitate cable *identification* where multiples exist.

OTOH a buried mains cable reveals it *location * by the magnetic field created by all the damn AC current flowing in it !!



..... Phil

Thanks for pointing out the inaccuracy of my post. My task is one of identification.
I just bought an inexpensive one from one of the references. I\'ll use my flashlight arrangement as a backup.
I did learn something from Jeff about cable locators - TY. Will file that away as I may be doing some of that in the future.

J

 

[Tim R]

On Monday, August 30, 2021 at 8:47:01 PM UTC-4, three_jeeps wrote:

On Saturday, August 28, 2021 at 9:03:05 PM UTC-4, palli...@gmail.com wrote:
timoth...@gmail.com wrote:
----------------------------------------------------
Sorry to confuse the thread with two different applications.

My thought was that if a signal generator can put a tone on my line, I could shut the breaker in the house, leave the shed dead, put the signal on the shed end, and trace the wire back to the house.
** LOL - that is NOT what tone generators do !!

Their job is to facilitate cable *identification* where multiples exist..

OTOH a buried mains cable reveals it *location * by the magnetic field created by all the damn AC current flowing in it !!



..... Phil
Thanks for pointing out the inaccuracy of my post. My task is one of identification.
I just bought an inexpensive one from one of the references. I\'ll use my flashlight arrangement as a backup.
I did learn something from Jeff about cable locators - TY. Will file that away as I may be doing some of that in the future.

J

Yes, I agree, thanks much for that link. There was much in there that had not occurred to me, especially about other current sources coupling to underground lines. It seems just possible though maybe not likely that I can find an AM radio or other device that will buzz a bit close to the line, and that the effect is larger if it\'s carrying a good current, worth a try anyway. I\'m pretty sure my line is shallow and maybe even DIY.

 

[Tim R]

On Monday, August 30, 2021 at 8:47:01 PM UTC-4, three_jeeps wrote:

On Saturday, August 28, 2021 at 9:03:05 PM UTC-4, palli...@gmail.com wrote:
timoth...@gmail.com wrote:
----------------------------------------------------
Sorry to confuse the thread with two different applications.

My thought was that if a signal generator can put a tone on my line, I could shut the breaker in the house, leave the shed dead, put the signal on the shed end, and trace the wire back to the house.
** LOL - that is NOT what tone generators do !!

Their job is to facilitate cable *identification* where multiples exist..

OTOH a buried mains cable reveals it *location * by the magnetic field created by all the damn AC current flowing in it !!



..... Phil
Thanks for pointing out the inaccuracy of my post. My task is one of identification.
I just bought an inexpensive one from one of the references. I\'ll use my flashlight arrangement as a backup.
I did learn something from Jeff about cable locators - TY. Will file that away as I may be doing some of that in the future.

J

Yes, I agree, thanks much for that link. There was much in there that had not occurred to me, especially about other current sources coupling to underground lines. It seems just possible though maybe not likely that I can find an AM radio or other device that will buzz a bit close to the line, and that the effect is larger if it\'s carrying a good current, worth a try anyway. I\'m pretty sure my line is shallow and maybe even DIY.

 

[Peter W.]

> Yes, I agree, thanks much for that link. There was much in there that had not occurred to me, especially about other current sources coupling to underground lines. It seems just possible though maybe not likely that I can find an AM radio or other device that will buzz a bit close to the line, and that the effect is larger if it\'s carrying a good current, worth a try anyway. I\'m pretty sure my line is shallow and maybe even DIY.

This might be possible for an acutely sensitive device - and most AM radios are not that. some basics, and a few assumptions first:

a) The underground cable in question is either UF cable, or several conductors run in some sort of conduit. If the conduit is metallic, or otherwise shielded, the AM radio trick will not work.
b) This cable is in the US, and so is single-phase, 240 V, and consists of two (2) hots, one (1) neutral and one (1) ground per present code. I will not speculate on Euro/Aussie codes or cables. We do know also from Phil that electricity has unusual properties down under.

So, if the goal is to locate the cable so as not to dig through it, proof-of-concept would suggest that if the target radio were to be placed near to say.... an active AC line cord inside, it should buzz. And it should start buzzing within 18\" or more, at least. Given that most ground is at least a little-bit-damp, and so will do some shielding, and the depth is unknown, this margin is needed.

Just a few thoughts - considering that if it were that simple, an underground power cable tracer would be a trivial device vs. their actual cost.

Peter Wieck
Melrose Park, PA

 

[Peter W.]

> Yes, I agree, thanks much for that link. There was much in there that had not occurred to me, especially about other current sources coupling to underground lines. It seems just possible though maybe not likely that I can find an AM radio or other device that will buzz a bit close to the line, and that the effect is larger if it\'s carrying a good current, worth a try anyway. I\'m pretty sure my line is shallow and maybe even DIY.

This might be possible for an acutely sensitive device - and most AM radios are not that. some basics, and a few assumptions first:

a) The underground cable in question is either UF cable, or several conductors run in some sort of conduit. If the conduit is metallic, or otherwise shielded, the AM radio trick will not work.
b) This cable is in the US, and so is single-phase, 240 V, and consists of two (2) hots, one (1) neutral and one (1) ground per present code. I will not speculate on Euro/Aussie codes or cables. We do know also from Phil that electricity has unusual properties down under.

So, if the goal is to locate the cable so as not to dig through it, proof-of-concept would suggest that if the target radio were to be placed near to say.... an active AC line cord inside, it should buzz. And it should start buzzing within 18\" or more, at least. Given that most ground is at least a little-bit-damp, and so will do some shielding, and the depth is unknown, this margin is needed.

Just a few thoughts - considering that if it were that simple, an underground power cable tracer would be a trivial device vs. their actual cost.

Peter Wieck
Melrose Park, PA

 

[Tim R]

On Monday, August 30, 2021 at 8:47:01 PM UTC-4, three_jeeps wrote:

On Saturday, August 28, 2021 at 9:03:05 PM UTC-4, palli...@gmail.com wrote:
timoth...@gmail.com wrote:
----------------------------------------------------
Sorry to confuse the thread with two different applications.

My thought was that if a signal generator can put a tone on my line, I could shut the breaker in the house, leave the shed dead, put the signal on the shed end, and trace the wire back to the house.
** LOL - that is NOT what tone generators do !!

Their job is to facilitate cable *identification* where multiples exist..

OTOH a buried mains cable reveals it *location * by the magnetic field created by all the damn AC current flowing in it !!



..... Phil
Thanks for pointing out the inaccuracy of my post. My task is one of identification.
I just bought an inexpensive one from one of the references. I\'ll use my flashlight arrangement as a backup.
I did learn something from Jeff about cable locators - TY. Will file that away as I may be doing some of that in the future.

J

Yes, I agree, thanks much for that link. There was much in there that had not occurred to me, especially about other current sources coupling to underground lines. It seems just possible though maybe not likely that I can find an AM radio or other device that will buzz a bit close to the line, and that the effect is larger if it\'s carrying a good current, worth a try anyway. I\'m pretty sure my line is shallow and maybe even DIY.

 

[Phil Allison]

timoth...@gmail.com wrote:
======================

Yes, I agree, thanks much for that link. There was much in there that had not occurred to me,
especially about other current sources coupling to underground lines.
It seems just possible though maybe not likely that I can find an AM radio or other device that
will buzz a bit close to the line, and that the effect is larger if it\'s carrying a good current, worth a try anyway.

** It would be a plus to put a triac dimmer controlled load on the end of that cable run.


...... Phil

 

[Phil Allison]

timoth...@gmail.com wrote:
======================

Yes, I agree, thanks much for that link. There was much in there that had not occurred to me,
especially about other current sources coupling to underground lines.
It seems just possible though maybe not likely that I can find an AM radio or other device that
will buzz a bit close to the line, and that the effect is larger if it\'s carrying a good current, worth a try anyway.

** It would be a plus to put a triac dimmer controlled load on the end of that cable run.


...... Phil