Locating a fault in a buried phone line

W

WD40

Member
Location
Philly
Occupation
Electrician
Hey gang this may not be the right group to ask but I am not online much so I figured I'd try,
I am looking for any tips tricks or tools how to locate a fault or buried splice box in a buried phone/data line besides a tone tracer?
They gave me a Ideal Linkmaster Pro that measures the slight capacitance of the cable and gives a length estimate.
There were two buildings connected by a shielded cable, and I mean shielded its almost like MC with a black plastic outer layer.
The innner wires are in some kinda grease.
The cables are typically spliced in one of those green above ground phone splice boxes you see about 6X6 X 2 ft tall.
Well the splice box gone and I got a cable at each building but can't find the lost splice in the middle.
Its about 800' each direction.
One cable measures OK, I actually get 800 some odd feet, and says all pairs open, the other gives bizarre readings, the length is counting up rapidly then it says "t/r network?"
Its a older tool but fresh batteries, I don't think there is any way the other cable is connected to a phone network, its a campus system.
Thanks in advance for any suggestions.
 
CoolWill said:
Time domain reflectometer?
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Unless you’ve had practice and the are better than what I had nowadays, +- 10% is a shot in the dark.

Hillybily1 has a good start. Next step is adding an actual fault locator. The one I had was $400 40 years ago. The make better now and they are good investment if you are interested in expanding your service. Otherwise, find a local contractor that’s already set up for it.
 
WD40 said:
There were two buildings connected by a shielded cable, and I mean shielded its almost like MC with a black plastic outer layer.
The innner wires are in some kinda grease.
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Ahh you young'uns. That's Bell System buried service wire. Used to connect the house with that dial phone on the wall.

Fault locator is what you need.

-Hal
 
zbang said:
One trick- do not connect the locator between both wires, short them and put the locator from there to a decent ground. I've used an old-style toner and pick-up to find lines, although not out to 800'. Worth a try if you have the devices, and anyone doing LV should.
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Yeah, it tends to cancel or reduce the signal strength.
 
Dynatel 573A.
I use it for UG faults in electric lines also.
Power lines for wells in particular.
Much easier than digging and hoping, checking voltage.
 
Thanks everyone for the suggestions turns out this is the right group to ask!

hbiss said:
Actually, make use of that copper shield and connect to that and ground.

-Hal
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Hal yes thanks I did disconnect the cable including its shield from the lighting arrestor where it enters the building then connected it to the red wire from my tone tracer, the connected the black from my tone tracer to ground. I tried a few combinations of pairs wt/blue orange/wt and shorted pairs also and nothing.
I did find a splice vault about 1/2 way and just to see if I could get tone at 400' only could on the pairs outside of the shield nothing off the shield itself when I tested that.
I'll look into renting or getting one of these more powerful locators.
Thanks everyone
--Ronny
 
WD40 said:
Thanks everyone for the suggestions turns out this is the right group to ask!


Hal yes thanks I did disconnect the cable including its shield from the lighting arrestor where it enters the building then connected it to the red wire from my tone tracer, the connected the black from my tone tracer to ground. I tried a few combinations of pairs wt/blue orange/wt and shorted pairs also and nothing.
I did find a splice vault about 1/2 way and just to see if I could get tone at 400' only could on the pairs outside of the shield nothing off the shield itself when I tested that.
I'll look into renting or getting one of these more powerful locators.
Thanks everyone
--Ronny
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When the utility (or their contracted locating company) comes out to mark lines when people use the one call locating service that is the kind of locator they typically will use. With the type of cable you have they hook their transmitter to the cable shield and that is what they are locating.

If using such a locator and there has been a break in the cable there likely is going to be signal loss beyond the break. You may not know precise location of break but will know fairly close to where it may be. If you have a locator that also has fault detection probe, you generally can be very precise with detecting the location of the break. They can be a little tricky and experience does help when it comes to learning all the quirks of using one of these. There may be some more modern ones than I am used to using that maybe aren't as tricky, IDK. I have had a hard time locating faults in unusually dry soil before. I learned (the hard way) long time ago that if soil is really dry and I am having difficulty in determining where the problem is that watering the soil for a couple hours in the suspected area will almost always turn into being able to find precise location rather quickly afterwards. The return probe on the unit I have detects the leakage from the cable you are tracing, dry soil doesn't conduct as well and makes it harder to detect that precise location.
 
hbiss said:
Have you looked at the price for that? Depending on the options $8 to $10K. Still, Dynatel was always the gold standard for utility companies.

-Hal
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Not the 573A- you're looking at the wrong model.

It's old. I bought two off eBay for $200 each, and both work.
 
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