Non Contact tester on amp probe vs. earth

[Buck Parrish]

Trying to find a bad spot in the urd #2 AL direct burial cable. When I touched the NC Tester to the cable in the ground. It would not alert to power being present. This is one of the good NC Testers made in to the meter / amp probe.
We checked the cable as it went in to the conduit and it alerted. (beep beep)

I'm thinking the voltage dissipated through the ground some how in the bad spot.
Since the customer was there I went ahead and uncovered it about 10 ft back to the meter. The uncovered part would alert as voltage present. But not when it was in contact with the ground.
The bad spot must be about 40-50 ft out where a truck got stuck. I never did find it. But I didn't install it, either.
It will have to be dug up.
My question is. If you have 240 - 120 on each line will that dissipate through the earth from the broke or bare spot? Or will the electrical wave the NC Tester requires to be effective, will that wave dissipate through the ground?

 

[PetrosA]

Trying to find a bad spot in the urd #2 AL direct burial cable. When I touched the NC Tester to the cable in the ground. It would not alert to power being present. This is one of the good NC Testers made in to the meter / amp probe.
We checked the cable as it went in to the conduit and it alerted. (beep beep)

I'm thinking the voltage dissipated through the ground some how in the bad spot.
Since the customer was there I went ahead and uncovered it about 10 ft back to the meter. The uncovered part would alert as voltage present. But not when it was in contact with the ground.
The bad spot must be about 40-50 ft out where a truck got stuck. I never did find it. But I didn't install it, either.
It will have to be dug up.
My question is. If you have 240 - 120 on each line will that dissipate through the earth from the broke or bare spot? Or will the electrical wave the NC Tester requires to be effective, will that wave dissipate through the ground?

The problem with using a NC tester on something like this (If I'm understanding you right, you're talking about something like a pencil tester built into a clamp meter) is that if there's a break underground, the earth around the break could be energized which will raise your potential to almost that of the wire, which will render the NC tester useless. It's the same thing you see if you put your hand around a hot wire in a panel, and try and test another hot wire fed off the same leg. The tester may not beep.

 

[kwired]

Non contact testers work off of capacitive coupling. Chances are the more moisture there is in the soil the poorer the capacitor is and you will not have results that trigger the device.

If you are willing to pay the mileage I can likely find your break for you without digging anywhere but near the problem. :happyyes:

You need a fault locator.