Have a private residential 200A underground service that lost a leg between the transformer and meter. The service is over 25 years old and the length of the triplex is between 200 and 300 feet. The POCO for that area simply said "not us, have fun". Anyone have any tricks for finding a break underground? A POCO from another area is going to return a favor and try to help us out with a new tool they recently got but have not had success with it on the one instance they tried it(they don't know how to work it yet I'm sure)
Bad underground service
- Thread starter benmin
- Start date
- Status
mdshunk
Senior Member
- Location
- Right here.
A thumper is generally the tool used to locate underground breaks in URD.
charlie
Senior Member
- Location
- Indianapolis
A thumper will over stress 600V cable. He is discussing new electronic equipment that will determine where the open point is located without damaging the cable in the process. :smile:mdshunk said:
mdshunk
Senior Member
- Location
- Right here.
Maybe, but they use it here every day for buried secondary. A TDR would be better.charlie said:
- Location
- Massachusetts
nakulak said:
I was thinking the same thing, I wanted to ask if anyone had any experience about that as well.
If you do find it and fix it will you be back next year for another repair?
ptonsparky
Tom
- Occupation
- EC - retired
I use an Ideal 62-142 that is about 15 years old. I beleive it was made by Progressive and about $1200 back then. I am sure there are others like it. The Ideal & those similar will put you within inches, even on 1/4 mile run. No damage to the cable. A cable locator is also helpful but not always needed for short runs. A TDR will work,(I have a new to me one on the way) but I wouldn't recommend it for first time out unless you have played with one a lot before hand.
Find the first fault, dig it up, search for a second, then repeat before you make any repairs. More than two or three splices in that run will warrant a new underground. Consider pvc conduit or DB if you are allowed by local AHJ.
Find the first fault, dig it up, search for a second, then repeat before you make any repairs. More than two or three splices in that run will warrant a new underground. Consider pvc conduit or DB if you are allowed by local AHJ.
nakulak said:
First I would like to find the break and what caused it. If it is deteriorating insulation allowing the AL to corrode and cause the break than YES we rip everything up and replace the wire. If it is a situation where maybe some ledge cut into the wire causing it to fail than a patch would be OK.
I don't know if the URD is in pipe or not so attempting to find the problem and fixing it is my high hopes right now. If I have to run a new service it will be under a road, driveway and 50' of wooded area.
ptonsparky
Tom
- Occupation
- EC - retired
Subsequent repairs are most likely caused by the guy that just dug up the last one. We clean back along the cable by hand and check for any damage that we may have done. Dents, nicks or abbrasions are cleaned, painted with scotchkote, maybe wrapped with 33 and painted again.
Crimp connections, heat shrinks or gel filled kits are my favorite.
Crimp connections, heat shrinks or gel filled kits are my favorite.
ptonsparky
Tom
- Occupation
- EC - retired
Oh, I see you are from Maine, good luck with rocks, we don't have many in this area. Use clean backfill.
ptonsparky said:
Ledge, rocks, public sewr, blacktop, woods and newly installed landscaping are against me.. In my favor is a adjoining POCO with a new tool (that they don't know how to use)
Do you know a website that explains the operation and fundamentals of the testing device from your previous post?
Marc, what is a thumper?
ptonsparky
Tom
- Occupation
- EC - retired
New landscaping just stands out and screams "Look here 1st!!"
No, I don't know of a website. Not reallly much to it. A signal or tone generator is connected to the faulted wire and earth via a probe. A receiver connected to two probes on an "n" shape handle picks up the signal pulse as you stick the probes into the ground. A little analog meter flicks in the direction of the fault. Basically saying "Go this way stupid." Once past the fault it tells you to "Back up stupid" Moving the handle until there is no deflection in the meter tells you to "Dig here". Conduit makes things much harder.
You must have all ends of the cables disconnected from line & load.
No, I don't know of a website. Not reallly much to it. A signal or tone generator is connected to the faulted wire and earth via a probe. A receiver connected to two probes on an "n" shape handle picks up the signal pulse as you stick the probes into the ground. A little analog meter flicks in the direction of the fault. Basically saying "Go this way stupid." Once past the fault it tells you to "Back up stupid" Moving the handle until there is no deflection in the meter tells you to "Dig here". Conduit makes things much harder.
You must have all ends of the cables disconnected from line & load.
charlie
Senior Member
- Location
- Indianapolis
It is a device for putting a high voltage on the cable for a very short duration and walking out to hear and feel where it "thumps". These used to be used on medium voltage cables but were sometimes used on 600 volt cables. We do not use thumpers at all any more due to the danger and damage factors. :smile:benmin said:
76nemo
Senior Member
- Location
- Ogdensburg, NY
Danger and damage factors, eh? Thumpers are truly impressive. Here's an old thread I posted about a fatality using a thumper, and this wasn't even in the field.
Click on the link I gave in the first post.
http://forums.mikeholt.com/showthread.php?t=101395
Click on the link I gave in the first post.
http://forums.mikeholt.com/showthread.php?t=101395
mdshunk
Senior Member
- Location
- Right here.
Oh yeah. You can hear the thud, and you can definitely feel it. You actually find the fault by walking around and the "locater" is the soles of your boots.mxslick said:
jrannis
Senior Member
- Location
- Fort Lauderdale/ Miami
Just replace it!
One day job.
Nice and new no problems.
I dont think it would benefit the HO to fix it and then have another problem in a year
One day job.
Nice and new no problems.
I dont think it would benefit the HO to fix it and then have another problem in a year
POCO kept stalling and out of desperation I tried to locate the break with testing items on my van. I found the break in the lost leg with a ideal wire finder kit that I use to find wires in walls. It was under a small tree they planted 2 monthes ago. It is obvious that the back hoe used to plant it did the damage.
Tree gone! service repaired. Life is good
Tree gone! service repaired. Life is good
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