Replace or use?

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ptonsparky

ptonsparky

Tom
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
EC - retired
megging.jpg

This is 1/4 mile of 4/0 4/0 4/0 2/0 Al direct bury in sand. One of those hots had two faults within 4' of each other that we repaired yesterday and has a third we located yesterday. Those were located from the West end.
L1 & L3 faults were located this morning about 6' from each other and were located from the East end.

While the voltage does come up we consider it all as failed, even the neutral though we may not be able to locate that fault.

Good wire registers in the Giga ohm range. These had a megger applied for 5 minutes each.

Just an example.
 
Is this newer cable or is it kind of on the old side?

I know the power companies have had problems with some of the older direct bury and eventually found it cheaper to replace than to keep repairing it.
 
Did the two faults you repaired look like obvious damage in those two specific spots, or non-specific degradation?

You might ask the owners how they feel about an expensive permanent repair vs. the probability of calling you back.
 
growler said:
Is this newer cable or is it kind of on the old side?

I know the power companies have had problems with some of the older direct bury and eventually found it cheaper to replace than to keep repairing it.
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Is older, 20 years or so? ​
This will all be replaced once the water table is lower than the 18" it is now.



Gophers and no conduit are the big killer, that and this field has lost covering. Depth is now 18-24" where it was probably 3'+.
 
drcampbell said:
Did the two faults you repaired look like obvious damage in those two specific spots, or non-specific degradation?

You might ask the owners how they feel about an expensive permanent repair vs. the probability of calling you back.
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AA0F22AC-1DEF-485A-A26B-887E667F51A1.jpg

These are are the first two faults with a good splice between the two. I know we put one of those repairs in but we would not have put two that close together so there has been another repair since. I suspect these were caused by tillage equipment. That type of splice is not prone to failure.
 
I have one set of thhn in conduit that tested at .01 at 1000vdc last summer. We found the spot where the conduit had been uncovered by cows, conduit broken and full of manure, and wires rubbed through. Repaired the wire (heatshrink and buttsplices, with a conduit clamshell around it). It was a 900' run, was the reason it wasn't just pulled out and replaced.

After repair, the wire still tested low, 0.9 at 1000vdc. Fault finder wouldn't locate any other bad spots though.

Still running so far...

In my experience, pretty much ALL direct bury wire after some years on it always tests low, like your readings show.

I don't usually worry about it or push for replacement until we start having fault after fault after fault. Then we work on the customer to let us go back in with Cablecon.
 
Cow said:
I have one set of thhn in conduit that tested at .01 at 1000vdc last summer. We found the spot where the conduit had been uncovered by cows, conduit broken and full of manure, and wires rubbed through. Repaired the wire (heatshrink and buttsplices, with a conduit clamshell around it). It was a 900' run, was the reason it wasn't just pulled out and replaced.

After repair, the wire still tested low, 0.9 at 1000vdc. Fault finder wouldn't locate any other bad spots though.

Still running so far...

In my experience, pretty much ALL direct bury wire after some years on it always tests low, like your readings show.

I don't usually worry about it or push for replacement until we start having fault after fault after fault. Then we work on the customer to let us go back in with Cablecon.
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I’ve lucked a few times and found a ground fault inside a pvc conduit but not enough times to say I’m successful.

Potatoes on this quarter. They will not wait for it to fail completely especially with three more spots located. Too much money involved.

I don’t have the equipment for Cablecon and a nearby Pivot dealer is the only one close that sells it. They bring in a good sized excavator.
 
ptonsparky said:
I’ve lucked a few times and found a ground fault inside a pvc conduit but not enough times to say I’m successful.

Potatoes on this quarter. They will not wait for it to fail completely especially with three more spots located. Too much money involved.

I don’t have the equipment for Cablecon and a nearby Pivot dealer is the only one close that sells it. They bring in a good sized excavator.
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We have one customer that has 2-3 faults on db wire every year in his circles, some years it's the same circles as the year before. Potatoes too. We can't get him to replace it no matter how many times we try. It's always "after harvest we'll do it....." We haven't replaced one set of wires yet.:happyno:

We do have the equipment to handle cablecon ourselves, but even if we didn't, our local irrigation supply will loan us a spooler that can be set on a trailer with the cablecon reel set on it.

Then all you have to do is drag it out with a pickup (if that's all you have) and then go back and toss it over the side into the ditch. Or talk the digger into using his excavator to drag it out for you.

Years ago, they used to do direct bury all the time around here. Then they figured it it needed to be in conduit so it lasted longer. Now everyone just uses cablecon because it's reasonable priced and fast.
 
Cow said:
https://youtu.be/L9723DHTBNk
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ptonsparky said:
It’s a very heavy black plastic? pipe with conductors in it. Typical is a 1500 foot spool. It can be plowed in like sprinkler pipe or via trencher/backhoe. Really tough stuff.
https://www.duraline.com/sites/default/files/downloads/adt_cic_5.pdf
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Thanks!
Never seen that around here. One of the POCOs uses a flex conduit in trenches, then feeds/pulls the conductors in, but haven't seen any with conductors already installed.
 
Little Bill said:
Thanks!
Never seen that around here. One of the POCOs uses a flex conduit in trenches, then feeds/pulls the conductors in, but haven't seen any with conductors already installed.
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The conduit you mentioned is probably HDPE. Does it come on huge reels? It isn't really all that flexible, Certainly not like LTNM flex but for utility work it flexes enough for what is needed, works great for directional boring applications or even to be plowed in, just pull off the reel as you progress instead of laying out ahead of time.
 
kwired said:
The conduit you mentioned is probably HDPE. Does it come on huge reels? It isn't really all that flexible, Certainly not like LTNM flex but for utility work it flexes enough for what is needed, works great for directional boring applications or even to be plowed in, just pull off the reel as you progress instead of laying out ahead of time.
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It is on reels, but IMO is flexible. It is corrugated and flexes through turns in trenches with ease. It looks like gutter drain/run-off pipe. Or a huge black "Smurf Tube":)
 
Little Bill said:
It is on reels, but IMO is flexible. It is corrugated and flexes through turns in trenches with ease. It looks like gutter drain/run-off pipe. Or a huge black "Smurf Tube":)
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Never seen any of that, sounds like is designed for more flexibility though. In theory conductors should pull easier also, with corrugations there is less surface contact between raceway walls and the conductor.
 
kwired said:
Never seen any of that, sounds like is designed for more flexibility though. In theory conductors should pull easier also, with corrugations there is less surface contact between raceway walls and the conductor.
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Most of the time they just push the conductors in, only seen them need a man at the other end once.
 
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