Any Ideas?

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JohnE

JohnE

Senior Member
Location
Milford, MA
Here's the situation: 100 amp underground service from a pole. 2 Years old. In 2" pvc. 50' pole to building. Lost neutral between pole and meter. Can't pull existing wires out to install new ones apparantly due to ice in conduit.

Any thoughts on thawing?

Any thoughts that broken conductor could be from ice? I pulled this through myself 2 years ago, so I know conductor was not damaged when it was installed. It was backfilled properly, because I was there to see it. I can't imagine what could cause the break in the neutral.

Typically the utility overlaps our riser pipe at the pole with a sort of plastic half conduit and uses some sort of duct seal to keep out water. On this one, they didn't overlap it so it seems water could have been running in. Actually seems lke they used a smaller half conduit since it was 100 amp which wouldn't overlap the 2".

Any thoughts will be appreciated.
 
Familiar with what we of the northern decendents call a thaw bow? Basically a glorified small welder. Put some load on the wires so as to get some heat going in the pipe, and hopefully pull them out then.

Also another trick, that can be combined with the above, if any air will pass through the pipes, put a vacuum on one end sucking, at the other end, another one, blowing.

Barring these simple tricks...it sounds like backhoe country if you have to install in UG.


edit: 40 + years in Alaska.
 
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cleanairgardening_1933_4136296


I've used this to unfreeze ropes frozen in conduits, but the ice was right at the 90 degree, all 3" of it... :grin:
 
How are you sure that the nuetral is gone, I mean was the nuetral verified still connected at the top of the pole? Seems odd that it broke in a conduit underground. Maybe someone did some digging(broke) in the area and thats why you can't pull out conductors. 50' is not too far, How far can a snake be sent in from each end. Maybe some sort of Windshield deicer and a combination of snake(1/4") can break it up. Assuming the deicer is compatible w/pvc of course.

Tom :confused:
 
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j_erickson said:
Here's the situation: 100 amp underground service from a pole. 2 Years old. In 2" pvc. 50' pole to building. Lost neutral between pole and meter. Can't pull existing wires out to install new ones apparantly due to ice in conduit.
Click to expand...

I may be wrong but if you lost the neutral it seems to me that there may be a break in the pipe and thus a break in the wire. I never heard of ice breaking a neutral but I haven't heard of lots of things.
 
I like Rocky's idea with the electric heating as there's no way I'd pour corrosive agents into a conduit- especially if the neutral has already beed "eaten"

Before I did much else, I'd actually try to measure the resistance of the neutral wire in place- sounds like you know it was good- this wasn't come kind of alum SE cable was it?
 
What is the frost line in MA? Here we bury our service lateral 30" deep so nothing is going to freeze that deep before the next ice age.

You may only have a little ice at each end of the pipe. I would dig it out at the ends and replace. You should be able to tell if there is ice in the pipe by seeing how deep the soil is frozen.

Have Fun. I think I'll go lay in the sun.
 
Davis9 said:
How are you sure that the nuetral is gone, I mean was the nuetral verified still connected at the top of the pole? Seems odd that it broke in a conduit underground. Maybe someone did some digging(broke) in the area and thats why you can't pull out conductors. 50' is not too far, How far can a snake be sent in from each end. Maybe some sort of Windshield deicer and a combination of snake(1/4") can break it up. Assuming the deicer is compatible w/pvc of course.

Tom :confused:
Click to expand...

Yep, nuetral verified at top of pole. There's been no digging. And we didn't try a snake yet. It was about 1 degree this morning. Problem arose yesterday and wind chill was below 0 all day. Fortunately there is no water in this building.

Again, I personally installed the pipe and pulled the wire. Direct burial "triplex", "URD", USE or whatever you want to call it. I think Iwas there for the backfilling, but don't exactly remember.

I guess it's possible that the reason I can't pull out the old wire is that there is a break in the conduit, and hence the neutral break. (How, I don't know) I just find it so unlikely being such a short run in a trench that was prepared properly and is fairly new.

I'm leaning towards Stickboy's idea. Thanks Stick.

Thanks to everyone for the replies. And keep them coming if anyone has anthing else to add.
 
growler said:
What is the frost line in MA? Here we bury our service lateral 30" deep so nothing is going to freeze that deep before the next ice age.

You may only have a little ice at each end of the pipe. I would dig it out at the ends and replace. You should be able to tell if there is ice in the pipe by seeing how deep the soil is frozen.

Have Fun. I think I'll go lay in the sun.
Click to expand...

Frost line is 4', though it will rarely freeze that deep. My thought is that the cold is running right through the conduit since top is open, so it doesn't really matter how deep the pipe is.

Again, I'm at a loss as to how this nuetral could have failed. It absolutely was not damaged while making the pull. Again only 50' 2/3 through a 2" pipe.

The other possibilities all seem not likely, too. Ground movement broke pipe and damaged wire. Something during backfilling damages pipe and wire. Rodent?? Very unlikely too, no?

I'll let you all know when I figure it out.

And have fun in the sun.:mad: I'm jealous.
 
stickboy1375 said:
Also I would install a snake at both ends to see where the problem starts and stops...
Click to expand...

I will. But not today. Fortunately this is a large detached garage with office and hobby space, but nothing where freezing will cause damage. Inconvenience only.
 
j_erickson said:
Again, I personally installed the pipe and pulled the wire. Direct burial "triplex", "URD", USE or whatever you want to call it.

Thanks to everyone for the replies. And keep them coming if anyone has anthing else to add.
Click to expand...


There was something in a thread here a little while ago (2-3wks?) about aluminum neutral/braid turning to mush or toothpaste underground...

"Underground feeder for detached garage"
here is the title of that post
edited to add above
 
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RayS said:
There was something in a thread here a little while ago (2-3wks?) about aluminum neutral/braid turning to mush or toothpaste underground...

"Underground feeder for detached garage"
here is the title of that post
edited to add above
Click to expand...

It shouldn't turn to mush. If anything, the extreme cold can make the wires more brittle, and aluminum is already more brittle than copper.
 
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