# Frozen Underground Conduits



## Dennis Alwon (May 9, 2009)

JAB said:


> Does anyone have an idea for replacing damaged conductors that are frozen in an underground conduit. i would like to replace them before the spring thaw. The conduit is 3/4" PVC with five #10 stranded.


Pour some antifreeze into the pipe????


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## RePhase277 (Feb 5, 2008)

JAB said:


> Does anyone have an idea for replacing damaged conductors that are frozen in an underground conduit. i would like to replace them before the spring thaw. The conduit is 3/4" PVC with five #10 stranded.


What damaged them? The ice? If so, then won't that just happen again with new conductors?

But as for getting them out, maybe a couple are still intact and you could short them at one end, and apply a heavy load through them, enough to heat the conductors and melt the ice.


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## BDB (Jul 9, 2008)

InPhase277 said:


> maybe a couple are still intact and you could short them at one end, and apply a heavy load through them, enough to heat the conductors and melt the ice.


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## RePhase277 (Feb 5, 2008)

BDB said:


>


What's the problem? A couple of #10s with say 40 A running through them would be enough to heat the conductors, but not damage them. I think something like a battery charger or welder would do pretty good.


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## 480sparky (Sep 20, 2007)

1. *Why* do you need to replace them?

2. If you need to replace them, why not do what you need to do in order to remove the old conductors, whether or not they get trashed. If they do, install new ones. Sounds like you're trying to spend a dollar to save a dime.


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## JAB (Feb 2, 2010)

JAB said:


> Does anyone have an idea for replacing damaged conductors that are frozen in an underground conduit. i would like to replace them before the spring thaw. The conduit is 3/4" PVC with five #10 stranded.


The insulation was worn through due to the lack of a service loop in a box and a u-pull pulled tight on the connectors. Using Ohm's law and a 12v battery I should be able to predict the current flow through the conductors. I can adjust the resistance by splicing lengths together for increased distance in 25 foot increments up to 125 feet. If I have enough resistance to place 50 amps DC on the conductors they should heat up. I would need one large battery. :blink: -a welder now we're talking.


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## RePhase277 (Feb 5, 2008)

JAB said:


> If I have enough resistance to place 50 amps DC on the conductors they should heat up. I would need one large battery. :blink:


A 12 V car battery can easily deliver 50 A. Hell, in a dead short it can deliver almost 1000 A. But I would suggest using a battery charger or welder with adjustable amp settings.


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## RIVETER (Sep 26, 2009)

*frozen*



JAB said:


> Does anyone have an idea for replacing damaged conductors that are frozen in an underground conduit. i would like to replace them before the spring thaw. The conduit is 3/4" PVC with five #10 stranded.


Do you know how deep the conduit is buried? By the time you read all of the answers you could dig a ditch and place the conduit deeper and eliminate the problem completely. I would imagine in Wisconsin that would be at least two feet deep.


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## Mike_586 (Mar 24, 2009)

InPhase277 said:


> What's the problem? A couple of #10s with say 40 A running through them would be enough to heat the conductors, but not damage them. I think something like a battery charger or welder would do pretty good.


Applying a heavy load is precisely how northern cities unfreezes frozen water lines, and something similar could easily be done with wires frozen in a pipe by someone who knows what they're doing.

That said, simply replacing the conductors will only be a band-aid solution.


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## drsparky (Nov 13, 2008)

I have been on sites with a half dozen of these running 24/7. If done properly they will thaw up to 10' deep.


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## RIVETER (Sep 26, 2009)

*frozen*



drsparky said:


> I have been on sites with a half dozen of these running 24/7. If done properly they will thaw up to 10' deep.


The ground surely cannot freeze that deeply...can it? I'm just asking.


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## drsparky (Nov 13, 2008)

4 to 5 feet in the north, depends on the cover.


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## RIVETER (Sep 26, 2009)

*frozen*



drsparky said:


> 4 to 5 feet in the north, depends on the cover.


Man...I bet that thrills the geothermal guys.


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