te12co2w

Good day to all. I typed in a search for ice in conduit, but found no posts. We are installing engine heater receptacles around the outside of a hotel parking lot. There is a 2" pvc from the mdp to an outside in ground junction box. That conduit has some wires in it now that I thought we would be able to use for pull wires. Those wires are currently feeding 208v parking lot lights. There are not enough wires there now for the receptacles we are putting in. We have found that the wires are frozen in place right under the paved driveway. We can't budge them. I was hoping not to encounter this problem, but we have. My question is this. Has anyone ever dealt with this problem and found a fix? I found some posts in here about concrete in conduit, but not ice. My only idea so far is to try to use a shop vac on blow in the mdp and try to force enough warm air down that pipe to break up the ice. I see problems with that. Maybe the air won't be warm enough. Once the pipe fills with air, no more air will be able to go down the pipe. If it did start to melt the ice, maybe a water dam would develop and block any more warm air. This is Wyoming, 13F below last night and it will get colder. Ground won't thaw until May or June. Earlier if we have a mild winter. Thanks

waco

Spring.

InPhase277

I know this may sound a little nutty, but can you overload some of the conductors in the pipe? Let's say the lights are wired with #10. If you could put the #10 on a 50 A breaker and put a large load on it, then the wire would heat up and melt the ice.

Then again, you may have 100 ft. of ice.

480sparky

Contact a sewer-rooter company.

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John Valdes

How do you know it's ice? "Under driveway" suggests to me a crushed conduit. I am not saying your are wrong, but I would make sure it is ice before doing anything.

TheRick

We have gone this route before...they force steam down the pipe, and then blow out the water after all the ice melts. We have done it with RMC though, not sure how the PVC will like the heat?

Good Luck!

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480sparky

I've had them auger it out.

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chenley

Sounds to me as if they have conductors in the pipe they want to salvage.

"That conduit has some wires in it now that I thought we would be able to use for pull wires."

480sparky

Sounds like they'd get trashed anyway, then. I missed that part. I doubt a sewer-rooter outfit would want to auger out a mess of copper.....

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waco

Probably worth a try to see if you can send vacuum cleaner discharge air into the pipe. I figure the ice won't be 100 percent or else it would break the conduit and any opening will allow that air to get through.

I have used warm antifreeze on empty conduit and I know people who used it on conduit with wires. They say it didn't hurt anything, but I don't know.

gilbequick

Why don't you just run hot water in the pipe? Run a hose from a sink in the hotel. Let it sit for a little bit and let it do it's job. When the ice is melted you could just suck and blow as much water out as possible and then pull some rags that fill the conduit snugly through the conduit to get the rest of the water out. This is of course, if you're positive it's ice in the conduit not concrete or a caved in pipe somewhere.

wallyworld

Whats the length of the run? I've used small diameter tubing with hot water and with steam. Both worked but if its a long blockage You'll have some time in it. Can you get a snake in from either end? If so can you measure how big the blockage is? I've only done it in 3/4 rigid, 2 pvc seems like a large area to clear

480sparky

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te12co2w

Thanks for all the replies. We did get ice on the end of the fish tape when we tried to push it. We also thought about having someone steam it out. That might happen yet. I wouldn't feel good about reusing the existing wires if that happens, but we might try it yet. No one steaming around here. They would have to come from at least 40 miles away or possibly 100 miles.
We also might try the warm antifreeze trick mentioned. I also don't know what that might do to a pvc pipe or wire insulation for that matter.
The existing wires are #10 thhn. I wonder if we could leave an overload on a pair of wires long enough to melt a hole through the ice and still not have it burn on the breaker terminals. I would not feel comfortable about leaving something like that to work overnight, and it might (or might not) take all night or even longer.
It's about 240'. Blocked 35-40' from the outside end. Much farther from the mdp. We had a 100' tape in there and it was still going. Haven't pushed the long tape in yet to see how far out the problem is. I'm afraid I'll find out I have 20' of ice or something. Then it really will be a springtime job. At least it is not a sewer pipe we are trying to open. That could be ugly.

BryanMD

We're going from suck to blow!

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te12co2w

Did you make up your own hot water/steamer? Or did you hire someone to do that? You mention small diameter tubing. That leads me to believe you made something just for this. If you did make it, how did you make the steam? Electrically? gas fired boiler?

John

You could try and melt the ice by connecting a welder to the wires. I have seen frozen copper water pipes thawed out using a welder. The best way would find a stick welder and monitor the amperage of the wires with a clamp on amp meter. Disconnect the wires at both ends and start with 30 amps and gradually increase the amperage until the wires start to get warm. Might work.

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wallyworld

I used a wall paper steamer, didn't tell them I was using it to thaw conduits. I'm in Maine and run into frozen pipes on occasion, it generally sucks. If you have a large distance frozen, I'd wait unless someone has deep pockets

bobelectric

We once used rock salt in a frozen 4"pvc 90. For fiber cable.the cable supplier said "min temp to pull,55 " Customer said get it in. It still works after 25 years.We never cleaned the salt out.

gilbequick

You can get an electric steamer from many retail stores relatively cheaply.
From small: http://www.amazon.com/SteamFast-SF-2...9649432&sr=1-2
To bigger water capacity: http://www.amazon.com/McCulloch-MC-1...649274&sr=1-20