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Old 12-27-2004, 09:08 AM
E718 E718 is offline
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Location: rural Iowa
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Default Thawing water pipes

I have an old SA200 Lincoln generator. I used to hook on to a pipe, one lead on each end turn on full power and thaw the pipe. The welder did the job for years with no ill effects on it so I know it works allright, A buddy of mine was doing that with his welder and got into a fire, property damage deal and his insurance company told him never to do that again. ( I am sure someone else in the neighborhood was feeding power back into the nuetral.) So I stopped too. What has been your experience with this process? Please don't tell me it will wreck the welder cause this one has been doing it for way past 30 years and no change in operation.
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Old 12-27-2004, 11:45 AM
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john pen john pen is offline
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I had a buddy that used to do the welder thing all the time without any problems...althought Im sure its not the OSHA approved method...
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Old 12-27-2004, 11:54 AM
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Old 12-27-2004, 12:40 PM
Franz Franz is offline
Join Date: Jun 2004
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This subject has been discussed to death and beyond in the last few years, and I have yet to see anything definitive. Old RED toumbstones came with a "Pipe thaw" tap labeled on the selector switch, but they haven't in years, probably due to lawyers.
Many gas drives were worn out thawing pipes, but now no welder manufacturer will even suggest the machine is capable of doing the job, again because of lawyers.
If you go to
on page 4 under options is the L2964-3 pipe thawing control. Lincoln published bulletin E695.1 back in 89, supposedly explaining the process, but they probably no longer offer the box or the bulletin.
There is a phenominon in DC circuits called "Multipathing" that will give you some interesting events no EE I ever met could explain beyond saying "multipathing" as he walked away.
If you click here and fill out the form you can get a bunch of information from General on their Pipe Thaw machine
From what I've read, the machines are basicly an AC buzbox delivering high amperage at around 5 volts. Personally, I don't think they are a good idea when used inside of a building, primarily because copper and even iron pipe tends to blow apart at joynts, and arc potential exists.
I damn well doubt you'll find any insurance carrier willing to cover you for pipe thawing, and most M&C liability policys have an exclusion written into them.
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Old 12-27-2004, 02:12 PM
Mike W Mike W is offline
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Join Date: Jun 2004
Location: Central Kali
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I once need to get a small generator apart, forgot the specifics. I used a variable power supply to put a few amps thru the coil to warm it up enough to get the forgotten part out.
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Old 12-28-2004, 09:47 AM
markct markct is offline
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Location: northfield, ct
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what most likely happened is that your friend had a broken joint from the freeze and that is where an arc took place, i would never use this method inside a house, but have seen it used outside on underground pipes, and in outbuilding where the pipe can be observed just cant be reached easily, i wouldnt feel safe doing it to a pipe that was inside a wall where i wouldnt know if it arced
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Old 01-04-2005, 02:07 PM
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Sberry Sberry is offline
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That isnt what happened. There were multiple electric servies on the same transformer, city water lines and a hi resistance joint in the pipe. The plumbing is bonded to the electric with bonded neutral at service entrance. The current went thru the ground wire, back on the neutral and to the next place, back down thru the ground to the water main. It took an alternate path and the current was high enough to overheat the plumbing to electric ground wire causing a fire. When I do this I remove the city water meter and insure there is no bond and have the shutoff wrench ready at the street, as soon as some water comes I unhook the machine and put the meter back in and turn the water back on. If the main had a seperate ground bar for all the equipment I spose you could remove the bond screw but lots of times they dont, they use the N bar. I wear rubber gloves removing bonds and meters too as you never know what stray currents are there in city systems. Have seen several amps at 120V. Here is an extensive thread on it.
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Old 01-04-2005, 07:40 PM
E718 E718 is offline
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Join Date: Dec 2004
Location: rural Iowa
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I bet you are right. All the electric outlets in the house shot flames out of them. The nuetral and the ground shorting out. Both the fire marshall and the insurance investigator left with out figuring out what happened. I thought there had to be AC power involved somehow, but I bet I was wrong. I have done it probably 100 times and not had any trouble except in pipe that was so rusty there was no metal left to conduct electricity. Or plastic where you just don't get any contact. Thanks
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