Thawing water pipes with a welder.

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I am very aware that thawing water pipes with electrical current can be dangerous. Yesterday, in Long Lake, NY, I came home from work only to see the Town employees thawing a neighbor's water pipe with the old welder they have been using for many years. As I was outside, talking to my immediate neighbor, he informed me they were coming to his house next because his water had froze. Before I came into my own house, I went to my truck and grabbed my electrical tester. I proceeded to the basement and tested for voltage on the copper water pipe, with the ground still connected to the water pipe, there was 1.1 volts AC. I put one test lead directly on the water pipe and the other to the buss bar in the main circuit panel. When the welder shut down, the voltage dropped to .1 volts.

Then, it was time for them to connect to the house next door. Knowing they were closer, and that they use AC volts, but not knowing how exactly how many volts they use, I disconnected the ground cable to the water pipe. I tested for voltage on the water pipe, there was 0 volts. The Town employee dragged one cable and hooked it to the fire hydrant directly across the road from my house. I assume they connected the other cable to the water pipe in the house next door. They started the machine, but something was wrong, and they shut the machine down. I did not have enough time to test for voltage. They then came over to my curb stop, took the cap off and inserted the key. After he thought he had a good connection, he hooked the cable up to the key. They started the machine and the same thing, something was wrong, so they shut it down. I can only assume they were too far apart with the cable to get the proper amperage.

They ended up hooking the lead to a Curb Stop on the neighbors house on the opposite side of the house they were attempting to thaw. They started the machine and began to charge the water pipe with AC volts. I took a reading at my incoming water pipe. Again, one lead on the water pipe (ground wire disconnected) and the other to the main buss bar. Voltage was now reading 3.4 volts. The voltage dropped to 1.8 volts but would spike to 3.4 volts on occasion. I can only wonder what the voltage would have been had they connected to my curb stop.

One thing that really upset me was the fact that the Town employee did not notify us of what was going to happen, and I think they should have, especially if they were going to be hooked to my curb stop. There has been problems in the past, using this method to thaw water pipes. They have burnt out phone systems, receptacles and electronics in homes. Fortunately, they haven't caused a fire in someone's home, however, that is just a matter of time. I've seen that happen in surrounding Towns and they no longer thaw water pipes with electricity.

In Canada, thawing water pipes with electric is outlawed. I believe the NEC needs to step in and regulate or even outlaw this practice in the United States. I'm surprised they haven't stepped in on this practice, that I know of, yet. Thawing water pipes with electric is not safe, period! I don't care how good one is, or how long they have been doing it, there is always the potential of starting a fire in someone's house or a neighbor's house, plus the chance of electrical shock to those using this practice. Also, thawing with electricity will only work with metallic pipe, it will not work with any plastic pipe. Steam or Hot Water Jetter are the safest way to thaw buried water pipe.

I look forward to reading any and all comments to this thread.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
This practice, while hazardous is outside the scope of the NEC so other avenues would have to be used to prohibit it. Our city prohibited it about 25 years ago after fires were started in adjacent houses on two occasions in a single winter.
 
This practice, while hazardous is outside the scope of the NEC so other avenues would have to be used to prohibit it. Our city prohibited it about 25 years ago after fires were started in adjacent houses on two occasions in a single winter.


My understanding of the Purpose and Scope of the NEC is to "Protect persons and property from hazards arising from the use of electricity". Using a welder to thaw water pipes is clearly the use of electricity and is a hazard, is it not? If this is true, then why doesn't the NEC want to tackle this hazard?. There have been houses (property) lost due to this practice. What else is it going to take before there is regulation on this practice, a death? Why not prevent that before it does happen?

What if the Town had hooked onto my curb stop and fed over 10v through the water pipe into my home? What if I wasn't here to disconnect the ground wire from the copper water pipe? What electronic equipment could have been destroyed, if not my entire house? What about my family??? My argument isn't just about me, my family and our property, it's about everyone. Why do we always have to wait for a tragedy to happen before regulation?
 

kwired

Electron manager
Location
NE Nebraska
My understanding of the Purpose and Scope of the NEC is to "Protect persons and property from hazards arising from the use of electricity". Using a welder to thaw water pipes is clearly the use of electricity and is a hazard, is it not? If this is true, then why doesn't the NEC want to tackle this hazard?. There have been houses (property) lost due to this practice. What else is it going to take before there is regulation on this practice, a death? Why not prevent that before it does happen?

What if the Town had hooked onto my curb stop and fed over 10v through the water pipe into my home? What if I wasn't here to disconnect the ground wire from the copper water pipe? What electronic equipment could have been destroyed, if not my entire house? What about my family??? My argument isn't just about me, my family and our property, it's about everyone. Why do we always have to wait for a tragedy to happen before regulation?

How do you propose the NEC should handle this? And even if they do put something in, how does it get enforced? Does the city water system department apply for permits and inspections before attempting to thaw the pipe in this manner?

This is not an installation method or procedure. POCO's could easily do something similar in nature by running high potential tests on grounded conductors that could result in undesired voltage or current in customer premises.

The problem is not the 10 volt rise on your water system it is when the current path ends up being through some equipment in your home other then the water pipe.

When they connected to fire hydrant or curb stop with one lead (and the other lead likely at the water entrance of the effected home) they likely had no circuit or too high resistance to allow significant current to flow, this is when things like grounded shields in phone line or TV cable lines can become parallel paths and current finds it's way to the other welder terminal through those items.

Thawing pipe with this method actually can work pretty well and fairly safe if you know what your current path is, but all it takes is one repair from sometime in the past where an insulating component was introduced and you have no path through the section to be thawed, but still may have other unknown current paths and can leave the welder connected a long time and never put any heat where it was desired.
 
Frikin amazing. glad I live in warmer climate.

Sometimes I wish I did as well.

There are ways to prevent water pipes from freezing, and they are all expensive. The least expensive way, in my town, is to run a bleeder. However, running a bleeder is a waste of good drinking water. It also cost's the Town to run the pumps, filters, etc.
 

kwired

Electron manager
Location
NE Nebraska
Sometimes I wish I did as well.

There are ways to prevent water pipes from freezing, and they are all expensive. The least expensive way, in my town, is to run a bleeder. However, running a bleeder is a waste of good drinking water. It also cost's the Town to run the pumps, filters, etc.

Does it cost less then having them re-install all the lines that are typically subjected to freezing in a manner that will assure they don't freeze?

How much of same water is sprinkled over lawns through the growing seasons?
 
How do you propose the NEC should handle this? And even if they do put something in, how does it get enforced? Does the city water system department apply for permits and inspections before attempting to thaw the pipe in this manner?

This is not an installation method or procedure. POCO's could easily do something similar in nature by running high potential tests on grounded conductors that could result in undesired voltage or current in customer premises.

The problem is not the 10 volt rise on your water system it is when the current path ends up being through some equipment in your home other then the water pipe.

When they connected to fire hydrant or curb stop with one lead (and the other lead likely at the water entrance of the effected home) they likely had no circuit or too high resistance to allow significant current to flow, this is when things like grounded shields in phone line or TV cable lines can become parallel paths and current finds it's way to the other welder terminal through those items.

Thawing pipe with this method actually can work pretty well and fairly safe if you know what your current path is, but all it takes is one repair from sometime in the past where an insulating component was introduced and you have no path through the section to be thawed, but still may have other unknown current paths and can leave the welder connected a long time and never put any heat where it was desired.

OK, my argument falls more within the Purpose of the NEC, not so much the Scope. However, if the Scope of the NEC is to " Cover the installation of electrical conductors and equipment, etc." then why isn't the practice of thawing water pipe with electricity taken into account when the code specifies the grounding of metallic water pipe?
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
My understanding of the Purpose and Scope of the NEC is to "Protect persons and property from hazards arising from the use of electricity". Using a welder to thaw water pipes is clearly the use of electricity and is a hazard, is it not? If this is true, then why doesn't the NEC want to tackle this hazard?. There have been houses (property) lost due to this practice. What else is it going to take before there is regulation on this practice, a death? Why not prevent that before it does happen?

What if the Town had hooked onto my curb stop and fed over 10v through the water pipe into my home? What if I wasn't here to disconnect the ground wire from the copper water pipe? What electronic equipment could have been destroyed, if not my entire house? What about my family??? My argument isn't just about me, my family and our property, it's about everyone. Why do we always have to wait for a tragedy to happen before regulation?

The NEC addresses the way to build and install electrical systems. I don't remember seeing anything in the NEC regulating an action or practice.
 

kwired

Electron manager
Location
NE Nebraska
OK, my argument falls more within the Purpose of the NEC, not so much the Scope. However, if the Scope of the NEC is to " Cover the installation of electrical conductors and equipment, etc." then why isn't the practice of thawing water pipe with electricity taken into account when the code specifies the grounding of metallic water pipe?
Probably because that is such a rare event compared to the other hazards that are minimized by bonding the pipes to the electrical system.

There are many uses of electricity that are outside the scope of the NEC.

Read 90.2 carefully.

I'm not saying use of the welder is right or wrong - just that it is not something within the scope of NEC.

One could be using same welder to actually weld and still have similar issues if you don't watch where possible current paths are, and this does happen at times especially at more industrial type applications.
 
How do you propose the NEC should handle this? And even if they do put something in, how does it get enforced? Does the city water system department apply for permits and inspections before attempting to thaw the pipe in this manner?

This is not an installation method or procedure. POCO's could easily do something similar in nature by running high potential tests on grounded conductors that could result in undesired voltage or current in customer premises.

The problem is not the 10 volt rise on your water system it is when the current path ends up being through some equipment in your home other then the water pipe.

When they connected to fire hydrant or curb stop with one lead (and the other lead likely at the water entrance of the effected home) they likely had no circuit or too high resistance to allow significant current to flow, this is when things like grounded shields in phone line or TV cable lines can become parallel paths and current finds it's way to the other welder terminal through those items.

Thawing pipe with this method actually can work pretty well and fairly safe if you know what your current path is, but all it takes is one repair from sometime in the past where an insulating component was introduced and you have no path through the section to be thawed, but still may have other unknown current paths and can leave the welder connected a long time and never put any heat where it was desired.

Exactly! I don't know how this could be regulated, right now, other than to have the local municipality prohibit the practice. I wonder what insurance companies think of this practice.
 

kwired

Electron manager
Location
NE Nebraska
Exactly! I don't know how this could be regulated, right now, other than to have the local municipality prohibit the practice. I wonder what insurance companies think of this practice.
Insurance companies likely have biggest influence in keeping this from happening, in particular the City's liability carrier.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
My understanding of the Purpose and Scope of the NEC is to "Protect persons and property from hazards arising from the use of electricity". Using a welder to thaw water pipes is clearly the use of electricity and is a hazard, is it not? If this is true, then why doesn't the NEC want to tackle this hazard?. There have been houses (property) lost due to this practice. What else is it going to take before there is regulation on this practice, a death? Why not prevent that before it does happen?

What if the Town had hooked onto my curb stop and fed over 10v through the water pipe into my home? What if I wasn't here to disconnect the ground wire from the copper water pipe? What electronic equipment could have been destroyed, if not my entire house? What about my family??? My argument isn't just about me, my family and our property, it's about everyone. Why do we always have to wait for a tragedy to happen before regulation?
It is outside the scope of the because the welder and the cables are not installed. In general the NEC applies to installed wiring systems and equipment. (90.2) Also there would be no enforcement method.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
OK, my argument falls more within the Purpose of the NEC, not so much the Scope. However, if the Scope of the NEC is to " Cover the installation of electrical conductors and equipment, etc." then why isn't the practice of thawing water pipe with electricity taken into account when the code specifies the grounding of metallic water pipe?
What would you suggest the code says? You have until the first Friday of November of 2017 to submit a proposed change.
 
Why would you place this in the electrical code? What Plumber reads it!:blink:

Being that an electrical charge is being applied to a metallic water pipe that the NEC says must be grounded, I thought this would be the best place to start. However, by reading the replies to my thread, I guess I was wrong. I'll take a different avenue to solve the problem. Thank you all for your comments. I truly hope than none of you ever have to go through this. In all, I was just trying to prevent the accident before it happens. Trust me, I will find a way to do it.
 

mopowr steve

Senior Member
Location
NW Ohio
Occupation
Electrical contractor
I am listening to the OP's argument but logic behind this practice using a welder should be safe from the standpoint that only current can flow between the leads of the welder since the transformer line/load windings are isolated from each other.
If memory serves me right I think my welder instructions even show how to thaw metallic pipes with it.
Now if there is a defect in the welder I could see problems.
Anyone wish to elaborate on what actually occurred when there were fire damages caused by using a welder?
 
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