# Why does code note require gfci breakers on electric water heaters? 2



## protechplumbing (Oct 10, 2008)

Well what the heck? I get back from work and things started getting nasty on that thread 

Anyway, I have a question for *macmikeman* (or any willing sparky.......or should that be "arcy")
Can you please explain why voltage would still be present on the other end of that water service pipe? I read the article that was posted on the previous thread but I just don't see how it's possible. If the transformers center tap is grounded, and water pipe is grounded, why will the voltage NOT travel to ground and shock the guy touching a ground wire in the house next door?


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## Magnettica (Dec 19, 2006)

Because there is no potential at that point in the system. Technically, those two points are already bonded downstream at the neighbors house. You do know that power company's do use the earth as a path for electrons to flow back to the source right?


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## protechplumbing (Oct 10, 2008)

Right, the 3 phases of power on the wires go into let's say a wye transformer and each phase travels thru a primary winding and then ground (I guess into an electrode) and the earth serves as the other "wire"?

My point is that the same principle applies to the secondary side of the transformer. If we take a single 120v phase (that's 120v to ground remember) and grab it while standing barefoot on the ground, we get shocked. Why? Because the xfmr is grounded and that completes a circuit.

And for the record, I don't really know what the deal was with arealplumbers situation, I was just commenting on the water pipe being a viable conductor to transmit voltage from one house to the next. I don't think that's viable because it's so well grounded (low resistance) compared to someone’s feet touching the ground, that 99.9999999999% of the current would be grounded thru the pipe verses the persons body.

I'm not trying to be combatitive here, I just don't understand what I'm missing. I'm not stupid. I did take quite a bit of electrical theory classes before I became a full time plumber (DC, AC and semiconductors) though it's been about 10 years. I understand how electrons flow. I understand that they must always travel in a circuit.


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## Magnettica (Dec 19, 2006)

Ok, so if you understand they flow in a circuit then realize what would happen if that circuit was interrupted by a broken connection to the transformer. That return neutral current is still flowing in a circuit if there is power in the home. Instead of current traveling back to the source through the homes grounded/ neutral connection, it is taking the path through the grounding electrode conductor. The NEC specifies that we properly bond any metal water piping system in any building to this neutral connection from the power company. So current is flowing on the copper water piping system instead of on the neutral connection. Normally, this current is flowing on the neutral connection but when it flows on normally non-current carrying parts, it is called objectionable current flow. And it's objectionable because people die from it.


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## ARealplumber (Aug 11, 2009)

Magnettica said:


> Ok, so if you understand they flow in a circuit then realize what would happen if that circuit was interrupted by a broken connection to the transformer. That return neutral current is still flowing in a circuit if there is power in the home. Instead of current traveling back to the source through the homes grounded/ neutral connection, it is taking the path through the grounding electrode conductor. The NEC specifies that we properly bond any metal water piping system in any building to this neutral connection from the power company. So current is flowing on the copper water piping system instead of on the neutral connection. Normally, this current is flowing on the neutral connection but when it flows on normally non-current carrying parts, it is called objectionable current flow. And it's objectionable because people die from it.


 I appreciate the answers your giving. This is why we plumbers know alittle about this problem...most of us have encountered voltage flowing through a copper pipe we have cut. This is a worthy topic. Many water and sewer providers have complained about this objectional voltage lighting up the guys doing repairs on the water mains in the citys streets.


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## protechplumbing (Oct 10, 2008)

I'm with ya except for the part about people dieing from it (at least in the scenario we were discussing in part 1). My point is that the current is going to travel back to the xfmr center tap via the ground itself. Why/How could a person become a path for that current when they would represent a relatively high resistance path relative to the ground itself?

Picture the pipe in the ground. I dig up one end of the pipe and touch it while standing on the ground. Why would the current flow threw me to get to ground when it's already touching the ground. How am I completing a circuit there?




Magnettica said:


> Ok, so if you understand they flow in a circuit then realize what would happen if that circuit was interrupted by a broken connection to the transformer. That return neutral current is still flowing in a circuit if there is power in the home. Instead of current traveling back to the source through the homes grounded/ neutral connection, it is taking the path through the grounding electrode conductor. The NEC specifies that we properly bond any metal water piping system in any building to this neutral connection from the power company. So current is flowing on the copper water piping system instead of on the neutral connection. Normally, this current is flowing on the neutral connection but when it flows on normally non-current carrying parts, it is called objectionable current flow. And it's objectionable because people die from it.


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## ARealplumber (Aug 11, 2009)

It will not shock you if you dig it up and touch it. But if you cut that copper pipe without bonding it 1st it can kill you. The current can flow through you to ground. I've cut a main copper water line in a front yard of a house and a blue arc jumped arcoss the pipe and shocked me. Not a tingle either...it lit me up.


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## protechplumbing (Oct 10, 2008)

In that case I could see getting juiced because you just disconnected most of the grounding electrode from the grounding electrode conductor. Because to have removed most of the surface contact area with the earth from that electrode you have increased it's resistance to earth substantially and now you ARE going to get juiced because your own resistance value is much lower now in proportion to the now higher electrode resistance. 
Plus if you happen to be touching the longer piece of now cut off electrode, you are now a substantially lower resistance path than before. If that is the case you have now raised the intact electrode's resistance while lowering yours. At that point you will get hit with some current, quite possibly a lethal current.

There is a distinct difference from those examples and the one that was supposed originally. Just to be clear.




ARealplumber said:


> I appreciate the answers your giving. This is why we plumbers know alittle about this problem...most of us have encountered voltage flowing through a copper pipe we have cut. This is a worthy topic. Many water and sewer providers have complained about this objectional voltage lighting up the guys doing repairs on the water mains in the citys streets.


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## protechplumbing (Oct 10, 2008)

Right. I've seen/ had that happen to me as well.




ARealplumber said:


> It will not shock you if you dig it up and touch it. But if you cut that copper pipe without bonding it 1st it can kill you. The current can flow through you to ground. I've cut a main copper water line in a front yard of a house and a blue arc jumped arcoss the pipe and shocked me. Not a tingle either...it lit me up.


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## macmikeman (Sep 12, 2005)

I cannot believe you two guys are still goofing around with this stuff. I told you politely Areaplumber what was happening. Yes the guy who wrote the magazine article might have done it with a bit more polish than me, but if I could write magazine articles myself, Then I WOULD, and NOT GO INTO ANY MORE ATTICS. I told Pro Plumber he was off on his " electricity wants to go to the ground" more than once, and I explained What and Why he was wrong. He continued to try to refute me based on his misconception of basic electrical facts. Even earlier in this whole crap arguement I explained nice and polite about how electrical current follows all paths back to the source, not just the path of least resistance, and some other plumber decided to try to refute me on that. Is this how all plumbers are???? When was the last time you saw me go onto your forum and try to explaing plumbing to you guys, and also get the facts and theory of it all ass backward, and than tell you you do not know **** about plumbing? Man now I see what all the fuss is about when people get mad at illegal border crossers........


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## macmikeman (Sep 12, 2005)

Magnettica, that was nice work. My complements.


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## Inner10 (Mar 12, 2009)

> Even earlier in this whole crap arguement I explained nice and polite about how electrical current follows all paths back to the source, not just the path of least resistance, and some other plumber decided to try to refute me on that.


Indeed, basically onece you become a path to ground for the current some of it will flow through you. 

Imagine this very simple scenario...you have a big bridge 6 lanes on each side, it connects Live City to Ground City accross a river we will call Copper Pipe River. So lets assume everyone in these two cities drive the same type of car....called Electrons. As the electrons constantly flow from one city to the other city a construction company comes along (say their called Plumber's Constructions co.) and instantly builds a really crappy highly resistive 2 lane bridge beside the existing one over Copper Pipe River. 

Cars will begin to use both bridges, now most will still use the 6 lane instead of the 2 lane but all of the sudden more electrons can go back and fourth thanks to the lowered "resistance".

Make sense?


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## rselectric1 (Sep 20, 2009)

then live city and ground city lived happily ever after


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## Inner10 (Mar 12, 2009)

After the bridge built by plumbers construction co. collapsed shortly after completion, killing many citizens of both cities....


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## Magnettica (Dec 19, 2006)

macmikeman said:


> Magnettica, that was nice work. My complements.


Thank you. Describing objectionable current flow is difficult enough to explain to an inexperienced electrician, much less trying to explain it to a non-electrician. It's just not an easy thing to describe, and that's not a knock on anyone -- including curious plumbers wanting to know why -- just that it's difficult to grasp. One thing to keep in mind is that the return current is attracted to the transformer because the grounded neutral provides a very low impedance path. Earth has a higher resistance to current so that is why it doesn't always flow all the time on the copper water pipes. But disconnect that neutral conductor and electrons will make their way back the transformer any which way they can. 

^^^

All this coming from an electrician who just failed an inspection for improper grounding.


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## protechplumbing (Oct 10, 2008)

Yep, that sounds accurate to me.



Inner10 said:


> Indeed, basically onece you become a path to ground for the current some of it will flow through you.
> 
> Imagine this very simple scenario...you have a big bridge 6 lanes on each side, it connects Live City to Ground City accross a river we will call Copper Pipe River. So lets assume everyone in these two cities drive the same type of car....called Electrons. As the electrons constantly flow from one city to the other city a construction company comes along (say their called Plumber's Constructions co.) and instantly builds a really crappy highly resistive 2 lane bridge beside the existing one over Copper Pipe River.
> 
> ...


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## protechplumbing (Oct 10, 2008)

Hey, we construct pipes not bridges. What do ya want from us? Shoulda hired a GC for dat.



Inner10 said:


> After the bridge built by plumbers construction co. collapsed shortly after completion, killing many citizens of both cities....


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## angus242 (Oct 20, 2007)

Inner10 said:


> Imagine this very simple scenario...you have a big bridge 6 lanes on each side, it connects Live City to Ground City accross a river we will call Copper Pipe River. So lets assume everyone in these two cities drive the same type of car....called Electrons. As the electrons constantly flow from one city to the other city a construction company comes along (say their called Plumber's Constructions co.) and instantly builds a really crappy highly resistive 2 lane bridge beside the existing one over Copper Pipe River.



Does the construction company need to be licensed in both Live City _and_ Ground City? Or maybe someone got them from an internet classified ad website called hackslist? :laughing:


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## Magnettica (Dec 19, 2006)

Inner10 said:


> Indeed, basically onece you become a path to ground for the current some of it will flow through you.
> 
> Imagine this very simple scenario...you have a big bridge 6 lanes on each side, it connects Live City to Ground City accross a river we will call Copper Pipe River. So lets assume everyone in these two cities drive the same type of car....called Electrons. As the electrons constantly flow from one city to the other city a construction company comes along (say their called Plumber's Constructions co.) and instantly builds a really crappy highly resistive 2 lane bridge beside the existing one over Copper Pipe River.
> 
> ...



Actually, the 2 lane bridge would have more resistance than the 6 lane bridge would. It's the same amount of protons returning to the source (transformer) just less room to move on a 2 lane highway. Lets say three lanes are (-) charged electrons and three of the lanes are (+) charged protons, if that (+) charged portion of the bridge were broken these protons would make their way onto the crappy 2 lane bridge built by Plumbers Contracting over Copper River and back to ground city because this GEC is bonded to the (+) charged grounded neutral conductor. 

Make sense?


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## Magnettica (Dec 19, 2006)

angus242 said:


> Does the construction company need to be licensed in both Live City _and_ Ground City? Or maybe someone got them from an internet classified ad website called hackslist? :laughing:


No, their are 2 different jurisdictions with 2 completely different sets of rules. :w00t:


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