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Old 09-15-2007, 04:09 PM   #16
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adding a ground to an ungrounded recepticle


Quote:
Originally Posted by Speedy Petey View Post
Buffalo, Stubbie is absolutely correct.
I suggest you read 250.130(C).
What exactly does 250.130(C) say about this?

All codes aside, it is illegal in Australia to use anything other than the designed device for earthing. Having said this, there are still some very old homes around that still use this method (water pipes) of earthing but if any reasonable electrical upgrade is done to the home, the earthing system must also be upgraded to current standard. Water pipes etc are for carrying water & as Buffalo said, they are not designed to carry fault currents. The only reason that this metallic pipework in domestic residences is earthed, is to facilitate equipotenial bonding.

I strongly advise against using anything other than a proper earth stake to facilitate an earth.

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Old 09-15-2007, 04:21 PM   #17
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elkangorito, you are way off on this. The US obviously has some vastly different codes than Australia.
If a metallic water pipe is present, and it is in contact with the earth for ten feet or more, it MUST be used as the primary grounding electrode. This must also be supplemented by another electrode. Typically a ground rod (or two) are used as supplemental electrodes.

NEC 250.130(C) states that IF a water pipe is being used as an electrode you can use it for connection to ground a circuit. Like I tried to say previously, by the time you do this you could have already run a whole new grounded circuit.
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Old 09-15-2007, 04:40 PM   #18
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adding a ground to an ungrounded recepticle


I'm not exactly sure why you mention using a proper earth stake for grounding. If you are talking about using one for equipment ground fault currents then you would find it hard to trip out your overcurrent device if using a ground stake as your sole path for ground faults. So I'm thinking we are having a communication problem based on our different systems.

In the USA the NEC 250.130(c) allows you to connect any grounding type receptacle or branch circuit extension where an equipment ground does not exist in the wiring means to any point on the grounding electrode system, grounding electrode conductor , neutral bar in the panel enclosure, or in grounded systems the grounded service neutral. In order for the water pipe to be used it would have to be at the point where it is considered the electrode for the service equipment. This is within 5 feet of entering the house and it must be connected to the service grounded conductor via a grounding electrode conductor usually a #6 or larger bare copper wire. The water pipe must be in contact with the earth for 10 feet after it leaves the house in order to qualify as a electrode for the GES. And it must be metal. It is not the fact that it is an earth ground it is because it is bonded to the service grounded conductor in the main panel just as the equipment grounds are for typical grounded branch circuit wiring. Any place else on the water pipe is not allowed.

I really don't like all this ego fighting but some people just think they are god's gift of knowledge and just can't handle being wrong. I don't direct this comment at any one person replying to this thread. And I welcome anyone to ask me why I state the things I do. One must be able to show his thinking through proper documentation and code references. If you can not say your wrong then you cannot learn. I would love to learn more about the electrical systems in other countries and understand why they do what they do that is different from the USA. Speedy and I have been on this forum for many months if not years and we do not always agree but we disagree with respect. And when we are wrong when proven wrong we fess up and learn from the experience. Being electricians does not make us always right, about our trade, there are many instance where I thought I was right and was proven wrong.....just part of realizing we don't know it all. Just don't call me stupid!!

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Old 09-15-2007, 05:13 PM   #19
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Quote:
Originally Posted by Speedy Petey View Post
elkangorito, you are way off on this. The US obviously has some vastly different codes than Australia.
If a metallic water pipe is present, and it is in contact with the earth for ten feet or more, it MUST be used as the primary grounding electrode. This must also be supplemented by another electrode. Typically a ground rod (or two) are used as supplemental electrodes.

NEC 250.130(C) states that IF a water pipe is being used as an electrode you can use it for connection to ground a circuit. Like I tried to say previously, by the time you do this you could have already run a whole new grounded circuit.
I've just finished reading the online 2005 version of the standard.

250.130(C) states;
"Nongrounding Receptacle Replacement or Branch Circuit Extensions.
The equipment grounding conductor of a grounding-type receptacle or a branch circuit extension shall be permitted to be connected to any of the following;
(1) Any accessible point on the grounding electrode system as described in 250.50"

250.50 states;
"Grounding Electrode System.
All grounding electrodes as described in 250.52(A)(1) through (A)(6) that are present at each building or structure shall be bonded together to form the grounding electrode system....."

"250.52 Grounding Electrodes.
(A) Electrodes permitted for grounding.
(1) Metal underground water pipe.

A metal underground water pipe in direct contact with the earth for 3.0m (10ft) or more...........and electrically continuous...........to the points of connection of the grounding electrode conductor and the bonding conductors......"

What I gather from all of this is that metal water pipes CAN be part of the grounding system provided that it is electrically continuous. I also get the impression that since it may not be a part of the grounding system, then it could be unreliable insofar as being used to earth something. Obviously, its' earth capabilities would need to be tested to ensure its' reliability.


Despite what the code says you can get away with, I will always trust a device that is designed to be an earthing conductor as opposed to a water pipe, whose electrical capabilities are unknown until properly tested & proven.
Obviously the standard is trying to be flexible with regard to safety versus cost. However, due to the unknowns of a metal water pipe, I feel a safer solution would be to connect the receptacle to a determined earth. Afterall, earthing is the single most important thing in domestic installations & I feel that there is no room for error. Saving 5 cents may end up costing your life.

Sometimes one has to exceed the code in order to satisfy a better level of performance & therefore safety.
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Last edited by elkangorito; 09-15-2007 at 05:21 PM.
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Old 09-15-2007, 05:35 PM   #20
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Attached is a basic diagram I made for laymen to use in Thailand. Thailand & Australia use the same distribution system - the TT system, although the voltages are marginally different.

Sorry, I had to compress it to get it attached.
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File Type: zip Residential wiring.zip (8.8 KB, 18 views)
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Old 09-15-2007, 05:58 PM   #21
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I'm with stubbie. To clear a fault and open the breaker or fuse you must have a low impedance path to the source. The code and common sense requires that the ground and the path back to the source (neutral)are connected at the service and no where else. Speedy, its probably something simple I'm not thinking of but wouldn't it be OK to get a ground from a grounded circuit. Or is it not allowed because all the conductors aren't together all the way back to the panel. It seems though that it would be safe, though. The point of the ground at the recp. is to bond the metalic parts of the receptacle back to the source right? It seems like a ground connected to the source Somewhere is better than no ground at all, right? Feel free to set me straight, the computer has never hurt my feelings.
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Old 09-15-2007, 06:04 PM   #22
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adding a ground to an ungrounded recepticle


Kangaroo


I'm just not following your thinking about needing a listed earthing device (copper wire as an example) to a ground stake to provide a low impedance fault path for the receptacle grounding terminal.

The water pipe electrode is connected to the grounded service neutral via an #6 or larger bare copper conductor. This is just as "electrically continuous" if not more than all your branch circuits relying on good wire nut connections at several points to get fault current to the grounded conductor.

There is no compromise in safety IMO. You would need to test the listed means also because they are not electrically continuous once they hit a wirenut or other connecting means.

Which would you rather have a solid #6 copper wire from your receptacle to the service neutral bar that has no splices as the grounding electrode system has or a #14 branch circuit wire that has 10 wire nut connections on it before it lands on the service neutral bar. I see no advantage to safety there at all.

It is "permitted" because it would not be practical to to connect all your wiring means to the GES, they provide this alternative for ungrounded receptacles to facilitate safety not cost. It is the intent of the CMP for that code section to make available an equipment grounding means for the single family dwelling that has non-grounding outlets.... it has nothing to do with safety compromise to cost. There is always above code installations... provided the homeowner can afford them, and many can't so you need to get off that band wagon. Connecting an equipment ground as specified in 250.130(c) is far better than using an outlet adapter or only a gfci without equipment ground in regards to safety.

Can you explain where you are coming from with all this earthing need to provide equipment ground capability? I'm not getting what you mean. Earthing in the USA is an intentional connection to earth this is not the case for the equipment ground here we bond it to the service neutral to provide a low impedance fault path back to the source where the centertap is then grounded to earth. Maybe I'm just making this to hard and you are saying the same thing.

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Old 09-15-2007, 06:21 PM   #23
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adding a ground to an ungrounded recepticle


Kangaroo


Ok that diagram helps a bunch. It appears we are no different here than where you are as far as earthing and things that are grounded. What your diagram shows as the Earth Link at the enclosure is what we call the neutral bar here in the Usa. Seems we are just chasing each others tail.

Now if you look at that diagram of yours take one of the green wires and disconnect it from the earth link and then connect it to the ground rod or the wire to the ground rod bonded to the earth link. This is what the NEC says you can do. As for the water pipe replace the ground rod and make it a water pipe (not buried of course) and your equipment ground connection will be within a foot or less of the bonding wire going to the earth link Do you see any compromise in the safety of either method? Your still bonded to the earth link which has a main bonding jumper (MEN?) to the service neutral.

You seem to be wanting to walk a mile out of your way to demean the NEC as compared to the Australian way of doing things. If it's alright I have better sources for clarification of US codes than someone reading a NEC code section for the first time and telling me what it means. Not meant as an insult but really don't you think you are stretching it a bit? I will agree however that you are entitled to an opinion.

Thats not a diagram for a layman its one you would typically see in a grounding and bonding course book for electrical apprentices. A layman is not in that catagory.

As for the water pipe not being continuous that is exactly why they only allow a connection close to where the grounding electrode conductor clamps to the water pipe. If a connection were made elsewhere this would be very risky in that you may have a dielectric union or plastic section of pipe interrupting the integrity of the metal water pipe. Also if the hot water pipe is not bonded to the cold water pipe any connection to it would compromise the fault path. You need to think outside the box a little and give us a bit of credit here in the USA. I have given credit to you I expect the same in return.

BTW.... I just loved the Crocodile Dundee movies and the Crocodile Hunter series was one of my favorites. I see his daughter is now doing what her Dad was so obsessed with, that is really a cool deal.

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Last edited by Stubbie; 09-15-2007 at 07:23 PM. Reason: added thoughts
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Old 09-15-2007, 07:24 PM   #24
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adding a ground to an ungrounded recepticle


Quote:
Originally Posted by elkangorito View Post
Despite what the code says you can get away with, I will always trust a device that is designed to be an earthing conductor as opposed to a water pipe, whose electrical capabilities are unknown until properly tested & proven.
Obviously the standard is trying to be flexible with regard to safety versus cost. However, due to the unknowns of a metal water pipe, I feel a safer solution would be to connect the receptacle to a determined earth. Afterall, earthing is the single most important thing in domestic installations & I feel that there is no room for error. Saving 5 cents may end up costing your life.
It has nothing to do with "getting away" with something. Like I said, it is a far less preferable tactic than running a new circuit. It simply is something that is allowable to do.
Also, in an example such as the one in question, you are NOT using the water pipe to ground anything.At least in as far as providing the safety ground that opens a breaker in the case of a fault. This ground comes from the GEC which goes back to the panel which is also connected to the water pipe in the same vicinity.



Quote:
Sometimes one has to exceed the code in order to satisfy a better level of performance & therefore safety.
Sorry, but I consider statements like this the product of either not knowing what the requirements are, or from the more is always better theory.
The minimum code IS absolutely safe. To say it is not is to not know the code.
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Old 09-15-2007, 07:28 PM   #25
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Quote:
Originally Posted by Stubbie View Post
Kangaroo


Ok that diagram helps a bunch. It appears we are no different here than where you are as far as earthing and things that are grounded. What your diagram shows as the Earth Link at the enclosure is what we call the neutral bar here in the Usa. Seems were are just chasing each others tail.

Now if you look at that diagram of yours take one of the green wires and disconnect it from the earth link and then connect it to the ground rod or the wire to the ground rod bonded to the earth link. This is what the NEC says you can do. As for the water pipe replace the ground rod and make it a water pipe (not buried of course) and your equipment ground connection will be within a foot or less of the bonding wire going to the earth link Do you see any compromise in the safety of either method? Your still bonded to the earth link which has a main bonding jumper (MEN?) to the service neutral.

You seem to be wanting to walk a mile out of your way to demean the NEC as compared to the Australian way of doing things. If it's alright I have better sources for clarification of US codes than someone reading a NEC code section for the first time and telling me what it means. Not meant as an insult but really don't you think you are stretching it a bit? I will agree however that you are entitled to an opinion.

Thats not a diagram for a layman its one you would typically see in a grounding and bonding course book for electrical apprentices. A layman is not in that catagory.

As for the water pipe not being continuous that is exactly why they only allow a connection close to where the grounding electrode conductor clamps to the water pipe. If a connection were made elsewhere this would be very risky in that you may have a dielectric union or plastic section of pipe interrupting the integrity of the metal water pipe. Also if the hot water pipe not bonded to the cold water pipe any connection to it would compromise the fault path.

Stubbie

Thanks for the lighter explanation Stubbie. I think I can understand it now.
The reason for my concern is that IEEE (& hence Australian Standards) don't use the US style earthing (referring to water pipes or other undesignated earthing conductors) is because of the unreliable nature of;

a] earth continuity,
b] earth impedance.

associated with such things.

If you're interested, I have put together some extracts from the Australian Standard AS/NZS 3000:2000, which indicate these problems & therefore preclude the use of such non-electrical components.

I'm sorry it's a bit long winded but it may help you to see where I'm coming from.
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File Type: zip earthing summary.zip (6.4 KB, 8 views)
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Old 09-15-2007, 07:39 PM   #26
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Yes....thank you for the link. I think I may have added a few edits to the last post not sure if you saw them or not.

Anyway I'm not here to fight with you or pass insults. I would like very much to learn from you without our egos getting in the way.

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Old 09-15-2007, 10:36 PM   #27
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Ok I read through it and find it very similar to the US. I have to admit I had to blow the dust of my metric conversion chart to get a grasp of the sizes of your earthing electrodes outside the simple stuff like 16mm. this is the standard size for our rod electrodes. I did notice for a horizontal installation they require the rod to be 3 meters in length, thats a bit over half meter longer than our code requires for the same. We can however install above code and bury or drive longer ones or more than required. It just isn't very practical. As you have to make your own if going longer than 10 feet. A 10 foot rod is available but uncommon in residential applications.

Anyway thanks for the stuff on the way you earth..

It may interest you that I see you have jumped to using the term earthing where it differentiates from grounding. The NEC is finally going to do the same in 2008 after confusing the heck out of us for years

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Old 09-16-2007, 09:05 AM   #28
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Stubbie....

I understand that the NEC states the water pipe is made part of the GES. However, the code also states that any equipment used must be listed for the purpose.

If you had a water pipe listed to carry fault currents, then I would agree. A water pipe manufacturer can obtain UL listing for its pipes to carry fault currents, just like any other manufacturer.

I understand that you are referring to the continous path back to the grounded conductor in the MDP.

It seems you are asking us to accept your opinion on one section of the NEC regardless that the same opinion contradicts another.

This really would be a question for the Code making panel
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Old 09-16-2007, 11:15 AM   #29
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So does this mean I have to rip out all the ufer grounds I've installed since the '05 code change? Because i'm pretty sure that all that rebar ain't listed. I'll start shopping for jackhammers today and scanning the internet for the elusive UL listed rebar so I can instuct all the footer guys to buy it so I can be code compliant like Buffalo says
I should be... This kind of stinks though because the ufer ground(20 ft of rebar buried in the concrete footer) is by far the best ground of all when compared to the pipe and the rods. It is all moot if it isn't tied back to the source.
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Old 09-16-2007, 12:13 PM   #30
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Quote:
I understand that the NEC states the water pipe is made part of the GES. However, the code also states that any equipment used must be listed for the purpose.
I don't think you have quite reached an understanding of how the code book is meant to be used. And you evidently have never applied 250.130 in your career. Do you have a handbook version? Have you ever seen the clause "unless modified elsewhere". since when did everything have to have a listing. I think you need to look at the beginning of your code book a little better.

Quote:
If you had a water pipe listed to carry fault currents, then I would agree. A water pipe manufacturer can obtain UL listing for its pipes to carry fault currents, just like any other manufacturer.
The water pipe is a grounding electrode at the entrance to the dwelling and 5 feet inside and the 10 feet in contact with the earth. Just exactly what do you not understand about that? It will carry huge amperage and voltage in a lightning strike!! Maybe read 250.130(c) to your ahj or inspector and see if they can help you with it. It is not my opinion!!
Quote:
It seems you are asking us to accept your opinion on one section of the NEC regardless that the same opinion contradicts another.
I have no clue what your talking about. ITS NOT MY OPINION

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This really would be a question for the Code making panel
Guess where this answer came from? Again it is not MY opinion.

The exposed interior water piping is not part of the grounding electrode system. The interior metal water pipe between its point of entrance to the building and the connection of the grounding electrode conductor is part of the grounding electrode conductor. The only permitted connection point for an EGC installed per 250.130(C)(1) would be between the pipe's point of entrance and the point where the GEC is connected to the water pipe.

When on earth are you going to get educated??????

I've tried to stay out of your foot in the mouth attitude and constant questioning of the professionals here as to whether you think they are right. You have failed to show any proof or code documentation other than YOUR opinion in virtually all your replies and you have come on this forum with the most incorrect replies in a long time and frankly you are Embarassing this forum.

Try saying I'm wrong in the mirror a few times then it will get easier for you.

Please find somewhere else to make a fool of yourself. All that crap about your qualifications is falling on deaf ears at this point.

Yeah...... you finally pushed my button. Consider yourself lucky I edited the part about the dog house.


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