Ground Rod For House ?

[w_tom]

An example demonstrates the earthing problem. A 12 AWG wire from wall receptacle maybe 50 feet back to mains box has less than 0.2 ohms resistance. That same wire would have something like 120 ohms impedance. Lets say a tiny 100 amp transient seeks earth ground via that 50 foot wire. Therefore a wall receptacle - and adjacent electronics - will be at something less than 12,000 volts. Will that transient seek earth via that safety ground wire? Of course not. It will also seek other and destructive paths via adjacent electronics.

Wire length is but one reason why a wall receptacle safety ground is not sufficient as earth ground. Also explains why plug-in protectors are so ineffective.

Essential to minimizing wire impedance are wire length, no sharp bends, and other characteristics cited previously. Also important is a concept cited by Bud--

The quality of a service entrance protector is only as effective as its earth ground which is why distance to that earthing is so critical and why single point earthing is essential. That means the 6 AWG wire does not go up over a foundation and then down to an earth ground rod. That wire goes through foundation somewhere just above the ground rod so that wire distance is shorter with sharp bends eliminated. Also important is that earthing wire remain separated from other non-earthing wires to avoid induced transients.

Yes, lower resistance does help which is why high reliability facilities such as electric substations expand their earth ground to also lower resistance. It is also why earthing should be planned when the footing are poured. Equipotential being another aspect of superior earthing.

Unfortunately we still don't build as if the transistor exists. We still do earthing as an afterthought. Effective earthing addresses concepts in excess of that performed by conventional household earthing. Equipotential being a concept of transistor protection that is not as essential to human protection. If we built buildings for effective transistor protection, then Ufer grounds would be routine; and not some afterthought to supplement water pipe ground such as ground rods. Even water pipe would enter a building adjacent to all other utilities to contribute to transistor safety.

Even NEC requires all incoming electrical utilities be earthed to a common point for human safety - a problem still found even in some new homes.

That 20 foot requirement from NEC is article 800.40(A)(4):

Same paragraphs is also found in Article 820.

Cinergy demonstrates how to solve earthing problems created when utilities arrive at wrong locations. A problem often created by service installers or builders who still have not learned about proper earthing:

Concrete encased grounding (Ufer grounds) were so well proven even before WWII as to even protect munitions from direct lightning strikes. If water pipe earthing was so effective, then why do they implement Ufer grounding even in buildings with water pipe grounds? Halo grounds are but another way of improved earthing.

Aga> As I said protector blocks for cable and TV should be immediately

[Bud--]

I never talked about branch ckts and don't want to start now. If I did I would want a citation for 120 ohms. Impedance of ground rod and water pipe would be relevant.

Perhaps because a supplementary ground is required for a water pipe because it may be replaced by plastic and ground rods are way worse than either. Not obvious who "they" are. If it is gfretwell, in a current thread he says the gound conductivity near him is very bad. Sounds like the Ufer is a foundation ring. An unrelated video tape shows driving a

10' rod in Florida with a water table about 3' down, connecting 120V and getting a current of about 1.5A (implies 80 ohms ground resistance).

Halo grounds are but

Probably mean ground ring in NEC. Phaser uses halo (in the air) and it isn't what you want.

----------- I actually only planned to respond to your citations in response to me and pop: >

Cinergy in effect talks about a common ground reference which I have emphasized several times. We probably substantialy, but not entirely agree on this. Nothing on water pipes and ground rods which we don't agree on.

I have no idea what at that site is relevant

bud--

[Pop]

That's a grand collection of misquotes and minsinformation and hooey references that are irrelevant to most anything here. Like I said before, I'm not inclined to continue to debate these OT side trips of useless misinformation. If you'd like to have a sensible, detailed debate, start a new thread where it belongs. People are beginning to complain about responses that have nothing to do with the OP's questions, and I have to agree it does make it hard to find a meaningful response if there is one.

[Pop]

That same wire would have something : like 120 ohms impedance. At what frequency, and what are the approx reactive components? See, this is the kind of non-information I'm talking about.

Lets say a tiny 100 amp transient : seeks earth ground via that 50 foot wire. Therefore a wall : receptacle - and adjacent electronics - will be at something : less than 12,000 volts. Time? Duration? Energy? What is the power in each component? Think about it.

Will that transient seek earth via : that safety ground wire? Of course not. It will also seek : other and destructive paths via adjacent electronics. No, ALL freqs/rise/falls will not seek the same path. Think about it. : : Wire length is but one reason why a wall receptacle safety : ground is not sufficient as earth ground. Also explains why : plug-in protectors are so ineffective. I don't recall anyone saying that was the case. Did they? : : Essential to minimizing wire impedance are wire length, no : sharp bends, My gosh, what are you doing, applying field theory and waveguides? This is exactly what makes your possibly well intentioned information so useless. I'm surprised you left out the skin effect and a few other nice nouns you could have dropped in there.

and other characteristics cited previously. Also : important is a concept cited by Bud-- : > Clamping all incoming wires to the same the same ground : > reference is the best way I know to protect electronics. ... Where did anyone claim it wasn't? The "best" wasn't the question; sufficient or acceptable were the words, IIRC.

: The quality of a service entrance protector is only as : effective as its earth ground which is why distance to that : earthing is so critical and why single point earthing is : essential. That means the 6 AWG wire does not go up over a : foundation and then down to an earth ground rod. That wire : goes through foundation somewhere just above the ground rod so : that wire distance is shorter with sharp bends eliminated.

Uhh, the sharp bends problem isn't for impedance or electrical considerations; it's physical properties related. Think about what you're saying.

: Also important is that earthing wire remain separated from : other non-earthing wires to avoid induced transients. I don't think that was any part of the subject; true but not directly relevant. : : Yes, lower resistance does help which is why high : reliability facilities such as electric substations expand : their earth ground to also lower resistance. It is also why : earthing should be planned when the footing are poured. : Equipotential being another aspect of superior earthing. Superior earthing: What's that go to do with anything? Completely irrelevant to the subject matter. : : Unfortunately we still don't build as if the transistor : exists. We still do earthing as an afterthought. Effective : earthing addresses concepts in excess of that performed by : conventional household earthing. Equipotential being a : concept of transistor protection that is not as essential to : human protection. If we built buildings for effective : transistor protection, then Ufer grounds would be routine; and : not some afterthought to supplement water pipe ground such as : ground rods. Even water pipe would enter a building adjacent : to all other utilities to contribute to transistor safety. More irrelevance; no point to the entire para. : : Even NEC requires all incoming electrical utilities be : earthed to a common point for human safety - a problem still : found even in some new homes. "Even NEC"?

... More attempts at double-speak and name dropping clipped. : : Again, to answer the original poster's question - water pipe : earthing alone is no longer sufficient to meet code. Upgrade : to accomplish more than just meet code. Transistor protection : is only as effective as a building's earth ground.

To take your bent for a moment, a "transistor" is defined as an e-b-c junction with physical leads attached. Semiconductor technology does indeed use the concept of transistors within chips et al for analogic discussion, but they are not transistors unless, like you, a person wished to take the word apart into its components, and work from there. It's also possible, still in your realm of fuzziness, to build a computer system with NO earth reference, but with controlled references, which will operate perfectly. I used to use such a system daily in my routine daily work for many years. And BTW, resistance IS a component of Impedance. If you wish to use the terms interchangeably, you need to add the words pure and reactance to your talk.

Don't be a blatherskite. : : Bud-- wrote: : > As I said protector blocks for cable and TV should be immediately : > adjacent to the panel so all wiring is clamped to the same ground : > reference. You don't explain how a ground rod would help in this : > instance. Adding a ground rod near the FAX is not going to provide : > a low impedance to keep the ground reference for the FAX the same : > as the incoming neutral. : > ... : >

: > Incoming utilities listed have to have protector blocks near the power : > panel to get a common grounding reference. : >

: > How does a 10 foot wire to a high resistance ground rod provide a lower : > ground impedance than a grounding electrode conductor and water pipe? : > This is cental to your arguments. Perhaps you could explain and also : > provide some citations that support your view. : >

: > For a 500A service the conductor to a ground rod has to be #6. The : > conductor to a water pipe has to be 2/0 - 3.5 x the area. How come? : > Surges include high frequency components for which impedance is : > important. Grounding electrode conductor and water pipe has one : > function of limiting surges. : >

: >> Another problem with using a cold water pipe as an earth : >> ground connection - code wants each utility to be earthed less : >> than 20 feet to the common point. : >

: > Cite the code. : > ... : >

: > Clamping all incoming wires to the same the same ground reference : > is the best way I know to protect electronics. That requires the : > protector blocks to be near the electrical panel. (More properly : > thay have to be near each other.) That is likely a lot more : > important than resistance or impedance to ground. If all wiring : > was clamped to the same reference with no ground connection could : > electronics see a difference. : >

: > > Gfretwell has posted how homes are now being built so as to : > > provide superior transistor safety in pictures at: : > >

> >

: > This is a concrete encased electrode which I said is probably the second : > best electrode (after water pipes). It is one of 3 electrodes that must : > be included in a ground system, if present. (The other 2 are water pipe : > and building steel, which a home doesn't have.) Not included: ground rod. : >

: > > Another also demonstrates better earthing. None of this : > > would be required if city water pipe was sufficient as earth : > > ground for transistor safety: : > >

> >

: > Most of us don't put 55 foot high lightning rods in our back yard. Not : > particualrly relevant. : >

: > ------------- : > With regard to: Bud-- does not even quote code to justify his post. You : > do not understand why water pipes are required to have a SUPPLEMENTAL : > electrode and don't listen to people who do understand. Since arguing : > the code is pointles, I tried Physics - ground resistance. That doesn't : > seem to work either. : >

: > bud--

[chocolatemalt]

Not sure how wise it is to add to this discussion, but...

You may want to consult a qualified commentary book on the NEC for better explanations. One that I found extremely helpful is Practical Electrical Wiring, 18th Edition (2002 NEC) by Richter and Hartwell. It's been around awhile, the latest author Hartwell is a master electrician and Code Panel member, and I think this book has been endorsed numerous times in this conference.

It explains (Chapter 16: Installing Service Entrances and Grounds): "In a large city with cast iron water mains and everyone connected through copper water laterals, the total resistance to ground from any given connection [on your water pipe] may be less than 1 ohm, about as good as possible." It goes on to say that the reason for requiring supplementary electrodes (per NEC 250.53 as you quote) is due to possible future replacement of water supply pipe with plastic or insertion of dielectric unions. If that has not taken place, the pipe is by far the best grounding electrode the average house can hope for. This correlates with what the electricians in this newsgroup have been stating.

I have an older house with no supplementary electrode, but will be installing one (probably with 3 or 4 rods) to comply with Code when I upgrade my service. But with a 3/4" copper supply pipe entering my basement, buried about 10' deep for the 30' straight run to the main line in the street, and countless miles of deeply buried main water lines connected to that... How could a couple of 5/8" diameter, 8' long rods in my yard ever compete with that? If a lightning-induced surge came down my wires after I installed the rods, I'd have to wonder if more than even a few percent of the amps would choose to drain out in the sand and clay around those grounding rods instead of into the water main network.

If that supply pipe were replaced with plastic, then yes, the grounding rods would become vital, and that's why (in my understanding) they are required by NEC 250.53(D) as preemptive protection against that change.

[w_tom]

Hey Pop. You remember what transistors are? They are things you said are not inside electronics today. Transistors

- those things found inside integrated circuits no longer exist? That is my point. You argue without a technical grasp of reality - including a claim that transistors are no longer used. The code is quite specific. That water pipe earth ground is not longer sufficient to earth a building.

The > That's a grand collection of misquotes and minsinformation and

[w_tom]

Provided was an example of wire impedance (it was not a discussion of branch circuits); which explains WHY each earth ground connection must be short, no splices, no sharp bends, not inside metallic conduit, etc. Wire has impedance which is why short wire length is critical to earthing for transistor protection.

To repeat what was posted: Cinergy also demonstrates solutions to bad construction - where the utilities don't enter at a common location. The need for single point earthing is good for human safety but essential to transistor safety.

Above is about earthing for the secondary protection 'system'.

demonstrates earthing of the primary protection 'system'. Layered protection 'systems'. Each layer of protection is defined by its single point earth ground. also demonstrates another earth ground that contributes to transistor protection.

Polyphaser discusses protecting incoming wires from lightning. If your house is not adjacent to a 50 foot radio tower, then a 'tower' that lightning seeks is your house or those utility poles that connect directly to household transistors. Earthing that applies to protecting radio towers also applies to home protection. To lightning, that tower and those incoming house wires are same.

But then Polyphaser - an industry benchmark - discusses more that just radio towers. What does Polyphaser discuss? Their products? Of course not. Polyphaser discusses earthing - the most critical component also in a home protection system. What is discussed here? Earthing the house - for same reasons that Polyphaser describes in:

Same principle that were once standard in places that had electronics - radio stations and telephone switching stations

- are now necessary in other buildings that also have electronics - the home.

Why extensive earth> w_tom wrote:

[w_tom]

Reasons provided for the supplementary electrode - plastic pipe, etc - are what most agree on. What some non-electricians are having a problem with are other electrical and electronic reasons why a water pipe ground is not sufficient. Involves parameters that concern engineers - that include and go beyond an electrician's code requirements. Remember, code is only about human safety. But the earthing system also performs other functions - such as transistor safety.

One reason why a water pipe ground is not sufficient - it does not belong to the electrical system and therefore can be compromised: plumber disconnects a pipe that is electrically hot, plumber installs plastic pipe, etc. All these reasons provided previously are not in dispute (except where one only wants to argue).

Your reasoning only assumes resistance. Grasped the concept of impedance. Resistance of ground rods at signficantly less than 25 ohms is sufficient for transistor protection. So if you lower resistance to 2 ohms, have you improve things by 10 times? Of course not. 2 ohms is only a minor improvement - provides a marginal improvement. Lowering resistance provides an exponentially decreasing advantage. But impedance, as discussed elsewhere, is a major bottleneck to transistor safety.

If water pipe ground was so good, then why do high reliability facilities that only used copper water pipes still install Ufer, wire mesh, and other grounds as demonstrated in:

The water pipe ground with all that lower resistance is still not sufficient for earthing. Again, if looking at resistance, then other aspects of earthing, summarized in previous posts, are being ignnored. Notice why those posts are so long. Notice the so many application notes about earthing for laymen at: is more to earthing than just low resistance. If you only want to meet code, then only worry only about resistance. But reasons why others don't rely on a water pipe ground are found in electrical concepts such as impedance and equipotential. These are parameters that electricians need not learn, are not part of the human safety code, and have been made important by household transistors.

The code says water pipe must be supplemented for th> Not sure how wise it is to add to this discussion, but...

[Pop]

Hmm, , you're pretty closed minded and ignorant. When you can't confuse someone with rationalization disguised as facts you get "interesting". I suspected a troll early on - too bad I and others bothered to feed you.

[Bud--]

Might have been the best post in the thread.

bud--