Suplemental electrode conductor

[rasmithircgov.com]

Re: Suplemental electrode conductor

Bennie, are we in agreement that when available metal water piping is sized per 250-66 and that you can't just through a #4 to it.

 

[roger]

Re: Suplemental electrode conductor

Pierre, when it comes to rods, they are simply placebos as far as anything but helping in lightning or seriously high surges.

Roger

[ June 06, 2003, 06:42 PM: Message edited by: roger ]

 

[electricmanscott]

Re: Suplemental electrode conductor

Bennie, I use the water pipe as a grounding electrode. The suplemental rods are bonded to this through the grounded service conductor. This is accomplished by connecting the suplemental conductor to a lug in the meter socket as per 250.53(D)2

 

[rasmithircgov.com]

Re: Suplemental electrode conductor

Art. 250-24 (a) NEC 1999 at the end of the paragraph says,"The grounding electrode conductor shall be connected to the grounded service entrance conductor in accordance with (1) through (5).1 being, The connection shall be connected at any accessible point from the load end of the service drop or service lateral to and including the terminal or bar to which the grounded service conductor is connected at the service disconnecting means. So yes the means of which you are doing it is correct. the Grounded service conductor is from the drop and lateral all the way to the 1st means of over current protection. After that you have grounded conductors (not grounded service conductor) and equipment grounds.Excuse me for butting in.

 

[electricmanscott]

Re: Suplemental electrode conductor

Never butting in here all replies welcome. I read that the smae way as you. My original question was must the suplemental electrode conductor be one continuous length from wherever it starts to the last rod. I can't say that I have a clear answer on this.

 

[wocolt]

Re: Suplemental electrode conductor

Scott
As far as I know you can use three (3) Acorns, but from the meter can continuous from the first rod to the second another piece of no.6 can be used with the extra clamp.

WmColt

 

[bennie]

Re: Suplemental electrode conductor

The ground electrode conductor is the one, and one only, from the neutral bus to the first component of the ground electrode system.

This conductor should not be spliced. All conductors after that are bonding(shorting)conductors, and can be spliced. This is single point grounding.

Ground electrodes, when separately fed, and not bonded(shorted), constitute multi-point grounding(earthing).

[ June 07, 2003, 09:53 AM: Message edited by: bennie ]

 

[bennie]

Re: Suplemental electrode conductor

At one time, the last earth connection by the utility company, was from the meter base to a driven rod.

This was when meter gaps were used. These were air gaps set for flashover at 4 KV. This was to prevent high voltage from appearing on the customer service ground, when a winding to winding fault develops in the distribution transformer.

The possibility of a feed through, is the only reason for the customer ground system. The high voltage will appear on all three conductors of the service. The neutral is the only one that connects directly to the panel enclosure.

Low side surges, from lightning strikes, are rare on domestic power. The usual result is a layer to layer fault on the distribution transformer.

 

[pierre]

Re: Suplemental electrode conductor

To all who may be interested,

Take a look at the post I wrote in '25 ohms or less'.

 

[wocolt]

Re: Suplemental electrode conductor

IT is not spliced, to the first ground rod is one continuous wire. Then a second clamp is used on the first ground rod and (Bonded if you will) to the second.
This is the way is it recommended to install the second ground rod.
Secondly and most important it is OKed by the AHJ. More importantly in my area we are not allowed to drop a ground from the meter base so we make two connections to the service panel, one for the ground, No larger than a no.6 and then run a connection to the water pipe.
The power company and the inspectors dont like it and will gigged it, if we do it .
The prevailing opinion is once the seal is put on the meter it is not accessible, I learned a long time ago it is easier to run to the service panel than to argue the point.
Even thourgh it is permitted by code.
As far as the two connections to one rod as long as you have two listed lamps and the first section is un-broken what is the problem.

WmColt

 

[tom baker]

Re: Suplemental electrode conductor

A grounding electrode conductor can be spliced with an exothermic weld or irreversible compression splice. 250.64(C):
(C) Continuous. The grounding electrode conductor shall be installed in one continuous length without a splice or joint, unless spliced only by irreversible compression-type connectors listed for the purpose or by the exothermic welding process.

 

[bennie]

Re: Suplemental electrode conductor

You are correct Tom. Again I am thinking more on the residential level. There is no need to splice a ground electrode conductor if installed properly, even if it is allowed.

 

[tom baker]

Re: Suplemental electrode conductor

Yes it would be faster just to replace the GEC. I was just pointing out a GEC can be spliced.

 

[wocolt]

Re: Suplemental electrode conductor

The NEC also provides for the option of running a grounding electrode conductor to "EACH" grounding electrode individually as provided in 250.64(F).
where the interior metal water pipe is used as a part of the grounding electrode system or as a conductor to bond other electrodes together to create a grounding electrode system, 250.52(A)(1)
requires that all connections to metal water piping electrodes take place within the first 5 ft. from the point the water pipe enters the building.
in 250.52(A)(1) Water pipe electorde, and 250.53(D)(2) Supplemental electrode is required to supplement the water pipe in the event we lose the water pipe to a plastic replacement at least there will be a grounding electrode.
When only these two are available, if in tact, the water pipe is the primary electrode, and its conductor is considered the Grounding electrode conductor. Hence sized with the larger of the two cables.

This said, Bennie, your objections are noted and understood. HOw many times have I seen where the waterpipe was originally grounded but the homeowner had cut them years ago because they were some kind of nuisiance.
Also I have seen as I am sure everyone else has where the Grounding Electrode conductor has been run some 60 to 70 feet from the service panel to the water pipe, suppose to be as short as possible but not alway practicable.

WmColt

 

[bennie]

Re: Suplemental electrode conductor

I agree that more than one ground electrode conductor can be run to the ground electrode system, but not to a separate electrode. When the electrodes are bonded they are one electrode. When not bonded they are multiple ground electrode systems.

The earth is a common impedance, therefore it can not be a bond.

What will happen if two separate electrodes are connected individually to the neutral bus, and a transient impulse causes high current flow. The current will divide in the ground electrodes according to the impedance. This will create a potential difference in a small area of the earth.

Bond the same electrodes, connect one ground electrode conductor to one electrode. There will not be a voltage gradient when a high current is flowing.

[ June 08, 2003, 01:26 AM: Message edited by: bennie ]

 

[rasmithircgov.com]

Re: Suplemental electrode conductor

Bennie, I've had a revalation finally understand what you meant about bonding after the first electrode. Sorry it took so long to get through my thick head.So it is a GEC to the first electrode and connections appling to it are different after the first(BONDING)to create a system.

 

[rasmithircgov.com]

Re: Suplemental electrode conductor

Bennie if running seperate connections to electrodes originating from the terminal bar in the main where the Serv. Grounded Entrance Condutor is are you still having this gradientt problem you are talking about. Are they one system bonded together at the Grounded Service Ent. Conductor or Individual Systems and if so can you ellaberate further?

[ June 08, 2003, 05:15 AM: Message edited by: rasmithircgov.com ]

 

[hornetd]

Re: Suplemental electrode conductor

Originally posted by wocolt:
Do "I" feel it necessary? NO of course not but when comming aboard you first salute the National Ensign then the OD.
I still believe the extra ground rod is to help enhance the utility overall grounding system.

WmColt

That is the correct military practice but in Sea Explorers we teach the boys to render three salutes. The first is toward the main mast because sailors kept their shrines there in ancient times. The second is to the national ensign. The third is to the OD. This is to serve as a ongoing reminder of the proper ordering of their obligations. God comes first, the country comes second, the service or organization comes third.
--
Tom