# grounding electrode systems



## SWDweller (Dec 9, 2020)

You need to run a wire to all metal piping systems, no matter the distance. You need to bond to building steel by code.

Where did you find you only need 2 sources of ground? Typically in NA we use a single point ground. Why is the distance a problem? You get paid for the work do it correctly.

I suggest some reading in NEC 250 and the Soares Book on Grounding.

The drawings are rudimentary and have incorrect information.
NEC table 250–94(a) suggests #0 Cu or #3/0 Al for grounding.
There is a table near there for bonding the water and steel structure.

Do you realize the amount of unfused conductors you have on the 400 amp service page
Where I live that would NEVER be allowed.


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## paulengr (Oct 8, 2017)

In North America we refer to everything as grounding which is what makes it so confusing.

Specifically connecting an electrode to a single jumper to the neutral is not as important as you might think and it doesn’t get bigger as the project grows. If your power system lacks this connection (ungrounded) it is insulated from the Earth which builds up a charge in the capacitance (two conductors separated by an insulator…get it?) This causes major issues with transients (surges) every time you get a fault on anything that is actually grounded. So it drains the charge away. Plus it helps with lightning on incoming service drops. I’m specifically speaking to the stuff buried in the ground here. Bonding has an entirely different purpose. It maintains a low impedance path back to the transformer so fault voltages are low enough to prevent serious shock and injury and hopefully provides enough fault current to trigger the breaker. All this is called “grounding” too.

As far as one or two or twenty electrodes it’s pretty common to see massive ground grids for buildings. A lot of commercial guys like to Cadweld every column and run all the pigtails out to a “ring electrode”. All that is purely lightning protection and very simple to do for the iron workers. It can be tied into the electrical ground as can water pipes and other buried services but that’s really all it’s for. The two electrode rule is one of the more idiotic Code requirements. Specifically the Code calls for one electrode with a resistance of 25 ohms or less or two electrodes with no resistance requirement. That’s obviously ridiculous. If I put two or a hundred electrodes in dry sand or rocky soil I won’t get to 25 ohms. And the 25 ohm requirement is completely arbitrary anyway. But the tine required to do a proper 3 point grounding test takes much longer than driving a second rod. So everyone drives two rods. The exception is with utility substations and large radio transmitter towers. They love to bury as much wire and steel as possible.

I have done the test route once. The room was concrete all the way around so it just wasn’t practical to put in another ground without drilling through unknown territory and no practical way to dig it up either. We couldn’t prove it was two electrodes. So we did the ground testing route and had it all set up when the inspector got there. So he looked at it and after he went back to look at his Code book he was satisfied.


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## Majewski (Jan 8, 2016)

paulengr said:


> In North America we refer to everything as grounding which is what makes it so confusing.
> 
> Specifically connecting an electrode to a single jumper to the neutral is not as important as you might think and it doesn’t get bigger as the project grows. If your power system lacks this connection (ungrounded) it is insulated from the Earth which builds up a charge in the capacitance (two conductors separated by an insulator…get it?) This causes major issues with transients (surges) every time you get a fault on anything that is actually grounded. So it drains the charge away. Plus it helps with lightning on incoming service drops. I’m specifically speaking to the stuff buried in the ground here. Bonding has an entirely different purpose. It maintains a low impedance path back to the transformer so fault voltages are low enough to prevent serious shock and injury and hopefully provides enough fault current to trigger the breaker. All this is called “grounding” too.
> 
> ...


what about the word "bonding"


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## yankeejoe1141 (Jul 26, 2013)

Majewski said:


> what about the word "bonding"


I always have to think is this grounding versus bonding, like when I’m doing a pool and such.


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## splatz (May 23, 2015)

Robbie Rob said:


> ...The problem is the water meter is 500 plus feet away. Can I go to bulding steel instead of going all the way to the water mater?


You can run a bonding jumper to the water pipe electrode using the metal structural frame of the building as a conductor, *if the building steel is suitable*.


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## SWDweller (Dec 9, 2020)

As Paulengr indicated, testing can be hard. I was to do a 4 point at a place up in the mountains of New Mexico and found all of the ground around where I was was locked down by security measures. Finally told the engineer that we would have to pass on the test unless he could connect us with people who could drive the stakes in the secured areas.
Beautiful spot they created the Atom bomb there in the 40's.


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