Ground rods

[NMCB13]

Would the use of stainless steel ground rods be better than stantard copper ground rods in florida?

 

[Dennis Alwon]

In SC coastal areas they use to require at least a copper ground rod due to the corrosive nature of the salt in the sand. Stainless Steel may outlast copper ( I am not sure) but I believe that copper is still suitable.

 

[Dennis Alwon]

Here is a manufacturers sight
http://www.erico.com/products.asp?folderid=164

It appears ss is better but is it necessary??????


Copperbonded Ground Rods

Resist corrosion better than galvanized rods allowing for a 30-year service life in most soils
State of the art manufacturing process ensures uniform plating thickness
Average tensile strength of 80,000 psi and straightness tolerance of .010" per linear foot
Exceed the requirements of ANSI?/UL? 467-1984, CSA?, and ANSI/NEMA? GR-1


Stainless Steel
Features
Type 304 solid stainless steel
Service life up to 40 years
For use in highly corrosive soils
Pointed and sectional rods available
Contact ERICO for other sizes

 

[bphgravity]

Do you mean standard galvanized ground rods?

Copper would be your best choice in my opinion. Here is part of an article from IAEI magazine:

Life Study of Rod Type Grounding Electrodes
Ground rods can be constructed of uncoated steel if they are equal to or greater than 5/8" in diameter. This diameter requirement allows for mechanical rigidity for installation as well as mass to allow for deterioration by corrosive action; a ground rod that starts out at 5/8" will take more time to corrode away than one that started out at ?".

It is a very common misconception that the copper electroplating on a rod is used to increase the conductivity. It is not. The resistance of the earth compared to that of the rod itself makes the improved conductivity of the copper plating insignificant. Copper electroplated rods utilize the corrosion prevention characteristics of copper to extend the life of the electrode by as much as 30 years in most soils. The resistance to corrosion allows the copper electroplated rod to be smaller in diameter than the galvanized or steel equivalent. This is also true of stainless steel rods, but the cost of stainless steel is prohibitive for use in everyday installations. The corrosion resistance characteristics of copper-plated steel were demonstrated clearly in the National Bureau of Standards Circular 579 titled ?Underground Corrosion.? This study examined more than 36,000 specimens testing over 300 varieties of ferrous, nonferrous and protective coating materials in 128 test sites in the United States. The study shows that a typical 10-mil copper plating on steel will provide about 40 years of service life versus 13 years for the typical 3.9-mil coating of zinc on a galvanized rod. The results of this study were further corroborated by the ongoing National Electrical Grounding Research Project test of ground rod performance, originally initiated by the Southern Nevada Chapter of IAEI. The results were definitive: The typical copper electroplated rod was virtually free of corrosion while most galvanized rods showed severe deterioration and corrosion after 11 years of service.

 

[bphgravity]

Also, check out this report:

http://www.erico.com/public/library/fep/strike/LT0540.pdf

 

[Pierre C Belarge]

Brian
WOW!
Ground rods that I drove 25 years ago are probably gone or nearly gone...
this should make for an interesting topic about the second ground rod requirement. I may have driven 10 copper ground rods in the years, 100s of gal though

I wonder if the Copper Org had anything to do with this paper?

 

[bphgravity]

I recently had the opportunity to see a couple ground rods pulled up during the demolition of a 45 year old building. They actually looked pretty good. So much depends on the soil conditions and climate.

 

[brian john]

Bryan: I agree with that, my house in Alexandria VA was built in 1929 the utility water line was installed then and still intact when I replaced it in the 80's (steel pipe) though when cut into 1' sections I could not see through it.


How many houses built in the 60' and 70's still have their original copper water lines? Most of them I would bet. Heck Washington DC had wooden lead lined water pipes still in use till a few years back, these were supposedly installed in the late 1800's

 

[mikehughes8]

Geez
I think they just need to start using gold for ground rods. They are affordable, non-corrosive, and they are better conductors :smile:

 

[brian john]

Mike give me a heads up when you start using the new gold standard rods, I'll test (remove) them for you.

 

[JohnJ0906]

Geez
I think they just need to start using gold for ground rods. They are affordable, non-corrosive, and they are better conductors :smile:

affordable for who? Maybe Bill Gates, but not me!

 

[stickboy1375]

The earths resistance is so high anyway, do ground rods actually prevent any damage from lightning anyway? Is there actually any scientific proof? Or are we just wasting our time driving these things???

 

[JohnJ0906]

Actually, when I took Mike Holt's grounding/bonding semanar last month, he talked about the earth itself having very low resistance. It is the contact resistance between the ground rod and earth that is measured.

 

[stickboy1375]

so whats the next step? stop wasting our time or do we come up with something better?

 

[bphgravity]

The earths resistance is so high anyway...

Actually, the earth is like an infinite number of resistors in parallel. The total resistance ends up less very small.

do ground rods actually prevent any damage from lightning anyway? Is there actually any scientific proof?

No. Most recent studies show ground rods are very ineffective at reducing the surge impedance of a lightning strike. There are too many components of lightning's transient current and voltage for a typical grounding system to effectively carry and distribute into the earth. The best protection against lightning remains bonding of all metallic and conductive parts of a structure and a NFPA 780 compliant LPS.

Or are we just wasting our time driving these things???

Most likely...

 

[stickboy1375]

So why is the NEC so hardcore about bonding anything to the earth? We know very little about lightning yet impose so many rules about it..?

 

[brian john]

Bryan:

ground rods are very ineffective NFPA 780 compliant LPS.

You can't have your cake and eat it too CAN YOU.....NFPA780 requires ground electrodes.

Why are they in the NEC, who has the guts to pull that article out? And there are many who live and die by the rod in the earth (or 2 rods to avoid testing).

 

[bphgravity]

I am certain you know what I mean by my comments Brian.

Driving a ground rod at a service and calling that lightning protection is ridiculous.

Installing a NFPA 780 compliant LPS at least has the makings to be called lightning protection.

Many have lived and died for the most useless causes, but that is no indication to have faith in their convictions…

 

[brian john]

Bryan I KNEW what you meant, I just like to inject a little humor (I KNOW and it was very little humor).


I met a salesman that would have gone fist and cuffs (as grandpa us to say) with you (well me) if you said anything negative about his dissipation array system, and a number of large data centers in our area bought into his pitch.

 

[LarryFine]

So why is the NEC so hardcore about bonding anything to the earth?

Let's suppose you have an existing building, no slab (or access), completely gutted, getting a new electric service, and a completely non-metallic water system.

If the choices are made electrodes or none, what would be your preference? You'd be happy with a floating (as far as the building is concerned) 'grounded' conductor?