What is the point of using a copper "bonded" grounding rod?

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ericsarratt

ericsarratt

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I've been reading up on UL 467 and grounding rods. To be UL listed a rod must have 10mils of copper--that is very thin.

Does the 10mils of copper get scraped off the steel when the rod is pushed into the ground?

How long does it take galvanic corrosion to remove the 10mils of copper from the rod? Doesn't that defeat the purpose of the rod in a few years?

I notice there are solid copper rods and copper coated rods. What do you tend to use and why?
 
I use whatever, the ground rod doesn't really do much anyway so who cares.

I imagine how long a rod lasts is going to vary a lot between different soils.

I've never seen a solid copper rod. I'm not saying they don't exist by they must be very uncommon.
 
ericsarratt said:
I've been reading up on UL 467 and grounding rods. To be UL listed a rod must have 10mils of copper--that is very thin.

Does the 10mils of copper get scraped off the steel when the rod is pushed into the ground?

How long does it take galvanic corrosion to remove the 10mils of copper from the rod? Doesn't that defeat the purpose of the rod in a few years?

I notice there are solid copper rods and copper coated rods. What do you tend to use and why?
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I moved an office trailer one time that had been there for like 10 years. I pulled the ground rods out with a forklift. They looked fine. I reused them at the new site.
 
If there are no other electrodes in the scenario there will need to be two rods unless your EC has the equipment to prove 25 ohms to earth for a single rod. Note an ohm meter will not do it.
 
roger said:
If there are no other electrodes in the scenario there will need to be two rods unless your EC has the equipment to prove 25 ohms to earth for a single rod. Note an ohm meter will not do it.
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In one of my really old textbooks, the test was to connect the ground rod to one of the 110v hot leads and see what amperage fuse it could blow
 
ericsarratt said:
....

Does the 10mils of copper get scraped off the steel when the rod is pushed into the ground?
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Not in my experience. Sometimes I've had to pull a rod out after a couple feet for a different try. If the soil is soft enough to do that, there's no meaningful damage.
ericsarratt said:
How long does it take galvanic corrosion to remove the 10mils of copper from the rod? Doesn't that defeat the purpose of the rod in a few years?
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Unknown but if the copper layer oxidizes it's still the interface between the steel and the earth. Would the oxidized copper layer be less conductive than the earth itself? Not sure it makes a meaningful difference.

ericsarratt said:
I notice there are solid copper rods and copper coated rods. What do you tend to use and why?
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I use a listed rod because it's relatively easy to get and passes inspection.
 
Copper clad steel is much cheaper than solid copper.

Copper is a more 'noble' metal than steel. Instead of the copper slowly corroding away protecting the steel, it is the steel that would corrode (assuming the steel is exposed, say through a cut in the surface)

Jon
 
Flicker Index said:
Keeps them tweakers away.
www.tdworld.com

Cutting Out Copper Theft

ComEd works to discourage the increasing problem of pole ground thefts.
www.tdworld.com www.tdworld.com
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I am already worrying about the 4 awg copper wire for the new rods. I was thinking of enclosing it in PVC conduit from the bottom of the box to just below grade it just to keep it out of sight.
 
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