Copper grounding rods

[john.b]

Hello everyone, i building my first ground mount and have two questions about the grounding rod.
1st i see you can buy either solid copper or copper clad/plated, which are the best to use ?
2nd i only have around 10" of soil then i'm down to solid natural rock so all my post holes have been dug out using a jack hammer, holes are 24" x 24" x 36"x depth, will i be ok to drop two rods in the post holes one either side of the array and concrete them in, it may be possible for me to hammer a small hole in the bottom the length of the hammer chisel 14" and get the rod down further but my main concern was will the grounding work if the rod/s are encased in concrete.

Take care
john

[bcroe]

Properly organized, the concrete with some conductors make a great ground. Bruce Roe

[Sunking]

John what do you think the ground does for you under normal operating conditions?

A1. 10 foot copper clad steel rods are used. Coul dno timagine anyone using solid copper rods as they would be too expensive and no way to hammer them in.

A2. There is no better ground than concrete encased electrode.

[solarix]

Read up on something called a UFER. Your concrete footings should qualify. Of course, what really matters is what your inspector thinks....

[foo1bar]

A1. 10 foot copper clad steel rods are used.

Around here it's normally 8' ground rods.
Some places allow 1/2" diameter some only allow 5/8".

But I agree with you and others - a concrete-encased electrode (Ufer) makes sense in a situation like this where you're placing concrete anyhow.

[Sunking]

John I see you have not returned as of yet. Let me offer you this.

For the solar panels the only purpose a Earth Ground serves is for lightning protection and touch potential. Otherwise it has no other function. So if lightning strikes the panels, there is a planned path to earth to discharge, or prevent someone from being shocked if they touch the structure. The panels would work without any earth ground just fine. If the panels are on the roof of your house poses a significant threat from Lightning. However on a Ground Mount the risk are significantly lower. So what is important is you follow minimum electrical codes.

OK you are stuck or perhaps trapped yourself in a Ground Rod Box. You think that is the only way it can be done because you have no experience or knowledge of electrical codes. I would also bet you have no idea what the earth ground is for. Fact is the code offers you all kind of options.

250.50 Basically states all electrodes available at a building or structure defined in 250.52 (A1) through (A8) shall be bonded together and used. Where none exist electrodes using 250.52 (A4) through (A7) shall be used.

• A1. Metal Underground Water Pipe
• A2. Metal Frame of building or structure.
• A3. Concrete Encased Electrode
• A4. Ground Ring
• A5. Rod and Pipe aka 8-foot ground rods or 3/4-inch conduit used as raceway for the PV conductors.
• A6. Other listed electrodes
• A7. Plate
• A8. Metal underground objects.

What your inspector is going to look for to comply with 250.53 (2) is that you are using at least 2 Electrodes from the choice of the 8 above. So you have Concrete Encased Electrodes sort of, and Metal Framing embedded into the concrete sort of so an Inspector might or might not want a good know electrode like a Ground Ring.

All a Ground Ring is ring encircling the structure of not less than 20 feet, in direct contact with dirt, and a minimum conductor size of #2 AWG conductor. In other words dig a shallow trench around the structure say 6 inches deep, lay #2 AWG tinned bare solid copper, and bond it to one of the post encased into the concrete.

The two best electrodes are Concrete-Encased and Ground Rings. It will make the inspector smile and give you a check mark (done).

FWIW do not confuse ground with equipment ground. They are not the same and have different functions.

[Sunking]

Around here it's normally 8' ground rods.
Some places allow 1/2" diameter some only allow 5/8".

Code requires minimum 8 feet length. Code requires copper clad steel rod to be 5/8 inch unless otherwise listed. NEC 250.52 (A)(5)(b) if you want to look it up.

[john.b]

Hello everyone and many thanks for all of your replies.
I must apologize when i ask a question on a forum i always try and add as much info as i think needed so people have a better idea of what i'm asking, i should have mentioned i'm in the UK so my code will be different to yours so will look that up to see what it says.

My main concern which has been answered was not knowing if the concrete would form a bond with the solid natural rock in the ground or if it would form a shield and isolate the rod from the surrounding natural rock.

So i'll go do some reading on the UK code and will take things from there, again thank you all for your help.

Take care
john

[Sunking]

OK John since you are in the UK, there are no requirements.

[john.b]

Hi Sunking, wow that's great and very surprising as the UK has some strange do's and don'ts,
Thank you again for all your help
Take care
john

[Sunking]

Hi Sunking, wow that's great and very surprising as the UK has some strange do's and don'ts,
Thank you again for all your help

You are welcome. Relax the Pipe Stands embedded in concrete are more than adequate for your country. In this application all you need to to minimize touch potential differences under normal operating conditions, and the pipe stand in dirt will do that just fine. US codes are more restrictive and go beyond normal operating conditions. We have more lawyers and idiots than UK does.