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Joined: Jan 2005
Posts: 5,460
Likes: 3
Cat Servant
Member
Maybe this is one of the more mundane topics, but I believe it is worthy of a dedicated discussion.

When doing a service change, we often are required to “bang in” a ground rod (or two) and connect them to the service. We also need to provide attachment points for landing ground wires by the cable / alarm / satellite guys. Here’s where things get confusing; Local ordinances often modify NEC rules, and trade practices vary considerably.

How do you do the job? I’d like to focus on these details:
-- Do you drive the rods below grade?
— If so, how are the connections inspected?
— What tool is used to drive the rods?
— What wire do you use?
— How do you protect the above-grade portion of the wire?
— Do you bond the wire to the buried end of the conduit? How?
— How do you connect multiple rods together?
— Do you take any steps to protect the wire connecting multiple rods?.

I’m in the middle of a service change, and my practices seem to be unusual around here. I’ve had some trouble finding my usual hardware.

Please post pictures; I plan to do so later this week.

Joined: Jul 2004
Posts: 9,954
Likes: 34
G
Member
If you are using an 8' rod, it needs to be driven flush to or below ground. (8' of ground contact)

When I was looking, they generally left a little dirt out so I could see it and back filled later. If it was above grade, I loaned them my 2# hammer wink

I have seen rotary hammers used but here in Florida you could drive it with your Kleins.

#6 solid is all you need but I see #4 used to sidestep the physical protection thing. (Gets back to that "severe" damage thing) They typically bring it above grade next to the building if it is unprotected.

Protection is usually RNC if present.

If it is metal, there is an appropriate fitting that bonds the raceway to the rod clamp. Engineers will tell you high frequency transients will use the raceway and ignore the wire.

Typically the GEC passes through the first clamp and terminates at the second rod clamp unbroken along the way.

RNC or the afore mentioned metal raceway with appropriate fittings if it is not just bare solid, below grade.


Greg Fretwell
Joined: Apr 2002
Posts: 7,389
Likes: 7
Member
Reno

Yes, flush or below grade; some soil left out for inspection
Roto hammer or a small sledge hammer.
#6, stranded, bare, or solid if it's available
Above grade is 3/4" sch 80 PVC, mostly for appearance
No bond/choke required for PVC
Wire is continuous as Greg said, 250.94, to rod to rod
Rod to rod is buried, in PVC or neatly attached to the structure.

Just FYI, I did not do a lot of resi, mostly comm.


John
Joined: Jan 2005
Posts: 5,460
Likes: 3
Cat Servant
Member
I’ve completed the job and hope to soon have pics to post, as an aid to discussion.

The ground was firm, best described as compressed mud. Digging maybe nine feet of 8” deep trench with two 12” pocket holes was a snap.
'
Driving the rods with an SDS-Max roto-hammer was a snap. I’d estimate a total of fifteen minutes for both of them. I was able to start them by pushing the first six inches in by hand. My shiny new roto-hammer runs on a pair of 18V batteries.

I saw an original variation of the pile driver on the internet. Imagine a very big sledge with the handle replaced by a one-inch pipe. By slipping the pipe over the rod, you can hammer the end of the rod without getting on a ladder. Looks to be a great way to start the rod; I might have to make one!

As to burying the wire: I don’t see any depth requirement in the code; applying the usual conductor burial table seems improper. Your thoughts?

About the wire itself: When the requirement for a second ground rod was instituted, a speaker at the local IAEI seminar explained that it was NOT the intent of the code to require a single continuous wire to run from panel to rod to rod. Using one wire to run from the panel to the first rod, and a second wire between rods.I note that NONE of the usual fittings have their terminals oriented to facilitate a continuous wire passing through.

Joined: Jul 2004
Posts: 9,954
Likes: 34
G
Member
You can easily thread the wire through an acorn before you put it on the first rod. That is usually what I see.
The burial is just to protect the wire from weed eaters and lawn mowers. If you think it needs more protection you can always slip it through some sch 80 RNC.
That "pile driver" idea has been around forever. Fence installers always have one on the truck, usually with 2 big handles.


Greg Fretwell
Joined: Jan 2005
Posts: 5,460
Likes: 3
Cat Servant
Member
I used to have a two- handled pile driver. Perhaps I was not clear in describing the variation I saw.
The variation looks a lot like a big sledgehammer. The difference is that the “handle” has been replaced by a length of pipe. The idea is to slip the pipe over the rod, stand the rod up, then push the driver up — only to let it free-fall down the rod. No need to climb a ladder.
Contrast this operation to the usual pile driver, where you carry the tool up the ladder with you, then make your first blows while still on the ladder.
Once the rod is driven most of the way in, you reverse this variation and use it like a tamper (not like a hammer). Again, you’re working while standing, rather than bending over to grab side handles.

Joined: Jul 2002
Posts: 8,443
Likes: 3
Member
Hi John,
It's been a while. grin

We use this sort of thing over here in New Zealand to protect our earth rods:

Earth Rod Protection Box

Personally, I've either used an apprentice with a hammer/sledge hammer or a Hilti concrete/impact drill with a large socket on the end.
The worst thing you can have happen when driving an earth stake is have it strike a stone in the ground and have it come up behind you.
That is our soil here.

Joined: Nov 2022
Posts: 1
D
New Member
Foundation grounding is used as a grounding conductor for all metal structures of the building as well as lightning protection. It is known that grounding is required for any building. Foundation grounding is a mandatory requirement for all new construction. The grounding circuit here is embedded in the foundation in order to effectively protect against corrosion. When reinforcing the foundation in our new house, we decided to trust www.almightyconstructionnw.com because they have a lot of experience with cement and I am not sure that I can do a screed on the floor. Also, they suggested I do the wiring right away and hide everything under the framing that would connect the basement to the kitchen.

Last edited by Denis; 11/07/22 12:26 PM.
Joined: Jul 2004
Posts: 9,954
Likes: 34
G
Member
The Ufer (concrete encased electrode) is now in our building code too and that eliminates the need for a made electrode like a rod. I have both types of electrode here all bonded together with #2 copper, just because I came up with a bunch from a botched computer room built. I bonded the footer steel on my addition and connected it to the GES. Perhaps my biggest Ufer is an inground concrete pool but you can't say that out loud. NEC purists have their hair catch on fire if you do. Copper doesn't lie tho. There are multiple connections between the MBJ and the pool, mandated by the various code sections referring to grounding and bonding.


Greg Fretwell
Joined: Jan 2005
Posts: 5,460
Likes: 3
Cat Servant
Member
Trumpy, that’s a very elegant solution. Alas, the exposed few inches of rod leaves an opening for some jackalope to object that the “entire” rod isn’t in direct earth contact. Conceivably one could do something similar using a “hand hole.” Check zoro.com for the Adamax 910 to see what I’m describing.
Instead, we’re put in a position where we need leave the connections exposed, filling in after inspection.

The “Ufer,” or concrete encased electrode, is a better way in every way. My new garden shed has a length of wire in the slab — just in case I later add power. Alas, there remain millions of homes built before our codes accepted this method. My own 1957 house was “grounded” by the simple expedient of wrapping / tying a small wire around a water pipe.
The service change I just completed was on a house that was first built in 1933, then added to several times over the years and had brick sheathing added. Slab on grade — no crawl space. I don’t think it was grounded at all.

The point is that the humble ground rod is going to be around for many more years.

As I grew up I saw the EGC requirements change, each change making the wire stouter and the protection more robust. Between the lawn mower, the weed-eater, and copper-stealing drug addicts requirements reached the point where installing the EGC became one of the most physically demanding parts of a service change.

Rules now call for:
— Two rods, at least six feet apart;
— The wire can be insulated — any color EXCEPT green,; and,
— We need to provide an exposed connection point for the data guys to land their grounds. For many years this connection point exposed the wire to damage.

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