When adding a grounding electrode to reach <25? when using a rod, is it permissible to for example, install a second acorn type clamp on the first rod and then run a piece of #6 copper to the second rod located at least 6 feet away from the first rod? The alternative would be to use only one clamp on the first rod and run through the clamp (uncut) to the second rod.

Yes, it is permitted.

Ryan
I thought the GEC had to be without splices except for specified connectors. I don't the the acron clamp was one of these clamps.

The GEC is the conductor from the Service Neutral to the Ground Electrode System (GES). The GES consists of all the various electrodes which are bonded together. At any one electrode is where the GEC stops. Past this, they are electrode bonding conductors and I don't see any splicing prohibitions on those.

The only thing you have to watch is when different size bonding wires are used. Lets say you have a #4 to a water pipe and then a #6 from there to two rods. You can't run a #4 GEC from the service to the rod because the bonding wire to the pipe is too small. Running a #4 GEC to the water pipe would be OK. Running a #4 GEC to the first rod would be OK as long as a #4 connects the first rod to the pipe. Even if there was a #6 from the first rod to the second this would still be OK.

George:
The issue around here was that second #6 was put under the acorn. It is listed for a single conductor only.

Mark:
I have never came accross an installation, as you described. It reads like you are running a #4 from the panel to the water pipe, and then a #6 to the ground rods????
I have never seen that, now I'll have to go get the bible!! WHAT DO YOU GUYS THINK??

John

I have had to do something similar several times. Since we are locally required to enclose the GEC in pipe, and the pipe/ ground rod connector does not allow for the wire to continue elsewhere, it is necessary to use an additional pipe/rod clamp, and run a separate pipe, with a separate wire, to the next ground rod.

Simply put 2 acorns on the first ground rod and you are good to go.

250.62(F) is a powerful section that it seems like few people come to grips with. The handbook has a picture that clearly shows the ramifications of it.


This allows both installations that George asks for, provided you use two connectors for the seperated GEC.

A little tip that this section allows is great for a large building. Say you have your switchgear near a building steel column. However your cold water is 500' across the warehouse which happens to be next to another building steel column. Simply bond your switch gear to the first column and bond the 2nd column to the cold water. Thus saving 500' of GEC.

One catch, engineers will often exceed NEC requirements and require seperate conductors. But, that is not required per the NEC.

Morning John


I think it is fine.

I have gone from a large service to building steel then 200' - 250' across the building I jumped from building steel to water service saving the long run of 3/0 between the water line and the service.

Here is a Handbook image that shows some possibilities.



Bob

OK how about if the electrode in question is a Ufer. I pick it up at the service disconnect and 300' away I find another piece of turned up Rebar, can I bond my water to that?

Based on the discussion and the image above, if the turned up rebar is closest to the water, I don't see any reason not to use it.

If any portion of the water is nearer to the service, then AHJ would probably say no.

Bob:
Good evening (long day for me).
What you have in your drawing is a 'no question' job, and there is no issue.
The way I read (past tense) the original post.

...Lets say you have a #4 to a water pipe and then a #6 from there to two rods. You can't run a #4 GEC from the service to the rod because the bonding wire to the pipe is too small. Running a #4 GEC to the water pipe would be OK. Running a #4 GEC to the first rod would be OK as long as a #4 connects the first rod to the pipe. Even if there was a #6 from the first rod to the second this would still be OK."

I read that as going from a resi service panel to the water pipe, and from the water pipe to the rods....just don't sit right...never have seen anyone go that route, even the 'lectrician named "self" & his buddy "homeowner". The route everyone around here takes is panel to water pipe, panel to rods; excluding the McMansions with ufers.

John

Gentlemen- as usual these threads seem to drift. That's not a bad thing because it brings in good information. BUT- The orginal post only talked about rods. Nothing was mentioned about steel or water . And for my money- two rods with a jumper (#6 awg cu) between them would constitute a grounding electrode system satisfying the code minumum requirement unless, there were other electrodes present. That said- a single Maximum size 6 AWG cu run to either rod gets the job done. The size of the service is a moot point.

It might not sit right with you Hotline1, but it is perfectly allowed by the NEC.

Study the path the GECs take in the picture iwire posted. A lot of electricians with way more experience than me are shocked by it. The are many tales of required paths GECs are to take, yet they are not based on the code.

[This message has been edited by dmattox (edited 09-21-2005).]

"A lot of electricians with way more experience than me are shocked by it."

No pun intended, I'll bet.

Hi John, I am not following you on this.

As log as one keeps the wire size correct for the route they take all is good.

Either of the following will meet code.

Panel > 4 AWG > Water Pipe > 6 AWG > Ground rod.

Or

Panel > 4 AWG > Ground rod > 4 AWG > Water Pipe.

They sure do but I did not see the actual subject drifting to much here.


I agree.

Greg


I think that is an excellent question.

Here is my answer.

I do not consider the cement itself to be an electrode. Think of what the NEC calls it.

"Concrete-Encased Electrode"

That being the case you would have to hook into the electrode itself not just another rebar.

IMO the rebar would have to be tied together continuously for that 300' in order to do what you ask.

Personally I would not be comfortable doing it that way but IMO the NEC allows it.

Bob-

Just out of curiosity, if you were able to verify that the rebar was indeed tied together for the entire 300', would you still be uncomfortable with the installation? Personally, I'd be quite comfortable with it. The key is knowing for sure that the bar is tied together. As far as the length is concerned, the electrode needs to be at least 20' but can (and most times is) longer than that.

Bear in mind the NEC says a Ufer is only worth a #4 cu GEC. The connection between rusty rebar is only being lapped and somewhat loosely tied with rusty wire. Still OK with it?

I was hoping someone might have heard of a real test to see how much the concrete adds to the connection.
I think of this like the dirt between those rods within the "well of influence".

Guys:
I'nm not trying to start a war..the point that I'm saying is that I have not seen anyone run a EGC to the water, and from the water to the rods. Nor did I say it may be a violation.


John

I think the code says quite the opposite. No matter what size the switchgear is a #4 is enough.

Lets make the question a little simpler. You have 1200 kcmil SEC. You have a #4 copper as a ufer. You attach 3/0 from the switchgear to start of the ufer. At the other end of the ufer you attach 3/0 and bond to cold water. Is this legal?

I personally think the code allows this by 250.62(F), while I consider it wrong.

Hotline1, I do most of my work in Union County, NJ, and I too would never run #4 on a 200 amp service to the water ground and from there run #6 out to the ground rods. I was just never taught to do it that way. I do understand, though, how everything is bonded together.

iwire, that image paints a very clear picture of the discussion. Thanks.

George:

I would say that if both conductors were put under the same acorn clamp it could not be done. If the second clamp were provided on the ground electrode (rod) Then it would be ok. COde does not limit the number of acorn clamps. It is even shown in the Soars book.