Building Steel Concrete Encased Electrode and Ground Rods

[jar546]

I have a question that I believe will garner different answers.
If I have a new building with a new electrical service and prior to pouring the foundation, a code-compliant connection of a properly sized Grounding Electrode Conductor (GEC) to the rebar in the footing is made that connects the GEC to hundreds of feet of #4 rebar, is a ground rod(s) even necessary?

I will say that I often see a triangle of 10' ground rods for the Grounding Electrode System (GES) in addition to hitting building steel such as footing rebar, but are the ground rods even necessary to comply with the code at that point?

 

[jar546]

I will go first to get the party started.

My answer is no, if you connect a new service GES to a Concrete Encased Electrode (CCE) then there is no requirement for a supplemental electrode such as a ground rod or rods.

If however, your GES is connected to a ground rod, then you must provide a supplemental ground rod.

 

[wwhitney]

If however, your GES is connected to a ground rod, then you must provide a supplemental ground rod.

I'm going to quibble slightly with that, if you need 0 ground rods because you have a CEE, and you choose to install one ground rod for fun, you can call it an auxiliary electrode (250.64) and not comply with the "25 ohms or another ground rod" rule.

Cheers, Wayne

 

[jar546]

I'm going to quibble slightly with that, if you need 0 ground rods because you have a CEE, and you choose to install one ground rod for fun, you can call it an auxiliary electrode (250.64) and not comply with the "25 ohms or another ground rod" rule.

Cheers, Wayne

Wayne, Taken out of context. I am talking about a new installation that has no building steel option and chooses the ground rod option. That is when the auxillary comes into play.

 

[Mr. Inspector]

So what do you do when the electrician can't find the connection that was put in during the footing inspection because it got lost or buried.

 

[jar546]

So what do you do when the electrician can't find the connection that was put in during the footing inspection because it got lost or buried.

What connection? The CCE?
If they can't find it and it is no longer accessible, they have to put in 2 ground rods.

 

[north star]

# ~ #

I will say, "No, not required !".........That said though, some coordination
and actual communication about where the grounding connection to the
CEE is, would be required and documented.........Also, while not required,
if the area [ i.e. - most of Florida ], has a history of lightning \ straying
currents, it is recommended to have additional grounding.........Then there
is that whole "costs thingy" involved..........Who would pay for additional
grounding if the NEC or the FEC doesn't require it ?

# ~ #

 

[Beniah Naylor]

What connection? The CCE?
If they can't find it and it is no longer accessible, they have to put in 2 ground rods.

We would make them either find a piece of rebar to bond to, or pour a new concrete encased electrode due to 250.50 stating that all electrodes present must be bonded together. Rebar is present, so it must be bonded. Pouring a new CEE works because if multiple concrete encased electrodes are present, you only have to bond to one per 250.52(A)(3).

I used to hold the same view, drive two ground rods and be done, but I went back and read the comments from the code making panel when they put 250.50 in the code, and again when they changed the wording in the early 2000s made me change my mind.

Two ground rods would be a heck of a lot easier though, and probably doesn't reduce any safety. I could certainly see the benefits of that approach.

 

[jar546]

We would make them either find a piece of rebar to bond to, or pour a new concrete encased electrode due to 250.50 stating that all electrodes present must be bonded together. Rebar is present, so it must be bonded. Pouring a new CEE works because if multiple concrete encased electrodes are present, you only have to bond to one per 250.52(A)(3).

I did the same at one point but was told that was overreach. What year are the comments you are referring to. I would like to research the CMP notes.

 

[ICE]

250.50 Grounding Electrode System. All grounding electrodes as described in 250.52(A) (1) through (A) (7) that are present at each building or structure served shall be bonded together to form the grounding electrode system. Where none of these grounding electrodes exist, one or more of the grounding electrodes specified in 250.52(A) (4) through (A) (8) shall be installed and used.

Exception: Concrete-encased electrodes of existing buildings or structures shall not be required to be part of the grounding electrode system where the steel reinforcing bars or rods are not accessible for use without disturbing the concrete.

 

[jar546]

Exception: Concrete-encased electrodes of existing buildings or structures shall not be required to be part of the grounding electrode system where the steel reinforcing bars or rods are not accessible for use without disturbing the concrete.

BINGO - which is why I had to stop requiring this going all the way back to Pennsylvania.

In my current jurisdiction, you can't even schedule the footing, slab pour until you've already been signed off on the CEE bond.

 

[Beniah Naylor]

These are the main ones. My memory is hazy, but I recall from my research that sometime after 1978 they rearranged 250.80 code sections to be in the 250.50 area where they are today. They did not change anything of substance relating to CEEs that code cycle, they just moved the requirements.

 

[ICE]

In my current jurisdiction, you can't even schedule the footing, slab pour until you've already been signed off on the CEE bond.

I usually verify the CEE (ufer) at the footing inspection.

 

[jar546]

I usually verify the CEE (ufer) at the footing inspection.

Yes, however, multidisciplined inspectors are not the norm here, and not allowed in some counties.

 

[ICE]

Yes, however, multidisciplined inspectors are not the norm here, and not allowed in some counties.

I have never been what you might call "disciplined". However, as you are well aware, I have been disciplined multiple times. And by the way, I too am not allowed in some counties....but mostly cities.

 

[wwhitney]

BINGO - which is why I had to stop requiring this going all the way back to Pennsylvania.

Seems like when a permit covers placing concrete that would create a new CEE, that's not a CEE "of an existing building," so the exception would not apply.

Cheers, Wayne

 

[wwhitney]

Wayne, Taken out of context. I am talking about a new installation that has no building steel option and chooses the ground rod option.

That was not specified in post #2, and if anything my reading of the context of that post is that there is already a CEE connected to the GES. Certainly if the ground rod(s) are the only grounding electrodes (other than metal water piping), then you either need to prove one ground is 25 ohms to ground or less, or provide a second ground rod.

My point was that if you have one ground rod connected to the GES, and if deleting that ground rod would still leave you with a compliant GES, then there's no need to do either of those things.

As to the question of whether ground rods are required when you have a CEE, the answer is obviously no.

Cheers, Wayne

 

[jar546]

My point was that if you have one ground rod connected to the GES, and if deleting that ground rod would still leave you with a compliant GES, then there's no need to do either of those things.

We completely agree with each other.

As to the question of whether ground rods are required when you have a CEE, the answer is obviously no

While we agree on this, I still have some of my peers requiring it, even though they are wrong.

 

[Mark K]

Suggest that since we are talking about a UFER ground no ground rods are required unless you consider the ufer ground a ground rod.

 

[wwhitney]

While we agree on this, I still have some of my peers requiring it, even though they are wrong.

Tell them to read the second sentence of NEC 250.50 more closely, which ICE quoted in post #10: "Where none of these grounding electrodes exist, one or more of the grounding electrodes specified in 250.52(A) (4) through (A) (8) shall be installed and used."

Although I have heard of POCOs who require ground rod(s) even if there is a CEE. Maybe as an "easier for the linemen to field verify" measure. In which case an inspector can reasonably say "the electrical code doesn't require any ground rods because you have a CEE, but the POCO does, so you better install them or you won't get your power hooked up." But not fail an inspection for that.

Cheers, Wayne

 

[Beniah Naylor]

Although I have heard of POCOs who require ground rod(s) even if there is a CEE. Maybe as an "easier for the linemen to field verify" measure. In which case an inspector can reasonably say "the electrical code doesn't require any ground rods because you have a CEE, but the POCO does, so you better install them or you won't get your power hooked up."

This is exactly how it is in my jurisdiction.

 

[ICE]

The last district office that I was assigned to has five inspectors. Half of them (2.5 inspectors) refused to require a buried metal water main to be used as a grounding electrode.


I had written a correction to run #4 copper to the water main. Here is how a local city BO sees it:

"So he said that this city allows #6 to the rods and you are done. I wondered about bonding the water pipe. He said that the gas meter is usually near the el. service so they run a #6 to the gas pipe.... then they jumper between the gas, cold water pipe and hot water pipe at the water heater with whatever wire is on hand. Great news as the contractor had plenty of #6."

The buried metal water main is bonded via gas pipe.

 

[Mark K]

Tell them to read the second sentence of NEC 250.50 more closely, which ICE quoted in post #10: "Where none of these grounding electrodes exist, one or more of the grounding electrodes specified in 250.52(A) (4) through (A) (8) shall be installed and used."

Although I have heard of POCOs who require ground rod(s) even if there is a CEE. Maybe as an "easier for the linemen to field verify" measure. In which case an inspector can reasonably say "the electrical code doesn't require any ground rods because you have a CEE, but the POCO does, so you better install them or you won't get your power hooked up." But not fail an inspection for that.

Cheers, Wayne

How does the statement

"..so you better install them or you won't get your power hooked up." differ from extortion.?

 

[wwhitney]

How does the statement "..so you better install them or you won't get your power hooked up." differ from extortion.?

Take that up with the power company, not the building department.

But from the power company's point of view, it would be a required safety measure. They want the electrical service grounded at the customer's premise, and they want to be able to verify that externally. So they make an external ground rod a requirement. I think sometimes the power company only requires one ground rod, which makes the distinction I made in posts 3/17 actually matter.

Cheers, Wayne