Concrete Encased Electrode

[mkgrady]

I'm wiring an addition to a home. I'm assumming a CEE will be required because the addition will have rebar in the footing. If no rebar was being installed would I still need to install a CEE? Since the home already has a GEC conductor to the water pipe and to ground rods does the GEC have to go all the way back to the service or can it go to the subpanel in the new addition? Can the GEC be spliced or does it have to be one continous piece?

 

[George Stolz]

Check with your AHJ.

If you're not upgrading the service, then it very well could be that you can disregard it.

If you wish to upsell a CEE to the customer, you could try that before consulting the AHJ. Now would be the time to add one, if they wanted it. I don't know how I'd sell one myself, but...

Edit to add:

If no rebar was being installed would I still need to install a CEE?

If no CEE is present, then there is not one to connect to. See 250.50.

Since the home already has a GEC conductor to the water pipe and to ground rods does the GEC have to go all the way back to the service...

No, you are permitted to run a bonding jumper from electrode to electrode. 250.64(F).

...can it go to the subpanel in the new addition?

Easy answer is, no. 250.24(A)(1), 250.64(F).

Can the GEC be spliced or does it have to be one continous piece?

That's what makes the last question difficult. 250.64(C)(3) allows you to connect to an accessible busbar. It's kind of a fringe idea to use a subpanel for that "accessible location." I wouldn't try to pull it myself, because I haven't thought it through much yet.

Now, if you run your conductor to the water pipe or ground rod instead of the service, then it is a bonding jumper (between electrodes). See 250.53(C).

 

[mkgrady]

I should have said, I already checked with AHJ. He wants the CEE. I'm posting questions because I didn't think it was required on an existing home with no service upgrade. Maybe I need it because the builder IS putting rebar in the footing. I'm still wondering if NEC requires it when there is no rebar in the footing.

 

[infinity]

I should have said, I already checked with AHJ. He wants the CEE. I'm posting questions because I didn't think it was required on an existing home with no service upgrade. Maybe I need it because the builder IS putting rebar in the footing. I'm still wondering if NEC requires it when there is no rebar in the footing.

No rebar, no CEE required. Recently did an addition with a new service and the GC installed 3/8" rebar and poured the footings before we were awarded the job. The inspector questioned why the CEE wasn't installed so we showed him the Architects drawing with 3'8" rebar in the footing. That was the end of the conversation since you're not required to 'make' the CEE only requirement is to use if 'if available'. If the service is already there and not being upgraded I don't see how you could be required to add a CEE since it wasn't required when the service was installed.

 

[George Stolz]

I should have said, I already checked with AHJ. He wants the CEE. I'm posting questions because I didn't think it was required on an existing home with no service upgrade.

If you're still in doubt, ask the inspector's boss.

There could be rules (in writing) requiring electrodes to be installed/connected when a certain amount of work is to be done on an existing structure. Comparing the amount of time connecting to the CEE, versus time researching the specific laws in place, it would probably be easier to just comply.

Maybe I need it because the builder IS putting rebar in the footing. I'm still wondering if NEC requires it when there is no rebar in the footing.

I did an edit on my first post, sorry. No, if there is no CEE already present, then the NEC does not require you to install one. There may be local laws that would change that, however.

A CEE is an excellent electrode, it would improve the grounding electrode system of the house. What that improvement will bear remains to be seen.

 

[mkgrady]

Thanks for all the replys.

 

[George Stolz]

I'm a little overbearing, so personally, if left to my own devices, I would go the "investigate" route.

 

[Cavie]

CEE is a requirement of a new service in new construction. An addition does not require you to install one. It is not required that you ground the footer steel, the requirement is to ground the service using the footer steel. Even upgrading the service would not require you to use the footer steel as you would have to distroy the existing concrete footer to attach to it. Add a room with new footers and a new service then yes you would have to us it. In new construction, the 2005 code says "If Present". That means that if some provision wasn't made to make it accessible during construction, you will get out the jack hammer and find it. In 2002, you got away with 2 ground rods because the code said "If availible". different story.

 

[W6SJK]

UFER Required

UFER Required

If a new non-reinforced footing is being installed when a new service is installed, and it is at least 20ft in length, then you must install at least 20ft of #4 or larger copper to be used as a (UFER) grounding electrode. If the service is already installed under a previous permit, you should not be required to add a UFER. But it would be a good idea to add it.

Of course the AHJ rules and there may be local ammendments to back him up.

 

[infinity]

If a new non-reinforced footing is being installed when a new service is installed, and it is at least 20ft in length, then you must install at least 20ft of #4 or larger copper to be used as a (UFER) grounding electrode. If the service is already installed under a previous permit, you should not be required to add a UFER. But it would be a good idea to add it.

Of course the AHJ rules and there may be local ammendments to back him up.

I disagree. There is no requirement to make a CEE if one doesn't exist. You may do so as a personal choice but you are not required to put 20' of #4 in a footing that does not contain rebar.

 

[W6SJK]

I disagree. There is no requirement to make a CEE if one doesn't exist. You may do so as a personal choice but you are not required to put 20' of #4 in a footing that does not contain rebar.

If that is true, then why is the 20ft of #4 given as a replacement for rebar? When would you ever use it?

If it wasn't required in situations with no rebar, they wouldn't have listed it. If the footing is "available" i.e. not poured yet, then you have to use it, either by connecting to rebar if it exists, or making your own electrode using 20ft of #4 or larger... Look at the 2005 NEC handbook.

 

[infinity]

If that is true, then why is the 20ft of #4 given as a replacement for rebar? When would you ever use it?

If it wasn't required in situations with no rebar, they wouldn't have listed it. If the footing is "available" i.e. not poured yet, then you have to use it, either by connecting to rebar if it exists, or making your own electrode using 20ft of #4 or larger... Look at the 2005 NEC handbook.

I disagree with your logic. If for example I used 20' of rebar in the footing would I still need to pound in two ground rods? The answer is no, even though the ground is 'available' to except the rods. You can choose to make the CEE with 20' of a #4 conductor but you are not required to do so.

 

[W6SJK]

If for example I used 20' of rebar in the footing would I still need to pound in two ground rods?

No you do not need the ground rods, not because they are not available, but because ground rods are not required where UFER grounds are used.

But I understand what you are saying about "available." Maybe this discussion that we are having is why San Diego county has addressed this by making UFERs mandatory in any construction that includes new concrete foundations.

The fact that 250.50 requires the electrodes, and that there is an exception for existing concrete, leads me to believe that if I don't meet the exception for existing construction, then I must install a UFER as defined by (7), using rebar or wire.

 

[mkgrady]

If that is true, then why is the 20ft of #4 given as a replacement for rebar? When would you ever use it?

If it wasn't required in situations with no rebar, they wouldn't have listed it. If the footing is "available" i.e. not poured yet, then you have to use it, either by connecting to rebar if it exists, or making your own electrode using 20ft of #4 or larger... Look at the 2005 NEC handbook.

I looked in the handbook as you suggested and can't find where #4 cu wire should be used where rebar isn't being installed in a footing? Can anybody point to it?

 

[JohnE]

I looked in the handbook as you suggested and can't find where #4 cu wire should be used where rebar isn't being installed in a footing? Can anybody point to it?

You won't find it. That's not a requirement.

 

[W6SJK]

I looked in the handbook as you suggested and can't find where #4 cu wire should be used where rebar isn't being installed in a footing? Can anybody point to it?

Look at the second paragraph of the explanation after 250.50. "This section was revised for the 2005 Code to clearly require the inclusion of a concrete-encase electrode..." It goes on to say that the requirement is for rebar or wire... except in existing buildings.

Steve

 

[JohnE]

If that is true, then why is the 20ft of #4 given as a replacement for rebar? When would you ever use it?

If it wasn't required in situations with no rebar, they wouldn't have listed it. If the footing is "available" i.e. not poured yet, then you have to use it, either by connecting to rebar if it exists, or making your own electrode using 20ft of #4 or larger... Look at the 2005 NEC handbook.

You would use it if you want to make a choice of having an electrode with a very low resistance to ground. You don't have to use 20' of #4 if there is no rebar.

 

[Shockedby277v]

Any ways around adding a CEE after cements been poured??

 

[George Stolz]

I agree wholeheartedly with Trevor. You may elect to install a CEE by the second method if one is not present already, but you are not required to install a CEE if none exists.

Any ways around adding a CEE after cements been poured??

Groveling, pleading, bribery, flattery, presents...

As far as adding a CEE, that's been covered. There is no requirement to add one.

But if you need to connect to an existing CEE after pour, then jackhammering and concrete sawing are about the only way I know of.

Once, I heard of a guy actually hammerdrilling a hole in the concrete, and jamming a wad of #4 (20' worth) into the hole, thinking he was in compliance.

 

[JohnE]

Look at the second paragraph of the explanation after 250.50. "This section was revised for the 2005 Code to clearly require the inclusion of a concrete-encase electrode..." It goes on to say that the requirement is for rebar or wire... except in existing buildings.

Steve

Steve,

I don't have my book with me, but I've read that article many times. It was revised by changing the phrase from "if available" to "if present" with regards to the CEE. Meaning if there is rebar, you must use it. It does not mean that you must install 20' of wire if there is not rebar present. Essentially the 20' of copper wire is not present, unless you put it there, in which case you must use it.