Sometimes it gets missed, cutt off, stubed up in an inaccessible place. I wonder if requesting a DEC Statement from FBC would clarify this requirement.



Now, Never heard it called a 7-Iron. I have a 7-Iron manufactured by Cleveland and is good for about 150 yards on a good day. As far as Mr. Doohickey goes, My Mother explained to me who he was when I was very young.

Doohickey???
That's what you use to bend rigid with. LOL

getting hard to keep track of all these technical terms

Does anyone allow only a #4 bare to a concrete encased electrode to be used as the "grounding electrode system" for a 400 amp residential servce?

I hear rumor that is all some are requiring.

Neal
COTInspector

YES! A #4 GEC to a concrete encased electrode / as the CEE would be sufficient for a 2,000 amp service as well.

I have to ask some dumb questions;
Why is Table 250.66 still in the Code Book, maybe we can get Bill Pancake to get it removed if no one uses a fully sized grounding electrode system anymore?
When does a grounding electrode as described in 250.52(A) (1) through (A) (7) become present?
If the foundation is already poured when the electrical contractor arrives on the site is he now exempt from using the concrete encased electrode as part of the grounding electrode system (not present anymore right)?
If the electrician has #2 copper wire and a ground rod on his truck when he pulls up on a site, is he now required to install a ground ring and a ground rod (present right)?
If none of the electrodes exist how many of grounding electrodes specified in 250.52(A) (4) through (A) (8) are required to be installed and used, one or more?
Would it also be ok to ground a 2,000 amp service with one ground rod connected to a #6 copper grounding electrode conductor if there are no other electrodes present?
If this GES has greater than 25 ohms resistance, we can just add one additional ground rod tie the 2 rods together with a #6 and call it a properly grounded system?

I personally do not believe, especially after re-reading Chapter 6 in the Soares 10th edition several times, that a #4 GEC to a 250.52 (A) (3) electrode for any service above 200 amps, meets the performance requirements stated in 250.4.


Neal Burdick
COTInspector

Neal, you have to use what you have available and the engineers figure out how effective they are. They have decided a #6 will carry all the current a rod will sink and a #4 will carry all you get from a Ufer. 250.66 really refers to more effective electrodes like a whole city full of metal pipe. Once that got down to a minimum of 10' of pipe in contact with the soil (the rest being plastic), I imagine a #6 would do the trick there too.
We may be entering a time when there are no decent ground electrodes. In my house, I imagine the concrete pool shell is the best electrode but it is only required to be bonded to the MBJ in the panel with a couple of 12ga copper EGCs (the light and pump)

As for the Ufer being available, it should be part of the footer inspection. I know I used to look at them all the time when I was inspecting.

Table 250.66 is required to be used "except as permitted in 250.66(A) through (C). So, GEC's bonding metal underground water pipe and metal frame of the building or structure electrodes are sized to the Table. Also keep in mind that other bonding and grounding components are sized to Table 250.66 such as Equipment Bonding Jumpers on Supply Side of Service.



No. The electrode is present. This is not a code issue but a cooridnation issue. It is the responsibility of the builder to properly schedule his contractors to perform work at the appropriate time. It wouldn't make sense for a builder to install all the drywall in a structure before the electrical wiring has been installed, just as it doesn;t make sense for a builder to pour the footings prior to the CEE being installed.



Of course not. Remember, section 250.50 requires all the electrodes that are present to be BONDED together to form the GES. It is only when they do not exist at the strucutre that you are required to create / install the electrode.



YES!



YES!



Then as soon as you become a PE or electrical engineer that is free to design the grounding electrode system on your prjects in any manner you wish, we can only enforce the requirements of the code as they are written.

GOOD QUESTIONS !!!

Please don't assume that a footing that is twelve inches deep in dry sand is much of a connection to earth. I recall that E.E.'s in Saudi Arabia salt the sand and saturate it for an earth connection...I can check for continuity from a steel doorjamb in a damp basement but get no continuity above grade level...The deeper you go and the more moisture in the earth the better...Ufer, pilings, made electrodes...whatever. Biddle Instruments had an old book on grounding and part of it is incorporated into the 'Soare's' Book...It may be available online.

I still find it hard to believe that a 3/4" copper water pipe (let's say 10'6" long) in direct contact with the earth is a better electrode than a concrete encased electrode.
Does anyone know where that test data maybe found online?


Neal Burdick