No, it "Shall not be required to be larger than #4 copper wire". The paradox is, if you have metal water pipes in the house, that connection needs to be sized to 250.66, even if you think it might be plastic where it goes into the ground.
Thank You Greg. This is new construction with Pex, and no gas at all. So the Ufer is the only grounding electrode. Our local AHJ seems to think there must be at least one GEC in the system sized to table 250.66, so if there is only one grounding electrode they consider it the "main grounding electrode" and want the GEC sized to the table regardless of the grounding electrode type. They will only allow the #4 to the Ufer as a tap from another GEC sized to table 250.66.
I guess it's easier for me: the EE calls out the GEC system conductors.
As a general principle most AHJ are not going to allow downsizing bonding connections in the GEC System.
So if you have a Ufer using # 2 then that self same #2 is expected to be brought up to the GEC bonding/grounding rail in the Service.
Strictly speaking, a Ufer is a concrete encased electrode. Yet, it is commonplace for 'Ground Ring' sized conductors to be encased in concrete, too. Strict construction of the terms would require Ground Rings to be set bare into the soil, underneath the pour. I never see that.
Out my way, #4 Ufers are explicitly mandated for 200 A Services. No ifs, ands or buts.
Since one is expected to have an UNBROKEN CONDUCTOR RUN from the GEC up into the Service any effort to complicate it by downsizing with an irreverseable ( Cadweld/ultra-compression connector ) connector are entirely uneconomic.
All of which makes me wonder why such brain matter is focused upon shaving that last itsy-bitsy bit of copper out of a job.
To my mind, the very short runs involved with GEC Systems make them no place to concentrate ones energies.
Instead, focus on clean, quick installations. That's where one makes it or breaks it.
Iím not sure Iím following this. Is the inspector saying that a GEC sized per Table 250.66 is required to be run and connected to the #4 CU for the Ufer? If so, I would think that since 250.66[A] clearly says that portion of the conductor that is the sole connection to the CEE/Ufer only needs to be sized at #4 CU, the #4 from the Ufer should be able to be run to the main service equipment and connected to the neutral bus as is without issue. Donít we basically do the same thing with #6 CU and ground rods?
Your inspector is just further confirming his confusion about 250.66. At a certain point you should just do what he says and get on with your life. You might prevail in an appeal but I doubt you will win.