250.66(B)Connections to Concrete-Encased Electrodes. Where the grounding electrode conductor is connected to a concrete-encased electrode as permitted in 250.52(A)(3), that portion of the conductor that is the sole connection to the grounding electrode shall not be required to be larger than 4 AWG copper wire.
Another reason to go for #4. It seems to fit in a portion of this code between (*) pysical damage, and severe physical damage.
250.64(B) Securing and Protection from Physical Damage. A grounding electrode conductor or its enclosure shall be securely fastened to the surface on which it is carried. A 4 AWG copper or aluminum or larger conductor shall be protected if exposed to severe physical damage. (*) A 6 AWG grounding conductor that is free from exposure to physical damage shall be permitted to be run along the surface of the building construction without metal covering or protection where it is securely fastened to the construction; otherwise, it shall be in rigid metal conduit, intermediate metal conduit, rigid nonmetallic conduit, electrical metallic tubing, or cable armor. Grounding conductors smaller than 6 AWG shall be in rigid metal conduit, intermediate metal conduit, rigid nonmetallic conduit, electrical metallic tubing, or cable armor.
[This message has been edited by e57 (edited 12-09-2006).]
Mark Heller "Well - I oughta....." -Jackie Gleason
The code would permit a #8 GEC for this application. The #4 is the maximum required by the code for a GEC to a concrete encased electrode, but Table 250.66 applies and the use of smaller conductors is permitted. The smaller wire may not require and physical protection. It could be stubbed up in a stud space and run to the panel. If there is a wall finish no additional protection would be required. Don