Sorry for mention this again but I think the right size is #3/0 copper as the minimum grounding electrode conductor.. I been preparing myself for the master exam and all the questions from exam preparations that are related with minimum size of grounding electrode conductor are answered based on the information provided, on this Question we only have a 3000 Amps/460V that need a carry conductor bigger that a 1100 KCMIL and table 250.66 show a #3/0 as the minimum size grounding electrode conductor. If electrodes are specified then exceptions and notes shall be apply.
What is the minimum size of grounding electrode required to handle 3,000 AMPS 460 Volts.
There is not specification of what type of electrodes will be used, the only info provided was : (what is the minimum size of grounding electrode required to handle 3,000AMPS 460 Volts), table 250.66 show for a 1100 KCMIL OR OVER use #3/0 Copper for grounding ELECTRODE. That would be my answer..
If the question specified an electrode, say a metallic water pipe, you would be right but since there is no specified electrode it is very possible it could be a lowly rod and the Table doesn't come into play.
This appears to be worded like a WI masters test question. IIRC
So what is the Most correct answer based on the info given? #6 IMO
MINIMUM GEC with the limited info.
Gotta admit my knee jerk thought was 3/0 but the do say Minimum and do not specify the electrodes.
(A) Connections to Rod, Pipe, or Plate Electrodes. Where the grounding electrode conductor is connected to rod, pipe, or plate electrodes as permitted in 250.52(A)(5) or (A)(7), that portion of the conductor that is the sole connection to the grounding electrode shall not be required to be larger than 6 AWG copper wire or 4 AWG aluminum wire.
A poorly written question for a qualifying test.