What size wire do I need for a 400 amp residencial service. And what size wire do I need for the grounding electrode?

Won't your electrician have all this information?

I am the electrician WITHOUT HIS CODE BOOK. I was look for some quick help to avoid an extra trip to the job site. stanfortyman, why can't you give a simlpe answer? I have read several of your post and none have been helpful to the question asked. Why do you even bother?

Don't bother replying, I won't use this post again with people like this out there.

Well then why don't you state this from the start. People can be so evasive when asking for help. THAT is why I sometimes don't give a straight answer.
If you are still interested post back. If not then have fun.

What type insulation are you planning on?

What conductors are you planning on using, copper or aluminium?

From T 310.15 (B)6 - 400 amp will use 400 KCMIL (Copper) and 600 KCMIL (AL) T 250.66 - Ground would be 1/0 copper and 3/0 aluminium.

Don, don't forget...

250.66 Size of Alternating-Current Grounding Electrode Conductor.

(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.

This is what I mean by evasive questions.
This guy throws this open ended question out there with absolutely no detail as to the situation or why he is asking, then he gets mad at me? Nice.

If he can come here and ask this question he can also Google the question and in about 30 seconds he'll have his answer.

I call a big B-S that he is an electrician. If he was he would know T310.15(B)(6) is for sizing residential services (this is first year stuff) and simply Googling that would get his answer.

I intentionally left the code site out of my response, because, he's an "electrician?", maybe?

I just gave the table information because that's all he asked for.