200 amp socket is 400' from 200 amp panel what size wire?

You might want to consider have the power co. put in a transformer and drop.

Are you going to need 120/240?

Just using 120Vac to ground, you will need 900 kcmil to get an acceptable voltage drop.

Have you calculated the necessary load?

We have three power poles on our property that I want to eliminate. The power company quoted $5,000.00+ for a on ground transformer and buried cable.
I would have to bury 200' from the transformer to the house. Thought it would save me some money doing a run to the pole on the road 400'.
Yes need 120/240. Have not calculated the necessary load. Thank you

We have three power poles on our property that I want to eliminate. The power company quoted $5,000.00+ for a on ground transformer and buried cable.
I would have to bury 200' from the transformer to the house. Thought it would save me some money doing a run to the pole on the road 400'.
400' is way too far to go with "standard" size wire. You are going to have to go up in size to go that far.

IMO I would go with the power company's quote. A transformer closer to the house (250' or less) is a MUCH better installation.