200 amp service 450 feet underground will 250 urd cable be enough.

If you truly need 200 amp, then you will need 350 kcmil conductors for 450 ft. That will give you just under 3% voltage drop leaving you an additional 2% end to end recommended max of 5% voltage drop.

Also, if this from a main service panelboard to a downstream panelboard, then you must use a four wire feed to the downstream panelboard and an independent grounding and bonding system must be set up at the secondary site.


Neutral from the main service panelboard must be isolated from the grounding system at the secondary panelboard.