What size aluminum triplex wire should be used to supply 2 200 amp services 150 feet from transformer pole ?

Seems your question got missed.


This is not really practical to try to deliver 120 volts at 150 feet and have the capacity for 400 amps. Assuming the maximum load of each 200 amp service to be 80% of full rating, would mean the calculations would be based on 320 amps, or 160 amps for each service entrance.

So each service should be treated separately.

Each service will need a minimum of #4/0 aluminum to keep the voltage drop below the recommended 3%.

Check with your local utility. My local one recommends a 200 amp service can use #4/0 up to 215 feet, based on the same Vd calcs and tables published by the NEC.