What size wire for a 100 amp service 250 ft run from transformer to home?

Answer 1

This is a voltage drop question. To answer this question a voltage has to be stated. The higher the voltage to the circuit becomes the smaller the wire size needed. After a certain voltage point the wire size will remain constant and the voltage drop at the load will become smaller.

Answer 2

Answer for USA, Canada and countries running a 60 Hz supply service.

This is a voltage drop question. Since it is connected to a home both voltages will be stated.

A 3/0 aluminum conductor will limit the voltage drop to 3% or less when supplying 100 amps for 250 feet on a 240 volt system.

A 400 MCM aluminum conductor will limit the voltage drop to 3% or less when supplying 100 amps for 250 feet on a 120 volt system.

Answer 3

Normally you would use AWG # 3 wire for a service entrance. But considering you are running this 200 feet you need to go with AWG # 2 wire to have an acceptible voltage drop of only 2.60%. You will then have 233.75 volts which is acceptible.

Answer 4

This is a voltage drop question. To answer this question a voltage value must be stated. Since it is a 100 amp panel the assumption will be made that the service is a 120/240 single phase.

A #500 MCM copper conductor will limit the voltage drop to 3% or less when supplying 100 amps for 800 feet on a 240 volt system.