AWG # 6 copper
AWG-8 wire can safely carry 30 amps to a load 100 feet away.
Use 2/0 AWG.
#6 wire stranded
Please use the Discussion Area to explain the significance of the "100 feet".
you would use #2 aluminum urd wire for a 100 amp service
This is a voltage drop question and a voltage needs to be stated.
This depends on whether the wire is copper or aluminum. In aluminum, you need to go UP one wire size to carry the same amount of electricity, because copper is a better conductor than aluminum. The normal ratings are as follows for the most common wire sizes in houses Copper 14 gauge=15 amps 12 gauge=20 amps 10 gauge=30 amps 8 gauge= 40 amps 6 gauge= 50 amps and so on. it goes all the way to a 2/0 which will carry 200amps In aluminum you step up a size, as in 12 gauge= 15 amp 10 gauge=20 amps and it would take a size 4/0 aluminum to rate at 200 amps, which is pretty much the standard household amperage requirement in most places in the US
A # 14 copper conductor will be fine to carry 8 amps at 120 volts. This size conductor is rated at 15 amps.
A 3/0 aluminum conductor will limit the voltage drop to 3% or less when supplying 150 amps for 150 feet on a 240 volt system. This size will allow the conductor to be loaded to 120 amps. 150 x 80% = 120 Conductors are only allowed to be loaded to 80% or their rated capacity. If you need the full 150 amps then you would need to use a wire with a rating of 190 amps. 190 x 80% = 152 amps A 4/0 aluminum conductor will limit the voltage drop to 3% or less when supplying 190 amps for 150 feet on a 240 volt system.
A 300 MCM copper conductor, with a voltage drop of 3%, is needed when supplying 50 amps for 600 feet on a 120 volt system.
A #6 copper wire with an insulation factor of 75 or 90 degree C is rated at 65 amps.