A 125 amp panel or subpanel requires # 2 gauge feeders and neutral. (# 2 awg is rated for 130A) However, depending on the existing load in your main 150A panel you likely don't have enough power to operate a 125 Amp subpanel.
4 AWG in copper.
2nd answer:
Note that while 4 AWG is legal to run per NEC, if the panel is heavily loaded you will exceed the recommended maximum voltage drop (3%). For that length of run it would be advisable to increase the wire size to lower the voltage drop.
Normally you would use AWG #6 but for this long run and voltage drop I would recommend you use AWG # 4.
A 2/0 aluminum conductor will limit the voltage drop to 3% or less when supplying 125 amps for 150 feet on a 240 volt system.
A #2 copper conductor with an insulation factor of 90 degrees C is rated at 130 amps.
Use AWG # 1/0 gauge copper.
You will need to run AWG #4.
Re Question with the voltage that you will be using.
Depends on the size of the sub-panel in that garage. If you are installing a 60 amp sub-panel 400 feet away from the main service panel then use AWG # 4.
For that distance I would run AWG # 3 copper and install a sub-panel.
A #8 copper wire with an insulation factor of 75 or 90 degrees C is rated at 45 amps.
I would install a 60 amp sub-panel and use AWG #3 copper.
Re Question with the voltage that you will be using.
Depends on the size of the sub-panel in that garage. If you are installing a 60 amp sub-panel 400 feet away from the main service panel then use AWG # 4.
A #1 copper wire with an insulation rating of 90 degrees C is rated at 140 amps.
For that distance I would run AWG # 3 copper and install a sub-panel.
A #8 copper wire with an insulation factor of 75 or 90 degrees C is rated at 45 amps.
Yes, they are the same size wire.
I would install a 60 amp sub-panel and use AWG #3 copper.
A #6 copper wire with an insulation factor of 75 or 90 degree C is rated at 65 amps.
This is a voltage drop question. A voltage must be stated to answer this question.
Use #10 copper.
# 6 copper wire.
The voltage of the solar panel is less important than the total amperage. Proper wire size is determined by amperage that will be going through the wire. Wire INSULATION determines the voltage that a wire can carry.