2 AWG Aluminum.
2 AWG Aluminum for 100 Amp Service.
#2 aluminum for 100 amp
#2 wire copper
you would use #2 aluminum urd wire for a 100 amp service
4 AWG is required for 100 amp service. That converts to 25 mm2.
A 100 amp service requires that you use AWG 4 copper wire or AWG 2 aluminum wire.
Look at the value of the breaker or fuses that control your main electric panel. look at the wire size coming in to the main lugs on service panel, I am assuming you don't have a main breaker or you would look at the breaker rating to determine service size. 2/0 copper or 4/0 aluminum service size 200 amps, #4 copper or # 2 aluminum 100 amp.
A #1 aluminum conductor with an insulation of 90 degrees C is rated at 105 amps.
I would recommend you use AWG # 2 copper or AWG # 1/0 aluminum for that distance and amperage.