Copper wire gauge sizes are not equivalent to aluminum wire gauge sizes. The gauge sizes for copper and aluminum wires are different due to their differing electrical conductivity properties. It is not possible to directly convert a copper wire size to an equivalent aluminum wire size.
enameled round aluminum wire enameled flat aluminum wire enameled square aluminum wire
Today the only use of aluminum wire is in service entrances and underground feeds where the larger sizes are needed. By using aluminum the overall project wire costs are kept to a minimum even with the bigger size needed over copper. Wiring branch circuit in aluminum has not been vogue for many years now.
AWG # 6 copper or AWG # 4 aluminum
For a 100A subpanel, a minimum of 1.5-inch Schedule 80 PVC conduit or 1.25-inch rigid metal conduit is recommended. As for the aluminum wire, for a 100A feeder, you would typically use 1/0 AWG aluminum wire for a 3-wire setup or 2/0 AWG aluminum wire for a 4-wire setup. Always consult local electrical codes and a licensed electrician for precise specifications for your installation.
Wire size is rated by Amperes of current. You did not mention the wire size of the aluminum wire, so there is no way to answer your question. The voltage rating is more a rating of how good the insulation around the wire is.
Copper wire gauge sizes are not equivalent to aluminum wire gauge sizes. The gauge sizes for copper and aluminum wires are different due to their differing electrical conductivity properties. It is not possible to directly convert a copper wire size to an equivalent aluminum wire size.
Don't use aluminum wire inside the house.
enameled round aluminum wire enameled flat aluminum wire enameled square aluminum wire
250 MCM aluminum minimum
A 100 amp service requires that you use AWG 4 copper wire or AWG 2 aluminum wire.
The key parameter in sizing wire is the current requirement. Once you know that you can look up value in a wire gauge table. The length of the run is important for longer runs because of the resistance of the wire itself. Aluminum wire requires a larger diameter than copper for the same current. Once you calculate the wire size you can then size the conduit.
Today the only use of aluminum wire is in service entrances and underground feeds where the larger sizes are needed. By using aluminum the overall project wire costs are kept to a minimum even with the bigger size needed over copper. Wiring branch circuit in aluminum has not been vogue for many years now.
An alternative to copper wire is aluminum wire. Aluminum wire is a less expensive option compared to copper and is commonly used in electrical applications where cost is a primary consideration. However, aluminum wire may have lower conductivity and can be more prone to oxidation.
300 kcmil @ 75°
AWG # 6 copper or AWG # 4 aluminum
3/0 or250 aluminum