I'm having a hard time finding 125 amp 1/O aluminum service wire in San Antonio. I am moving my sub panel and need about another 20 feet of wire. Can I splice copper wire to the aluminum service wire since it is readily available at most retail home improvement stores? If so, what type of connector should I use? I know I have to scuff/sand the aluminum and apply an anti oxidizing compound.

Thanks.
Jerry.

Something like this pre insulated connector rated for al & cu works great.

Thank you. Hope I can find this. Do you know who makes it? I've been googling like crazy. Since you suggested this connector, I am assuming it's OK to mix aluminum and copper feeder wire? I've read many many threads that warn against it. All of my branch circuits are copper. Just my service wire is aluminum. I don' t want to create a fire hazard, but also don't want to spend the $$ on copper feeder from the main to the sub. It's about 80 feet. Of course the primary is to avoid fire risk even if I have to buy new copper wire. Wonder why it's so tough finding aluminum here? I can only find 2 2 2 4.

This is one brand:

NSi Industries: Polaris Black

Each wire will be separated from the other in its own port. AL and CU wire cannot be connected directly together, and must be separated with a connector rated AL/CU.

#2 Al is very popular for the popular 100 amp services. 125 Amp is not very common, must be why the #1/0 Al your seeking is not found.

I assumed you have checked with electrical distributors, and not just big hardware stores?