I have an old, small house where electrical was updated about 20 years ago.
Description of electrical hook up: I have the main power coming into the meter, with a panel box adjacent to the meter. It splits: one supply via a dual-pole (correct terminology?) 60 amp breaker to the garage sub panel and another supply via a dual-pole 60 amp breaker to the house sub panel. This house sub panel is fed by a thick wire (writing on the wire states "aa 8030 type se xhhw-2 style R... 2 AWG" and also says 4 AWG. The house sub-panel is rated for 125 Amps. There is currently a 50A dual pole, and various other breakers feeding circuits throughout the house. See below picture. The dryer, washer, and water heater are in the garage.
I am updating the labeling to match the circuits. There is possibly an unused circuit breaker as well (the ?). There are also two empty slots in the box.
Also, I know there is some rust on the box. This is not from rain, but rather heavy humidity.
Question: Can I hook up a split AC unit to this box? The unit states a 20 amp 220V breaker (so 20 amp dual pole?)