[Carl n Susan]

I am not an electrician but I am positive each A/C has it's own circuit breaker! Each unit requires a 20 amp circuit. Two units on the same circuit is a non-starter. The labeling of each circuit breaker in the fuse box is notoriously inaccurate. Each circuit breaker should be (once again no guarantee) on different feeds of the two 50 amp legs.

You should get a 50 amp connection and test each circuit breaker to ensure you know what it controls.