Re: tap conductors
The ten foot tap rule applies to feeder taps. Your description looks more to be a branch circuit that you would like to extend to another load. The term "tap" generally refers to conductors that are rated smaller than the circuit OCD they are connected to. Is that what you are really doing?
I would question if the two units will or can be on at the same time, and if that load will exceed the rating of any conductors or the OCD protecting the circuits. My assumption is that the original circuit was not intended to serve more than the A/C unit load.
