I think that I just verified that I have 2 dedicated conductors between the 2 controllers. On one end (where the old RC 7-A is) I have the RED and the WHITE in a 5 conductor multi-strand (the other 3 conductors are not in use). On the other end (where the ESPM is) I have 2 PURPLE single strand conductors terminated; one on the COMMON terminal and one on the MV terminal. With the RED and WHITE opened up on the RC 7-A end, I turned on the ESPM controller on the other end and I am getting 28 volts on the RED and White at the RC 7-A end.
I guess now it is just a matter of getting 2 ISOLATORS and wiring them in as per the instructions.
Am I missing anything??????????
Again, thanks to all who have replied. This one was out of my league but it is becoming a little clearer now.