I want to connect a 16 zone rachio controller to my existing system. The existing wiring is 12 gauge twisted wire. There does not seem to be room for 16 + 2 common wires of this size. Also, the connection board was not intended for this size twisted wire. I plan to use a separate connection block. The wires to the valves are long, some are 100 ft. What is the smallest or recommended size single strand (solid copper) wire to use to enter the controller?
I realize this is a poorly designed legacy system, but to change it is a big deal.
The crux of this question is, what size wire should I use to go from the existing wire into the rachio controller. This will be a short 8-10 inch run.