I'm wiring up a Generac 20 KW. The fourth one in the last month. Every one of them has had a very long run to the ATS and much of it is outside the house. The runs have been about 100 feet long with lots of changes in direction. Conduit and multiple JB's would be way too much work so I have been running #1 Aluminim SER for the power and switching over to copper in a JB with Carflex and #3 copper for the final connection.
The control wiring consists of three low voltage (12 volts) wires and three line voltage wires for voltage sensing of the normal and generator power. The minimum size wire is #18. I have been running 18-3 sunlight/weather resistant for the low voltage and 14-3 UF for the line voltage. I have run these cables to a WP JB and switched over to 1/2" with THHN and carflex for the last few feet The cost of the UF and running a seperate 18-3 seems like more work and cost than it should be.
If the runs were much shorter I would run conduit for everything. The changeover from AL to CU would be eliminated and I could run all the control wires in one conduit (6 # 18 thhn in 1/2 inch). I'm looking for suggestions on how to combine the control wiring into one cable. As far as I know I can't buy 18-6 UF cable. Is there anything I'm missing?