I’ve seen conflicting commentary on what gauge wire and quantity of conductors should be installed for various components.

I believe sensors (door, water, windows) should receive 22/4 solid and a siren should receive 18/4 solid

All of these should be home runs to the main panel (which may or may not receive 110v, likely with some transformer). From the main panel, I’m uncertain what should feed secondary panels. Do these secondary panels require 110v or is low volage wiring used to interconnect with the main panel?

I’m completely lost as to how the smoke/CO detectors integrate. Currently, all of my smoke and CO detectors are interconnected with 14/3 110v wiring. If I wanted the smokes to communicate with the alarm panel, how would I go about doing so?

I didn’t originally intend on having my cameras integrated into an NVR, but I may be reconsidering. Any helpful threads on this topic would also be very much appreciated.