First make a diagram of wiring then get cable markers and mark cables as follows,common rail neutrals mark 0,common rail positives 1,and all circuits follow on from there,from fuse board say radio 2,ESC 3, sound 4,lights 5,this will make it easy to trace cables and find faults,keep a copy of wiring diagram in boat in a waterproof sleeve,bunch cables up and cable tie together.I use bootlace ferrules on the end of cables and good quality connectors (not chinese ),I have used this method and have never had a problem (touch wood) over the years,Ray.