Wiring depends on how you run your trains. DC and DCC need good power distribution and is dependent on current draw. The bigger the RR and the bigger the engines require bigger wire and multiple feeds. I do not run 'big' current for my DC and DCC trains. I do run #14 UV outdoor wire (read 12 volt yard lighting) wire and it suits my needs which are mostly LGB single motor engines on 3 separate tracks. I do have 3 feeders on my big loop, only one feeder on my small loops. Big loop is 12 foot diameter track, small loop for 2 axle engines are 4 foot diameter.