I picked up some trailer light wire in the automotive section at Walmart. It has served me well as bus and feeder wire. There are four 16-18 gauge strands, each 25 ft long, and they are bonded together. The price was between $12-$13. I pulled off the white wire for my my common wiring, and pulled off the brown for my block wiring. I left the green and yellow wire attached and uncut to run from the layout to my MRC 400 Tech 4 power supply. After I zip tie the wire to the cord and an extension cord, I can move around with the power supply like a big remote control.