ETA offers wire kit of stranded 12-guage UL wire for wiring ETA-ECM20 modules together plus additional length for wiring incoming AC to an AC mains panel. 140-inch of each color of green, white and black are included. Note, as reference, it takes around foot of wire between ETA-ECM20 modules, if they are wired on same incoming AC main. It is highly recommended that wire needed for job is carefully measured. It may take more than one ECM-ACIN wire kit depending on how many AC mains and distance from AC mains panel. It is not necessary to use atlas ECM-ACIN wire kit as long as it is 12-gauge and UL listed.