Lighting, Stereo and Electrical Wire gauge for light bars? June 16, 2015 What gauge wires are you guys running on your light bar set up? I am going to build a relay box to run light bars and lighted whips and want to know what gauge to use on the secondary side to the lights and battery. Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window) Related