Both sets of lights are running off different wires. Each light has a ground and then thr switch also has a ground. The fuse is on the wire going from the battery to the switch. I have 1 fuse per set of lights becasue that is what came with it. The fuse that came with it is the glass style. I like BigMikes idea, if i can get a couple smaller lights i might just do that. I still have to go to the hardware store.