I have always used the jumper wires and connector wires that are accessories of the manufacturer of the LED under cabs I use. I have seen a lot of different wires used by other contractors when I go out on service calls. I've seen guys run landscape low voltage wire, cat5e, and a few others to connect their transformers to the light and jump light to light. The lights I use are usually 24v what wire do you guys run for this? The connecters and jumpers from the manufacturers are really over priced just trying find places to cut costs.