RD hardwire questions
The point is that you only need to fuse a circuit so that it limits the possible current flow to what the wire can handle. In this case, the IGN port in the fuse panel is a 15-amp circuit. If you wired your radar detector with at least 12-gauge wire and kept the total wire length under about 10 feet then you don't need a separate fuse. However, most people use 16-gauge or 18-gauge for hookup wire so a smaller fuse is necessary. I recommend you add an inline fuse of around 5-amps to be safe.





