How to Wire a Car Fuse Box | DoItYourself Wires provide the means between the system and the car fuse box. It is highly recommended that you use an amperage that is higher than the needs of the accessories you’re going to plug into. The issue here is that, if the wires cover maybe the same or less amperage, they can pull more electrical current causing overheating in the wires.Author: DIY Staff How To Wire a Car Radio to a Fuse Box | It Still Works Adding new wiring directly to a modern fuse box can be tricky and usually requires some advanced soldering skills. However, you can save considerable time by purchasing a fuse tap. A fuse tap plugs into the fuse box just like a normal fuse and has a wire with a crimp connector you can use to connect to the power wire from the car radio.