They are connected to other things in the car, but they get power from the other end after you remove them from the alternator. They are powered from the other end where they are attached to the battery. The wisdom of not connecting them is a fail safe. If they are connected to the alternator, and say your 4 ga line fuse blows, your car would still charge and you might end up overheating those stock wires, resulting in a fire. If they are not connected, you would realize the fuse blew and could then fix it.