cigarette lighter question

Point to consider is its usage. Today we commonly plug everything except cigarette lighters into those power ports. The fuse should protect the wire though. A 15 amp fuse should supply most anything you plug in there. If you expect a high draw there, larger components would be required. For instance, I have a thingy here that turns 1 lighter well into 3 wells/ports. I'm sure it could overheat the cars wiring with enough stuff drawing current though it.