ALTERNATOR PLUG SHORTED OUT AND CAUSED A HIGH POTENTIONAL OVERLOAD THAT CAUGHT THE ALTERNATOR ON FIRE. THE SHORT DID NOT TRIP ANY FUSE IN VEHICLE. FIRE WAS VERY INTENSE. THE FIRE QUICKLY SPREAD TO ADJACENT COMPONENT AND MELTED PLUG WIRES, WIRE HARNESSES. FIRE ALSO DAMAGED HOOD AND RIGHT FRONT FENDER. THE FIRE WAS QUICKLY SPREADING WHEN HELP ARRIVED TO EXTINGUISH THE FIRE. AND YET NO FUSE EVER TRIPPED TO ENGINE ELECTRICAL TO STOP SHORT!