As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE TAIL LIGHT POSITIVE LEAD SHORTED TO GROUND BY CONTACT WITH A TINNERMAN NUT IN THE RUDDER. THERE WAS NO EVIDENCE OF TRAUMA TO THE WIRE. ONLY A PINPOINT OF CONTACT WAS EVIDENT THE NAV LIGHT BREAKER DID NOT TRIP AND THE WIRING BURNED FROM THE TAIL TO THE CIRCUIT BREAKER PANEL, TAKING OUT HALF THE BUS WITH IT. THE FIRST WIRE BURNING STARTED A CASCADE OF SHORT CIRCUITS. THIS DOMINO EFFECT SEQUENTIALLY TOOK OUT ADDITIONAL CIRCUITS UNTIL THE MAIN BUSS BREAKER OPENED.