As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PIC REPORTED SPARKS AND SMALL AMOUNTS OF SMOKE EMITTING FROM OVERHEAD C/B PANEL DURING THE APPROACH PHASE OF THE FLIGHT. SUBSEQUENT TROUBLESHOOTING REVEALED A BROKEN GROUND WIRE MAKING INTERMITTENT CONTACT WITH A 28V BUS BAR. NO SECONDARY INDICATIONS OR FAILURES WERE NOTED BY THE PIC AND THE AIRCRAFT LANDED SAFELY AT THE HOME BASE OF OPERATIONS.