What was found
ACFT DEPARTED, ENROUTE WITH 2 PASSENGERS, 2 HOURS INTO FLIGHT, JUST PRIOR TO INITIAL DESCENT, ACFT EXPERIENCED A COMPLETE ELECTRICAL FAILURE AND LOSS OF PRESSURIZATION AT FL430. FLIGHT CREW REGAINED CONTROL OF PRESSURIZATION AROUND FL330 AND RESTORED PWR TO NR 1 COMM RADIO. ACFT DIVERTED AND MADE A VISUAL NO-FLAP APPROACH & LANDING. ACFT OVERRAN RUNWAY APPROX 50 FT INTO MUD. NO PASSENGERS OR CREW WERE INJURED AND ACFT HAD MINOR DAMAGE. AFTER INITAL INSP, SUSPECT LT MAIN BUSS C/B ISSUE BUT UNABLE TO CONFIRM THIS TO BE THE PROBLEM AT THIS TIME. ADDITIONAL INSP AND MAINT NEEDED TO CONFIRM C/B OVERLOAD. (K)