A LEAR 25G IN DSCNT AT FL300 LOST ALL ELECTRICAL POWER TO ESSENTIAL BUSSES AND BUS TIE BREAKERS OPENED. LOST ALL AVIONICS AND THREE ALTIMETERS.

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BEGAN DSCNT FROM FL430. ENTERED TOPS AT 350 FT AND TURNED ON NACELLE HEAT. AT APPROX FL300; ESSENTIAL BUS AND TIES BREAKERS BLEW. LOST ALL AVIONICS AND ALL THREE ALTIMETERS. TRIED A RESET AND FAILED AGAIN. SECOND RESET ON LEFT SIDE RETURNED POWER TO PLT FLYING INSTRUMENTS. CONTINUED ON TO DEST. (ABOUT 4 MINS. THE LAPSED TIME FOR THE WHOLE SOLUTION WAS APPROX 3 MINS.) ACFT IS RVSM APPROVED. EQUIP AFFECTED; ALL NAV; COM; FMS; DME; 3 ALTIMETERS; MFD; EHSI; IVSI; AND PRESSURIZATION AUTO FUNCTION AND XPONDERS. APPROX 30 SECONDS PRIOR TO FAIL; WE ENCOUNTERED TWO MOD TO SEVERE THUMPS OF WAKE TURB. IT IS A POSSIBILITY THAT THE ENCOUNTER CAUSED A SHORT TO GND. WE ARE GOING OVER THE WIRES; ETC; TO ISOLATE THE PROB. IT WOULD BE A DEFINITE IMPROVEMENT TO HAVE AN 'OLD STEAM GAUGE' AS A STANDBY ALTIMETER. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR SAID THE LOSS OF ELECTRICAL POWER WAS TRACED TO THE TWO ELECTRICAL SPLICES AT THE BOTTOM OF THE CIRCUIT BREAKER PANELS. THESE SPLICES ARE THE MAIN FEED TO THE CIRCUIT BREAKER BUSSES AND SHOWED EVIDENCE OF OVERHEATING WITH THE PLASTIC INSULATION FLAKING OFF. THE RPTR BELIEVES THE TWO THUMPS OF SEVERE TURB PRIOR TO THE LOSS OF POWER MAY HAVE SHORTED ONE OR BOTH SPLICES TO GND; OPENING THE BUS TIE BREAKERS. THESE SPLICES WERE THE SUBJECT OF A SERVICE BULLETIN ON THE LEAR 23; BUT DID NOT APPLY TO THE LEAR 25. THE RPTR EXPRESSES CONCERN ABOUT THE LOSS OF ALL THREE ALTIMETERS AND SUGGESTS ADDITION OF THE 'OLD STEAM GAUGE ALTIMETER.'