What was found
(CAN) WHILE THIS A/C WAS TAXIING OUT PILOT NOTICED A BURNING SMELL & THEN SMOKE IN VICINITY OF BREAKER PANEL ON LEFT SIDE OF COCKPIT. SHUT OFF MASTER SWITCH, SHUTDOWN ENGINES & EVACUATED A/C. ON INVESTIGATION FOUND THAT A 20 GAUGE WIRE WAS BURNED ABOUT 1.5 FT IN VICINITY OF BREAKER PANEL. IT ALSO BURNED ABOUT 4 OTHER WIRES IN THIS VICINITY AS WELL. WIRE THAT INITIATED PROBLEM WAS A POWER WIRE THAT OPERATES FASTEN SEAT BELT & NO SMOKING LIGHTS. IT WAS VERY HARD TO DETERMINE WHAT IT HAD SHORTED ON. ALL WIRES WERE REPLACED & PROTECTIVE SHIELDING WAS INSTALLED. BREAKERS FOR THIS SYS ALSO REPLACED.