A CPR LJ60 FLC AT SJC RPTS CONFUSING TAXI INSTRUCTIONS RESULTING IN A POSSIBLE RWY INCURSION.

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WE WERE PARKED AT FBO ON THE E SIDE OF THE FIELD. OUR INITIAL TAXI CLRNC WAS TO TAXI TO RWY 30L VIA TXWY Y. AS WE TAXIED OUT OF FBO; IT BECAME APPARENT TO ME THAT TXWY Y DID NOT GO TO RWY 30L. TXWY Y ONLY PARALLELS RWY 30L. A BETTER TAXI INSTRUCTION WOULD HAVE BEEN SOMETHING ALONG THE LINES OF 'YC' OR 'YB.' WE CAME TO A STOP AT INTXN YC AND I ASKED THE CTLR IF IT WAS OK TO CONTINUE TO RWY 30L VIA 'CHARLIE.' IN SPEAKING WITH THE SUPVR; THE CTLR CAME BACK AND STATED 'AFFIRMATIVE; CHARLIE-YANKEE TO RWY 30L.' ON ONE HAND; HE SAID AFFIRMATIVE TO MY REQUEST TO CONTINUE TO TAXI ON 'CHARLIE' TO RWY 30L; BUT THEN ISSUED A CLRNC TO CONTINUE TO TAXI VIA 'YC' TO RWY 30L. MY OPINION WOULD HAVE BEEN FOR THE CTLR TO HAVE SAID 'NEGATIVE; XXXXX; TURN L AND CONTINUE TO TAXI VIA YANKEE-BRAVO TO RWY 30L.' THERE WAS VERY LITTLE GOING ON AT THE FIELD AT THE TIME AND I FEEL THAT THE CTLR SHOULD HAVE REALIZED THAT HE HAD AN ACFT HOLDING SHORT OF AN ACTIVE RWY AND WAS ABOUT TO CROSS. WE CONTINUED TO TAXI VIA 'CHARLIE' FOR AN INTXN DEP FROM RWY 30L. WHEN WE CALLED WE WERE THEN INFORMED OF A POSSIBLE PLTDEV. POSSIBLE FACTORS TO INCLUDE IN A CAUSE: DUTY TIME (11 HRS AT TIME OF OCCURRENCE); NIGHT OPS; UNFAMILIARITY WITH E SIDE OF ARPT. THE PF DID INITIALLY QUESTION ME AFTER WE WERE GIVEN THE CLRNC; 'AFFIRMATIVE; CHARLIE YANKEE TO RWY 30L.' I TOLD HIM THAT WE HAD BEEN CLRED TO TAXI TO RWY 30L; AND; PER THE AIM; INCLUDED APPROVAL TO CROSS ALL TXWYS AND RWYS. THE INITIAL TAXI CLRNC WAS CONFUSING AT BEST. IN TALKING WITH THE SUPVR AFTER THE FACT HE STATED THAT TXWY Y EVENTUALLY MERGES INTO TXWY B TO GET YOU TO RWY 30L.