MECHANIC FOR A B757-200 REPORTS CONFLICTING CIRCUIT BREAKERS NOMENCLATURE FOR ENGINE REVERSER DEFERRAL. NOMENCLATURE FOR THE LOCATION CHART AT THE BEGINNING OF MEL DIFFERS FROM THAT PROVIDED IN SECTION 'Q.' BOTH DESCRIPTIONS ALSO VARY FROM THE ASSOCIATED ONBOARD AIRCRAFT LABELS.

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I WAS ASSIGNED TO INVESTIGATE A #2 ENG AMBER REV INDICATION ON THE EICAS ON ACFT X. I WAS INSTRUCTED TO PUT IT ON MEL COND A. ALL PAPERWORK AND PROCEDURES WERE COMPLIED WITH. THE PROBLEM OCCURRED ON STEP 1 SECTION O; THE STEP REQUIRES 2 CIRCUIT BREAKERS TO BE PULLED. THE NOMENCLATURE FOR WHICH CIRCUIT BREAKERS ARE TO BE PULLED IS DIFFERENT ON THE LOCATION CHART AT THE BEGINNING OF THE MEL; FROM THE DESCRIPTION IN SECTION O. THESE TWO DESCRIPTIONS ARE DIFFERENT FROM WHAT IS LABELED ON THE AIRCRAFT PANELS. THE EVENT WAS THAT THE WRONG CIRCUIT BREAKER WAS PULLED. AFTER RETURNING BACK TO THE MAINTENANCE SHOP I BEGAN TO DOUBT THAT I HAD PULLED THE RIGHT CIRCUIT BREAKER; SO I LOOKED IT UP IN THE MANUAL AND DISCOVERED I HAD PULLED THE WRONG ONE. BY THAT TIME THE AIRCRAFT HAD ALREADY TAXIED OUT. MAINT CONTROL INSTRUCTED THE PILOTS TO PULL THE CORRECT CIRCUIT BREAKER AND RESET THE OTHER ONE. THE EVENT OCCURRED BECAUSE OF TIME CONSTRAINTS AND CONFUSING MEL INSTRUCTIONS. A SUGGESTION WOULD BE TO LABEL THE MEL BOOK TO REFLECT WHAT IS ON THE AIRCRAFT.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THE MEL LISTS THE CIRCUIT BREAKERS AT THE BEGINNING OF THE MEL AND THEN LATER LISTS THEM AGAIN; BUT USING DIFFERENT WORDS FOR THE SAME CIRCUIT BREAKERS. ADDING TO THE CONFUSION ARE THE SAME CIRCUIT BREAKERS ON THE B757-200; WHICH ARE ALSO LABELED DIFFERENTLY FROM THOSE LISTED AND REFERRED TO IN THE MEL CIRCUIT BREAKER LISTS.