AFTER INSTALLING A COCKPIT APU START PANEL ON A B757-200; A MECHANIC IS LATER INFORMED BY HIS MANAGER; THE START PANEL WAS NOT EFFECTIVE FOR THAT AIRCRAFT.

Narrative

I AM A LONG TIME AMT WITH MY AIRLINE. IN THE MORNING I INSTALLED AN APU START PANEL IN ACFT X. EVERYTHING OPERATED NORMAL AND NO ACFT INCIDENCES OCCURRED. BUT; THE MANUFACTURER'S PART NUMBER I INSTALLED WAS NOT EFFECTIVE FOR THAT ACFT; EVEN THOUGH IT WAS THE SAME CARRIER PART NUMBER. I USED THE IPC MANUAL TO VERIFY THAT THE MANUFACTURER'S PART NUMBER I INSTALLED WOULD CROSS TO THE SAME CARRIER PART NUMBER AS WHAT THE IPC CORRECT EFFECTIVITY SHOWED. I FAILED TO SEE THE MANUFACTURER'S PART NUMBER I INSTALLED WAS NOT EFFECTIVE FOR MY ACFT. THE IPC IS CORRECT AND I SHOULD HAVE LOOKED AT THE MANUFACTURER'S PART NUMBER INSTEAD OF THE CARRIER PART NUMBER FOR THE CORRECT EFFECTIVITY. THE SERIAL NUMBER I ENTERED IN THE ACFT LOGBOOK WAS DETECTED BY CARRIER'S PARTS SYSTEM AS BEING INCORRECT EFFECTIVITY FOR THAT ACFT. 2 DAYS LATER; THE APU PANEL I INSTALLED WAS REMOVED AND THE CORRECT EFFECTIVITY PART NUMBER APU PANEL WAS INSTALLED WITHOUT INCIDENT. I WAS MADE AWARE OF THIS MISTAKE BY MY MGR. PAYING MORE ATTN TO THE IPC WOULD HAVE PREVENTED THIS INCIDENT.