AN SMA PLT VIOLATED CLASS B AIRSPACE.

Narrative

ON A FLT BEGINNING AT DUSK FROM COS VFR; I WAS RADAR VECTORED SUBSTANTIALLY E OF A DIRECT LINE FROM COS WHICH WOULD HAVE AVOIDED THE CLASS B AIRSPACE. SINCE I WAS VECTORED E; I CONTACTED DENVER APCH AND THE CTLR GAVE ME A DISCREET SQUAWK CODE. JUST PRIOR TO OBTAINING CLRNC TO ENTER CLASS B AIRSPACE; I EXPERIENCED AN ELECTRICAL FAILURE IN THE AIRPLANE. MY BACKUP FLASHLIGHT WAS IN MY FLT PACK IN THE BAGGAGE COMPARTMENT AND I WAS THEREFORE UNABLE TO REACH IT MYSELF AND IT TOOK SOME MOMENTS WITH THE ASSISTANCE OF THE PAX TO FIND IT AND PASS IT TO ME. BY THE TIME I GOT THE FLASHLIGHT AND WAS AGAIN ABLE TO DETERMINE MY POS RELATIVE TO CLASS B AIRSPACE; THE GPS INDICATED THAT I WAS RIGHT ON THE LINE OF THE LIMIT OF CLASS B AIRSPACE. REALIZING THIS; I IMMEDIATELY TURNED TO AVOID A POSSIBLE INCURSION OR FURTHER INCURSION IF THERE WAS ONE INTO CLASS B AIRSPACE. IMMEDIATELY AFTER MAKING THE TURN; I WAS GIVEN CLRNC BY DENVER APCH TO PROCEED DIRECT ON COURSE THROUGH CLASS B AIRSPACE. I WAS NEVER INFORMED OF ANY INCURSION. THE AIRPLANE IS CURRENTLY IN THE SHOP FOR ELECTRICAL REPAIRS AND A THOROUGH CHKOUT. I HAVE SINCE POSITIONED A PROMINENT MOUNT FOR THE BACKUP FLASHLIGHT; IN CASE OF ELECTRICAL FAILURE; AT THE PLT'S FINGERTIPS.