What was found
(CAN) AFTER TAXI IN AT YVR THE NR 2 AC INVERTER FAIL LIGHT ILLUMINATED AS WELL AS XS2 BUSS FAIL LIGHT ILLUMINATED. RESET THE NR 2 INVERTER SWITCH FAILED TO RESET THE SYSTEM. MAINTENANCE TROUBLESHOOT THE PROBLEM BACK TO A FAULTY RELAY WITHIN THE CABIN LIGHTING SYSTEM. FURTHER INVESTIGATION FOUND THE LIGHTING RELAY CHATTERING, CAUSED A FLUCTUATING VOLTAGE ON THE XS2 BUSS RESULTING IN THE NR 2 INVERTER TRIPPING OFF LINE. AFTER TRACING THE HISTORY OF THIS PROBLEM IT WAS FOUND THAT IN MORE THAN ONE OCCASIION THE CABIN LIGHTING HAS CAUSED A TOTALFAILURE OF THE AIRCRAFTS RIGHT AC BUSS THUS LEAVING CONCERNS AS TO HOW A SECONDARY SYSTEM CAN FAIL A PRIMARY SYSTEM ON THE AIRCRAFT.