As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
JUST PRIOR TO TOP OF CLIMB, RIGHT EMERGENCY AC BUS OFF. CONSULTED WITH MOCC, RETURNED TO AIRPORT. EPCU FAULT LOGGED AND FOUND B1-138 RCCB IN CAC SHOWED OPEN INDICATOR BUT B1-139 CONT CB WAS CLOSED. REMOVED AND REPLACED B1-138 RCCB IAW AMM, ALSO PRECAUTION REMOVED AND REPLACED B1-139 CB. EPCU RTS TEST PASSED IAW AMM.