As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AFTER TAKE-OFF THE CREW NOTED THE NR1 BLEED CONT CIRCUIT BREAKER POPPED. UPON RETURN TO DEPARTING AIRPORT MAINTENANCE FOUND THAT THE CONNECTOR PLUG CONNECTED TO THE BLEED PRESSURE REGULATING SHUT-OFF VALVE HAD BECOME OVERHEATED AND HAD LOST IT'S INSULATING PROPERTIES. THIS PLUG IS SUBJECT TO HIGH HEAT WHEN THE VALVE IS POWERED IN THE OFF SELECTED MODE.