Drawing upon the lessons learned from returning a small
sample of breakers that were voluntarily removed from service
following thermal image surveys, mill engineers elected to
collect a larger sample of breakers for return to the
manufacturer’s PIC for analysis. In August of 2008, a group of
11 more breakers that had been removed from service during
rotational outages based on routine thermal imaging of over
500 breakers. These 11 were also returned for evaluation.