Customer complaint: 86 lockout rolls to tripped position, breaker is open, load side of breaker has new ATS installed on load side of 4160D-480/277Y transformer. As of right now I see no reason to investigate the load side of the breaker. No flags from the electromechanical relays, (3) 50/51 and (1) 50G. Considering faulty 86 mechanism or control circuit? any thoughts?