Defective afci breaker
AFCI protection is sooo important.We often recommend GFI protection and forget to recommend AFCI's. Testing one inside a sub panel recently it did not trip as required leaving the bedroom circuit unprotected. If you have one in your panel you should check it per manufacturers recommendations, typically once per month. An arc-fault circuit interrupter ( AFCI ) also known as an arc-fault detection device ( AFDD ) [1] is a circuit breaker that breaks the circuit when it detects an electric arc in the circuit it protects to prevent electrical fires. An AFCI selectively distinguishes between a harmless arc (incidental to normal operation of switches, plugs, and brushed motors), and a potentially dangerous arc (that can occur, for example, in a lamp cord which has a broken conductor). AFCI breakers have been required for circuits in residential bedrooms by since 1999