What happens when the rated carry current is exceeded at the switching section (contact section)?

The symptoms depend on whether the contacts have power supplied to them only or they are switched as well.

1. Power Supply Only

Generated heat may cause deterioration of the contacts and/or conductor insulation, and reduce the springiness (reset force) of the contact springs.

2. Switching

Contact transfer, welded contacts, OFF faults, abnormal consumption, and increase of contact resistance may occur.