Last week there was an electrical incident on our residence: many of my neighbors had to turn off the devices minimum, unconfigured and sometimes more serious: the baker could make his daily bread. On my devices connected to the PCA (my 3 PCs LIT TV, box, router): no worries, they saw nothing happen. My microwave and VHS recorder stopped elsewhere in the apartment had lost time to witness the incident.
I do not know what it was, a transient overvoltage perhaps, but in any case the APC did his job ...