You may research in one of the air accident sites the case of the Air Transat A330 which was allowed to run out of fuel : no engine generator, no APU generator.It was just left with the batteries and the RAT.
The crew managed to glide it to the Lajes airport. And it still had the integrity of it's flight controls (granted without all the protections...).
That's about the most extreme failure you could imagine.
On the same subject, with engines available and/or the APU, a major el;ectrical failure will cause you to go into a failure research and isolation procedure, followed by a reset of most available components after the faulty generation system or bus has been identified and isolated.
Otherwise, it's pretty much like HiFI
's description. Difficult to elaborate any further than HiFi
did as power sources and system requirements are so numerous. We pilots learn and retain the most important switchings :For instance, the BA
incident (initial loss of captain's instruments and the upper ECAM) is a trigger for a faulty ac essential bus. Before anything else I personally would have confirmed the fault with the electrical panel (overhead) and tried to re-power it through its alternate source (in this case the #2 ac bus)...but as the saying goes, hindsight is always 20/20.