@calden
Elec Emergency Config essentially means loss of all generators. It assumes all AC Buses to be operational, just not powered. Therefore APU start will restore the normal AC power. AC bus loss is a different procedure and I don’t think Airbus even envisaged losing both AC buses at the same time
As for APU start on ground. The system logic is that on ground, you’re not getting enough power from the RAT and DC BAT bus is only connected to the batteries below 100kt. I don’t know the actual reasons for that, but basically if you’re on GND and above 100kt:
- RAT is not available (because min RAT speed is 140kt)
- BAT bus is not yet powered by the batteries
Hence - you can’t start the APU