The pictures below are worth noting to show what can happen when we don't enforce important safety code requirements regarding emergency power sources. In this case, 26 story residential building had to be evacuated with no power and no functional emergency generator resulting in pitch black stairways and corridors.

Emergency generator for 26-story high rise No exhaust connection No wiring connected Alternate view of disconnected wiring

(For more information regarding this specific incident, please contact Captain Tysh)