Originally Posted by CalebD
I'd like to know how an "AC unit" is involved with causing this fire.
+1 I've seen hundreds of HVAC failures, from small window units to 2000 ton chillers, and none of them caused a fire.
Now, a malfunctioning electrical system component, that's another story, and a much more likely culprit.
Additional note: For clarity, AC typically means Alternating Current, and A/C = Air Conditioning.