How do variable-frequency drives pass UL 508c failure of components testing?
This type of cap is subjected to the Breakdown of Components test where one of the caps is short circuited. 

If there are no flames / explosion, even if fuses blow then it can be Ok. The result must be no fire or shock risk... so if the door blows open its a failure if you can touch live parts.

This can be an expensive and exciting test... fire extinguishers at the ready!