Hi,
I agree with Wawa.
Your link says in full.
For worldwide use in electromagnetic interference (EMI) suppression in across-the-line applications requiring X2 safety classification. Intended for use in situations where capacitor failure would not result in exposure to electric shock. Not for use in "series with mains" type application
As a filter across the live and active they will be fine because in a properly constructed circuit you would have a circuit breaker of fuse in line to blow when the X2 finally broke through.
If the cap is in series with the active line as inbeing used to capacitively reduce voltage.
I the X2 capacitor breaks through, you will not have the capacitive impedance to drop the AC voltage, you will have FULL AC current and voltage flowing, thus letting the smoke out of you low voltage device you were using the X2 to volt drop.
Tom....
