Marshall, thank you for correcting me. When I first read your post my impulse was to Pooh Pooh the statement. However, I then remembered that I had a bag of Digikey caps that I had ordered some years ago for a centrifuge repair that I did. I managed to dig them out and sure enough these caps are rated @ 250VAC! These particular caps are "film", not ceramic as I stated.Actually if it's going across the AC mains you need one of those caps that are designed for doing that.
No problem, I use suppression caps quite often and always get the ones designed for that function, anything else tends to overheat and blow up after time.Welcome & thank you 'marsh' for your suggestion.
You're correct, in the old days I also remember the waxed paper caps used in AC situations, usually one leg to the chassis so in essence there would be very little if any current passing through them. Often there was a very high ohmage resistor in parallel with them. They were there to help reduce AC hum in the audio of radios and early TVs. You will also see them in early model guitar amps with a switch that chose which one of the AC main lines was going to the cap that went to the chassis. you put the switch in the position that had the least hum. The switching arrangement was probably due to there not being polarized plugs in those days so you had to switch to find the neutral.The odd thing is, and I'm going to have to dig though 40's and 50's vintage schematics to confirm it, but I could swear that back in the day the industry used plain old HV ceramics or those old tubular waxy models for this.