Voltage rating of safety capacitors (x/y)

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Hi!

I'd like to build a transformerless power supply, but I'm not sure if I can use 250V rated standard film capacitors (x2 for example). Mains voltage in my country is 230VAC, which means 324V peak DC, so this looks like not so good idea, but since those capacitors are used directly on mains or phase to earth / neutral to earth for Y capacitors, I think there shouldn't be any problem with this, although voltage rating is only 250V. So, would that work?

Thanks

[wraper]

Their rating is 250V AC (safety approval) and they are specially made for mains AC voltage and to fail safely. Their DC rating usually is above 600V. If you use regular 400V DC cap, it will usually fail within a few years.

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@wraper

Thanks for that! I have only one more question: what about capacitors that don't have much data on them (only voltage and capacitance), how could I tell if they're safety capacitors? I have a couple of dark-brown capacitors that look just like ordinary film capacitors, but I don't know if they're x/y or just ordinary film capacitors. It says ob them "JR or TR" and 105K 250V. I know they are 1uF +/- 10%, but as I said, it doesn't say whether they're standard or safety capacitors.

Best regards!

[wraper]

Safety capacitors are covered with various certification logos, also X2/X1 or Y2/Y1 should be marked somewhere too. Voltage rating should be with "~" symbol, or "AC", "VAC" or something like this.

It says ob them "JR or TR" and 105K 250V

most likely regular caps with DC rating

[pulse]

Ok, thanks again!