Posted by John Haine on 22/10/2020 15:10:58:
Don't worry, the capacitor from RS is rated for 440 volts working AC which is what you need. I think the one ndiy was referring to is 40 uF which is 10 times too big anyway.
Read my posts. I did not refer to any particular capacitor. That RS capacitor, if it will withstand 440V A/C Will certainly withstand 254V AC.
254V requires a capacitor that will work safely at 360V DC – but it must be a non-polarity conscious type.
That 440V AC one should withstand over 620V either side of zero volts. So plenty of safety margin.