Mains powered SMPS filter cap voltage value.

[diy didi]

Good day
I have a SMPS power supply that I'm repairing. After the Bridge rectifier there is a 82uF 400V capacitor.
Can I use a 350V capacitor? Why the 400V capacitor?
Rectifier voltage with a good capacitor measures 320V DC. Our mains is 230V AC at 50Hz.
Hopefully someone here can shed some light.
Thanks.

 

[Nigel Goodwin]

The voltage is mostly a question of "what you can get" and physical size, and a 350V will be fine - in fact you commonly see both 350V and 400V used.

Obviously depending on the reliability of your electrical supply, a 400V one would give a greater range for mains errors.

Is your mains actually 230?, or is it just nominally 230? - the UK stayed on 240, and the rest of Europe on 220, although all are 'nominally' 230. The 230V rating is for equipment, not the actual mains voltage.