Suitable varistor / MOV for 230V AC power supply?

[[Chrille]]

Hi,

I am in the process of designing a DIY power supply that is running on a 230V AC. I would like to add a varistor to the circuit as a safety feature for surge protection, but I am not sure what the specs should be. 230V RMS should equal ~325V peak voltage. Should I select a varistor that is rated slightly higher that the peak voltage like 350V or would a 230V, 250V, 275V or 300V varistor work? How do I know which is the best for my application? What should he energy spec (J) be?

Thanks!

[Solder_Junkie]

See https://incompliancemag.com/new-requirements-for-movs-used-for-surge-suppression-on-ac-mains-ports/

SJ

[5U4GB]

See https://incompliancemag.com/new-requirements-for-movs-used-for-surge-suppression-on-ac-mains-ports/

Which contains one of my pet peeves, "an MOV".  "An metal oxide varistor"?  Where's when you need him?

Ah, sorry, wrong thread.

[Terry Bites]

Its advisable to choose a MOV 20% above your maximum mains voltage.
See also
www.littelfuse.com/~/media/electronics_technical/application_notes/varistors/littelfuse_selecting_a_littelfuse_varistor_application_note.pdf