I am looking for a suitable series resistor (220k) for a 230VAC optocoupler input.
The device must meet requirements from EN60664-1. I am still trying to understand the final requirements, but from what I figured out so far, it must withstand a transient over-voltage of at least 5000V.
I was looking at some data sheets like the PO Series from VITROHM. For short transients, there is a maximum pulse voltage of 2000V specified.
Is using this resistor really a no-go or what exactly happens when this voltage is exceeded? If it was just about power dissipation, it would depend on the resistance.
I was not able to find any resistor with a higher rating. I have kind of a reference device (no schematic) and there are just some power resistors (unknown type) placed on the opto-coupler input as well, without any other protection/components.
Any suggestions how to design this?