I have made a small control panel using a 12F629.
I'm controlling a relay that has to switch a pump or a solenoid valve.

Since these inductive loads can couse peaks when switched I would like to protect my construction with a VDR-resistor.

I think that the VDR must be placed between Live and neutral on the mains-supply.

The mains supply it 230V AC so I suppose that a 250V VDR is what I should select, but how do I calculate if it shold be a 0.1W or 1W or?

Kind regards
Gert