How should I select appropriate capacitors to ensure compliance with IEC/EN 61000-4-2:2009 and IEC/EN 61000-4-5:2014 standards for my device?

Question

When applying the IEC/EN 61000-4-2:2009 and IEC/EN 61000-4-5:2014 standards for our device, our consulting firm recommended bypassing the input power jack to the chassis ground using two 33nF capacitors based on the device's circumstances.

To ensure compliance, I reviewed the test requirements and found that a voltage of ±4 kV can be induced to the device's body.

Should the rated voltage of the mentioned bypass capacitors be at least 4 kV to handle this level of test voltage?

Furthermore, considering the ±8 kV air discharge immunity requirement, how does this impact the choice of components?

Lastly, from a technical perspective, would it be more suitable to use X1, Y2 type capacitors or high voltage generic capacitors?"

Answer 1

Should the rated voltage of the mentioned bypass capacitors be at least 4 kV to handle this level of test voltage?

No, because there is limited energy from the surge transient and, that energy (when applied) will charge up the 33 nF capacitors to a much lower voltage. It's fairly easy to simulate for both surge and ESD; it's a case of a high voltage low pF capacitor in the test gun (or apparatus) sharing its charge with two 33 nF capacitors. The resultant terminal voltage might be a couple of hundred volts for 6100-4-5 surges and probably much less than 100 volts for an ESD discharge.

Simulation is your friend here.

from a technical perspective, would it be more suitable to use X1, Y2 type capacitors or high voltage generic capacitors?

Work out what the theoretical peak voltage is then, estimate the current pulse taken through the 33 nF capacitors when subject to the surge. If necessary you can use metallized film polypropylene capacitors if, the current surge is higher than a regular ceramic capacitor can handle.

It's a numbers game.