Maybe. i designed it withstand up to 30 kv, and the power supply is 15 kv nst.

@Metahuman I have destroyed capacitors with excess current, where the voltage was never exceeded.

@GeorgeRocheleau that doesnt make sense to me. Could you explain, please? The power supply delivers about 30 ma and the capacitor was right at about 9 nf. I mean, i guess i could see where an inductive spike or something could overvoltage it, but i don't understand how you could overcurrent something with a given reactance at a particular voltage.. My understanding is that voltage and amperage are proportional with resistance/reactance. Always looking to learn, though!

@Metahuman I don't know what circuit and waveform you are driving the cap, but if you are hitting the cap with high amperage, high frequency spikes, the internal resistance of the (ESR) of the cap could lead to overheating and then to self destruction, smoke flames, explosions, fun stuff.

@GeorgeRocheleau its a standard LC primary tank circuit with a spark gap.. Neon sign transformer would be outputting a 60 hz sine wave.

Oh, ive been witness to a few capacitor explosions, lol.

What im confused about is your statement regarding voltage and current. I don't see how a greater current can flow across a given impedence without a greater voltage.

Does ohms law only aply to resistive impedance, and not inductive or capacitive?