HV diode test

[jfphp]

Hello,
How can I test HV diode (service of several KV) ? There are alone, not mounted with capacitors. Standart diode test gives no result. If I apply HV to mesure the current I have to float the multimeter beyond the specs... Any idea ? Thank you.

[bktemp]

Apply a high enough voltage to make it conduct and check if the forward voltage drop is in the expected range. Most high voltage diodes have a forward voltage in the range 5-100V.
If it works, apply a high reverse voltage and measure the leakage current. Maybe you should add some protection across the current shunt in case the diode fails at a high voltage.

[Seekonk]

I tested a microwave oven diode last week and that had stacked a forward voltage of 7.5V.  For sure a HV diode will be at least 50V.