Make sure the DC flash has a longer ramp up time (eg start at 30 seconds) and also make sure there is a ramp down. Finally, allow time to discharge the appliance, for more information:
DC Hipot Testing –
The Leakage current measured is a better representation of the true leakage of the DUT as the capacitance is charged after the ramp time, as such is it a better test for products with large capacitance.
As a result the Pass limit can be set at much lower values, which means the trip would react at far safer levels for the operator, should they becomes exposed to the test voltage.
Overall test times are slower due to the need to ramp the test voltage to its final value. In certain circumstances this can be significantly longer than the actual test time.
The DUT must be discharged at the end of the test, this again may add to the test time but importantly can be a safety concern for the operator.
Only stresses the insulation in one polarity as opposed to both when using a AC waveform