Static Wick Testing
 

Anyone know the reason why we need to wet the tip of the static wick when doing insulation test with megaohm meter (between tip of static wick and base)?

To ensure a resistance path along the wick and not the surrounding air, which might just be humid enough to give a false reading.

Static wick tip is non-metal while the megger proble is conductive which causes not good contact when touching.
Remember that bad contact between wick tip and megger probe gains the resistance. Also the more resistance static wick is, the more quality it is. This drives the result is not reliable when evaluation the static wick quality.
That's why we have to make wet wick tip.