In any PCB design, it’s good practice to make sure that all copper has a clearance of at least 20mils from the board edge and any large holes. With most holes, the pad around it is usually big enough that your general copper-to-copper clearance rule will push the copper back far enough, but for holes without pads, or for NPT holes, we need a separate rule. Altium still doesn’t have a specific design rule for copper-to-hole clearance, but using a simple query we can create a rule that will only apply to the holes where the copper pad is not big enough:

IsPad and (HoleDiameter > 0) and (((HoleDiameter + 10) > PadXSize_AllLayers) or ((HoleDiameter + 10) > PadYSize_AllLayers))

Here is a screenshot of how the rule looks in Altium: