I have PCB with a clearance rule for nets that can be exposed for higher voltages:
In the schematic I put a blanket around the area I need to be assigned as higher voltages nets (I called this class "Line"):
However the unconnected pin (pin 12 of K2 relay) has no net assigned - no net class consequently. So in the topology the clearance is not corret:
Until I put some arbitrary net label (NC1).
This can be solved for simple cases like mine. But if there will be an IC with many unconnected pins needed to have a net class - it will be a tricky thing.
As Matt suggested I tried to put Net Class directive directly to the pin as the following: strange but this didn't work, the pin still has wrong clearance.