en60335-1-/A12:2006 29.3.Z1 The creepage distance through a possible hole is not considered relevant because it is only stressed when the second electrode (human body) is present.
IEC60335-1/A2:2006 19.13 After the operation or interruption of a control, clearances and creepage distances acrossthe functional insulation shall withstand the electric strength test of 16.3, the test voltage,however, being twice the working voltage.