How do I check a Class II appliance if there are no exposed metal parts?

As the appliance is covered in plastic, the possibility of electrical leakage occurring is greatly minimised. This is due to the plastic effectively providing insulation in the event of a live wire making contact with the internal casing of the appliance. For this reason conducting a thorough visual inspection would be essential, however a class II test would be conducted in combination by moving the probe to various locations on the appliance casing, in order to verify that there has been no degradation of the insulation.