Under what circumstances will the power adapter use insulation shielding technology?

In general, there are three common insulation protection technologies for power adapters, one is reinforced insulation technology, the other is additional insulation technology, and the third is basic insulation. Under what circumstances will the insulation shielding technology be used?
For example, during the working process of the power adapter, occasionally the surge in the circuit will suddenly be higher than the risk voltage, and then in order to ensure the normal use of the switching power supply, we must use insulation protection technology.
First of all, let's analyze the reinforced insulation technology. This method is relatively common. Its main function is equivalent to the double insulation effect. When using this technology for the circuit design of the power adapter, the minimum thickness of the single layer inside is greater than or equal to 0.4 mm is the best, so that several layers of insulation can be guaranteed, and this technology is also one of the many insulation systems to avoid electric shock.
The second type of insulation protection is basic insulation. This method is very common, and it is also the most basic method to solve the insulation protection of switching power adapters.
Finally, let’s talk about the additional insulation technology of the power adapter. To apply this method, we must first pay special attention to the fact that the minimum thickness of the single layer of additional insulation must be greater than or equal to 0.4mm, so that it will be effective. The principle of this technology is independently added to the basic insulation, which is the secondary cover of the power supply.