Safety Issues in EMI Filter Design

The concept of safety and how it impacts the biter sechon is summed up as follows  

But consider the case of a high-voltage mosfet (switch) mounted on the (earthed) metal enclosure (for better heatsinking). Clearly, we can t provide any level of protection through physical separation. So in this case, we need to place one layer of approved insulator between the mosfet and the enclosure. Note that in this position, the insulator serves as basic insulation.  

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