Hi folks! Please, check my logic. Here is well known schematic of usage AC-DC SMPS (for example, PC): L – phase wire, N – neutral wire, G – protective Earth. This scheme is actual for Europe. I don’t know how about US. I’m in confusing with three questions: 1) Y-capacitors don’t works well – do not suppress symmetrical interference (suppress, but high-frequency only). And only one of them works in low-frequency. 2) Shorts N to G cannot be detected by 1-pole circuit breaker. Returning current will flow thought shorts N+G. 3) N-wire break cannot be detected. Power Supply will works on G-wire until it burn down. 4) A vast of devices have direct connection between secondary (low-voltage) GND and G. What happens if G-path will has lower resistance than N? Power current will flow through G-wire, nor through N. The path of this current will unpredictable. Am I right? I’m not a native English speaker, please tell me in simple English. Thanks.