Yes, for the appliance and cord(s) to be treated as separate entities is what I meant. And I can indeed understand it being a bad idea with 120V, not least because, if we go by the IEC's current ratings, you'd be limited to:
- C5/C6 and C7/C8: 2.5 × 120 = 300W
- C9/C10: 6 × 120 = 720W
- C13/C14, C15/C16, C15A/C16A, C17/C18: 10 × 120 = 1200W
- C19/C20, C21/C22, C23/C24: 16 × 120 = 1920W
Well, the UL and CSA are willing to give significantly higher current ratings, but I wouldn't trust those, personally.
However, the possibility of adding 240V outlets (NEMA 6-15 or 6-20) in new US/Canadian houses has been discussed here before - not that I expect it to actually happen any time soon. (I don't know if "tamper-resistant" versions of them exist, though.)
The cylindrical objects mounted to some cords are ferrite cores, yes.
