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Comment by numpad0 | Hacker News Reader

> Idk. I don't have a PHD, but 220V sounds like 240V to me. I wouldn't do this.

220[Vrms] * 1.414 = 311[Vp-p] btw. HOW!?

Besides the ratio between the peak and effective value, you must also account for the standard tolerance of the nominal value.

The actual maximum peak voltage for the European mains, is 230 V * 1.15 * sqrt(2), because of a 15% tolerance. That is about 375 V. With a small safety margin, the minimum voltage rating for components connected to 230 V a.k.a. 220 V is of 400 volt.

Makes me wonder if that was how EV DCFC quickly settled with 400VDC. The voltage makes sense if it was somehow known that engineers has intuitions with safe designs for 400Vp-p systems.

I would be wary of relating any DC constraints to AC constraints and behaviour.

So the issue is that 220V is nominal in China, 230V nominal in UE and 240V is UK/part of Australia. So if anyone is preparing product for global market (as most are doing now) more likely then not will support all of this voltages. Thus is kind of normal (but wrong) to assume 220V sounds like 240V.

When the voltage was unified in UE, the nominal value was set to the median of 230 V, but its tolerance was raised from 10% to 15%, so that the new maximum peak value of 230V + 15% will match the old value of 240 V + 10%.

So now for all 220/230/240 V standards you have the same maximum voltage value that is used for electrical designs (about 265 V effective), so they are equivalent, regardless of the name.

True, however there is also old equipment. For example I have heard that light bulbs designed for 220V will last for noticeably shorter period of time ar 230V nominal circuit. That is why it is worth to check supported voltage. But you are right - newer equipment will suport all voltages.

Many charguers are now 100-240V, 50-60Hz, that is close to pluggable anywhere on Earth. (I burned one or two a long time ago, when I forgot to check and used a 120V transformed here with 220V)

Same thing happened to PC PSUs. I don't think there is a recent unit that still has the self-destruct voltage selector switch which pops them if you are in 230V land (and the switch is set to the smaller setting).

AC wiggles and wobbles.

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