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I have seen similar questions and the answers always move on to the physics of the transformer and a center tap. I get all that, I think. My question is whether sophisticated electronics (specifically EV chargers) can tell any difference.
More succinctly, will a European car charger accustomed to receiving 240V over a single Line and Neutral react poorly (or even know) when connected to the US grid 240V over two 120V split phase Lines?
Yes, there is a difference, but another thing is if it matters and it depends on how the charger is built.
240 VAC single phase means one wire is neutral at 0V potential (bonded to earth/ground somewhere in the system) and the other wire is the 240 VAC live. The typical US household system means you also have 240 VAC but with center-tapped 0V neutral so you have two 120 VAC live wires.
So basically a simple device would not care how it receives 240 VAC but a more complex device could.
If the charger has a non-polarized mains plug then it must have been made so that which way the mains input live and neutral are must be irrelevant. If it is a fixed installation or has a polarized plug then it may matter which way live and neutral are connected.
So there can be no generic yes/no answer for any car charger you might mean.
The difference between a single-phase product made for Europe and that for the US (240V) would be as follows:
More succinctly, will a European car charger accustomed to receiving 240V over a single Line and Neutral react poorly (or even know) when connected to the US grid 240V over two 120V split phase Lines?
No charger would be capable of recognizing the difference.
The European charger would work normally in the US, provided the 240 V supply is within 230 V +/- 5%.
However, the additional fuse would need to be incorporated.
If you wanted the circuit to be able to tell the difference, you could have it measure the power frequency. European grids operate at 50 Hz, and North American ones at 60 Hz. Easy enough to tell the difference if you're trying.
If you're wondering if it'll actually affect anything, almost certainly not. Especially not with modern electronics; old equipment with mains-frequency transformers could have problems if operated at a lower line frequency than it's designed for, but modern equipment based on switching converters doesn't generally care what the mains frequency is.
