fullsquare

i hope you get hazard pay for psychic damage

in many flats even recently built you don't get three-phase power, just single phase, but building divides single three-phase supply into three groups of single phase circuits like you say (do you really need 20kW in residential flat? one that doesn't use EV charger, built in 90s-10s?) i guess it depends on country also. separate houses tend to get three phase connection where i live

floating neutral will also be a problem in american-type two-phase installation, might be even worse (more frequent) on account of large number of lightly maintained transformers used (why on gods green earth there's few-kV medium voltage line going down every street, americans make it make sense)

Today many of switching mode power supplies accept anywhere between 100-250V

i'm afraid they might be for real

bases of pins are insulated, like in type C/E/F

you don't have to have three phase circuit to be affected by floating neutral in three-phase substation upstream. in some places in us there are 208v interphase three-phase circuits, which give 120v phase to neutral, which is distributed as a pair of wires as single-phase circuit. this is also normal way to deliver single-phase power in europe, as it's most efficient use of conductor. (from 400v three-phase circuits) in case more power is needed than single-phase circuit can deliver, three-phase circuit is installed

if there's switch on device, it's 2p1t meaning both phase and neutral are switched. if it's permanent, non-pluggable circuit, like lightning, it's okay if only phase is switched (neutral is connected permanently)

it's a bad practice to design appliance in such a way to assume that neutral will have low voltage, because in case of neutral failure in three-phase circuit you can get full voltage there, and there can be a couple of volts difference (sometimes more) between neutral and ground even in normal circumstances

it's better to cut off both live and neutral at the same time anyway, especially if there's no standard which is which. also, as device designer you don't know if it'll be used on a circuit that has neutral and phase where you think it'll go or not. (ie british appliance used on unpolarized circuit, like type F. adapters exist)

Type E/F carries 16A/230V, and nowadays there are shutters included which only allow two pins to be inserted at once, not one but not the other. There's no standard as of which pin should be L1 and neutral anyway, nor it should matter, and fuses in british plugs are to accommodate ring circuits, which were introduced as a result of copper shortages (ie decades of tech debt)

Or you could just use thicker wires like everyone else, or drop the use of ring mains, which is the actual reason why fuses in plugs were introduced. The reason why this was done was post-WW2 copper shortage. In other countries you'll see more likely star type circuit

I think that type A plug would be greatly improved in terms of safety and mechanically if it was put in a grounded metal shroud, in style of DIN connector https://en.wikipedia.org/wiki/DIN_connector it still would be compact, smaller than type F

is TRPV3 even involved in any way because last time i've checked some of best evidence points in direction of TrkB

UK uses type G. Type E/F plug has both contact for grounding pin like in type E and two sliding ground contacts on side like in type F. Sockets are either E or F, and i've mostly seen E