If you increase Ampere you must increase the width of the cable, or it will overheat. If you increase Voltage you must increase the insulation around the cable.

Resistive losses are related to current (I^2 R), so you need thicker wires to deliver the same power at a lower voltage. I guess it was decided that it wasn't worth the expense.

Sure, obviously. But you'd expect power requirements to be more or less the same, and the ideal wire diameter to be dependent on voltage. But instead what happened is that the wire diameter is more or less constant, and Europe just uses more powerful electrical devices.

> Europe just uses more powerful electrical devices

Aside from kettles? I guess maybe some people have electric heaters? What else pulls enough power that the extra voltage will matter? Vacuums maybe, but no, those are limited to 1600W.

Just looking up my local (German) retailer:

- Irons are commonly 2000-3200W (3200W is 14.5A at 220V)

- Portable Induction Stovetops are 3000W

- Deep Fryers are 2000-3000W

- Hair Dryers are 2000-2500W

And of course some things are connected via 3-phase 400V (3 220V phases, because of the 120° phase offset that's 400V between any two phases)

- actual oven + stovetop combinations, about 7000W for the stovetop, plus 1000W for the oven

- many tankless water heaters, 5000W-24000W seems common

The most impactful in day-to-day use are probably kettles and hair dryers, but with stovetops and water heaters there's probably a big difference in the prevalence in gas vs electrical, and tankless vs boiler simply due to wiring.

That's a good list, thanks. I'd be interested to know what the experience is like between a 120V hair dryer and a 240V model. I don't have enough hair to worry about such things, but my wife does, and it seems like her hair dryer gets hot enough that she usually turns it down a bit anyway.

The 'industrial' level appliances are probably less of an issue, because the wiring run is limited and you can customize it however you need to. I could go down and buy a 36kW electric tankless water heater today and wire it up without any difficulty. Though it would probably be worth upgrading my 200A panel in that case.

Ranges sound like they're probably pretty similar. Typical modern electric ranges in the US are about 10kW.

Three phases would be handy for reducing the cost of wiring, though. Cost me $1500 USD just for the wire when I ran four new circuits last year. Couple of them were 50A, which is partly why it was so expensive, but mostly it's just that copper is $$$. Any bigger than 60A and I'd switch to aluminum.

Also consider: your wife might not be the kind of woman who would use one on high. Pain tolerances among women, like men, vary.

I don't have first-hand experience with the difference in hair dryers either, but I imagine it's mostly air velocity? With more power you can turn more air scalding hot, meaning you can offer higher fan speeds without compromising temperature.

32A capable wiring is much more expensive. And if we are being honest, the number of modern appliances that need more than 1800W is very small outside of the kitchen. If it were a common problem people would be installing 6-20 receptacles, but that's pretty rare. I have exactly one, and it's in the garage.

Largely this is resolved by US houses having a lot more circuits. My bathroom has a dedicated 20 amp (2.4 kW) circuit for the outlets and a separate 15 amp (1.8 kW) circuit for the lights. Every bedroom in my house has its own 15 amp breaker. The kitchen has 3 20 amp breakers for different wall outlets, a 15 amp breaker for the lights, then a 30 amp 240v (7.2 kW) breaker for the cooktop, and a 20 amp 240v (4.8 kW) breaker for the oven.

For the a typical US house the standard feed into the house is 200 amps at 240v. So 48kW of power coming in we just segment it down a lot more.

It starts to become annoying when you have a home office for 2 people though. 2 PCs + 4 monitors and some random things in a room can start approaching the wattage limit. Especially given that I think it's not too common to have one circuit per room (anecdata: my house has one circuit for all outlets per story; not counting bathroom and kitchen which I believe are mandated by building code to be separate).

Lots of smaller (kw) circuits is safer than a few very large circuits. The NEC in the US actually stipulates that you must use different receptacle styles for higher ampacities specifically because it is less dangerous. If you run a small appliance on a 30-40amp circuit, you run the risk of that seemingly safe appliance pulling the full 40+ amps required to trip the breaker

Not sure if I understand - can you clarify? Did you mean that a normally safe 1.5kW appliance runs the risk of cooking itself if it's connected to a 40amp circuit? If yes, then sure, that makes sense.

> Lots of smaller (kw) circuits is safer than a few very large circuits.

Not fully convinced about the safety aspect but it definitely feels more convenient (can selectively turn rooms off if you need to work on something) - if I'm ever opening the walls, I'm going to switch to that approach. At the very least, I want to have a dedicated 20amp circuit in the home office...

Largely yes a 1.5 kW device (a 12.5 amp space heater for example) is less safe on a 40 amp circuit. Since if it fail pulling more load than designed but not truly shorted the breaker may not trip. But if you put that space heater on a 15 amp circuit it would most likely trip the breaker. As other commenters have said the UK addresses that risk with fuses in the plug.

Also I recently redid my kitchen and I added an additional 20 amp circuit just for the kitchen island outlets and it has been super nice.

Are safety concerns alleviated here by GFCI breakers? In what cases could this appliance pull more amps than it was designed for? I know it's not required for circuits outside kitchen and bathroom, but I was thinking about just replacing all the breakers with combined GFCI/AFCI ones (especially given that my circuits are so old that there's no ground on them, in which case code I believe mandates that the outlets are GFCI-protected and labeled as "no ground").

So the risk would be reduced. Since if the failure causes a electricity to travel anywhere other than the neutral it will cause the gfci to trip. A scenario where a device would pull more power would be a short developing in a heating element reducing its resistance. So it would just pull more power but all of the power is still going to the neutral and wouldn't trip the GFCI.

Also with replacing all your breakers it can increase safety. But first the breakers are not cheap. Second it can lead to a lot of nuisance trips, albeit that is better than it used to be with modern breakers.

Gotcha, so I guess it'll only protect from electrical hazard but fire hazard is still going to be there...

Breakers are probably going to be a bit cheaper and easier than opening all the walls to redo the circuits though...

Yeah your AFCI in theory is supposed to help reduce fire risk. Since failures like that cause arcing. But yeah it will be around $60-$80 per breaker, but there is definitely cheaper than ripping open walls to re-run wires.

GFCI is not a magic “make everything perfectly safe” - you could electrocute yourself to very dead without tripping a GFCI if all the power went down the main wires and none went to ground.

Britain solves this with fuses inside appliance plugs.

The continental European system doesn't really solve it, as far as I know, so you have thicker wires on low power appliances than you would in the USA.

The US also has fused plugs but their are not widely used for some reason. I see them mostly on Christmas lights, but I have also seen it on some small home electronics like a window fan and air purifier.

That’s usually because the lights draw such little power that a short at line amperage could turn them very hot without tripping a breaker.

The fuse prevents that.

Yeah sadly having separate circuits for each room is not required by the NEC to the best of my knowledge (and might be overkill depending on the situation). Usually though best practice is to have a separate circuit though for each bedroom. Depending on how your outlets are wired it might be possible to split them off onto separate breakers relatively easily though.