[mitthrowaway2]

And lo, there is verily even more information presented in the video than this thread has yet revealed. For what Alec says in the video is that this purge-the-cold-water advice is specific to North America, and he even explains the reasons why!

[bakje]

Haha I have to admit I didn’t watch the whole video.

In which case my comment still stands for those who also haven’t watched the whole video, which is probably a fair amount of people

[krige]

He does mention it has to do with voltage and heating systems. I think it's something he covered on his kettle vid.

[inferiorhuman]

He mentioned that it's not due to voltage but rather low current circuits. A 15 amp circuit translates to around 1,800 watts in the US and if you derate it to 80% of that like the NEC requires a continuous load you'd have around 1,440 watts available.

His argument is that appliance manufacturers are trying to simplify their lineup by making models that would work in homes without a dedicated circuit (15 or 20 amp). Although I can't think of a better argument that still doesn't quite sound right to me. The NEC has required dedicated circuits for dishwashers for quite a while now and IIRC that requirement has been for a 20 amp circuit for a few decades. Even though you typically only see 15 amp receptacles, kitchens have required 20 amp circuits for somewhere north of forty years.

I think a lot of his video is simply based on testing with crappy Whirlpool and AEG dishwashers. There's a reason why Bosch (and these days LG) dishwashers are pretty much universally recommended.

[Turskarama]

It's the same issue, if you have a higher voltage then you can get more power without increasing current.

For example in Australia a standard house circuit is 10 Amps, but because it's at 240V we can get 2400 Watts (realistically more like 2300) out of a _standard_ wall outlet that is in every room of your house.

[inferiorhuman]

It's not the same issue. The vast majority of kitchens in the US have 20 amp circuits (so 2,400 watts peak, 1,920 watts continuous) exclusively. It's a bog standard receptacle (NEMA 5-20R instead of 5-15R) that's backwards compatible with 15 amp plugs. In fact these days most 5-15R receptacles have identical guts to their 20 amp counterparts save for the additional provision for a horizontal blade.

The electrical code (NEC) has started moving towards requiring 20 amp circuits in other rooms and more 20 amp circuits in kitchens.

[Dylan16807]

But they're staying shy of the amp limit on purpose. So designing for 20 amps would be somewhat of a boost but not enough. While doubling voltage would actually fix the problem.

[inferiorhuman]

You're going to stay below the circuit breaker rating no matter the voltage. Nobody's going to put a 2,400 watt heater in a dishwasher designed to be used on a circuit that tops out at 2,400 watts because:

a.) I'm going to go out on a limb and suggest that most countries will place limits similar to the NEC's 80% rule.

b.) There are other high current draw devices in a dishwasher that will have to run concurrently like the water pumps.

Same with things like electric kettles. You're not going to find 1,800 watt kettles in the US even though they're designed for circuits rated at that. A quick peek at the kettles available in Australia show that most top out at 2,200 watts for the same reasons.

In the context of a dishwasher 240V would only get you more powerful heaters than you could run in the US if the circuits were rated at more than 10 amps. Voltage isn't the issue.

[mschuster91]

Meanwhile, here in Germany, we have 230V, but every standard wall outlet is rated for 16A continuous load over 1 hour so you can get 3.6 kW on each circuit.

Your standard home has a supply of 3 phase power @ 35A (southern Germany) or 63A (northern and western Germany), I think only the former GDR is at standard 3x25A, because like in many former Communist countries they had to save on expensive copper and aluminium, and since a lot of the GDR was heated by steam-based central district heating systems, you didn't need that much power anyway.

[whatevaa]

Lot's old homes and flats here limited to 5A or 3A 220v. If you don't use electric heating your power demands go down substantially, though 3A is a bit small these days.