[SoftTalker]

I think you certainly could set up a water heater with something like a clothes dryer lead and plug, but I've never seen it done. I'm not sure why kitchen ranges and clothes dryers tend to be plug-in and water heaters tend to be hard-wired; in my experience they all get replaced about every 10 years or so.

[ruduhudi]

Isn‘t that mostly a question of the wattage the appliance needs? Here in Germany we have a Max of 3000W on the regular plugs which is why, for example, stoves need special plugs. Not sure about water heaters though

[gizmo686]

The limiting factor for outlets is typically the wire, not the plug. A standard NEMA 14-30 plug that is often used here in the US for high power appliances like dryers and ranges can provide 24amps continous at 240V, for a total of 5760[0] watts. Electric water heaters typically run at around 4500 watts. If you need more power, NEMA 14-50 is available as well.

More capable options exist if needed, but I have never seen them in a residential setting.

[0] The 30 indicates that it supports a peak wattage of 30.

[kuschku]

A typical German water heater, e.g. from stiebel eltron, will be between 15kW and 22kW at three phase 400V, which is obviously too much for a regular outlet. Which is why it's usually wired directly, the same as stoves/ovens tend to be.

[CydeWeys]

Geez, three phase 400V using up to 22kW?! That would be quite a rare sight to see in the US. Afaik most houses only even get two of the three phases from the power line poles, for a max of 240V.

[ericvsmith]

This is a common misconception. US homes are not two phase, they are single phase 240 volts, called split phase because the single transformer leg is tapped in the middle to form two 120 volt lines, each 180 degrees out of phase with the other.

https://en.wikipedia.org/wiki/Split-phase_electric_power

Three phase circuits are 120 degrees out of phase.

But completely agreed that three phase 400V seems crazy!

[vl]

But isn’t it just “two phase”? I.e. how “true” two phase would be different?

Ok, help from our new common friend:

Yes, your statement is essentially correct. In the United States, residential electrical supply is typically a single-phase, 240-volt system that is "split" into two 120-volt legs. Each of these legs are 180 degrees out of phase with each other, which allows for both 120-volt and 240-volt circuits within the home. This arrangement is often referred to as "split-phase" electricity. It's not technically two-phase because a true two-phase system would have two waves offset by 90 degrees, not 180.

[bluGill]

A tankless electric water heater could use that much I suppose. I wonder if that is what Germany uses? Tanks take up more space, but they need a lot less power at once so they are kinder to the grid.

In the US houses get 1 of the 3 phases. That phase is split in half, and so each phase is 180 degrees. This is different from 3 phase power where each phase is 120 degrees. 3 phase is good for a few things, but for a water heater it doesn't matter, and most of the things 3 phase is good for you today will run off of an inverter for speed control which in turn can run off of single phase (3 phase is still better but only because you can use smaller capacitors)

[kuschku]

> A tankless electric water heater could use that much I suppose. I wonder if that is what Germany uses? Tanks take up more space, but they need a lot less power at once so they are kinder to the grid.

Tankless water heaters are much more common in rental apartments, and Germany has one of the highest quote of people living in rented apartments. And if space is at a premium, of course tankless heaters are preferable. Apartments are also the reason why electric stoves (again, using 400V tri-phase) are so popular in Germany.

[CydeWeys]

Just looked that up, apparently some tankless water heaters in the US will use up to 30kW, supplied as 240V/120A. Yeeeesh. That's one helluva circuit, and you better believe it's direct-wired too.

[CydeWeys]

It's pretty common to see 240V/50A plugs/sockets in the US. That's how you'd power e.g. an electric stove, and that's 12 kW in total which is quite a bit of power.

[kjs3]

I believe this is is generally correct. There's only so much power it's safe to deliver through a plug.

[SoftTalker]

How much power does a Tesla supercharger deliver through a plug? More than a water heater draws I would think? Maybe not?

[kjs3]

The water heater I just replaced lasted something more than 25 years. I don't expect this one to. But that's a different brand of "get off my lawn" than this thread is about. :-)

[rascul]

> I'm not sure why kitchen ranges and clothes dryers tend to be plug-in and water heaters tend to be hard-wired

The kitchen and laundry appliances are sometimes moved with the homeowner or tenant, but not the water heater. Also a plug can make it easier to pull out for cleaning.

[MandieD]

Kitchen ranges, clothes dryers, and literally every other appliance large or small are usually moved with the homeowner or tenant in Germany - until the last decade or so, rental apartments almost always came with completely empty kitchens, and it was on the tenant to fit in the cabinets, appliances and even the sink. Bathroom cabinets are also usually the responsibility of the tenant, but the toilets, sinks, and showers/tubs are built in.

On the upside, even a small studio apartment usually has enough space and an extra water hookup for at least a washing machine, so no dealing with other apartment residents or a public laundromat for laundry. Dryers are usually condensing; no need for an outside vent.

Until the last few years, short tenancies were unusual for Germans; in the little building we rented in before we bought our house, the other tenants had been renting there for 20-40 years! Given the terms of our contract, I gathered that they must have had very small, if any, rent increases written into their unrestricted contracts, and the only way to get them out was if the building owner decided to live in one of the units herself.

[SoftTalker]

Sometimes yes. Often they stay, especially if they are reasonably new and the buyer wants them. It's seen as a selling point that the buyer won't have to go out and buy appliances right away. Of course the hidden downside is that they are financing used appliances for 30 years so it's generally better if the buyer negotiates a lower price in lieu of appliances. But a lot of new homebuyers don't think about that.

But I'll grant that appliances are probably moved more often than water heaters are.