[Kirby64]

Until the US changes their AC power connectors, we just don’t have a use case for it frankly. When the entire system is going to always top out at 1200W or so (so you have an extra few hundred watts for monitors and such), we’re pretty limited to maximum amperage.

[ielillo]

The USA has 240 volt plugs. They are only used for high power appliances such as AC or ovens. If you want, you could add a plug for your high powered space heater AKA gaming PC.

[Kirby64]

I’m aware we have 240V outlets. They are just not used in a place where you would put a PC. Until there is a shift in need (I.e., every normal user would need more than a 120V plug could handle), you won’t ever see 240V outlets in offices. I suspect it will never happen.

In server areas and extremely specialized stuff? Yea, sure. But we’re talking desktop PCs here.

[tass]

There's also 20 amp circuits which are common.

Many houses run circuits that are rated for 20 amps even if they don't have the right outlet for it so this is an inexpensive upgrade for most.

[anankaie]

I did not realize the outlet impacts the amperage… Is it a rating issue, or is there an actual part there that will trip?

[ProllyInfamous]

Retired electrician's comments:

Most of the US utilizes the NEC for installation compliance. Per NEC, 15A-style outlets are "to code" on 20A circuits unless a single recepticle ("dedicated") circuit — in which case a 20A-style recepticle MUST be installed.

For any electric appliance (including computers) which operates for 3hrs+ ("continuously"), the circuit rating is reduced to 80% capacity (e.g. only 16A load allowed continuously on a "20A circuit" == only 1920W computers allowed on 20A circuit, 1440W on 12A).

Pro tip: check your own PSU, but practically all modern computers can handle AC input 100-240V (all you need is the correct IEC power cord for a 240 US plug).

I have fixed enough melted devices in my career to always twice-torque each&every connection I make. For temporary extension cords/plugs, "twist lock" ends are worth all the extra dollars.

Protips: use Eeez-Ox (a conductive paste which inhibits corrosion) for high-load applications (non-data, only). My own gamerig's AMD GPU has it (sparingly applied) within its dual 8-pin connectors. I supply the 8-pin connectors from a single pair of 8awg copper, which is directly soldered within the PSU's PCB power-take-offs... so only a few inches of 16awg for voltage drop (into the GPU), which reduces the amperage required (but is also unnecessary overkill).

[lsaferite]

> For any electric appliance (including computers) which operates for 3hrs+ ("continuously"), the circuit rating is reduced to 80% capacity

That's a new one for me. Do you have a reference for that? I'd love to read more.

[happyopossum]

It’s the whole chain - 20a outlets typically require 12ga wire instead of 14ga, a 20 amp breaker, and yes - the outlet is different. The 20a outlets add a horizontal opening to one of the 2 vertical slots, making a sideways T shape. Devices that require 20 amps will have one of those horizontal prongs to ensure you don’t plug them in to a 15 amp outlet.

[colejohnson66]

The outlet itself doesn't care, but the shape of the receptacle is supposed to restrict insertion of a 20 amp device into a 15 amp socket. You can stick a 15 amp device into a 20 amp socket, but not vice versa. The electrician should be installing 20 amp sockets if the cabling can support it, but many don't.

It's the difference between NEMA 5-15 and 5-20: https://en.wikipedia.org/wiki/NEMA_connector#NEMA_5

[tass]

> The electrician should be installing 20 amp sockets if the cabling can support it, but many don't.

I think this is mainly because the 20 amp outlets are kind of ugly, and the fact that barely anything actually uses a 20 amp plug.

In my house, almost every circuit has a 20 amp breaker and 12 ga (yellow) romex, but only a couple of outlets are 5-20.

[malfist]

NEMA 5-20 is only required for commercial. You can use NEMA 5-15 on a 20A circuit for residential in the US.

[jml7c5]

>The electrician should be installing 20 amp sockets if the cabling can support it, but many don't.

Electricians will almost always install 20 amp sockets where they can, but they avoid running 12 gauge wire because it costs about 50% more.

[manwe150]

The shape of the outlet is different for different current allowances (the spades are wider or rotated). It is supposed to allow an electrician to indicate that the whole circuit is rated to handle the higher expected load, and that there aren’t other outlets on the same circuit which might also try to use the whole current available. Basically a UI problem trying to encourage robust designs for use by non-experts

[engineer_22]

I envy my European friends' 240v electric kettles

[sangnoir]

British kettles draw so much power, the electric utility had to consider the additional power draw on the grid from synchronized tea-making during the commercial breaks of a popular soap opera, back when broadcast TV was king.

[IsTom]

And to drive that point home, we get induction stoves that run on three-phase 400V.

[engineer_22]

D':

[ryao]

It is odd that having 240VAC outlets installed in kitchens for kettles has not caught on. A NEMA 6-15R would allow for parity.

[diggan]

> I envy my European friends' 240v electric kettles

... do you not have electric kettles in the US? Foolishly, I thought this was a standard kitchen appliance all over the world, I've even seen it in smaller cities in Peru.

[ssl-3]

We do. Like others have said, they're unusual here -- in part, because culturally we drink a lot more coffee than we do tea, but also because heating a large-ish volume of water with a normal American outlet takes awhile.

My solution to drinking a cup of tea is also unusual: I have a no-longer-in-production Sunbeam Hotshot and I use it heat only as much water as I need right now.

It raises one tea-cup worth of water from whatever temperature it is that comes out of the cold tap to boiling in about 40 seconds.

I just dump a cup of water in, push one button to heat it up, wait until it boils, and then push another button to dispense that hot liquid into the cup that I'm using for tea.

It then turns itself off until next time.

[Kirby64]

We do, but they’re limited to much lower wattage due to the outlet limits. A typical US kettle is 1100-1400W, and takes maybe 1-2 minutes to boil. Kettles in the UK are typically 2.5-3kW.

[ryao]

Amazon lists 1500W models:

https://www.amazon.com/electric-kettles/b

[bongodongobob]

We don't have a need for an exclusive water boiling device as we aren't obsessed with tea. Most people drink coffee and the heating element is already built into the coffee maker. Idk what else you'd use it for. The stove works fine for boiling water without needing a separate appliance.

[lazide]

They’re far faster than a stovetop most of the time, have auto shutoff so you can wander away for a minute or two or not pay attention to it and not boil off a lot of water, etc.

Many parts of the world, it’s a good idea to boil water before using it for drinking, brushing teeth, etc.

So it’s actually really convenient for many use cases besides tea or coffee.

[db48x]

They’re readily available, but most households don't actually have one. Many more households have a coffee maker, which is essentially the same thing but specialized for dripping the boiling water through coffee grounds. Anyone else who needs boiling water just puts a pot on the stove, or possibly an old–fashioned metal tea kettle.

We could even use 240v electric tea kettles here in the US if we wanted to; most kitchens with an electric range and oven have 240v (or 208v) outlets to plug them in to. But those outlets are usually inconveniently located for counter–top appliances. It wouldn’t cost much to add another above the counter, but it is rarely done in practice. Of course, in many parts of the US natural gas heating is cheaper than electric so the houses there are built for gas ranges and ovens instead.

[flyingpenguin]

The problem there would be your breaker. I am not an electrition but I can tell you that when I tried adding a heated MAU to my house, I had to switch to a 120v washer/dryer because my electric panel did not have space for another 208v line.

(Note, my building is actually 3 phase 208 volt not 240volt so I don't have 240 volt plugs but 208volt plugs)

[snuxoll]

Not a criticism, but a question. Did you consider adding a subpanel? If you're running a new circuit I assume there was already some drywall patching to be done, seems like it would have been more cost effective and removed future headaches to just give yourself more breaker space.

[lazide]

At least in the US, a sub panel is an easy grand or two even if it’s right next to the main panel.

[snuxoll]

A lot is going to depend on labor rates for your local electricians, but that costing more than $500 where I am would be outrageous. I do my own electrical, but even I paid a licensed electrician to come handle installing a new panel since I did not have an outdoor service disconnect and didn't feel like fighting with the utility company over de-energizing and re-energizing my service. Ended up needing a lot more done, but the whole thing cost me $2500 to get a new service drop, outdoor meter main, and wiring run to the old panel (in the bedroom on the other side of the main) and the new panel (in the old furnace closed that's now my electrical / network room).

But really, doing a subpanel yourself to expand breaker capacity is a really simple project - most people if so inclined could do it themselves. Anywhere from $100-200 for the panel itself depending on how many spaces you feel like adding, up to $80 for a large enough breaker to feed it, and some tens of dollars for SER cable.

[lazide]

Agreed - I’ve ended up installing 4 (inspected) ones over the years myself, and one I paid an electrician for (they also had to upgrade the main service feed).

IMO, what usually drives up the price is the ancillary stuff - opening up a wall (and re-finishing it) because there isn’t enough physical space, or adding extra main panel capacity/service capacity because the main feed is insufficient, or having to run heavier than expected wiring because the only available space gets really hot (poorly ventilated attic space), or having to run surface conduit due to a specific challenge with framing.

Then add in labor (where I was in a high cost of labor area), and it can get expensive quick.

An actual surface mount subpanel and appropriate wires/breakers is usually only a couple hundred bucks total like you note.

[revnode]

We also have 20 amp wiring, 20 amp breakers, 20 amp sockets, and plugs too. A lot easier than going 240 volt. That will give you 2400 watts max.

[dcrazy]

Most residential wiring is 15A except for bathrooms.

[Sohcahtoa82]

And kitchens.

Otherwise, running your microwave, toaster, and coffee maker at the same time would likely trip the breaker.

And obviously, the stove/oven is on its own circuit unless it's gas.

[ryao]

My kitchen has at least 2 120VAC circuits, which seems to avoid this.

[Kirby64]

NEC code requires 2 separate 20 amp circuits in a kitchen. Usually they split the circuits across a countertop or window. It's been code since ... as far as I can tell, pretty much forever. Unless you're living in a house that is either non-compliant or built before NEC was required, then it should have this kitchen arrangement.

[bongodongobob]

Most kitchens don't run on only one circuit for the obvious reasons you've described.

[burnerthrow008]

Don’t forget garages, too.

[jml7c5]

Yes, but most people don't want to pay the thousands of dollars to get an electrician to do a rewire.

[mpreda]

Now I must use lots of rather thick cables in my desktop (because I run GPUs).

Imagine that the GPU would instead suck up all the power it needs through the PCIe connector, without all those pesky cables. (right now PCIe can provied 75W at 12V, i.e. 6.25A; that same current would provide 300W at 48V).

[masklinn]

The PCIe slot would not be sufficient even if the power architecture moved to 48V: the 12VHPWR are getting 600W pushed through them.

[anticensor]

Card-edge connectors are wattage-bound, they would still be limited at somewhere about 100W if upvolted to 48V.

[RetpolineDrama]

I pulled a fresh 20A (120V) circuit just for my 5090 build.

[Kirby64]

What power supply do you have that even has a 20A inlet? 20 amp breakers are common for outlets (especially in newer builds) but the outlets are still 15A outlets. And there is essentially no desktop power supply that exists that would exceed a 15A outlet currently.

[aaronmdjones]

> What power supply do you have that even has a 20A inlet?

ATX PSUs usually have IEC 60320 C14 inlets. The IEC 60320 standard itself states that this inlet is only good for up to 10 Amps.

UL is happy to ignore them and say that 15 Amps is okay. It wouldn't surprise me if someone else were happy to ignore that and say that 20 Amps is okay.

Even still, swapping a C14 inlet for a C20 inlet (IEC max 16 Amps, UL max 20 Amps) would be a relatively easy thing to do (EDIT: on a PSU that is already designed to take more than 15 Amps, obviously). Probably a warranty-voiding action though.

[lazide]

Notably, 20 amps @ 120v is 2400 watts.

[revnode]

https://www.amazon.com/dp/B09PJYMK77/zcF9kZXRhaWxfdGhlbWF0aW...

I'm sure there are power supplies for servers that go above 1600 watts too. If you really want to, you can ... but you really shouldn't.