Comment on Why don't Americans use electric kettles?
Rivalarrival@lemmy.today 3 weeks agoThe issue isn’t the voltage. It is the wattage. UK kettles draw 3kW. US outlets are (typically) only rated for 2.4kW. We can easily get dedicated 30A, 120v outlets that will provide 3.6kW.
US 240v is not the same as UK 240v.
The UK uses a single live phase, (240v with respect to ground), and a neutral (0v with respect to ground).
The US uses two live phases. Each phase is 120v with respect to ground, but they are 180 degrees apart from eachother. Phase to phase is 240V, but either phase to ground is 120v.
A UK kettle expects its neutral phase to be at the same potential as ground, which can’t happen in the US without a 1-to-1 transformer
scarabic@lemmy.world 3 weeks ago
Sounds like it would amount to much the same thing: you’d need some special wiring, and a kettle made to take advantage of it. No one has made that kettle.
Just curious though, since you seem to understand electricity better than I.
If it’s as you say, and all we need to do to get more energy is to raise the amps, then why do Americans still install 240V lines for laundry machines, ovens, large power tools, etc etc? Why don’t any of those just do what you said, and operate 120V at 30 amps?
Rivalarrival@lemmy.today 3 weeks ago
Watts are a unit of power. Regardless of voltage, if your appliance is drawing 3000 watts, it is heating up the same as any other device that draws 3000 watts.
Wires are not sized on the number of watts they can carry. They are sized on the number of amps they carry. If a wire is sized for 10amps, and you are using 12v, you can only get 120 watts through it. Increase the voltage to 120v, and you can get 1200 watts through that same wire. Increase to 240v, and you can get 2400 watts from that wire. The higher the voltage, the less copper you need to carry it. You need thicker insulation to handle that increased voltage, but insulation is cheap. It’s more dangerous to humans who come into contact with the wires, but you can build in additional methods to restrict human contact, such as fancy plugs and sockets.
The UK and Europe had a severe copper shortage when they rebuilt after WWII. They standardized on 240V to reduce the size of wires they needed in their homes. Instead of dozens of, low-amp circuits, they installed only a couple high-amp circuits for their entire home. They designed their household wiring so that the same circuit that powers the alarm clock on their nightstand is also used for their 3000-watt space heater.
They further reduced copper consumption by using undersized wire in a “ring” circuit instead of properly sized wire in a “branch” circuit. Failures in ring circuits are extraordinarily dangerous, because there is no immediate indication that they have failed. Each outlet receives power from two sides of the ring; if one side fails, they draw all their power from the other side, overloading the ring.
The US solution to these problems is intrinsically safer household wiring. We threw copper at the problem, because we had the copper to throw. But what we got in return was a vastly safer system. We managed to get a 240v system that only carries the risks of a 120v system.